A3-30 SOFTSCAPE

NPQS A3-30 Softscape Softscape

National Productivity and Quality Specifications (NPQS)

A3-30 Softscape

1 Version 1.0


CONTENTS

Page

1. 1.1 1.2 1.3 1.4

GENERAL Scope Related Sections Standards Trade Preambles

3 3 3 3 3

2. 2.1

PERFORMANCE REQUIREMENTS Requirements for Contractor’s Proposal

5 5

3. 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

MATERIALS AND COMPONENTS COMPONENTS Soil Sand Light Weight Aggregate Water Retention Polymer Slow Release Fertilizer Soil Mixes Trees and Plants Turfs Drainage Supports Water Landscape Lighting Masonry Planter Walls Planter Waterproofing

6 6 9 9 9 9 9 10 15 16 17 18 18 18 18

4. 4.1 4.2 4.3 4.4 4.5 4.6

WORKMANSHIP Supply of Plants Preparation Prior to Planting Planting Turfing Maintenance Chemicals

19 19 19 21 24 26 28

5. 5.1 5.2 5.3 5.4

VERIFICATION AND SUBMISSIONS Submissions Samples and Mock-Ups Inspections Defective Work or Materials

29 29 30 31 32

2 Version 1.0


CONTENTS

Page

1. 1.1 1.2 1.3 1.4

GENERAL Scope Related Sections Standards Trade Preambles

3 3 3 3 3

2. 2.1

PERFORMANCE REQUIREMENTS Requirements for Contractor’s Proposal

5 5

3. 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14

MATERIALS AND COMPONENTS COMPONENTS Soil Sand Light Weight Aggregate Water Retention Polymer Slow Release Fertilizer Soil Mixes Trees and Plants Turfs Drainage Supports Water Landscape Lighting Masonry Planter Walls Planter Waterproofing

6 6 9 9 9 9 9 10 15 16 17 18 18 18 18

4. 4.1 4.2 4.3 4.4 4.5 4.6

WORKMANSHIP Supply of Plants Preparation Prior to Planting Planting Turfing Maintenance Chemicals

19 19 19 21 24 26 28

5. 5.1 5.2 5.3 5.4

VERIFICATION AND SUBMISSIONS Submissions Samples and Mock-Ups Inspections Defective Work or Materials

29 29 30 31 32

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1.

GENERAL Read with the General Requirements section, and all other contract documents.

1.1

Scope This specification covers soft landscaping works for building projects, involving the planting and care for: a. Mature trees. b. Turfing. c. Hedge material d. Ground cover It also covers associated works such as subsoil drainage etc.

1.2

Related Related Section s Read this work section in conjunction with the relevant requirements of the other work sections as follows:

1.3

A1-70

External Masonry

A2-30

Applied Finishes for Flat Roofs

Standards Unless otherwise agreed by the SO, ensure all of the Works comply with the relevant requirements of the Standards and Codes listed below or referenced in the body of the Specification. Alternative Standards and Codes may be submitted to the SO, provided it can be demonstrated that the alternative Standards and Codes comply with the requirements of the standards specified. All Standards and Codes quoted are the current version, unless specific year references are noted. Singapore Standards SS 31

Aggregates from natural sources for concrete

Other Standards

1.4

BS EN 10244-2

Steel and wire products-zinc alloy coating

BS 3998

Recommendations for tree work

BS 4031

Recommendations for transplanting semi-mature trees

Trade Preambl es 1.4. 1.4.1 1

Contractor’s Submissions

The design intent for the soft landscaping works for the project is shown in the drawings. Base on the information available, engage qualified and experienced personnel to submit the following items to the SO:

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NPQS A3-30 Softscape

1.4.1.1

Temporary supports and maintenance to all trees and plants until established.

1.4.1.2

Select sources of supply for the plants and soil as required.

1.4.2

Co-ordin ation wi th Other Works

Take into account, that the works carried out are interfaced and co-ordinated with other trades in the project, namely: a. Lightning Protection b. External Sanitary Services c. External Sewer Services d. External Electrical Services e. External Drainage & Irrigation Services f.

External Lighting Services

g. External Fire Services h. External Security System The works shall also include the co-ordination of affected external building works, mechanical & electrical external service installations interfacing with the soft landscaping. 1.4.3

Spare Material

Deliver to site in strong protective packages marked for identification, and store where directed, components and materials for future replacement and repair. Refer to PSD for list. 1.4.4

Warranty

Refer to PSD for warranty requirements, if any. 1.4.5

Maintenance Manual

No item. 1.4.6

Protect ion and Maintenance

Protect and maintain in required conditions of all plants and accessories during construction until hand over. 1.4.7

Quality Contro l Plan

No item.

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2.

PERFORMANCE REQUIREMENTS

2.1

Requirements for Contractor’s Proposal Account for the following requirements when carrying out the contractor’s proposals in cl.1.4.1. 2.1.1

Wind Loads

There shall be no fracture nor any deterioration resulting from the Works being subjected to maximum wind pressures at the work site recorded by the nearest Singapore meteorological station over a 50 year return period. 2.1.2

Stability

The Works shall remain rigid and un-deteriorated when subjected to normal use. 2.1.3

Struc tural Movement and Movement Between Works by Others

Take into account, that the performance, appearance and proper functioning of the Works are not affected by any movements, settlement or deflection in the building structure, which can reasonably be expected to occur. Also take into account the construction accuracy of works by others to which the softscape works are attached. 2.1.4

Environmental Conditions

Take into account, that the Works are able to resist exposure to weather and moisture, and take all necessary precautions to protect the Works under such conditions.

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3.

MATERIALS AND COMPONENTS

3.1

Soil 3.1.1

Subsoil

Subsoil shall be: a. A free draining soil, to be used as fill materials. b. Generally taken from a level of 300 mm below the original surface, either excavated from the site, or imported from accepted sources. c. Free from all impurities including chemicals, oils, cement, unworkable clays and stones exceeding 50 mm in diameter.

