The TLX Sandwich!

The TLX Sandwich!

The problem?

How to achieve U = 0.13 W/m2K using Mineral Wool rather than PIR?

With a new build spec of 220mm deep rafters at 600mm centres, achieving a U value for the roof insulation of 0.13 W/m2K shouldn’t have been a problem. The TLX Approved Solutions Guide indicated that the most appropriate build up was to use TLX Gold taut and counter battened with 170mm PIR between the rafters.

So how was it done?

To put the sarking board under the rafters instead – so that the 170mm PIR solution became possible.

But then came the PIR shortage, and there was no rigid board insulation to be had from the local merchants - only mineral wool! There seemed to be no options left that would avoid an unacceptable delay to the project. But by fitting TLX Silver under the OSB, with battens each side creating air gaps, and with the TLX Gold over the rafters and 160mm 0.035 W/mK mineral wool between, 0.13 W/m2K was achieved.

TLX Gold served as the breather membrane and also prevented interstitial condensation occurring, and TLX Silver provided the vapour barrier on the warm side. Result: a low U Value TLX sandwich using mineral wool.

The Solution:

Using TLX Silver & Gold together as a combined insulation system.

For Technical advice on this solution - and more, call us on 01204 674730

Or to view our Approved Solutions Technical Guide - click: Here