Published: 20/10/2020
The scale of the task to evaluate the safety of buildings, following the Grenfell fire, is vast and the cost of carrying out the necessary remedial works will be costly, but just how costly? To demonstrate the significance of the work in this sector ‘Cladding External Wall System (EWS) FAQ’ was the most read article on rics.org in 2020 and over 5,000 EWS1 Forms were completed by the end of 2020.
BCIS have recently analysed two completed schemes for 8 and 9 storey blocks of flats. Both schemes were for the same client and negotiated with the contractor carrying out the previous cladding exercise. The projects analysed include the removal of the existing cladding and replacement with polyester powder coated aluminium rainscreen cladding.
Analysis shows that the cost of the new cladding makes up only part of the overall cost, in these projects, just 30-40% contract cost, with Preliminaries in the region of 30%. Preliminaries costs are likely to vary considerably to reflect access to the site and the number of storeys – many schemes will be significantly higher than the projects analysed.
Other costs included the removal of existing cladding and new flashings, on average 3.5% each and fire-stopping making up 4% cost. Risk allowances were included in the initial estimates to provide for works discovered during the project. The final cost of these items, including further fire-stopping and remedial works and additional access, amount to approximately 25% of the final contract value. Although these variations were within the allowances made, it demonstrates the difficulty in estimating costs with certainty at the outset.
Source: BCIS
It should be noted that fire safety works are not limited to replacement of cladding and additional measures such as fire stopping, repairs/replacement of internal fire doors, remediation of balconies and external features, remedial works to service voids and other works identified as part of a fire safety assessment may be necessary.
The BCIS resource data team, responsible for producing the Building Price Books and BCIS online rates database, have prepared guide prices for new works for various types of cladding. The costs per square metre for rainscreen cladding ranging from £220/m2 to £265/m2.
In the projects analysed above, the cost of the rainscreen cladding*1 rebased to UK average location 4Q2020 (excluding fire-stopping, flashings, and preliminaries) range from £300/m2 to £350/m2 (area of cladding) demonstrating the additional costs associated with reveals, soffits etc.
The final costs for the schemes analysed, including all associated works and Preliminaries, result in a cost for external wall cladding in the range of £800 to £1,100 per m2 area of cladding.
Estimates based on Gross Floor Area are unlikely to be appropriate as only areas of cladding identified as ‘at risk’ may need replacing. In the projects analysed the cladding to be replaced formed only 20% to 25% of the external wall area.
Increased demand for cladding remediation projects may cause capacity issues within the sector and this is likely to increase costs. One building products supplier has indicated an average 8% increase in costs for cladding materials applicable from January this year.
To further help the industry estimate the potential cost of recladding non-compliant buildings we urgently require further project data for analysis. If you are able to provide project costs for any recently completed schemes, we would like to include these in our studies; please contact contactbcis@bcis.co.uk.
All information will be treated as confidential and no reference to project names, data suppliers etc. will be provided without your approval.
*1 Of the projects analysed one was installed onto retained insulation and the other included the removal and provision of new insulation.