3.1.2

Top Soil Mixes

Top soil mix shall be as follows: a. free draining organic soil from horizons less than 300 mm from the original surface, b. a workable crumbly and lump free loamy character c. contain no grass or weed growth of any kind or other foreign material or stones exceeding 3 mm in diameter. Submit to the SO, I litre sample with back up soil test data before installation or mixing. 3.1.3

Import ed Topsoi l

Topsoil shall be: a. Free of any noxious or invasive weeds or grasses such as couch grass b. Free of any contamination from chemicals or any foreign matter such as glass or bricks etc. Stockpiles of imported topsoil shall be: a. No higher than 2.0 m high b. Must not be compacted through any site activity, c. Remain free of weeds d. Free of contamination arising from deleterious material. e. Protected as required, with suitable approved fencing to prevent any site personnel or site vehicles from compacting or disturbing the soil. Visual examination: the topsoil shall have a defined granular or blocky structure. 3.1.4

Topsoi l Const itu ent Criteria

Topsoil shall comply with the criteria as indicated in the PSD.

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3.1.4.1

Texture of Fine Earth Fraction (Lower Strength)

Clay content

(0µm - 20µm)

<15%

Silt content

(20µm - 50µm)

<25%

Sand content

(50µm – 2mm)

<85%

3.1.4.2

Organic Matter

a. 4 - 20% (by weight) at 65°F using Walkley Black RB427 b. No roots larger than 15 mm diameter or longer than 200 mm shall be allowed

3.1.4.3

Conductivity

a. Avery & Bascombe - 3.0 mΩ/cm b. Not more than 1500 micro Siemens using a 1:2.5 extract

3.1.4.4

Limit of Toxic Elements Threshold Concentration (Lower Strength)

Arsenic

< 40

mg/kg

Cadmium (total)

< 15

mg/kg

Chromium

< 1000

mg/kg

Lead (total)

< 2000

mg/kg

Mercury (total)

< 20

mg/kg

Solenium

<6

mg/kg

Boron (water soluble)

<3

mg/kg

Copper (total)

< 130

mg/kg

Nickel (total)

< 70

mg/kg

Zinc (total)

< 300

mg/kg

Phenols

<5

mg/kg

Total cyanide

< 25

mg/kg

Complex cyanides

< 250

mg/kg

Thiocyanate

< 50

mg/kg

Sulphate (water soluble)

< 1.2

g/litre

Sulphide

< 250

mg/kg

Polyaromatic Hydrocarbons (EPA16)

< 100

mg/kg

Sulphide (elemental)

< 5000

mg/kg

All units are mg/kg unless otherwise stated.

3.1.4.5

Acidity

pH: 5 – 7.5

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3.1.4.6

Nutrients (Lower Strength)

Nitrogen (total)

> > 0.2%

Phosphorous (available)

> > 26 mg/kg

Potassium (available)

> > 240 mg/kg

Magnesium (available)

> > 80 mg/kg

3.1.5

Exist ing Site Soil Types

If existing soils are available on site whether subsoil or topsoil, they should be tested prior to use and the results made available for inspection and approval. 3.1.6

Soil Condit ioner

Soil Conditioner shall be: a. Organic compost or b. Other fibrous approved organic matter suitable for mixing with topsoil to make a friable growing medium for plants. c. Resistant to rapid decay, free of soluble salts below 900 ppm, pH 6-7 and free of large lumps or debris. Submit 1 litre sample with back up test data before installation. 3.1.7

Organic Compos t

Organic compost shall be: a. Vegetable compost produced by a thorough horticultural or industrial composting process. b. Clean. c. Free from decomposed smell. d. Free from any rotting substances, debris, refuse, clay or visible fungus. e. Free from vermin. Submit samples and test data for approval before usage. All composts are to be sterilised before being packed for transport. Odorous materials shall be rejected. 3.1.8

Mulch

Mulches shall be: a. Approved friable-composted organic material such as Oil Palm husks, organic composts or an approved mix. b. Coco Peat will not be allowed on its own unless mixed into a proportion of 50-50 with another mulching material c. Free from soluble salts or toxic materials d. Resistant to rapid decay. e. Have a pH of between 5.5-7.0 Submit samples and pH values for approval, before use.

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3.2

Sand Sand shall be: a. Clean, washed sharp sand free from any contamination b. Conform to SS 31. Submit sample for approval by the SO.

3.3

Ligh t Weight Aggr egate Light weight aggregate shall be: a. Approved low-density inert material such as expanded clay or volcanic scoria or other porous aggregate capable of being compacted within the soil zone to 90% compaction without being crushed. b. Free from dust and debris, c. pH 6 - 6.5 d. Free of soluble salts. A 2-litre sample shall be submitted and tested, as part of the soil mix, for physica l and chemical performance.

3.4

Water Retention Polym er Water retention polymer shall be: a. A modified cross linked acrylic amide with co polymer bonding (polyacrylamide) usually available in its dry state as white or colourless crystals or pellets, b. Non toxic c. Capable of absorbing up to 400 times its own weight in water d. Slowly releasing water to planted materials upon demand. e. Biodegradable producing only harmless and non-toxic substances f.

Have an operating lifetime of not less than 5 years after installation.

g. Used according to manufacturer instruction. h. Usage of such water retention polymer shall not alter the characteristics of the surrounding planting medium.

3.5

Slow Release Fertili zer Refer to the PSD for proprietary product selected for the project.

3.6

Soil Mixes Unless otherwise agreed, use the following soil mixes as appropriate for planting subject to confirmation with the SO. Soil Mix Type

Use

Composition

A

For use in tree pits, ground level shrubs

Topsoil 50%

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B

and turf planting areas. This shall be mechanically cultivated to the correct proportions, prior to placement on site or backfilling.

Sand 20%

For use in planter boxes, planter beds and roof planter. This shall be prepared under controlled mixing conditions such as on a concrete floor to ensure even mixing and free from contamination.

Topsoil 40%

Soil Conditioner 15% Organic Compost 15%

Sand 15% Conditioner 15% Light Weight Aggregate 15% Organic Compost 15% Water retention polymer – to manufacturer’s recommendations.

