Flat Roof Insulation


Do you regularly enter your home after a long winters’ day to discover that your house is cold and unwelcoming? Alternately your home may feel as warm as a sauna during summer. What could be the issue? It is likely down to your insulation quality… or absence of it.

This can bring some disturbing issues, from the formation of condensation which, if left, can cause lasting damage, to energy bills being uncomfortably pricey. Truth be told, up to 25% of the warmth that a home loses spills through the roof space, requiring additional expenditure on the heating in your home.

Flat roof insulation is used to augment a building's energy proficiency and limit heat dissipation. Insulating a flat roof can prompt lower energy use, a reduction in condensation, and a reduction in related household bills.

What is flat roof insulation?how to use a multifoil in a flat roof

A flat roof is characterised as any roof that has a pitch of under 10 degrees. By and by a flat roof is quite simple to spot. Additionally, flat roofs don't have the space that you regularly partner with pitched roofs, so, they are generally a bit trickier to insulate.

Cold Flat Roofing: The traditional flat roof system is to install insulation between and under the rafters, with a 50mm ventilated air space under the timber deck.  

Why flat roof insulation?

As warm air rises, most energy dissipations are usually through the roof. Flat roof insulation is a fundamental device that can upgrade the energy proficiency of a building and reduce energy costs. 

From skyscrapers to private plans, industrial units, business offices, schools or medical clinics, flat roofs are a fundamental feature of the current UK building stock.

This developing pattern for functional flat roof spaces brings much more interest for efficient insulation systems.

Problems with insulating a roof

What are the most common flat roofing issues?

1. Ponding

Contrasted with pitched roofs, flat roofs don't have good drainage overall, and as such, they usually create ponding water – characterised as water that stands in a puddle on a roof for prolonged periods. Therein lies the issue since it can start to weigh on the timber deck and wear it out over time. 

2. Blistering

This occurs on your flat roof when little pockets of air or moisture get caught underneath the film or in the middle of layers of film. This deteriorates when the sun warms the roof up, which causes the pockets or air or moisture to grow, extending the film.

3. Warm development

Temperature changes can cause the roofing material to grow and contract, which is standard. Be that as it may, you must watch out for your roof for proof of this, as continual extension and withdrawal can debilitate the roof and possibly cause spills. This warm development can result in it pulling away from the edges of your roof over the long haul – leaving space for spillage and moisture passage into your roof.

How Multifoil insulation can help

Multifoil insulation is a robust vapour barrier. At the point where it is situated within the roof, it stops water vapour from getting into the roof structure, removing the chance of interstitial condensation.

Water vapour pressure inside the house is more prominent than the pressure outside. Just as warmth attempts to escape from the building, as does water vapour which is carried within warm air. The fundamental instrument by which water vapour is dispensed is through adequate ventilation. Vapour will thus attempt to diffuse through the dividers and roof. However, with TLX Silver, ventilation is not required.

Condensation inside the structure of the roof, known as interstitial condensation, can have an unpleasant effect. The abundance of water can prompt mould development and even structural damage.

That is the reason TLX Silver Approved Solutions contain an investigation into the danger of interstitial condensation, calculated to BS EN ISO 13788, which shows no risk of surface or interstitial condensation.

TLX Silver multifoil insulation has reflective, intelligent outer layers to keep heat inside the building. It is also the optimum thickness of 30mm, which allows it to give the best thermal benefit without compromising on space. This is particularly important when insulating a structure that is short on internal space, given the required 50mm ventilated air layer needed beneath the timber deck.   

TLX Silver multifoil insulation is fully BBA certified, a particularly prestigious level of acknowledgement, and has LABC registered detail status.

How to acheive building regulations using a multifoil

When introducing or improving insulation in flat roof, you must follow building regulations.

Multifoil insulation will help you meet the required U-value when used in conjunction with rigid board or mineral wool. TLX Silver is particularly successful at preventing air penetrability into the rafter space by fixing to the underside of rafters. The easiest way to alter the U value of the overall structure is to alter the thickness of additional insulation.

For instance, you can meet building regulation requirements, 0.18w/m2k, with 100mm of PIR board fitted between a 180mm rafter and TLX Silver underneath the rafter, based on 400mm rafter centres. However, if the space within the rafter permits, you can reach 0.13w/m2k with 160mm of PIR between a 240mm deep rafter.

Why you can only use TLX Gold in a pitched roof

Building regulations require a minimum 50mm ventilated air layer underneath the timber deck for a flat roof system. This is vital as it shields the roof space from extreme temperature varieties which can result in the build-up of moisture.

Along these lines, the TLX Gold multifoil insulation requires an optimum 20mm unventilated air gap underneath to ensure the reflection of heat.  Water vapour doesn't require a channel to get away from the roof as it can go through the layers of the multifoil into the tile secure space above and out through the tiles. Ventilation is just required above TLX Gold where the tiles are non-breathable, to stop condensation occurring between the tiles and the upper surface of TLX Gold.

multifoil insulation flat roofOur recommendations:

Flat roof insulation will enormously affect the energy proficiency of your property. Getting the insulation right the first time will manage the long-term risk of condensation and determine a decrease in energy costs going forward.  Installing the material correctly will allow the roof structure to fulfil its projected life expectancy, which, in terms of TLX Silver, has the lifespan of the roof in which it sits.


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