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Insulation for Loft Conversions

High performance PIR thermal insulation for loft conversions.

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The conversion of an existing loft space comes with a range of insulation challenges that must be considered when specifying insulating materials, such as the safety requirements of additional loads being laden on existing ceiling joists. Another consideration is to ensure loft conversions comply with the energy efficiency sections of building regulations. 

That means finding an insulation solution that achieves the necessary thermal efficiency in the pitched roof without encroaching on the available head height.

What Celotex products are suitable for loft conversions?

Celotex GA4000 is a high performance, rigid polyisocyanurate (PIR) insulation board with aluminium foil facings both sides. PL4000 is a composite product, featuring the same thermal insulation bonded to 12.5mm tapered edge plasterboard.

Both offer a low thermal conductivity, which keeps thicknesses to a minimum while achieving necessary performance targets. Together, they can provide the complete solution for the pitched roof and vertical stud walls of almost any loft conversion project, giving the following benefits:

  • Create additional, highly thermal efficient living space.
  • Reliable long term energy and cost savings.
  • Loft conversions deliver multiple energy efficient measures within one project.

GA4000 is lightweight and easy to cut, allowing it to be installed precisely and tightly fitted between timber rafters and timber stud walls. To compensate for the thermal bridging effect of the timber, a layer of PL4000 fixed over the internal face of the rafters and stud walls provides a continuous insulation layer that is so important to efficient building performance.
The plasterboard facing of the PL4000 gives an internal lining, installed in one operation with the insulation, ready for finishing and decoration.

Can I use Celotex insulation for loft storage?

A loft that is unsuitable for new living space could be used to provide extra storage space. While not technically a loft conversion, creating a space that achieves the best combination of thermal performance and practicality is important.

General-purpose boards like GA4000 and Celotex XR4000 can be laid over the ceiling joists, with boarding installed over them. Unlike the mineral wool loft roll that is usually installed in the ceiling, rigid PIR boards will not compress and lose their thermal performance, making them the ideal solution for upgrading the thermal efficiency of the ceiling while giving a suitable surface for storage and occasional access.


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Celotex products to consider

1200 x 2400mm
0.022 W/mK

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1200 x 2400mm
0.022 W/mK

Application Image Thumb View Product

1200 x 2400mm
0.022 W/mK

Application Image Thumb View Product

1200 x 2400mm
0.022 W/mK

Application Image Thumb View Product