The article is Titled
"When Is a Roofer Just a Roofer"
March 2023
issue 105 page 21
In the article I talk about how roofers are not trained and what they are expected to do without training no wonder the construction of roofs is so bad.
Extracts from the article
When Is a roofer just a roofer
With over 40 years of construction experience under my belt, I remember hearing of buildings put up in the 70s,
where the builders hadn’t installed the AVCL correctly in
walls. This led to horror stories in the press and on TV showing mouldy houses, rotted timbers in walls and buildings not fit for habitation. Luckily for me and my micro-business at the time, I was approached by one of the largest insurance companies issuing 10 year insurance-backed guarantees for new-builds. They wanted experienced construction workers to help diagnose the problems; these were indeed real homes from hell.
One of the first properties I dealt with was a new-build of 12 flats, and the top floor flats were all suffering from high humidity, with water dripping from the ceilings. When we stripped out the roof, all the booted and suited surveyors looked in and scratched their heads. At this point I started to realise that nearly everybody was confused as to what was happening. This was my first introduction to the second law of thermodynamics, manifesting as the problems you get with thermal bridging and controlling the transfer of energy through a building, vapour barriers, insulation and ventilation! Who knew where to put them? I certainly didn’t, and most of the people around me with letters after their names were also baffled. But one person, an old school engineer, talked sense, and he became my go-to mentor for many years before he retired. I was very fortunate as I was getting paid and learning at the same time.
If the majority of the suited and booted who write the specifications, don’t understand the full implications of the materials being specified and used, how on Earth can we expect the construction and roofing companies to understand the implications and consequences of what they’re doing and how essential it is to install such materials correctly?
Recently my son-in-law started working with me before lockdown; he had served his apprenticeship as an aircraft engineer, and he was astonished coming into the roofing trade, to see how unregulated it is. When I showed him all the British Standard documents that I refer to on a daily basis to get specifications, and told him how much they cost (£200 - £300 each), he couldn’t understand why they were not free to everybody. “How can you build something correctly if you don’t have free access to the correct information?'' And there lies a significant problem!
So we have roofers who are being asked to install insulation, AVCL and sarking felts. Each of these materials has to be fitted to the correct specifications or they could fail. Yes, of course we should read the manufacturer's specifications, but the biggest problem is that frequently roofers are working from drawings that give insufficient or incorrect information. Regularly I am given drawings that state “add a vapour barrier”, but no specifications on its vapour resistance are provided.
Nowadays I tend to do surveys only, trying to help customers resolve the situation of having had a roof installed incorrectly. I have great empathy with customers who have spent lots of money on a project that has failed and needs remedying or re-doing. However, I can also empathise with the roofer who has installed a roof incorrectly because they just weren’t clued up enough, or the roof has failed due to other trades persons breaching the roof system. The responsibility still lies firmly with the roofer and something like this could basically break their business and make them insolvent. All of this is a messed up concoction of a lack of information, insufficient or bad training, poor design and external intervention, i.e. other trades persons.
The manufacturers of materials do provide plenty of information and guidelines on how to install their products, but with so many different suppliers and systems available to form the buildup of a roof, the roofer not only has to read up on each product, but also has to find out if that product is compatible with the other products.
Let’s take smooth fibre cement slates; these have been around now for years, however hidden deep in the manufacturers’ specifications and in the British Standards document (BS 5534 2018 slating and tiles for pitched roof) is the fact that that these slates are classed as ‘air closed’, and that means they must be installed over a sarking felt that is:
air closed,
or HR (highly resistant to the transfer of moisture) (a new category),
or over cross battens and vented.
So smooth fibre cement slates cannot be installed directly over the most commonly available and used sarking felts (LR), without double battening, because the transfer of moisture to the underside of the slate could cause condensation and therefore rotting battens and fixings.
t’s not only the smaller roofing companies that are getting caught up with this mess of understanding product compatibilities, it's also the larger companies. Several times a year I do roof inspections on building estates that are still under construction; hundreds of units all with incorrectly installed materials, whether it be the roofing, sarking felt or the AVCL. The biggest and most common problem is loft conversions with cold roofs. I have never seen a cold roof installed correctly on a loft conversion. Last year I built a mockup of a loft conversion and demonstrated how hard it is to install an AVCL. Not only do you need to buy the correct product, but you need to buy the entire system - the tapes and fixings that go with the product. You then need to install it correctly so that it’s airtight. Leaving an apprentice or the labourers to do this is not the way to go! After it’s installed, it has to be looked after and cannot have holes cut into it by other trade persons, such as plumbers or electricians. Time and time again I see a cold roof installed with holes cut, not only through the AVCL, but also through into the insulation and the vented space behind, totally breaching the airtight seal, and therefore the thermal element of the roof. The amazing thing is that Building Control never seems to pick this up.
My conclusion is that roofers should not be asked to do other work outside of their main job, unless they have been trained in that area. However, I know this is easier said than done, because they are the people on the ground (or actually on the roof) at the time. This all really comes down to who is responsible for each item. With cold roofs, roofers often get contracted in to do the roof only, but still get the blame if the roof fails because:
there’s a lack of ventilation in other elements,
the AVCL hasn’t been installed,
the AVCL has been incorrectly installed,
lights have been punched through, breaking the integrity of the roof’s thermal element.
So what’s the answer?
Roofers should stick to roofing unless they really understand the implications involved in taking on installing these other elements.
Always follow the drawings and specifications gIven, and if the detail is not on the drawing or hasn't been provided, ask for it!
Don't take on the design element - it’s so easy to be helpful and say OK, let’s do it this way. By doing so you take on the responsibility of the design and this requires qualifications and personal indemnity insurance!
Make your paperwork clear as to what exactly you are doing and what your responsibilities are.
Keep up your continued professional development (CPD).
Over the years I have learned that you never stop learning. Im out doing roof surveys every day of the week and I just cant stop learning......