One of the UK's leading Spray Foam Insulation Specialists

Freephone: 0800 048 3348 Call Local: 01472 565 070

Call Locally On Mobile 01472 306 270

Skip to content
technical-overview

Technical Overview

The Best Product, The Best Service, The Best Price

Permaseal are an accredited installer of Duratherm which holds BBA Accreditation no 10/4771 in respect of our materials supplier Isothane Ltd.

SAVE as much as

40%off your heating bill

Contact us & start saving »
BBA Logo

Permaseal UK Ltd is an accredited installer of Duratherm which holds BBA Accreditation No. 10/4471 in respect of our materials supplier, Isothane Ltd.

Technical Overview

Failure to stop the flow of air through the home, office or factory envelope means that new air is constantly infiltrating the space and will require re-heating. Research conducted in America indicates that as much as 40% of the energy wasted in each home is caused by air infiltration, but by ensuring you minimise areas where air can enter will help to keep your energy costs down as the air won't need re-heating as often.

Permaseal's spray foam roof insulation can help you achieve this by upgrading the thermal performance of your roof. Principally used as a stabilisation medium on pitched roofs, it forms a seamless weatherproof barrier stopping wind, driven rain, snow and dust. It contains no nutritive value and will prevent access to vermin and birds. Humidity, moisture and condensation have virtually no effect on the sprayed polyurethane foam, which results in a cooler environment in summer and a warmer environment in winter.

Technical Specifications

The polyurethane spray foam is a 2 compound system comprising of isocyanate and resin in equal amounts. It is a 90% closed cell, spray applied semi-rigid polyurethane foam system. Sprayed polyurethane foam sets and expands within seconds of being sprayed and cures as rigid foam within 24 hours of installation. It is suitable for both internal and external roof applications and meets Part L of the Building Regulation Standards. The spray foam is HCFC and CFC free, has zero ozone depletion potential and has been tested in accordance with BS 476: Part 7: 1997 in relation to the spread of fire and has been categorised as Class 1. The application has a service temperature range of -15°C to 70°C. The Pirthane system is the only spray foam product currently available providing for a Class '0' (Zero) Surface Spray of Flame. It is installed in areas where the general public congregate, i.e. Shopping Centres, Libraries, Museums and any other buildings used regularly by members of the public. It has a Class '0' surface spread of flame so is entirely suitable for interior applications, and is the only spray foam application which has been developed to be coated with a compatible intumescent (fire retardant) coating. The foam, along with the coating, provides for an exceptional fire retardant barrier meeting every specification required by Architects and Council Planning Departments.

Typical U values

"U" Factor indicates the level of "U" Loss, which is essentially how much heat is escaping through your roof. A lower "U" Value means a reduction of heat loss, and so usually the thicker the foam the better the "U" Value. See indicative "U" Value analysis below: 75mm offers a "U" value of .34 100mm offers a "U" value of .24 125mm offers a "U" value of .2 (minimum requirement for New Build and similar developments) 150mm offers a "U" value of .16 The insulation materials detailed below indicates a comparison increase when compared to a foam thickness of 40mm. Polystyrene 64mm (60%) Mineral Fibre 72mm (80%) Cork 80mm (100%) Cellular Glass 88mm (120%) If the depth of the normal foam is 40mm you would need to combine other materials such as polyester, mineral fibre, cork and cellular glass, to increase the ā€œUā€ Factor and give the desired level of insulation. However there would be no adhesion or increase to the stability of the roof and it would be much more complicated and take longer to install. Compare this with an application of residential spray foam which is normally completed on the same day and will cause the least amount of disruption possible and has a number of distinct advantages.

Moisture in Roof Timbers

Concerns and reservations about the product are often centred on the potential problems of water retention on the load bearing roof rafters that are partly encapsulated within the foam. These concerns are completely unfounded and have no scientific basis. On an average roof rafter measuring 100m x 75mm, 35% of the surface area is left exposed. This, coupled with the fact that the polyurethane spray foam has the same ability to breathe as timber, results in no greater amount of moisture being transferred into the timbers once the installation has taken place.

Technical Specifications

The polyurethane spray foam is a 2 compound system comprising of isocyanate and resin in equal amounts. It is a 90% closed cell, spray applied semi-rigid polyurethane foam system. Sprayed polyurethane foam sets and expands within seconds of being sprayed and cures as rigid foam within 24 hours of installation. It is suitable for both internal and external roof applications and meets Part L of the Building Regulation Standards.

The spray foam is HCFC and CFC free, has zero ozone depletion potential and has been tested in accordance with BS 476: Part 7: 1997 in relation to the spread of fire and has been categorised as Class 1.

The application has a service temperature range of -15°C to 70°C.

The Pirthane system is the only spray foam product currently available providing for a Class '0' (Zero) Surface Spray of Flame. It is installed in areas where the general public congregate, i.e. Shopping Centres, Libraries, Museums and any other buildings used regularly by members of the public.

It has a Class '0' surface spread of flame so is entirely suitable for interior applications, and is the only spray foam application which has been developed to be coated with a compatible intumescent (fire retardant) coating. The foam, along with the coating, provides for an exceptional fire retardant barrier meeting every specification required by Architects and Council Planning Departments.

Typical U values

"U" Factor indicates the level of "U" Loss, which is essentially how much heat is escaping through your roof. A lower "U" Value means a reduction of heat loss, and so usually the thicker the foam the better the "U" Value. See indicative "U" Value analysis below:

  • 75mm offers a "U" value of .34
  • 100mm offers a "U" value of .24
  • 125mm offers a "U" value of .2 (minimum requirement for New Build and similar developments)
  • 150mm offers a "U" value of .16

The insulation materials detailed below indicates a comparison increase when compared to a foam thickness of 40mm.

  • Polystyrene 64mm (60%)
  • Mineral Fibre 72mm (80%)
  • Cork 80mm (100%)
  • Cellular Glass 88mm (120%)

If the depth of the normal foam is 40mm you would need to combine other materials such as polyester, mineral fibre, cork and cellular glass, to increase the "U" Factor and give the desired level of insulation. However there would be no adhesion or increase to the stability of the roof and it would be much more complicated and take longer to install.

Compare this with an application of residential spray foam which is normally completed on the same day and will cause the least amount of disruption possible and has a number of distinct advantages.

Moisture in Roof Timbers

Concerns and reservations about the product are often centred on the potential problems of water retention on the load bearing roof rafters that are partly encapsulated within the foam. These concerns are completely unfounded and have no scientific basis. On an average roof rafter measuring 100m x 75mm, 35% of the surface area is left exposed. This, coupled with the fact that the polyurethane spray foam has the same ability to breathe as timber, results in no greater amount of moisture being transferred into the timbers once the installation has taken place.

There has never been a reported incident, during the last 40 years, of a foamed roof collapsing due to timber rot.

Contact Us Want some advice from one of our friendly staff? Call 0800 048 3348 01472 306 270

Contact Us Want some advice from one of our friendly staff? Freephone: 0800 048 3348 Mobile Friendly: 01472 565 070