Reroofing without the need to counter batten?

11/08/2016

Going from design concept to product requires an understanding of exactly how the product is installed and actually performs in use - and in this respect a lot of thought  - as well as practical testing - goes into manufacturing something that is fit for purpose.

Breathable insulation is the keyinsulating breather membrane which does not need counter batten

If the design goal is to have an insulating product that can be used in the same way as a breather membrane, then it has to insulate, it has to be able to breathe, and it has to be able to fitted in the same way as a breather membrane – either by draping it between the rafters with the usual 10mm sag, or else stretching it taut then counter battening.

TLX Gold insulates by having a polyester core with internal reflective layers and also makes use of an unventilated air gap next to it; it breathes not only because the upper surface is a top quality breather membrane, but because all the other layers allow water vapour to pass through.

No need to counter batten?

When it comes to fitting on the roof, there are two reasons why you need either a drape or else the space created by a counter batten: firstly any water that does get through the tiles has to be able to run down to the eaves, and secondly there needs to be sufficient ventilated space under the tiles, as it’s this air movement that actually pulls the moisture created inside the house through the membrane and prevents it accumulating and condensing in the rafter space.

But if you want to put tile battens directly over a draped product then you have to make sure that the tile battens are able to compress it enough to hold it securely, and use nails that are long enough in accordance with BS5534. TLX Gold compresses down to 3mm to allow this. In between the tile battens the product is full thickness, thereby reducing the thermal bridging.

TLX Gold insulating breathable membrane draped

To make sure that the layers making up the product don’t simply fall apart when you cut it – a nightmare on a windy roof! - the outers are ultrasonically welded and the inner layers are glued.

The over lap flap and integrated tape will definately make the job easier

But that’s not all. How do you ensure that there is not a gap in the continuity of the insulation thickness?  Or conversely, that you don’t have a double thickness of insulation that is impossible to batten down. The answer is to add an extra lap of the breather membrane (that forms the upper surface) all down one edge so it can lap over the next roll down. To make it fool proof there is an integral strip of adhesive tape on this lower edge that mates with a matching tape on the upper edge of the next roll down.

But what makes TLX Gold unique is the patented gold under layer. The shiny surface reflects radiated heat back into the building, increasing the thermal performance, and even though it appears completely smooth, moisture is able to pass through it.

So counter batten or not? the choice is yours.

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