Warm Roof Insulation


What is the Part L Regulation?

Part L is the section of the Building Regulations relating to thermal efficiency standards and affects insulation and heat loss. The Part L Regulation is renowned for being a complex set of requirements, particularly with the amount of revisions it has seen over the past six years.

The 2013 changes will be the third of four planned revisions between 2007 and 2016 to help implement the zero carbon homes standard for which Government has committed to.

The 2013 amendments to Part L contain three key changes: Energy Performance Certificates, major renovation of existing buildings and the analysis of high-efficiency alternative systems. The latter are the two most significant changes for contractors.

Some commonly asked questions regarding Part L 2013

What happens if a roof doesn't comply?

If you view various web sites such as NRFC or CompetentRoofer they state you, the contractor or both can be fined up to £5000.00. I personally do not believe any such fines will ever be issued and these comments could be viewed as scare mongering, although this cannot be guaranteed and governing bodies as reputable as the NRFC would not make this statement if we’re not true. The fact is there are many 1000’s of roofs have been installed and are none compliant due to the total confusion of the Regulation. The time has come to be compliant as the problem will arise when a property is sold and the relevant paper work is not in place. It could be like trying to sell a property without a Fensa certificate for double glazing.

Can the Part L Regulation be avoided?

No, any avoidance is at the property owners own risk, although if you have the roof surface overlaid the roof does not have to comply.

Do I have to insulate my roof?

In the Part L document page 23 states if there is 100mm of fibre type insulation i.e. a Rockwool type product (or an equivalent resistance) and if it undamaged and is not being removed as part of the work the roof will comply. The homeowner can opt out if it can be proved that the payback period will be more than 15 years or the work is not technically feasible.

Helping you make the right choice

Major renovation of existing buildings.

This is probably the most significant change to Part L for roofing contractors. The amendments give clarification on the major renovation of existing buildings and how much of a ‘thermal element’ must meet the Part L requirements when it is being replaced or renovated. For the purposes of Part L, a thermal element is a roof, wall or floor which separates a heated dwelling from the outside. Any unheated part of a building is exempt from Building Regulations.

The importance of Ventilation Solutions

The risk of condensation can increase with the use of insulation, so to avoid any condensation due consideration should be made to ensure compliance with BS 5250 (Code of practice for the control of condensation in buildings).

The 2013 Amendments

Any renovation that accounts for either 25% or more of the total building envelope or over 50% of an element’s surface means the renovation of the whole element must comply with Part L thermal requirements. For example, if more than 50% of the existing roof is being repaired or removed then the insulation for the whole roof needs to improve on the relevant U-Value as stated in the Part L requirements.

There has been a lot of confusion about what types of renovation need approval under the existing Part L regulations. So to clarify this, renovation of a thermal element can mean: – Adding a new layer, i.e. cladding or rendering an external wall – Replacing existing layers, i.e. stripping down a roof to rafter level and replacing the tiles, taking cladding off a wall down to brick or block work and then re-cladding and replacing the waterproof membrane on a flat roof. So if a contractor is renovating or replacing more than 50% of a thermal element Part L compliance will be required.


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Guaranteed for Life

High-Tech Membrane Roofing Ltd offers a rock-solid unique LIFETIME guarantee. Our guarantee carries a 25-year full product and labour warranty fully transferable on request should the property be sold; the guarantee can be reassigned to the new property owners and will expire at the end of the 25-year term.

For all our clients who remain in their property at the end of the 25-year period, the guarantee will automatically extend and stay in force until the property is either sold or passed on allowing the guarantee to extend to a LIFETIME term.


Our Guarantee is part underwritten with a HomePro insurance policy. This offers a total piece of mind that in the unlikely event High-Tech were unable to honour our guarantee HomePro will take over all guaranteed liabilities.

The HomePro Value Plus will be purchased on your behalf. Being it is a fully paid-up underwritten policy will mean under no circumstances can the policy ever lapse. Please note the insurance industry are consistently changing guarantee periods. At the moment of time of writing the maximum period of time available for a paid-up policy is ten years


High-Tech are members of many consumer protection associations and approved installers. We have been members of the following associations for many years and have an unblemished trading track record.

We are members of the CompetentRoofer scheme, Full members of the National Federation of Roofing Contractors, A Fair Trades quality assured & trustworthy company, HomePro Endorsed, Trust A Trader, Check A Trade, Protan licenced installers, Sarnafil assured and Danosa registered suppliers and installers. The Protan and Sarnafil single-ply flat roofing membranes carry a 40-year BBA life expectancy certificate.