Substructure Taking Off

SITE PREPARATION

The first building operation is normally the excavation o f the topsoil for preservation over the whole area of the building and this usually forms the first excavation item in the Excavating and Earthwork Work Work Section of the bill of quantities. The area is measured to the outer extremities of  the foundations in m2 and the average depth often !"# mm is included in the description. EXCAVATION TO REDUCE LEVELS

Where the site is sloping or the ground levels are generally higher than is required then further excavation is required to reduce the level of the ground to the specified formation level. This excavation is measured in m$ as excavation to reduce levels giving the appropriate maximum depth range.

EXCAVATION OF FOUNDATION TRENCHES

%oundation trench excavation is measured in m$ stating the commencing level. 

Excavating below groundwater level is given in m$ as extra over any types of excavating.

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Excavating around existing services is measured in m as extra on items for excavating stating the type of service such as gas or water mains electricity or ES& cables or sewers.

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While excavating around existing services crossing excavation is an enumerated extra over item.

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&reaking out rock' concrete' reinforced concrete' b rickwork blockwork or stonework shall each be described and measured separately in m$ as extra on items of excavating.

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While breaking out existing hard pavings is measured in m2 stating the thickness as extra on excavating.

DISPOSAL OF EXCAVATED MATERIAL

The subsequent disposal of excavated material forms a separate billed item in m$ either of soil to be stored on(site used as filling to make up levels filling to excavations or to be removed off the site.

BASEMENT EXCAVATION

&asement excavation is measured to the outside of foundations in m$ stating the maximum depth range.

CONCRETE FOUNDATIONS

)oncrete particulars are to include the kind and quality of materials mix details tests of materials and finished work methods of compaction and curing and other requirements. )oncrete foundations include attached column bases and attached pile caps while isolated foundations include isolated column bases and pile caps. &eds and slabs include attached beams and beam casings. *n(situ concrete is measured in m$. +n a sloping site the concrete foundations will probably be stepped and it will be necessary to measure the additional concrete at the step and a linear item of  formwork to the face of the step. *f the concrete foundations are reinforced with fabric reinforcement the reinforcement is measured net in m2 stating the mesh reference weight per m2 and minimum laps. &ar reinforcement is billed in tonnes keeping each diameter ,nominal si-e separate although it will be entered by length on the dimensions sheet distinguishing between straight bent and curved bars. /ooks and tying wire and spacers and chairs which are at the discretion of the contractor are deemed to be included.

CONCRETE BEDS

*n(situ concrete beds are measured in m$ stating the appropriate thickness and including in the description where poured on or against earth or unblinded hardcore. Treating the surface of in( situ concrete is classified and given in m2. )ommon surface treatments include power floating trowelling hacking grinding sand blasting bush hammering and brushed. 0 tamped finish is deemed to be included. /ardcore and similar beds are measured in m$ classified as to whether the average thickness is 1 or  2"# mm the nature of the filling material and its source and3or treatment.

PRECAST CONCRETE FLOORS

Such work is measured in m2 the concrete reinforcement and formwork to be included in composite construction shall be described. 0nother alternative to reinforced in(situ concrete slabs on upper floors is to use precast concrete hollow core slabs grouted after laying. These are measured in the same way as the precast concrete beam and block floor. This type of floor has the advantage of faster erection times and the virtual elimination of shuttering and pouring of concrete.

OTHER SUBSTRUCTURE WORK 

&rick and &lock Walling &lock and brick walling is measured in m2 and described as wall in trenches stating the nominal thickness such as !## mm and whether there is facework ,fair finish on one or both sides. %acework  &rick facework is included in the measurement of the brickwork on which it occurs with a description of the kind quality and si-e of bricks type of bond composition and mix of mortar and type of pointing.

4amp(proof )ourses 4amp(proof courses are measured in m where it is 1 22" mm wide and in m2 where  22" mm wide. 5ertical raking hori-ontal and stepped work are so described. The description of the damp(proof course contains particulars of the materials used including the kind and quality of the materials. 6o allowance is made for laps 4e emed to be *ncluded.

4amp(proof 7embranes This work is normally measured as one continuous sheet in m2 stating that it is hori-ontal and  $## mm in width.