C

For use in planter on ground

Topsoil 40% Sand 30% Charcoal 15% Organic Compost 15%

D

For use as potting material

Topsoil 30% Sand 30% Charcoal 20% Organic Compost 20%

3.7

Trees and Plants 3.7.1

Selection

Refer to the PSD for list of plants selected for the project. Refer to drawings and schedules for location. 3.7.2

General Quality

Trees and plants supplied shall be: a. Free from disease, infestation and infection. b. First class representatives of their normal variety or species, having strong growth. Drawn plants with soft growth requiring additional supports other than specified are not acceptable. c. Have average or normally well developed branch systems together with good, fibrous root systems as expected of the species. d. Free from disfiguring knots, abrasions of the bark or wind injury or other disfigurements. e. Bear evidence of proper pruning. f.

Trees shall have a straight, sturdy, clean stem, a well-balanced branching head and an undamaged root system.

g. Conform to height and growth as specified in the plant schedule.

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3.7.3

Instant Trees (INS)

Instant trees shall be/have: a. Semi-mature trees specially prepared in advance for transplanting. b. Root pruning cleanly cut to diameter of root ball, executed at least 3 months in advance of transplanting. c. Minimum 450 mm in girth measured at 1 m from the ground. d. Minimum clear stem of 1.8 m measured from ground. e. Head of tree well balanced with a good body with minimum 4 main branches, each branch at least 500~1000 mm in length giving an overall height of 3~4m. f.

Any saw cuts being clean and free from rips or splits and trimmed smooth after cutting with a sharp knife.

g. Any wounds painted with approved insecticide/fungicide solution and reapplied once per week until leaf growth has established.

3.7.4

Extra Heavy Standard Trees (EHS)

Extra heavy standard trees shall be/have: a. Large size nursery grown trees pruned during growth in order to achieve a tight, well-rounded head and a straight stem clear of leaves or twigs. b. Possess 200~250 mm in girth measured 1m from ground. c. Have a clear straight stem of minimum 1.8m. d. ‘Heads’ which are full bodied and well balanced with minimum 4 main branches giving an overall height of 4~5m at time of planting. e. Have a well-defined central leader. f.

Root ball dimensions: Diameter 750 (minimum depth 600 mm).

g. Branching / leaf spread to be 2.2 ~ 2.4m diameter. Pruning at time of removal from nursery is not permitted. In dry conditions trees are to be sprayed with an approved anti transpirant approved by the SO. For Columnar, Fastigiate or Conifer tree varying from this description refer to the schedule of plants. 3.7.5

Heavy Standard Trees (STD)

Heavy standard trees shall be/have: a. Medium size nursery grown trees pruned during growth to produce a tight, well rounded head and a straight stem clear of leaves or twigs. b. Have 100mm~150mm in girth as measured 1.0m from ground level. c. Have a clear straight stem of minimum 1.8m. d. ‘Heads’ to be full bodied and well balanced with minimum 4 main branches giving an overall height of 2.5m~3.5m at time of planting. e. Have a well defined central leader. Pruning at time of removal from nursery is not permitted. In dry conditions trees are to be sprayed with an approved anti transpirant to be approved by the SO.

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Root ball dimension: diameter 350mmx300mm deep minimum. Branching/leaf spread 1500mm ~ 1800mm diameter. 3.7.6

Feathered Whip s (SFW)

Feathered whips shall be/have: a. Medium sized nursery grown trees having a single straight stem and unbroken leader giving an overall height of 1.5m ~ 2.5m. b. Fully furnished with evenly spread and balanced lateral branches down to ground level and shall be 620mm~1000mm in girth measured 1m from ground. c. Have a strongly developed fibrous rot system. d. Container grown. e. Leaves or branches shall not be cut off before planting. f.

Root Ball dimension: diameter 350mmx300mm deep minimum.

g. Branching/leaf spread 500mm diameter.

3.7.7

Whips /Sapli ngs (SAP)

Whips shall be/have: a. Young trees grown from seeds or cuttings, which are trimmed or pruned, furnished with branches down to ground level. b. Trees shall that have a single straight stem and unbroken leader between 900 mm ~ 1500 mm overall height. c. Trees with stem thickness, which varies with species but should possess a strong stem which does not bend over. d. Trees with a strongly developed fibrous root system. e. Cultivated in container. Leaves shall not be cut before planting. f.

Root ball dimension: diameter 200 mm x 250-mm deep minimum.

3.7.8

Palms

3.7.8.1

Single Stem Palms

Single stem palms shall have a clear straight trunk. Heights shall be as measured from root collar to based of lowest leaf sheath, and shall be as specified in the plant schedule. Acceptable tolerances to variations in stem height sha ll be plus or minus 200 mm. Heads of palm shall be well balanced with minimum 7 leaves and a healthy growing apical shoot, all free from pest and disease. Root Ball dimension shall be in proportion to stem heights as follows: Stem Height

Root Ball Diameter

Depth

1m

400mm

400mm

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3.7.8.2

2m

750mm

600mm

3m

900mm

600mm

4m

1200mm

750mm

Multi Stem Palms

Multi stem palms are palms, which naturally grow as a multi stemmed clump by sending out suckers. This category includes Chrysalidocarpus, Pinanga, Cyrtostachys and Ptychosperma species. Palms shall have a minimum of four stems each with a clear trunk height of 1.5m from root collar to the base of the leaf sheath. There shall be at least three leaves on each stem and evidence of one new growing shoot per stem, all free from pest or disease attack. Imported palms shall be acclimatised for at least six months before removal from the nursery. Root Ball dimension: Diameter 600mm x 300mm deep. Smaller multi stemmed palms such as Rhapis and Licuala species shall be as above but with stem height 900 mm from the base of the root collar to the base of leaf sheath. These plants shall be grown in containers. 3.7.9

Timber Tree Suppor ts

Timber for all tree supports shall be tanalised, peeled, round wood, de-barked and seasoned to 25% or less moisture content prior to impregnation. Each tree shall be supported by a half round timber cross brace fixed to 2 numbers upright timber posts. Posts shall be 80-100 mm diameter and 2.0m long half round timber. Cross braces shall have the same diameter. At least 1.0m of the posts shall be driven below ground level. Rubber spacers and rubber straps or similar approved shall be used to attach each tree to each cross brace. The spacers shall be used to cushion the tree stems from chaffing on the cross braces. 3.7.10

Shrubs , Herbaceous Plants, Ground Covers etc.

