TLX Gold - setting the Gold standard?


The original Insulating Breather Membrane

TLX Gold was the first insulating breather membrane multi-foil on the market and we think that it remains the best, in spite of a number of competitors copying the concept.

Robust and the easiest to fit too

It was designed to be easy and robust to fit – not to fall apart in your hand on a windy roof like some. That’s why it has ultrasonically welded seams and a membrane lap extension on the long edge that marries onto an integral adhesive tape on the next roll down. This facilitates fitting and ensures continuity of the insulation without cold spots, and conversely, without lumpy double thickness layers on the overlap that are uneven to batten over.

Less is more

TLX Gold insulating breather membrane can be drapedBeing a thinner product than its competitors, the R-value (a measure of the amount of thermal protection the product provides) is rather less – but additional thickness should not be thought of as a benefit, because not only does it mean that a product is bulkier, especially on the overlaps, but it takes up space that would be better occupied with low conductivity PIR board if you need to achieve the lowest possible U-value in the rafter depth available.

The only material of its type which can be drapedTLX Gold insulating breather membrane can easily be draped when fitting

Because the TLX Gold at 33mm thick compresses down to only 3mm, this means that it can be used draped between the rafters with the tile battens straight over, with no need to raise the roof by requiring counter battens as do competitor products.

No risk of Interstitial Condensation?

Its patented shiny gold underside is fully breathable and responds to increases in humidity by becoming more breathable – unlike perforated aluminium sheets. Because of this and the fact that it provides insulation at the coldest point through the rafters, this means that moisture migrating up through the plasterboard does not reach dewpoint conditions - so there is no risk of interstitial condensation, even when there is no vapour barrier below. This makes it particularly suitable where there is an existing ceiling.

The breather membrane forming the upper surface is our high-tensile UV25 membrane (water vapour resistance 0.21 MNs/g), with the product as a whole having a breathability of 0.50 MNs/g. Since both TLX Gold and UV25 are BBA-certified there’s no need for us to confuse by implying that the breathability figure of an unspecified breather membrane is the whole-product breathability.

BBA Certification is keyTLX Gold insulating breather membrane can easily be draped when fitting

The plethora of various certificates is where things get really confusing. In order to get a BBA (British Board of Agrément) certificate that guarantees the quality, performance and suitability of a product, multiple samples from standard production output are sent for testing to various British Standards by accredited test houses – which can include the BBA itself. The results of these form the basis of a product’s Declaration of Performance, including such things as tensile tests, breathability and core R-value (which has to be a very worst-case value based on multiple samples).

Nowadays the BBA isn’t the only certificate provider – there are some European certifiers that may use slightly different (and more favourable) test methods whilst still falling within the BS test methods. Even if a product has a BBA certificate, it is not required to use the BBA-tested values in promotional literature – a more favourable previous result carried out by another test house may be quoted. We use BBA-tested values for our U-value build-up calculations, and when you see our BBA logo this means that we actually do have a BBA certificate, - we’re not trying to mislead by pretending that just because a single sample was sent for a single test to be carried out by the BBA that we can describe the product as BBA-certified and display the logo. And our certificates are current and do apply to the actual products we are selling. If the certification isn’t freely available on the manufacturer’s website and doesn’t match up with what is in the promotional literature then one wonders what this says about the product.

Well, call us old-fashioned but we like to stick to the BBA requirements, even if that means we have to quote absolutely worst-case R-values. And we don’t add on R-values of air gaps like everyone else because this can get downright misleading – like the TLX Gold copy which quotes an R value with 2 horizontal air gaps (as in a wall) – even though under an insulating breather membrane there is only 1 heat-reflecting air gap below! Or omitting to point out the amount of space the draped product and the air gap will actually occupy, so you end up with no air gap at all. (TLX Gold used draped, plus the unventilated air gap, requires a minimum of the top 50mm of rafter space).

LABC approved solutions tooTLX Gold insulating breather membrane has Local Authority approved solutions

The build-ups we suggest will give the U-values they say they will if our installation instructions are followed. Like many manufacturers, we have an LABC Certificate, with Registered Details status granted if the particular build-ups submitted are checked and approved.  However, this does not mean that all the build-ups and claims you can see in manufacturers’ literature are Registered Details – far from it! In our Approved Solutions Guide you won’t see any instances of vapour barrier multifoils being used in multiple layers or in build-ups that may lead to condensation problems, or fudging the dimensions so you end up without any heat-reflecting air gaps.

And if you have any questions about TLX Gold insulating breather membrane or need advice about how to achieve a particular U-value then contact the Thermal Hotline on 01204 674730, where we’ll only advise you to use TLX Gold if it is suitable for your intended use.

Read the case study related to this post

View our LABC approved Gold solutions HERE

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