Chartered Building Surveyors

Asbestos roofs are still very common in the UK as it’s estimated by the UK’s Land Registry, that more than 75% of those ever installed are still in service today.

That says a lot about the strength and quality of the material, but the original predicted life span was only 40-50 years. Given that the majority of asbestos roofs were installed in the 1960′s and 1970′s, a lot are now reaching the end of their life and will need replacing.

However, the lifespan does depend on a number of factors, including geographical location, maintenance, etc., as we’ve seen plenty that were installed in the 1930′s and are still pretty much as good now as they were when they were installed.

The truth of the matter though, especially on larger industrial properties, is that roofs are not particularly well maintained and probably only receive any attention unless they are leaking, in which case, a series of patch repairs are carried out, probably due to lack of capital budget, because whatever you do to an asbestos roof is likely to be expensive.

The Options

Patch Repairs – these are localised repairs to fix specific problems. As a roof ages and starts to deteriorate, leaks begin to appear around roof lights, fixings and gutters. When a reactive maintenance approach is taken, the immediate problems are often solved with temporary repairs using materials like torch-on sealants, silicons, fabric, paints and self-adhesive tapes.

Such repairs can last a long time, but most fail relatively quickly due to temperature variations and because the correct preparation was not carried out.

Cleaning & Coating – Larger asbestos roofs on industrial and commercial buildings can sometimes be cleaned and coated to prolong the life of the roof. In such cases, the entire roof is usually treated in one application. Usually, the better coatings are guaranteed by the manufacturers, but care must be taken in your choice of contractor, because unless the manufacturer’s instructions are followed completely, your guarantee will not be valid.

As building surveyors with considerable experience with asbestos roofs, we recommend cleaning and coating a roof only in limited circumstances, depending on whether you own the property or you are leasing it – and for how long.

This is because once a roof deteriorates to the point that it requires coating, it is likely to suffer further deterioration. Most older asbestos roofs suffer some degree of de-lamination of the asbestos cement roof sheets. Once there is evidence of water ingress to the actual panels (rather than through holes in the roof itself), water can become trapped within barely visible fissures.

In extremely cold conditions, the water freezes and the fissures expand, breaking the surface of the asbestos cement sheet away, taking the coating with it in most cases.

Even a rubberised or otherwise flexible coating will not necessarily protect from this happening and we have seen many examples where coated roofs have broken down in this way.

It should be pointed out that it usually the failure of somebody to spot the existence of fissures in the sheets that leads to this problem, which is why an independent roof survey is strongly recommended before contemplating this type of repair – it could save you tens of thousands of Pounds.

Over-cladding - Asbestos roofs can sometimes be over-clad with metal profile sheets, leaving the original roof in place. Using a frame system, the metal sheets are laid directly over the roof and in most cases, additional insulation is also provided between the two roof surfaces. At the same time as over-cladding a roof in this way, it is good practice to also renew roof lights, since new roof lights are relatively inexpensive and will let in far more light than old ones, which tend to break down and discolour after being in place for many years.

Over-cladding an asbestos roof will provide you with a longer-term solution than any coating system and it is usually cheaper than replacing the existing roof. However, there are a few things to take into consideration.

First of all, the structure of the property has to be considered. These days, industrial and commercial buildings are made to pretty precise calculations, with everything being done by computer to take into account the loadings that will be placed up the building, taking into account the additional weight of snow for example.

Back in the days when asbestos roofs were being installed, this was not the case. A structural engineer would carry out manual calculations for supporting steels and then add in some tolerances. This was actually a good thing, since the structural steels were more likely to be over-specified, meaning that they probably would take the additional weight of an over-cladding system. But, that isn’t always the case.

We recommend therefore, as part of the due-diligence process, that the structure is examined by a structural engineer prior to commencing such a project.

Other things to consider are that over-roofing still leaves an old asbestos roof in place. Additionally, the height of the building will change, which may require permissions from the local authority before works can commence.

Re-Roofing - Often seen as the last resort solution on larger properties because of the cost, yet in some cases, a complete new roof is the best and most cost-effective solution. New modern roof sheets generally comprise a twin wall metal roof panel with varying degrees of insulation contained within.

Ever-changing energy performance targets set by the government mean that the thickness of the insulation is always changing, but all panels supplied these days will be compliant with current building regulations.

The cost is the major consideration, since changing an asbestos roof is very expensive and there are no short-cuts.

We would recommend a new roof in cases where a long lease is in force (more than 10 years), or when a client actually owns the building, but the use of the building would also need to be considered.

Heath & Safety Issues

Any roofing work is dangerous, but asbestos roofs have their own unique set of difficulties and consequently, a major element of cost, no matter what solution you choose, is going to be in this area. In fact, the health and safety precautions are likely to cost at least one third of your total expenditure.

This should be considered when making your decision, because the costs will be incurred whether you are coating, over-cladding or re-roofing.

There are various elements of costs. The major one will be the scaffolding and access system – tens of thousands of pounds can be spent here. Next comes the internal netting. In most cases, especially where people are working beneath, a double netting system will need to be employed to prevent people, tools and debris from falling into the space beneath. The cost varies, but there are no cheap short cuts.

Scissor lifts or cherry pickers will need to be hired and in some cases, walkie-talkies used to allow communication between workers on the ground and those on the roof.

Given that these costs will be incurred anyway, it is worth considering the most long-term solution right at the start, because with a coating system in particular, it is almost certain that you will spending money replacing your roof in ten years time.

A new roof will usually give you around 25 years life expectancy.

Proposed Legislative Changes

The Control of Asbestos Regulations 2006 specifies which asbestos works are licensed.

Asbestos roofing works is not licensed and therefore can be carried out by any competent roofing firm, though many are reluctant to work on larger projects.

Under new proposals, the Health & Safety Executive in England is currently looking to introduce a new classification called Notifiable Non-Licensed Work (NNLW).

This could have the impact of making all larger over-cladding and coating jobs notifiable to the HSE.

Also, those people working on the roofing project would be required to have 3 yearly medical examinations, with the results being kept for 40 years.

This means that it will become even more important to have the correct advice and help with such projects – and of course, our specialist knowledge in this area becomes even more valuable to our clients.

It is vitally important, especially with HSE notifiable work, that all of your health and safety issues are properly addressed throughout the project, since it’s likely that any asbestos roofing works will attract a lot of attention from the HSE.

This means random, unannounced site visits and safety audits. Can you afford to take the risk of using less than competent contractors, or failing to understand the health and safety implications?

Why use A Surveyor?

As Chartered Building Surveyors, we will give you an unbiased and professional opinion based on many years experience in this very specialised area.

Our roof report will provide you with options and budget costs based on your own unique circumstances and once delivered, we can help you with the decision making process and then manage the entire project from start to finish, including helping you decide on the right contractor to use, by running a competitive tendering process on your behalf.

Our management fee is charged as a percentage of the value of the works, but typically, we save our clients considerably more than this, both in terms of financial savings and of course, the peace of mind in knowing that the job has been completed correctly in accordance with the manufaturer’s guarantee requirements, as well as looking after all health and safety requirements and where necessary, HSE notification.

To discuss your asbestos roof issues on industrial or commercial property, please call us on 0121 711 7110 .

There’s no obligation, just friendly and free initial advice from real asbestos roofing experts.

For more information, please see our specialist asbestos roofing web site: www.asbestosroofing.co.uk