Loft insulation & Loft Conversions

Loft Insulation

Loft insulation & loft conversionsThe loft space can be insulated, either by insulating the floor of the loft or underneath the rafters. A layer of Insulation at rafter level keeps the loft void warmer and prevents the build-up of condensation.


  • High Insulation values
  • Prevents condensation: complies with Approved Document F ‘Alternative Approach’ for non-ventilated roofs. Calculations are made using the method in BSEN ISO 13788:2002 (and BS 5250 Appendix D): Code of Practice for Control of Condensation in Buildings

Your chosen installer will perform a survey prior to installation to check suitability, i.e. the roof should be structurally sound with any defects resolved prior to installation.

Loft conversions

PU foam is used in loft conversions to provide a seamless layer of Insulation, fill voids and provide exceptional levels of energy efficiency.

Loft conversions have to meet the 2006 Building Regulations amended Part L with a U-value of 0.18W/m2K; as well as The Building (Scotland) Regulations 6.1(b) and 6.2; The Building Regulations (Northern Ireland) 39(a)(i) and 40(2). This is simple to achieve with the application of PU foam by applying 150mm of PU insulant. Where there is insufficient depth PU foam can be used in conjunction with other Insulation systems such as multi-foils or polyurethane boards over the face of the rafters.

Foil-faced plasterboard is recommended to increase the water vapour resistance on the warm side of the Insulation and to provide a low emissivity for better thermal performance.


  • Provides structural stability to the roof (preventing ingress of rain, snow, storm damage)
  • High performance, versatile material suitable for filling voids
  • Air leakage is eliminated
  • There is no requirement for a ventilated air gap


  • Rafter Insulation – this can be plastered over in loft conversions
  • Wall Insulation
  • Floor Insulation
  • Void Insulation

BUFCA installers will check the roof for suitability prior to installation – any defects should be rectified prior to installation.