5 minute read
- Retrofitting insulation to improve energy efficiency is a tough task. Particularly when you have an old, listed building in desperate need of an upgrade
- What to do with an old roof protected by listed status œ TLX Gold 2-in-1 insulating breathable membrane has the answers¦
- TLX Gold can reduce radiant heat lost through the roof by up to 86%
When it comes to upgrading insulation in line with current building regulations, councils around the UK have a tough job of ensuring an adequate level of insulation whilst maintaining a sympathetic approach to the historic nature of the buildings themselves. Such was the case for Calderdale Council. They successfully sought funding from the Public Sector Decarbonisation Scheme for thermal improvements to the roof of the historic Halifax Town Hall. Being a grade II listed 19th century building, admired for its grand interiors, sculptures and its classical sandstone exterior, it is a well-established and renowned landmark of this old market town.
A roof in disrepair
Over recent years, the roof was showing the typical signs of its age. And upon inspection of existing pitched roof area, no form of insulation was found, meaning any heat generated from the inside was quickly lost. During winter months, the complete lack of insulation made for terribly cold conditions. Therefore, a sympathetic uplift to the roof was long overdue to bring it in line with modern standards and to prepare this building for the upcoming winter. Building control require a U value of 0.18w/m k for a re-roof. Although since this is a listed building, getting the best possible insulation without altering the roofline was a comfortable compromise.
The solution for listed buildings
Although Halifax Town Hall was exempt from the target U value of 0.18w/m k, with its listed status, another stipulation is that there should be no alteration to the existing roofline. Therefore, any insulation added should fit seamlessly and require no change in roof height. TLX Gold could satisfy this requirement as it can simply drape directly over the top of the rafters. And since it compresses down to 3mm, there was no change in roof height.
2-in-1 insulating breathability œ what about condensation?
TLX Gold multifoil insulation combines a breathable membrane with insulation properties like that of a non-breathable PIR board. However, unlike PIR board, each and every layer of TLX Gold allows water vapour to escape, meaning there is no condensation risk associated with its use, even without a vapour barrier. TLX Gold is Sd intelligent. It responds to its environment, adjusting its rate of breathability according to fluctuations in humidity. When humidity increases, the permeability of TLX Gold increases to accommodate this, and similarly, when humidity decreases, the permeability decreases.
The build up:
TLX Gold was draped over the rafters, with 50mm of a breathable slab insulation in-between them and 15mm of a breathable straw-lime lining board beneath. The completed project saw the roof U value drop from 3.69w/m2k, to a U value of 0.39w/m2k, resulting in a significant reduction in heat loss.
The old-style construction made for a tricky refurbishment. Therefore the ease of installing TLX Gold was great news for the roofers. They were able to fit adjoining sections together by the help of integrated tape situated on the overlap breathable membrane flap, and since TLX Gold is so lightweight, the experienced roofers made lightwork of the installation.
Further case studies detailing the use of TLX Gold can be found HERE
