Bill of Quantities

The bill of quantities may or may not be a contract document. The bill of quantities is a detailed schedule or description of the works prepared by a quantity surveyor in accordance with standards published and agreed by the quantity surveying profession.

The bill of quantities will describe the materials and inputs required for each element of the job. Bills of quantities may be very substantial.

A bill of quantities may not necessarily be prepared or if it is prepared, it may not be part of the contract.

There are different forms of RIAI contracts depending on whether or not the bill of quantities forms part of the contract.

The RIAI short-form contract does not contemplate a quantity surveyor or bills of quantities being part of the contract. It does not envisage significant variations in the work. Where variations do occur they are to be measured on a fair and reasonable basis using the relevant prices in the specifications unless another price has been previously agreed.

Bills a Contact Document

There are two forms of RIAI contracts. In one, the bill of quantities forms part of the contract. In another, it does not. The GLDA contracts have equivalent versions.

If the bill of quantities is not part of the contract they are a guide to the extent of the work. They also form a schedule of rates from which variations might be measured. In this case,  any variation between what is actually required and the bill will not lead to a price variation.

In contrast, if the bill of quantities is a contract document they are the quantities provided under the contract. Any variations from them are a variation. This typically happens that the employer’s quantity surveyor quantifies the job and prepares the bill of quantity. This is the basis on which tenders are sought from contractors.

The bills are unless otherwise stated, to be measured in accordance with the method of measurement of building works last issued by the Society of Chartered Surveyors in Ireland and the Construction Industry Federation. Apart from this, nothing contained in the bills is to modify the contract.

The rules on measurement of works are prepared and updated from time to time by the Society of Chartered Surveyors and the Construction Industry Federation. Errors in the bills whether by way of description of quantities do not vitiate the contract but their correction is a variation.

Bills and Variations

Where the agreement does not provide that the bill of quantities are a contract document the contract is deemed to provide for the quality and quantity of works set out in the drawings and specifications to the contractor before signing the contract is to furnish the architect with a schedule of rates.

The schedule of rates is a copy of the estimate upon which the contract’s tender is based or where a bill of quantities is prepared for contract purposes the rates provided in it by the contractor.

Where variations arise from changes in the law the amount of any increase or decrease is certified by the architect and varies the contract. This will cover changes in tax rates and also certain regulatory steps by the state.


Variations in the contract do not render it void. The whole essence of the RIAI contract is to allow for prospective variations or adaptation to circumstances as the works evolve.

Any verbal instructions or directions given by the architect in relation to the works to the contractor by way of variation shall be confirmed in writing within five working days. If the same is not confirmed within four to five working days it is deemed to be authorized and accepted.

Variations are to be measured by the architect or quantity surveyor. The contractor’s representative is to be given an opportunity to be present and is entitled to information notes and measurements. The contractor is to be given a copy of the measured bill of variations on or before the architect certificate for payment for the variations.

The valuation of variations takes place in accordance with a number hierarchy of default rules. The rates in the bill of quantities are used where the work is of the character similar to those and carried out under similar conditions.

If the rates of variations are not of a similar character or carried out under the same conditions the rates are to be a basis of the price in so far as reasonable, failing which a fair valuation is to be made upon rates for similar works in the locality.

Where the above basis of measurement does not properly measure and value the work in the architect’s opinion the architect contractors the value of variations in accordance with equivalent rates in the bill of quantities on their absence of certain published rates. The rates are effectively based on prices in the various trades and on the quantity of materials.

Where the variation is of a  character and extent such that in the opinion of the architect the contractor sustained a loss by reason of having incurred expenses in consequence of the variation, an additional sum by way of reasonable compensation is to be added by the architect.

If two variations and nominations to find a measurement shows a credit on the contracts the contractor shall be entitled to an allowance of 10 percent of that credit. This is not applied to PC provisional or contingency sum.


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