Roof Insulation

For Your Loft Conversion

The good news is that the technology surrounding insulation materials and their installation has improved massively in recent years.

The bad old days of having to use awful fibreglass rolls (see picture) are long gone and highly efficient rigid foam insulation boards are now the norm.

Because of the nature of loft conversions and the size of a typical roof space it is essential to keep the thickness of the insulation material to a minimum whilst still achieving maximum efficiency.

And rigid foam insulation boards that are faced with foil and usually supplied as a 2400x1200mm sheet are ideal for this.

Another material that has been used extensively for roof insulation is expanded polystyrene. These white boards though do not perform as well as their foam counterparts.

As a result double the thickness would be needed which is obviously a waste of space that cannot be accommodated in a modern loft conversion.

Multifoil sheets have been very popular amongst builders as the material is only 30mm thick.

There is some debate about whether or not multifoils are as efficient as the manufacturers claim and the material is not allowed by some local building control officers.

The situation is complicated though because some BCOs will accept a building regulations application that specifies the use of multifoils.

The only advice here is to check with the building control office before deciding to use the material.

When deciding which material to use one of the important factors to take into account is the heat conductivity value. The basic rule to remember here is that the lower the conductivity value the better the performance and the less thickness required.

Some typical conductivity values are:

Polyisocyanurate 0.017 – 0.021Phenolic 0.020 – 0.027Polyurethane 0.021 – 0.027Polystyrene 0.033

The lower end (and best) of the scale is achieved with foil facing on the boards.

The Polyisocyanurate rigid foam boards are very popular with builders and seem to the roof insulation material of choice at the moment.

For more info see the related pages below or complete the form at the bottom of the page for a free no obligation quote from tradesmen near you for your loft conversion project...

Boarding A Loft With Chipboard

Foil Roof Insulation

Insulating A Loft Hatch

Loft Insulation

Loft Conversion