3.7.10.1

Shrubs

Shrubs are woody perennials of generally multi stemmed and bushy habit ranging from 3~4.5m down to 500 mm in height. Shrubs shall have: a. No less than three main stems. b. A well-balanced and bushy with strongly developed fibrous root systems. c. Pruning in advance as required to achieve the specified height tolerances. d. Branches which ‘break’ from the base of the plant just above root collar. e. A well furnished body with leaves right down to ground level.

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f.

Been grown in containers of suitable dimensions for the species.

g. Flowers at time of planting.

3.7.10.2

Herbaceous Plants

Herbaceous plants are non-woody perennials usually of a clump forming habit. Plants shall have: a. A well-developed main stem or stems with good symmetry. b. A healthy root system and are free from pest or disease. c. Clumps of herbaceous plants which may include rhizomes, corns, tubers or roots. d. Soil undisturbed by lifting with evidence of growing shoots emerging above soil level. e. Been grown in containers unless specified as being produced by alternative method. f.

Flowers at time of planting.

3.7.10.3

Groundcover plants

Groundcover plants are low growing 500 mm or less or prostrate shrubs or herbaceous plants whose habit is to totally cover the soil. All groundcover species shall be evenly balanced to allow equal growth in all directions. Plants shall have fully developed roots, leaves and flowers at time of planting. Rooted cuttings are not allowed. All plants are to be cont ainer grown. 3.7.10.4

Rooted shoots

Rooted shoots of certain spreading groundcover plants shall be used where specified, planted as ‘sprigs’ as opposed to established plants in soil. Plants shall be rooted shoots and shall have at least one shoot of the minimum dimensions stated in the Schedules and evidence of vigorous root growth. Recent cuttings with underdeveloped roots are not allowed. 3.7.10.5

Climbers

Climbers are plants whose growth habit is to climb upwards by means of twining stems, tendrils or clinging roots. Plants shall be grown to reach the recommended size using stocks no less than one year old, and no more than five years old at time of contract. Plants shall have at least two leaders, shoots up to the recommended height, a vigorous root system, and flowers at time of planting. All plants are to be cont ainer grown.

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3.7.11

Hedging Plants

3.7.11.1

Tall Hedging Plants

Tall hedging plants shall be trees such as Casuarina, previously prepared to establish a uniform height, and complete all around foliage cover to the stem from ground level upwards. Plants shall be of a minimum overall height of 1.8m with one vertical stem, leader removed to promote side branching from ground level and a strongly developed fibrous root system. Root ball Dimension: Diameter 500mm x 300mm deep, minimum. Tall Hedging plants shall be prepared by root and branch pruning at least 4 months before transplanting and shall be shaped according to the drawings and the SO’s directions. 3.7.11.2

Low Hedging Plants

Low hedging plants shall be shrubs such as Ehretia, Acalypha Siamensis or Ixoras as suited to regular clipping, previously prepared to establish a uniform height and complete foliage cover to the stem from ground level upwards. Plants shall be a minimum overall height of 500mm with a minimum of 4 branches rising from ground level, with a strong, well-developed fibrous root system. Branches shall be well-covered in leaves down to ground level. All plants shall be container grown in suitable size containers. Hedging plants shall be prepared by root and branching pruning so as to achieve ‘box’ shape, at least 3 months before transplanting. 3.7.12

Container Grown Plants

Container grown plants shall mean shrubs which have been grown in containers sufficiently large to hold the developing root system from seed or cutting and shall be filled with suitable nutrient rich, free draining compost. Container grown stock shall be well watered prior to despatch from the nursery and shall remain in the container until planted on site, whereupon the container shall be carefully removed to avoid soil disturbance. Empty containers are to be removed from site. 3.8

Turfs 3.8.1

Close Turf

Close turf shall be/have: a. Stoloneferous Axonopus Compressus containing not more than 10% of other perennial grass within a typical grass sod or mat of 300 mm square, with a well developed root system growing to a minimum of 25mm soil bed, free from stones or extraneous roots. b. Cut mechanically or by hand to give an extra thickness and texture. c. Free from weeds, fungus, pest, disease, contamination or pollutants. d. Kept moist, under shade and in exceptionally dry weather to be kept well watered at the nursery or turf farm in order to keep full green leaves structure.

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e. Planted within 24 hours after lifting. f.

Must not be dry, brown or wilting.

g. Not contain any weed.

3.8.2

Fine Turf

Fine turf shall be/have: a. Fine baled rhizomatous grass such as Zoysia or ‘Bermuda’ grass unless otherwise indicated. b. Be live grass sod or mat at least 300 mm square with a well developed root system, growing in a minimum of 25 mm soil bed free from stones or extraneous roots. c. Cut mechanically or by hand to give an even thickness and texture. Submit samples of 300mm x 300mm turf squares for approval. 3.9

Drainage 3.9.1

Subsoi l Field Drains

Subsoil field drains and trenches drains shall include: a) Drainpipes b) Inspection pipes c) Filter fabric or filter membrane d) Stabilising aggregate substrate e) Aggregate filler f)

Connections of under drainage system to storm drainage network, according to the invert levels of the storm drainage system

