The Government is introducing new building regulations requirements in June 2022 as follows: -
New dwellings - Full Plan and Building Notice submissions after 15th June 2022 or previously submitted and not started by 15th June 2023:
Approved Document Part F: Ventilation - Requirements revised.
Approved Document Part L: Conservation of fuel and power - Requirements revised.
Approved Document Part O - New requirements considering overheating.
Approved Document Part S - New requirements requiring electric car charging points.
Extensions and alteration Full Plan and Building Notice submissions after 15th June 2022 or previously submitted and not started by 15th June 2023:
Approved Document Part F: Ventilation - Requirements revised. (Including replacement windows)
Approved Document Part L: Conservation of fuel and power - Requirements revised. (including new U-values)
To assist with new Part L requirements, please see the following guide:
Part L Insulation Guide – Dwellings 2022
(K. value in brackets)
Floors - 0.18W/m²K (P/A = 0.5 - 1.0)
Concrete slab
- 120 - 150mm Jabfloor HP 70/100 (0.032)
- 150 - 200mm Jabfloor 70 (0.038)
- 90 - 100mm PIR insulation (0.022)
Beam & Block
- 120 -150mm Jabfloor HP 70/100 (0.032)
- 150 – 200mm Jabfloor 70 (0.038)
- 90mm – 100mm PIR (0.022)
Timber suspended (joists@400c/cs)
- 200mm Glass fibre slab (0.035)
- 130 - 150mm PIR (0.022)
Walls - 0.18W/m²K
Dense Block or Brick, Cavity, Aerated (0.15-0.24) Block (Inner)
- 100 mm Dritherm 37 batts (0.037) (+ 62.5mm Insulated Plasterboard on dabs)
- 100mm Dritherm 32 batts (0.032) (+ 52.5mm Insulated Plasterboard on dabs)
- 150mm Dritherm 32 batts (0.032) (Wet plaster)
- 100mm PIR (0.022) (with 50mm clear cavity)
Block, Cavity, Block (Aerated 0.15-0.24)
- 100 mm Dritherm 32 batts (0.032) (+ 32.5mm Insulated Plasterboard on dabs)
- 150mm Dritherm 37 batts (0.037) (Wet plaster)
- 85mm PIR (0.022) (with 50mm clear cavity)
Medium Dense Block, Cavity, Medium Dense Block
- 180mm Dritherm 37 batts (0.037) (Wet plaster)
- 100mm PIR (0.022) (with 50mm clear cavity)
Brick, Cavity, Studwork
- 100mm stud regularised -> 90mm PIR (0.022) (between) + 40mm (internal)
- 150mm stud regularised -> 110mm PIR (0.022) (between) + 25mm (internal)
Solid blockwork (Aerated)
- 215 mm thermal blocks (0.11)
- 70mm PIR (0.022) (On battens, + Plasterboard)
- (52.5mm on dot and dab only achieves a max of 0.30W/m²K)
- 265 mm thermal blocks (0.11) (reduce PIR by 10mm)
Solid brickwork (215 mm)
• 100mm PIR (0.022) (On battens, + Plasterboard)
Timber walls (studs @, 400c/cs)
Tile hung, or render on ply
150mm studs regularised
- 140 mm Dritherm 37 (0.037) (Between studs)
- +50mm PIR (0.022) (Over studs)
- 110mm PIR (0.022) (between) + 25mm (to internal face)
100mm studs regularised
- 90mm Dritherm 37 (0.037) (Between studs)
- + 70mm PIR (0.022) (Over studs)
- 90mm PIR (0.022) (between) + 40mm (to internal face)
Roofs (joists/rafters @, 400c/cs)
Flat roof - 0.15W/m²K
Warm Deck (Insulate Perimeter)
- 150mm PIR (0.022) (Includes 6mm ply)
Cold Deck (Allow 50mm airflow above insulation)
- 150 + 25mm PIR (Between and under joists)
- 120 + 40mm PIR “
- 100 + 50mm PIR “
Pitch roof (@400 c/cs)
Insulation at ceiling level - 0.15 W/m²K
(Between and over joists)
- 150mm x2 (300mm) Fibre glass (0.044)
- 150mm PIR (0.022) (between) 40mm PIR (0.022) (over joists)
Insulation at rafter level 0.15W/m²K
- 215mm PIR (0.022) (Between rafters)
- 140 mm PIR (Between) + 40mm PIR (under)
- 120mm PIR (Between) + 50mm PIR “
- 100mm PIR (Between) + 60mm PIR “
- 90mm PIR (Between) + 70mm PIR “
- 75mm PIR (Between) + 75mm PIR “
- 50mm PIR (Between) + 90mm PIR “
(*** At 600c/cs, insulation can be reduced a little***)
Note. This information is produced as an 'on-site' guide and manufacturers data should be used where possible.