Worsley is a leafy suburb on the outskirts of Greater Manchester that shows little trace of the activities that made it a centre of the Industrial Revolution on the Bridgwater Canal. A new development of 24 houses in the area aimed to offer good value family accommodation. And the insulation buildup chosen had to achieve the required U value, yet also make economic sense.
The problem: how to provide a value build up that will achieve U=0.18, yet keep the room-in-roof cool in summer?
The building has trussed rafters 200mm deep at 600mm centres. So, the solution was to use 150mm of mineral wool with multifoil insulation below. It was secured with a 38mm deep batten to create an unventilated air gap. Across this, heat reflects back, giving a U value of 0.18 W/m ²K.
Using mineral wool rather than PIR board makes for a cheaper solution. Plus it has benefits in terms of fire resistance and sound insulation. If lower U values were required by the SAP calculation, then in 200mm deep rafters 175mm of 0.035 W/mK grade wool would achieve 0.16, and in 225mm deep rafters 0.15 can be reached.
TLX Silver also offers the benefit of being an excellent vapour control layer and providing airtightness. Although its shiny surface reflects heat back into the building, itâₒs often overlooked that such a low emissivity surface also does not radiate heat – even though heatwaves are a relatively rare occurrence in the North-West! TLX Silver is able to reduce the amount of heat entering. This is a welcomed a benefit in summer when rooms in the roof are prone to overheating.
Adding a layer of TLX Silver to the inner face of timber frame walls can make a big difference to the U value, as well as providing a useful service cavity and functioning as the vapour control layer. Added value indeed!
The solution: TLX Silver offers a cost-effective solution when used with mineral wool. It minimises solar heat gain, plus acts as a vapour barrier as well.