All trenches and drainage shall be lined with filter membrane laid over the based of the trench and up the sides with sufficient membrane to wrap over the top of the gravel back filling with minimum overlap of 300 mm. Filter membrane shall be undamaged and approved by the SO. Base of trench to have a layer not less than 30mm and not more than 50 mm depth of fine granite chippings 8mm ~ 12 MM diameter or coarse sand laid to accurate falls for bedding the perforated pipes. Drainage pipes shall be approved prefabricated subsoil drainage system with proprietary accessories. Free ends of all pipes unless connected to a rodding eye shall be capped with a fitted perforated end stopper and fixed in position. Where subsoil drainage pipes pass under paths or structure the pipe shall be a nonperforated pipe joined at either end to perforated pipes, and shall be surrounded with concrete haunching. Submit thickness and nature of haunching to the SO. PVC pipes with drilled holes are not permitted. Trenches are to be backfilled with 100 mm up to the finished level with clean coarse grained sand or crushed granite chippings 8~12mm diameter free of any fine particles. The gravel shall be lightly compacted. 16 Version 1.0


Edge to drainage trench shall be lined with sacrificial timber segregating strip, 100 mm x 12 mm thick, level with established landscape platform for ease of grass cutting. Submit to the SO, preliminary survey of drainage pattern and invert levels prior to commencement of work. 3.9.2

Pipes

For Precast concrete or cast iron pipes, refer to structural specifications. 3.9.3

Drainage Gravel

Gravel for drainage layers shall be 20 - 25 mm, mainly round, clean gravel, free from fines. Granite chipping 8~12mm diameter. Submit sample for approval by the SO. 3.9.4

Filt er Material

Proprietary material. Refer to the PSD for selected product for the project. 3.9.5

Drainage Mats

Drainage mats shall be/have: a. 400 x 600 x 30 mm thick refer to the PSD for proprietary product selected Enclosed by approved filter material, laid over base of planter boxes. c. Individual sections close butted. d. Returned 300 mm up the edge of planters or planting beds. e. Protected with approved liner to prevent damage from grass cutting operations. f.

Covered with filter fabric secured by filter fabric cement with 300 mm overlap.

3.9.6

Filter Fabric

Refer to the PSD for proprietary product selected. Use in conjunction with manufacturers approved fastening method.

3.9.7

Filter Fabric Cement

Shall be an approved non-solvent bonding agent. 3.10

Supports 3.10.1

Staples

Staples for fixing wire to timber shall be 40 mm x 4 mm zinc coated to BS EN 102442. 3.10.2

Undergro und Guys

Provide1 kit per tree unless otherwise agreed. Adhere to manufacturer’s instructions and recommendations. 17 Version 1.0


Submit suitable system to meet performance requirements. Submit written details (including samples for approval. Submit data justifying the proposals are adequate for the required loading. Guy wires shall be driven into the ground or fixed to timber deadmen. 3.10.3

Timb er Deadmen

Timber deadmen shall be pre-treated 150 x 125 mm timber sections with minimum length of 1.5m. Install 4 deadmen per tree consisting of 2 laid across width of trench and 2 ran lengthwise along the trench over the drainage layer. Submit details for deadmen installation for approval. 3.10.4

Timb er Sleepers

Timber sleepers for deadmen shall be the following size: 1.50m length - 150mm x 125mm section. 3.11

Water Water shall be free from impurities.

3.12

Landsc ape Lig hti ng Provide proprietary product as indicated in the drawings and schedules. For cabling requirements refer to electrical specifications.

3.13

Masonry Planter Walls For material requirement refer to section A1-70 “External Masonry”, clause 3.0.

3.14

Planter Waterproof ing For material requirement refer to section A2-30 “Applied Finishes for Flat Roofs”, clause 3.4.

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4.

WORKMANSHIP

4.1

Supply of Plants Carry out the following: a. Liase with the nursery to arrange and co-ordinate the deliveries of plants. b. Inspect carefully all plants prior to delivery to the site and ensure himself of the health and vigour of the specimens before accepting them. c. Off-load all plants either to their final locations (after acceptance of delivery), or to a temporary holding location. Any plants off-loaded to a temporary holding location shall be heeled in by covering the rootball liberally with sharp sand. d. Maintain all off-loaded plants in accordance with proper horticultural practice as accepted by the SO. e. Hold all delivered plants vertical. f.

Make provision for all measures required for the short-term storage of trees on site prior to final placement.

g. Ensure that plants in transit are adequately protected against desiccation or damage. h. Be liable for the healthy establishment of all plants.

4.2

Preparation Prior to Plantin g 4.2.1

Excavatio n of Trenches and Beds

4.2.1.1

Tree Trenches

Excavate all tree trenches to 1150 mm deep and 1.80m wide along the tree lines shown in the drawings. Break the base of excavations to allow free drainage, and create falls to one side towards land drains. The depth of excavation allows for: a. 150mm Drainage Layer b. 550mm Subsoil c. 450mm Topsoil

4.2.1.2

Hedge Planting

Excavate 600mm Overall depth and allow for: a. 450mm Topsoil b. 150mm Subsoil

4.2.1.3

Areas Adjacent to Planting Beds Areas

Excavate to a depth of 450mm and allow for 450mm Topsoil. 4.2.1.4

Seeded and Turf Areas

Excavate 300mm depth to allow for 300mm Topsoil. 19 Version 1.0


4.2.2

Pre-plant ing Coordi nation

Prior to planting, convene a meeting at the Site to: a. Review preparation, procedures, scheduling required and co-ordination with related Work. Review methods and procedures related to:

I. Condition of substrate, conditions of site, and other preparatory Works performed by other building trades. II. Required submittals III. Programme of Work and verify availability of materials, personnel, equipment and facilities needed to make progress and avoid delays. IV. Required inspections and material usage accounting procedures. b. Review forecasted weather conditions and procedures for coping with unfavourable conditions including possibility of temporary protection. c. Verify the pH level of existing site conditions for each type of plant and method to alter the pH level of site conditions to suit plants. Submit proposal to SO. Record discussions of conference, decisions, and agreements reached and furnish copy of record to each party attending. 4.2.3

Drainage and Irrigati on

Construct all drainage works including subsoil drains prior to planting. Refer to structural specifications for workmanship requirements. 4.2.3.1

Inspection Pipes

Install Inspection pipes with caps at every tree along tree lines to connect with gravel drainage layers. 4.2.3.2

Irrigation Points

Provide and install irrigation systems as required. Coordinate with MEP Contractors for connection to the building system. 4.2.4

Laying Soil

4.2.4.1

Subsoil

Spread subsoil into trenches (avoiding compaction) to a level of 500mm below the finished ground level allowing for settlement whilst allowing for the placement of rootballs at correct levels over the installed deadmen. 4.2.4.2

Spreading of Topsoil

Provide depths of topsoil as follows: a. Grass: a minimum of 300mm depth b. Shrub: a minimum of 450mm depth c. Tree Trenches: a minimum of 450mm depth Do not compact topsoil. Do not work under wet weather. Do not saturate topsoil.

