Mr Roofer

As a keen gardener I have been waiting for the weather to warm up a bit so that I can get on and start the garden for summer 2006. Well, okay, the weather is still freezing for this time of year, cold, wet, windy and miserable. A perfect recipe for staying in doors or taking a holiday to a warm climate. Global warming?!

The weather has certainly been responsible for the record number of enquiries we have received in the last week. Poor insulation and badly leaking roofs all prompting a flood (to coin a phrase!) of enquiries. A trip down to Bristol revealed a young lady with a large house with the central heating turned up full tilt but with the house still freezing cold, it was warmer in my car! Alas, the roof was unsuitable to spray foam so we declined to quote and I resisted her protestation that another “respected and national” company had quoted her for foam roof insulation. I explained why the roof was unsuitable (tiles known to cause leaks by capillary action and recommended she invest in either a new roof and roof insulation or forget the idea. The roof had roofing felt but this was sagging all over the place and ripped. The roofing felt was needed with this type of tile as a final barrier. Polyurethane roof grade foam is unsuitable as a final water barrier as it its slightly open cell structure will eventually let water pass through. This type of foam is water resistant and not water proof and what this young lady needed was a water proof barrier if this roof was not to leak into the loft area.

Anyway, I left the idea with her that the roof was unsuitable to spray foam as is. Time will tell if she takes my advice or goes with the “respected and national” company. I will report progress as an interesting “our advice us against the competitions” situation where I know the advice we gave is 100% correct and let readers know what the customer has decided to do.

I was alerted to a “competitor” web site by a customer yesterday. This web site, leaving aside the very poor grammar, claimed to be BBA accredited and even shows a picture of a van proudly displaying the BBA logo on their home page. They even claim “BBA 25 year approved system”. All lies I am afraid, the company in question is not BBA accredited in any shape or form and certainly has no rights to claim any reference to the BBA.

This led me to think about con men and rogue traders. If a company cannot be honest in their advertising then clearly no consumer should have any faith in using that company, what other lies are they trying to get you to swallow? But how does a consumer evaluate and establish who are the con men and rogue traders? It seems help is at hand; contact Local Trading Standards if you are at all suspicious of a trader. Also, check web sites like http:// www.blagger.com and http://www.vetted.com/ to see if anyone else has raised concern about the company in question.

And always speak to existing customers of the company, ask for 10 or more references of the last 10 jobs completed, not the usual 2 or 3 because even rogue traders are astute enough to ensure that their brother and uncle will give a good reference. It becomes harder to manufacturer references the more there are and the more recent, ask for the last 10 rolling jobs completed as the references you take up. If you do not get this (all Rooftherm customers get this, we automatically ask each customer if they are happy to act as a reference, we have not had one customer refuse) or the company refuses claiming rubbish about data protection and so on then you already have your answer.

It seems our articles are upsetting some of our competitive neighbours. We received out of the blue an email yesterday from a distributor marketing Dow Chemical’s Froth Pak system. This email threatens legal action against us for mentioning the fact that Dow Chemical’s Froth Pak polyurethane spray kit are not fire rated. We quote below from Dow’s own web site on their frequently asked questions page on Froth Pak:

http://www.dow.com/buildingproducts/frothpak/faq.htm#faq15

“Is FROTH-PAK fire rated?
No. FROTH-PAK is not a fire rated foam. “

and

“Is FROTH-PAK flammable?
Cured FROTH-PAK foam itself is NOT flammable, but it is combustible. The foam will burn if exposed to sparks or flames, and it will present a fire hazard if exposed to temperatures above 240°F. See Fire Rating Issues.”

and

“Warning: The foam produced by FROTH-PAK is organic and combustible and may constitute a fire hazard. Do not expose foam to flame or temperatures above 240°F (116°C).”

Our article can be found at:
Roof Insulation - a Spray Foam DIY Proposition?

We would welcome any comments from anyone who thinks we have misinformed. Seriously.

Apparently this distributor wrote to claim that the Froth Pak kits they supplied were B2 fire rated. There is no mention of B2 ratings on Dow’s web site in relation to Froth Pak’s. To be fair to the distributor, they did send us a copy of the laboratory reports (German) they had supporting the fact that the chemical they were supplying was B2 rated but the report itself did not specifically mention anywhere “Dow Froth Pak”. It did make a reference to the word as a trade name “134A Froth”. Presumably they are the same thing?

