Flat Roof Insulation from Roof Technology

Flat Roof Insulation

Install flat roof insulation onto your existing flat roof and don’t pay any VAT on the entire project! Call us now for more information on 0118 9455511.

Upgrading the Insulation on an Existing Flat Roofs

We all know that flat roofs are notoriously renowned for the loss of heat. With Roof Technology’s mechanically fixed & bonded insulation products, we are able to insulate your flat roof to current Building Regs standards.

If you have a heated room below your flat roof, then you will want to have adequate insulation, otherwise the room below will be difficult and costly to keep warm. It is difficult to tell how much insulation there is in an existing flat roof just by looking, but if it was built before 2000 then there probably isn’t enough.


Your flat roof should have a layer of insulation built into the structure at some level. When an insulated roof is built, the insulation layer can be included at different levels within the structure. The roof may be described as “warm roof” or “cold roof” depending on whether the insulation is above or below the main roof deck.

Adding insulation to an existing flat roof sometimes requires the removal and replacement of some part of the existing structure. It is also important to carry out any insulation work in a way that minimises any risk of condensation building up within the roof structure. ”A warm roof" solution is the simplest way improve the insulation on your roof, and elevate condensation (subject to roof design)

Improving flat roof insulation is most often carried out when some part of the roof needs to be replaced for other reasons – for example, when the weatherproof layer has started to leak. However, it is possible to insulate a flat roof at any time, Roof Technology products enable insulation to be quickly with minimal disruption.

In most cases if your roof deck is in good condition (assessed by a pull out test or core test) we are able insulate your roof without the disruption of removing the existing water proof cover saving you money & reducing the amount of waste going to landfill.

This process will give you a flat roof that will be insulated to current Building Regs standards, and a new roof cover that has a manufacturers guarantee of 20 years.

When you improve the insulation on your flat roof the entire project will be VAT exempt.

Building Regulations

In April 2006 the Government of England and Wales implemented changes to Building Regulations Approved Document L (Conservation of fuel and power). These revisions have a significant affect on homeowners and domestic roofing contractors. 

The regulations were changed to implement the EU Energy Performance of Buildings Directive (EPBD), which aims to reduce energy use in domestic buildings by 20% compared to the 2002 regulations. 

There are essentially two designs used in the construction of a flat roof to include insulation. 

Cold deck (fig 1) 

This is the most common construction and can be the least thermally efficient. This roof design can also be prone to the manifestation of condensation within the roof void. From the room ceiling up the build is as follows: the ceiling is attached to the roof joists that support the roof construction. A polyethylene vapour barrier is laid into the roof void and mineral insulation is loose laid between the rafters. The roof deck is then fixed to the rafters and the water proof membrane is then installed. In some cases this construction may have to be ventilated to avoid condensation.

Flat Roof Insulation Cold Deck

Flat roof cold deck

Warm deck (fig 2) 

This is the most modern method of construction and should be used were possible (although not all situations are able to accommodate this design). 

From the room ceiling up the construction is as follows: The roof joists support the roof construction the internal ceiling is attached to these. On top of the joists the roof deck is fixed. A vapour barrier is laid on to the deck and the appropriate thickness of insulation is fixed to the roof deck. The waterproof roof cover is then installed. 

This method of insulating the roof alleviates the formation of condensation in the roof void, and complies with the current building regulation.

Flat Roof Insulation Warm Deck

Flat roof warm deck

OPTIM-R Roofing System 

Roof Technology are experienced installers of the next generation of insulation products for flat roofing 

Kingspan OPTIM-R is a rigid vacuum insulation panel, encased and sealed in a thin, gas-tight envelope, giving outstanding thermal conductivity and the thinnest possible solution for flat roofing insulation. Ideal for situations where low u values are required, & design constraints mean that insulation depth is an issue. 

Kingspan OPTIM-R Roofing System provides an insulating performance that is up to five times better than other insulation materials. 

OPTIM-R installation is specifically designed for each installation. 

The vacuum insulated panels are installed with rigid thermoset (PIR) insulation infill panels which can be cut to fit around problem areas such as roof lights or ventilator kerbs. 

The Kingspan OPTIM-R Roofing System is designed for use where there is a requirement for low U-values and the thinnest possible roof build-up. It is particularly suited for applications where there may be little space for installing new roof insulation, for example in buildings with planning height restrictions, terraces, balconies & flat roofs with low window thresholds. 

Roof Technology are able to provide design & costs for any application where these high preforming products might be of benefit.

What Our Customers Say...
  • Great service from the start, very efficient and professional. The finished product was far better than we had imagined

    Mr & Mrs Peters

  • The installers were extremely polite, very tidy and efficient. Pleasure to do business with them

    Mr P Rostron

  • Good work and courtesy. Quality to be tested during next stormy and rainy season, as well as next autumn & winter

    Mr Erbolat

  • The team working on site were courteous and professional, also very patient and conscientious with the very fiddly bits.

    Claire, Oxfordshire

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