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Rework or remove and replace topsoil that is accidentally compacted as directed by the SO. Spread compost over topsoil surface, within the confines of the trench to a consolidated depth of 75 mm, within the top 450 mm. 4.2.5

Deadman

Set out and install timber deadmen anchors as indicated in the drawings. 4.2.6

Weed Contr ol Prior to Plantin g

Suppress all weed growth before any planting commences by the application of any approved contact herbicide used in accordance with the manufacturer’s recommendations. Maintain in a weed-free condition to top soiled areas at all times by approved chemical means or by hand as required. 4.3

Planting 4.3.1

General

No planting allowed when the ground is waterlogged. Protect roots of plants to prevent drying out while waiting planting. Adopt proper horticultural practice. Use only approved mechanical aids, otherwise execute planting by hand. 4.3.2

Setting-out

Peg out individual tree positions in accordance with agreed planting plan. Figure dimensions in planting plan by the SO to take precedence, where dimensions are not shown setting out to be guided by defined paths, paving or other works. Scaled dimension may be used. Minor refinement to the design with adjustments to lines, levels and grouping of plants during planting process is required. Planting shall not commence until sets out positions have been approved. Any planting where positions were not approved prior to planting may require adjustment. Trees shown at regular spacing shall be accurately and evenly spaced in true lines and true to level. Where planting is likely to take place prior to hard landscape construction works, setting out dimensions will be critical and must be done in strict agreement with other trades. Plants shall be spaced evenly so that when established they will completely fill the areas indicated. Extent of the area to be filled by each species shall first be defined by plants spaced around the perimeter. 4.3.3

Care of Plant s

Pruned out any damage, which occurs.

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Heeled in plants delivered to site in containers in specially prepared trench if not used within 3 days of delivery. Trench to be covered with clean sand and plants to be well watered thoroughly and regularly until required. Containerised and pot grown plants which are not planted on arrival on site shall be watered frequently to prevent drying out. Replaced all plants, which have dry out to the extent that their health or visual appearance is affected. Water all containerised plants before planting, unless directed otherwise. Allow for protection of top soiled areas, stacking of materials, tracking an d trampling over top soiled areas are not allowed. Replaced any topsoil that becomes unsuitable due to contamination, loss of structure, or for any other reason during site operations. Plant only when the soil is reasonably dry to prevent damage to the soil structure. 4.3.4

Planting Root-balled Plants (Trees)

Plant trees delivered from nursery to same soil mark on stem with soil distributed evenly around root system. All works to comply with BS 4031 o r Singapore equivalent. Semi-mature trees are to be lifted by the root ball only. No lifting stress on the main trunk allowed. Use mechanical lift for unloading from the lorry and placing in the prepared trench. All terrain cranes are preferred. Lifting gear shall have the ability to span at least two complete avenues working left to right. Plan access routes for planting between the clear avenues bisecting tree planting beds to minimise disturbance and compaction of soil. Such disturbance/compaction shall be addressed after completion of all tree planting and before ground cover planting or grass seeding commences. Provide for means of inspection by way of a pipe set vertically through the overall depth of the pit. Do not glaze or compact surfaces during excavation. If any glazing or compaction occurs it shall be thoroughly roughened and worked to ensure unrestricted movement of water. Orient trees to present the best face to an edge of road or building. Prior to planting the root ball shall be measured and make necessary adjustments to the trench. Set tree in the trench so that the top of the root ball is 100 mm proud of surrounding ground levels to allow for settlement. Cover and dress exposed root ball with soil mixed with 3 parts sand to 1 part topsoil as 80mm blinding. Plant trees to give a vertical trunk and leader. Examine outer surface of the root ball to detect for damage, by rolling back or cutting the root ball cover. Any hard surfacing or glazing shall be carefully slit or scarified. Spread fertiliser on the finished surface in accordance with manufacturer’s recommendations.

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Provide a single Wavin watering pipe 80 mm diameter, or as approved, or as indicated on the detailed drawing. Fit watering pipes with fitted plastic caps. Anchor trees securely such that root balls do not pivot in the soil u nder windy conditions. Protect root balls using three-way treated softwood root ball covers where anchors are used. Prune any broken branches after completion of planting. Pared back damaged areas of bark neatly to sound tissue and all cuts and wounds over 25 mm in diameter should be treated with a fungicidal sealant to BS 3998, or Singapore equivalent. Irrigate trees by hand immediately after planting until such time as the irrigation system or maintenance program is functioning. Soil moisture cells to be installed to tree pits as directed by the SO. Protect trees with PVC collar protector and/or fencing immediately on completion of planting. 4.3.5

Tree in Car Park Divid ers

Evacuated trenches to 1150mm depth allowing for 150mm gravel drainage layer, 500mm subsoil and 450mm topsoil. Trenches width shall be 1500mm. Install perforated land drains wrapped in filter membrane laid in the drainage layer and ensure connection to carrier drains within tree planting trenches. Install an aeration/watering pipe with a cap at ground level for each tree. Install 100 mm diameter inspection pipe to the drainage layer for each tree. Install a soil moisture cell to every tenth tree. 4.3.6

Planting Shrubs /Ground Cover Plants

Plant shrubs and / or ground cover at the same depth as previously grown, care being taken to avoid damage to the root system and stems. Position plants such that their best side shown to the front. Bare and carefully spread out roots and packed around with the fine soil. As the rest of the soil is returned it shall be well c onsolidated and firmed round the roots to eliminate all air pockets. Remove sufficient soil from the soil bed to enable the roots to be fully spread. 4.3.7

