Case Study:
Apartment Block Roof Renewal

Project Overview

1960s apartment block with deteriorating flat roof in need of replacement.

The best value was sought and the residents were keen to minimise the legal liabilities of the Construction (Design and Managment ) Regulations (CDM).

The original roof was completed with bitumen felt, laid over a strawboard (often called Stramit, sometimes erroneously called woodwool) roof deck. If water is able to pentrate moisture can lead to significant deterioration of the deck and make it unsafe to access and worsen water ingress.

Dabinett designed the roof scheme, produced the tender package, acted as Principal Designer under the CDM Regulations and were contract administrators.

Project Requirement

The existing roof of a 1960s apartment block was nearing the end of its life, replacement was required.  The residents and managing agents wanted the best solution at the best price, they instructed Dabinett to advise and deliver.

Dabinett designed a roof renewal scheme and liaised with a roofing manufacturer to obtain a long guarantee.  The tender package was then issued to contractors for competitive tendering.

The costs received back, for the same specification works, varied by circa £20,000 from lowest to highest.  Dabinett reviewed the tenders to analyse where there were consistencies and if there were any arithmetic errors.

All too often managing agents will procure works directly from contractors.  This can have implications in respect to design liability, criminal liabilities with regard to the CDM Regulations and a lack of control and clarity over costs.

With Dabinett instructed the exact specification was known and competitive tenders were recieved back.  From experience competitive tendering is 20-30% cheaper than negotiated contractors between the client and contractor.

Checks of the tenders found no errors, nor any concerns with the returned costs.

Project Outcome

The roof was completed on time and to budget, with greatly improved thermal insulation to reduce energy usage in the coming years.

The competitive tendering of the scheme offered the client a significant saving over procuring directly from a contractor.  The fees charged by Dabinett were offset by savings and the peace of mind for the client in knowing that independent professionals had overseen the project.

Building surveys by Dabinett


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