4 Minute read
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Renovating a grade II listed building will always come with a particular set of challenges, we detail how to overcome some of these using TLX Gold
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Whilst achieving a particular u value in such a project is not necessarily a priority, we advise how you can achieve the lowest possible
A building in disrepair
Uninhabited for many years, this grade II listed farmhouse building had fallen into a state of disrepair. So much so that most of the original roof had collapsed. The new owners realised the extent of the work needed to bring the home back into a habitable condition. So they called upon a trusted, local architect to find a solution which would re-invigorate the dwelling. They also needed a greater level of insulation, bringing the old building more in line with modern standards.
Experienced in the field, the architect on the job was keen to find a product that would maintain a high level of insulation. Preventing condensation risk was paramount to avoid any further unwanted structural damage. Our 2-in-1 insulating breathable membrane, TLX Gold, was the product of choice.
Achieving the required U value
As a single layer draped over rafters, TLX Gold used on its own achieves a U value of 0.69w/m2k. Considering a completely uninsulated roof has a U value of 3.67w/m2k, this is a massive energy saving. However, insulation requirements have tightened over the years. And the local building control advised a U value of 0.35w/m2k was required. So, our technical team stepped in to calculate the most effective way of achieving the stipulated standard. Add 50mm of PIR board in-between the rafters with TLX Gold draped over to achieve 0.33w/m2k. This solution satisfied building regulations for a listed building.
More than just an insulating breathable membrane
There was scope to install additional insulation between the rafters, but not underneath. This is because the client would like to see more of the roof structure inside the finished room spaces. Any compromise on the character needed to be minimal, if at all. Since the rafters were 100mm deep, there was more than enough space between them. TLX Gold was fitted, plus 50mm of PIR board. Given its listed status, the roof couldn’t be raised. But using TLX Gold simply draped over the rafters requires no change in roof height. Tile battens and tiles were added simply above the layer of TLX Gold, meaning the roof didn’t need to be raised at all.
Managing Condensation risk
TLX Gold multifoil insulation has a shiny, breathable under surface reflects heat. Therefore, the roofers could maintain an unventilated air layer beneath it. Trap a layer of warm air between TLX and PIR board to enhance the insulation profile. TLX Gold manages condensation risk effectively as it is fully breathable. So any moisture carried in the air can easily escape through the roof space. It has Sd intelligence, meaning that it adjusts its rate of breathability according to fluctuations in internal humidity. ‘ Essentially, the more vapour in the air, the more it breathes. You require no additional vapour barrier beneath the rafters.
Space Saving Multifoil Insulation
TLX Gold provided a great space saving solution by performing 2 jobs in 1. It successfully manages condensation risk, so there was no need for a vapour barrier under the rafters. Therefore, the homeowners could maintain the character of the building. Plus they could limit the insulation profile whilst achieving fantastic thermal benefit. This roof will benefit in the short and long term, since TLX Gold has a lifespan of the roof of which it is a part. Plus, the thermal energy saving benefit will translate to savings on energy bills through colder months.