Pruning

Allow for canopy reduction and pruning of trees and shrubs after planting. 4.3.8

Fertiliser

Spread fertiliser on the finished surface of each shrub planting station in accordance with the manufacturer’s recommendations. 4.3.9

Mulching

Apply mulches in a 50 mm layer o ver the entire surface of shrub and ground cover beds. 23 Version 1.0


Mulching to be reapplied to all plating areas every 3 months after initial installation until the end of the Maintenance Period or until complete surface cover by vegetation is achieved. Initial mulching is to take place within 2 days of installation of planting. 4.3.10

Post Planting Weed Contr ol

Maintain all planted areas in a weed-free condition at all times without injury to plants. Use only qualified and experienced staff when employing herbicides and shall ensure that herbicide applications are carried out in accordance with current safety regulations and manufacturer’s instructions. Advise the SO of the which he rbicides used and what specific conditions must be maintained for their effective use and formally inform the SO of safety measures to be adopted for the use of herbicides. 4.3.11

Watering

Maintain a watering program for all plant material, especially those in containers to keep plants in a healthy state for successful establishment. Lack of availability of water will not release the Contractor from his obligations to replace all dead or dying plants at the end of the first season of growth after planting or any plants which have suffered visually. 4.3.12

Timber Tree Suppor ts

Install timber tree supports in accordance with practices adopted by National Parks Board unless agreed by the SO. These shall be aligned parallel to either adjacent kerbs or hedges. 4.4

Turfing 4.4.1

Cultivation

Ripped grass beds at 300mm centres to 200mm depth and rotated to a depth of 100mm incorporating pre-seeding fertiliser, thereafter raked or harrowed to produce a fine seed bed tilth approximately 25mm deep and lightly consolidated with an approved roller. Remove stones over 50mm in diameter to tip. Shape and grade subsoil to finished formation levels. Remove surplus subsoil. Remove subsoil considered unsuitable in any way for use in making up formation levels to grass areas. Spread topsoil to a minimum depth of 300mm over finished subsoil formation levels or drainage levels. Topsoil shall be rotated to a depth of 250mm incorporating fertiliser or other soil improvement measures to be agreed with the SO. Raked out or harrowed to produce a fine bed of approximately 25mm deep and lightly consolidated with an approved roller. Stones over 50mm shall be removed to tip. Finely grade grass beds during cultivation to remove all minor hollows or ridges, such operations being carried out when the soil is dry and friable. Final finished surface shall have a smooth and even fall or gently rolling curves between the finished level and the boundary of the areas.

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Arrange levels to give gentle falls for drainage and any ponding developing after completion of cultivation shall be made good. Use wooden planks or plywood boards for access during turfing operations to prevent compaction of soil. Incidental compression of completed graded topsoil shall be racked over before laying of sods. Re-cultivate all compacted areas. Water and complete within same working day all areas of completed turf. 4.4.2

Close Turf Operations

Lay close turf sods onto prepared ground with leaf turf upwards, close butt jointed to achieve uniform cover. Top dressed turf area with fine sifted topsoil mix to give even smooth surface. Lightly compact by treading or with wooden beater to ensure even coverage Water turf area immediately after planting using a find spray to avoid disturbance on soil. 4.4.3

Grass Establi shm ent Cut and First Cut

When grass reaches 50mm height, turf areas are to be cut to an average 30mm height and lightly rolled. This shall be repeated for a second cut. Cuttings are to be removed from site. Grass shall be established and maintained and presented as: a. Uniform dense sward between 25-30mm high. b. Healthy and attractive green condition, free from brown/discoloured edges and patches, c. Free from excessive thatch d. Free from evidence of disease, fungus, moss, or other weeds. The surface shall be even and free from irregularities, stones and other objects greater than 20mm diameter and free from bare patches. All interfaces with paved su rfaces/structures shall be edged to maintain a crisp and even junction. The number of grass cuts shall be sufficient to maintain the sward at the required level. Final cut prior to completion to be conducted in presence of building landscape maintenance team. 4.4.4

Rolling

When the grass has grown 50mm high the areas are to be lightly rolled in two directions with a roller not exceeding 0.25 tonne. All bare patches to be re-turfed. 4.4.5

Grass Cutti ng

4.4.5.1

Generally

Grass cutting shall be carried out with tools or machines properly sharpened and set. Remove clippings from site.

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4.4.5.2

First Cut

Prior to cutting, all stones exceeding 50mm diameter in any direction shall be removed from the surface. When the grass is approximately 100mm high it shall be topped without tearing using a rotary mower to leave 25-50mm growth. 4.4.5.3

Second Cut

When the grass reaches 75mm high the second cut shall be carried out with a rotary mower reducing the grass without tearing to 25 mm high and all grass clippings shall be spread evenly to prevent damage to grass beneath. 4.4.5.4

Additional Cuts

During the growing season the grass shall not exceed 50mm high. The margins of seeded areas shall be trimmed with edging shears at the time of every second mowing. Grass shall be normally maintained at 25mm height. 4.4.5.5

Completion

Prior to the issue of the Completion certificate the grass shall have been cut at least twice as above. Grass areas will only be accepted when germination has proved satisfactory and all weeds have been removed. 4.4.5.6

Edges

Where grass abuts planting areas, kerbs etc., these shall be defined to straight lines or neat curves as shown on the contract drawings. 4.5

Maintenance 4.5.1

General Requi rement

Maintenance for soft landscape include: a. Watering b. Weeding c. Mulching d. Pruning e. Disease and insect control f.

Dust cleaning from leaves

g. Adjustment of guy wires/tree ties h. Grass cutting to ensure successful establishment i.

Litter clearance up to completion

j.

Visits to site as necessary , to verify well being of a ll planting and activate an y measures to protect health of plants and equipment to standards required.

k. Undertake after care works only during suitable weather conditions During the execution of aftercare works, make good any damage caused including replacement if necessary.