The B2 fire rating is used mainly on continental Europe and is originally a German standard. As we understand it, the German B2 fire rating standard is equivalent to rating Class E BS EN11925-2 in the UK which describes materials meeting this requirement as moderately flammable. The test itself is no where near as stringent as a BS Class 1 fire test. British Standard class 1 has been become over the years the de facto standard for the polyurethane spray foam industry in the UK. But more to the point, BS 476 part 6/7 under current building regulations can only be met by class 0 and 1 materials. In other words, a B2 rated product does not meet this requirement. We are also at a loss to understand why a distributor to the UK market would obtain a German laboratory B2 rating. It appears to us that if you are marketing to the UK building industry then you would use UK standards, e.g. BS EN11925-2. Such testing is done by the Building Research Establishment at relatively little cost and the fire certificate would carry a UK standard.

Our advice is very simple. We do not believe that a B2 or Class E rated polyurethane has any place in the roof of a building due to the increased fire risk hazard and it certainly has no place in a public building under current Building Regulations. And the vast majority of the UK spray foam polyurethane industry supports this view. The insurance industry generally has a hard time accepting anything less than Class 1; they have no intention of seeing their profits go up in smoke! Try obtaining insurance on a building where B2 rated materials have been used and you’ll likely be disappointed. The solution to us is simple, supply the UK market with Class 1 rated kits. We believe there are a number of such rated kits coming onto the UK market. Perhaps we should become a distributor of Class 1 kits ourselves?!

There has been a bit of interest recently within Rooftherm about aluminium foil insulation. This is a composite product that is about 25 to 30 mm thick and comes in 1 metre or so wide rolls. The foil is basically a sandwich of fibre insulation materials and aluminium foil. The idea is that you simply stable it to studs or rafters, plant a 25 mm thick batten on top of it and fixed to the underneath rafter or stud (this will compress the foil to zero thickness at this point) and then install plasterboard by fixing to the planted on battens. This sounds a simple and quick procedure and it is claimed that a 0.2 U value can be achieved by this method, very impressive if true.

Heat energy is primarily lost from a dwelling by three main methods, conduction, convection and radiation. The aluminium foil method is said to effectively stop radiated heat energy and partially stop convection and conduction. Most other insulation products work by preventing conduction and convection heat escape so clearly this product has an advantage as it will also prevent radiation heat escape.

I will digress for a moment before coming back to foil insulation. The building regulations require that buildings are so designed and built so as to minimise cold bridging. Cold bridges are foamed when heat can be conducted out of a dwelling by, for example, steel work. Timber joists and rafters are also now considered to offer a method of heat escape by conduction and are now treated as cold bridges. The design and build of a building needs to take this into account and insulation board or spray foam is typically used to insulate the bridging material and stop conduction. Cold bridges can be minimised but it is inevitable that a number of points will still remain that will act as cold bridges, we after all have to fix something to something which needs to be fixed etc. Spray foam minimises cold bridges in a loft conversions, for example, because it can be sprayed top side of the rafter and prevents the rafter from conducting heat to the tiles or slates. Timber laths will still present an area of cold bridging but the footprint they present is minimal when compared to the whole and can be ignored since the design has minimised the main cold bridge, the rafter itself. Spray foam systems have been successfully applied to loft and barn conversions using this method for quite a good many years now and all give good excellent insulation values if installed at recommend depths (minimum 75mm), well within the building regulations U value limits.

Now, the aluminium foil method clearly does not minimise cold bridging since it is compressed at the point battens are affixed. Moreover, aluminium being highly conductive will exacerbate a timber cold bridge. This immediately throws up the question as to whether or not an aluminium foil system can ever comply with building regulations. An aluminium foil systems will present large cold bridges so it is doubtful if it can be used in loft conversions just on this point alone.

Next comes the question of the claimed U value achieved. There is on this point a paucity of independent and creditable scientific data. Rooftherm will watch this space but it is interesting that a number of polyurethane foam manufactures have challenged the claims made by the aluminium foil insulation system and have conducted independent laboratory testing. This testing seems to indicate that the U value achieved is in fact greater than 1, a not very impressive figure and hopelessly short of complying with building regulations as to be not a viable method. The only conclusion Rooftherm can come to at this stage is that we cannot offer it as a solution to our customers since the jury is still out on this method of insulating. We do intend however to follow this up and see which way the claims and counter claims go.

For the record we have no axe to grind one way or the other on aluminium foil insulation systems. If it is conclusively proved to work and accepted by building control inspectors in the way that spray foam is we would offer it as an option for roof insulation, we have even set up accounts for the purpose but await fuller and more scientific testing before recommending it to our customers.