The short video presentation below outlines some of the issues involved with taking off quantities for below ground drainage.

Traditionally a contingency sum was included to allow for unforseen additional costs but clients have always asked questions as why this allowance is necessary.

Partitions are referred to on NRM2 in three work sections; 16, 20 and 22. Which section to use often causes confusion.

Surface water is water on the surface of the site and excavations. Disposal of surface water is deemed to be included in NRM2 Section 5. However SMM7 had previously required disposal of surface water to be measured as an item and confusion can occur as to what constitute surface water and ground water.

Provisional quantities should be avoided whenever possible, as rates can loaded in the hope of quantities increasing when remeasured.

Where appropriate, additional information shall be given to ensure full clarity of description. If in doubt give additional information regarding quality and location of work. For example, if the majority of brickwork is at ground floor level but there is also some at roof level the QS should measure the high level brickwork separately in the bill of quantities stating its location.