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4.5.2

Adj ust ment to Semi-Mature Tree Guys

Re-tensioned tree anchors periodically to maintain taut, prevent excessive wind rock and to compensate for settlement. Protective coverings shall be regularly checked and made good where necessary. Tree ties, cross braces and posts shall be maintained secure and tight at all times, periodically checked and adjusted as necessary to prevent rubbing, or tightened to prevent rocking. 4.5.3

Re-firming

All plant material shall be r e-firmed periodically. Ensure that all plants remain firm in the ground, and any plants loosened due to strong winds or surface water movement shall be re-firmed as required. 4.5.4

Pruning

Remove dead twigs or water shoots occurring on the clear stems of trees. Cut back any species requiring pruning to encourage bushiness. Allow for topping/crowning reduction to all trees. Employ skilled operatives for pruning without any brushing or tearing of the bark. 4.5.5

Site Cleanliness

Maintain the site free from all spillages of fuel, building debris, clippings and excessive leaf litter and all litter and objects greater than 50 m which are not germane to the site. 4.5.6

Weed Contr ol

Keep planted beds free from weed either by hand, mechanical or approved chemical means. All relevant Statutory Laws a nd the manufacturer’s instructions concerning the handling, use and storage of the chemicals must be followed. Dispose of containers and other contaminated equipment in an approved manner. 4.5.7

Maintenance of Grass Areas

Give a minimum of 48 hours notice to building owner and user of intention to maintain grass areas before commencement of maintenance operations. Carry out the following maintenance elements: a. Irrigation b. Spiking c. Feeding d. Weed control

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4.6

Chemicals Employ only qualified and experienced staff when using herbicides and fungicides and shall ensure that applications are carried out in accordance with current safety regulations and manufacturer’s instructions. Inform building owner and user at all times of which chemical is used the specific conditions to maintained effectiveness and safety.

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5.

VERIFICATION AND SUBMISSIONS

5.1

Submissions 5.1.1

Submissions

Include in construction program, event for submission of the following information: a. Company profile and track record b. Name and contact number of intended supervisor c. CV of intended supervisor d. Name of the tree and plant supplier e. Name of the grass supplier f.

Name of the topsoil supplier

g. Method statement, showing installation quality assurance h. Maintenance approach to be adopted after completion i.

Name of sub-contractor(s), if any

j.

Method of supports for intended planting materials, both horizontal and vertical methods of supports.

k. Brief program showing times for procurement and installation. l.

Information of landscaping contracts current or completed during the previous 5 years and details of Quality Control Procedures adopted.

m. Confirmation of acceptance and allowance or all requirements in the specification n. Sample of deed of warranty o. Samples and mock-ups

5.1.2

Post Tender Submis sio ns

5.1.2.1

Soil

Submit for approval the following: a. Written analysis of topsoil before importing soil to site. b. A report on the suitability of the topsoil for the intended softscape works. c. Recommendations to improve quality and soil handling recommendations.

5.1.2.2

Contractors Documents

Submit for approval the following documents: a. Shop drawings of landscaping incorporating the ground and planting sections and support requirements. b. Equipment to be used c. Setting out plans.

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d. Detail program showing detail times for procurement and installation.

5.1.2.3

Sources Name

a. Tree supplier b. Other plant material supplier if different from tree supplier c. Source of topsoil to be imported for use d. Source for fertiliser e. Source of water to be used f.

Source for pesticide and herbicide to be used

5.1.2.4

Shop Drawings

5.1.2.5

Samples

5.1.2.6

Materials Certificates

5.1.2.7

Executed Warranty Deeds

5.1.3

Maintenance

Submit for approval: a. A written programme of Aftercare – Continuing Works prior to completion and throughout the 24-month maintenance period. b. Date for submission of monthly activity report indicating record of maintenance carried out during contract period. Maintain a record of all visits with reference to those maintenance tasks carried out and submit this record as required. 5.1.4

Maintenance Manual

No item. 5.1.5

Warranty

Submit the warranty to the SO upon completion of the works, if required under clause 1.4.4. 5.1.6

Quality Control Plan Submission

No item. 5.2

Samples and Mock-Ups 5.2.1

General

Agree source of planted material with S.O. at ten der stage, and arrange visit to the nursery to agree quality of planted material. In the case of grass and turfing a one meter square of sample grass or turf to be submitted with documentation certifying origin of sample and sufficiency of quantity for intended work.

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Tag and mark plant selected for project at nursery and agreement to schedule and method of deliveries.

5.2.2

Soil Samples

Soil samples shall be identified with the SO’s approval. Each soil mix shall be tested at an approved soil-testing laboratory. Soil analysis shall include the following information: a. pH b. nutrient values (N,P,K) c. soluble salt content (Electrical Conductivity) d. physical structure (sand, slit, clay and organic content as a %) e. toxic substances (heavy metals) f.

recommendation for amelioration

g. bulk density. Submit test result in advance of intended date of installation. Proposals of ameliorating measures to be submitted with test results. If multiple sources of soil mix are to be used, a one-litre sample from each source shall be submitted together with test results and amelioration measures. Additional test sample may be required if there is deviation from samples is detected in the course of delivery. 5.3

Inspections 5.3.1

Grass

Inspection with the SO shall be conducted after 28 days or as agreed within contractor’s program, after laying of turf looking for evidence of green healthy growth and to the satisfaction of the SO. The following shall be evident: a) Even cover of at least 90% of turf area with leaves and spreading shoots of Axonopus Compressus. b) Free of perennial weeds or disease c) Healthy, vigorous and showing a strong developed root system. Any settlement due to lack of compaction to be corrected by application of top dressing with finely sifted soil to a maximum depth of 25 mm. For depression greater than 25 mm the affected area shall be lifted and the depression filled with sifted topsoil and lightly compacted and the affected area re-turf to desired grade. 5.3.2

Defects Liabil ity Period

At the end of Maintenance Period and Defects Liability Period, conduct a joint inspection of the works with the SO.

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A3-30 SOFTSCAPE

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