What is a warm roof construction?

Many times we get asked about warm roof constructions and how they compare with cold roofs.  This signifies a growing generation of customers who want to find new and innovative ways of conserving energy and saving money on household bills.  As more and more of us are making the use of outdoor space and adding on flat roof extensions, conservatories, man-sheds and summer houses, a warm flat roof construction can be just what is needed to keep warm, dry and insulated particularly in the winter months.

Basically, a warm roof construction is formed by placing insulation over the top of the roof structure. This means that the timber structure beneath is warm, which is why the term ‘Warm Roof ‘ is formed. This type of warm roof system is highly recommended by architects and specifiers in the UK as it avoids the need for ventilation of the roof structure. It is  also one of the easiest ways of insulating a flat roof as none of the existing roof is opened up as a rule.


Why isn't it necessary to install ventilation in a Warm Roof?

In order to avoid the need for ventilation, a continuous vapour barrier is installed in between the timber sub-deck and the insulation layer; this then prevent the movement of vapour and helps to eliminate the risk of condensation.

What is a Cold Flat Roof construction?

A Cold flat roof is where the insulation is placed between the joists under the flat roof, leaving the roof and the roof timbers cold.

Insulation and Building Regulations

Did you know that since April 2006, if you are refurbishing 50% of your roof, you are required by law to upgrade the insulation on your flat roof? This is to comply with the conservation of fuel and power in existing dwellings Part L Vol1 & 2.

Obviously, complying with these regulations comes with additional costs as scaffolding is normally required and costs for additional or new insulation.

To help you with these extra costs, the government had set up an incentive scheme to help homeowners meet their CO2 emissions targets. Previously they had reduced the amount of VAT you have to pay from 20% to 5% which was a huge saving. This also applied to any other work required as a result of your insulation upgrade. However, now a house extension warm flat roof with new fascia boards, guttering, roof covering and insulation is zero rated for VAT in an effort to encourage more households to install environmentally friendly energy systems, at a time when bills are reaching all-time highs.

The cost saving for a warm roof could be significant, and depending on the size of your flat roof you could save around £300.00 in heating costs each year.

New Warm GRP flat roof system

R&D’s Eco Warm roof upgrade

R&D’s warm roof upgrade is suitable for all the roof systems we offer. The continuous overlay of thermal roof insulation which we install, will help to reduce any cold bridging, or to put it in simpler terms can reduce any pockets of heat leakage.  As a result of its insulating qualities, it can be an ideal solution for your roof, and can be overlayed on your existing roof, provided that the timber structure is sound.

Some of our key points:

  • In order to achieve the U-Value required and avoid the risk of interstitial condensation, we use 120mm PIR insulation boards along with the required vapour barrier
  • R&D Roofing fit either an EPDM rubber flat roof system or a GRP Fibreglass system. Both of these come with a 20 year guarantee and a much longer lifespan.

Warm Roof Construction

Warm roof construction
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Find out how much a warm flat roof might cost you…