Can I paint over an Asbestos roof?

This is a question we get a lot — and yes, we have a solution.

So often, perfectly sound asbestos super six roofs are removed and replaced with iron unnecessarily. Building owners are told that their roof is not sound anymore and is a health hazard to staff and the environment.

In a number of cases this can be true. But before the owner embarks on this expensive exercise, they should get an approved asbestos consultant to give them a professional opinion. Getting the correct advice on the actual state of the roof could save many thousands of dollars.

Existing asbestos roofs have probably been in place for many years. In the case of the New Zealand Naval Dockyards the material had weathered and protected their facilities for close to 65 years, right on the coast in the most severe environment, with no corrosion or breakdown of the substrate. Then they received advice from "consultants" that the roof must be removed. The cost of maintaining the existing roof would have been minimal, but now that it has all been replaced with iron, the costs of maintaining it for the next 65 years will more than likely be substantial.

So what are the alternatives?

If your roof is not breaking down with fibres coming away from the substrate and is still in a sound state, then why not encapsulate the surface?

Asbestos does not corrode, does not create condensation, and is a good acoustic insulator. It will therefore withstand salt-laden coastal environments. Because asbestos is subjected to thermal expansion, it is important that you do not apply a rigid protective coating or material such as fibreglass, as this can cause the roof sheets to crack.

A flexible protective membrane that has memory is the ideal encapsulation membrane — and that is why Noxyde anti-corrosion waterproofing membrane is the ideal choice.

The asbestos substrate does require an anti-mould and fungal treatment before this can take place, and the roof fasteners also require checking before Noxyde is applied with an airless spray in a two-coat application.

Noxyde does not become brittle and will remain flexible for in excess of 30 years — and this has been recorded historically. The cost savings can be substantial, and a 65-year-old asbestos roof could probably go another 65 years without replacement. Noxyde keeps the asbestos dry, so there is no further moisture ingress and surface growth.

In summary

If you have a large asbestos roof, don't be talked into its replacement with a product that will potentially corrode and require anti-corrosion maintenance for its entire service life.

We can put you in contact with qualified asbestos consultants who are familiar with the encapsulation process, and can give you sound advice as to whether your asbestos roof can be salvaged.

If it is not in good condition, then you will be advised to replace it. If it has not cost you anything to maintain, don't be sold a roof that will.

Contact us with your asbestos roofing details and a proper assessment can be arranged.