AsbestosRoofing.co.uk

If coating isn’t viable, or not preferred, the next most cost effective solution is to over-clad the existing asbestos roof, usually with a modern metal profile.

Depending on budgets, it is often desirable to also consider over-cladding any asbestos wall profiles to give a complete facelift and add value to an older property.

Usual health and safety practices apply and regulation scaffolding adds a considerable amount to the cost of the job. It’s therefore often more cost effective to overclad an entire roof than it is to replace blocks of failed sheets and sky lights.

Roofing contractors will often prefer to conduct patch repairs to cracked and damaged asbestos roof sheets, but this is often a false economy, because once problems begin to occur, they tend to recur on a regular basis, which is good for the roofing contractor, but not for you.

With an over-cladding system, the original asbestos cement roof sheets remain in place and new skylights are usually installed to replace the old ones which are usually delaminated and discoloured.

The addition of new roof lights can make a significant difference to the amount of light that enters the building and will often result in decreased energy usage.

To fix the new over-cladding, a grid is usually placed over the existing roof and new metal roof sheets are fixed to it, along with new roof lights, fixed down with self drilling fixings, which are fitted with sealing washers and protective caps. Insulation is laid between the old and the new roof to prevent condensation build-up and of course, to provide additional thermal insulation.

There are several things to consider about over-cladding;

• The original asbestos cement roof remains in-situ therefore, you will always have an asbestos issue, though this shouldn’t be a problem.
• You may require permission from your local authority, since the roof will be higher than originally intended.
• The local authority might specify a higher level of insulation than normal to meet emission targets – other building regulations might apply.
• The existing structure might not support the increased weight of an over-cladding system, so structural calculations will be required.
• Provision might need to be made to increase drainage capacity since water runs off a metal roof much quicker than an asbestos roof.
• Building Regulations & Planning Permission adds to the cost.

If you would like to arrange a roof survey and feasibility study on such a project, please call David Carter on 0121 711 7110 (Mon-Fri 8:30am to 6pm only please).