Limestone facade: net cladding, reveals and cornice
A civic building facade is clad in 40 mm limestone panels fixed to a concrete frame with stainless steel brackets and anchors. The quoted facade area is 180 m² measured over the structural openings. There are ten windows, each 1.50 m wide × 1.47 m high, giving 22.05 m², and the measured opening area is taken as 22 m². Each window has a 250 mm recessed reveal returning to the frame. A moulded cornice projects 300 mm and runs 42 m along the entrance elevation. The contract measurement rules require: cladding measured net to the face of the wall; openings over 0.50 m² deducted; reveals and returns measured separately in linear metres where they exceed 200 mm; cornice measured in linear metres; brackets, anchors and sealant included in the cladding rate. The contractor has priced the full 180 m² as plain cladding and now claims the reveals and cornice as extra.
1. Calculate the net cladding area, the linear metres of window reveals and the cornice length, and state the measured items.
Read the worked answer
The quoted 180 m² is a gross area over the structural openings, so it includes the window voids. Net cladding = 180 − 22 = 158 m². The 22 m² is deducted because each window is well above the 0.50 m² threshold.
For each window, the reveal perimeter is 2 × (1.50 + 1.47) = 5.94 m. Ten windows give 59.4 m of reveal. The 250 mm return exceeds the 200 mm rule, so it is measured separately in linear metres rather than absorbed into the cladding area.
The cornice is measured separately in linear metres: 42 m. The measured items are therefore 158 m² of cladding, 59.4 m of reveals and 42 m of cornice. Brackets, anchors and sealant are not separate items because the rules include them in the cladding rate.
2. Is the contractor entitled to payment for the reveals and cornice? How should the QS deal with the fact that the contractor priced 180 m²?
Read the worked answer
The claim is valid in principle but not in the form submitted. The contractor was entitled to be paid for reveals and cornice as separately measured items, provided they were not already included in the cladding rate. However, the contractor priced 180 m² of plain cladding, which includes the 22 m² of window voids. That area is not cladding and must be credited.
The QS should build the valuation from the measured items: 158 m² at the cladding rate, 59.4 m at the reveal rate and 42 m at the cornice rate. The 180 m² priced by the contractor should be replaced, not added to. If the cladding rate was expressly stated to include returns up to 200 mm, the 250 mm reveals are still separate, but the QS should check the rate build-up for any double allowance for brackets or sealant.
The QS should also check whether the 22 m² deduction should be 22.05 m²; the contract uses measured opening area, and the stated 22 m² is the agreed measurement.
3. During construction the architect changes the reveals to a 150 mm return. What is the measurement effect, and what else should the QS check before adjusting the valuation?
Read the worked answer
A 150 mm return is below the 200 mm threshold, so the reveals are no longer measured separately in linear metres under the stated rule. They are treated as part of the cladding face or included in the cladding rate, depending on the precise wording. The QS should delete the 59.4 m reveal item and check that the cladding area measurement reflects the revised geometry.
The change may also affect the cladding area itself: a shallower reveal can change the extent of the face measured and may alter the window deduction. The QS should check whether the variation is an instruction with valuation implications, whether the contractor has already procured the 250 mm anchors or brackets, and whether the cladding rate included a specific allowance for 250 mm returns. The QS should not simply delete the reveal item without checking for a credit or addition on the cladding rate.