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Insulated Garden Rooms

Cosy Garden Rooms have a construction method that is similar to the way timber frame houses are made.  The insulation in our garden rooms works as follows:

Foundation and Floor

  • Minimum 100mm (4") concrete foundation with 2 dampproof membranes

  • 25mm silver backed solid foam insulation over the entire floor area - no cold spots

  • 18mm floor boards 

  • 8mm click-lock flooring

  • Total of 150mm minimum from the ground with layers of insulation


Cosy Garden Rooms have a unique 5 layer wall system of fibre board, cavity, insulation, OSB cladding and weatherproof exterior boarding.

  • Starting from the inside, 8mm MDF wall board (good insulation levels as packed fibres and small air pockets in comparison to cold mineral based plaster board), grooved or plain with optional additional feature walls for additional insulation for heat and sound proofing

  • 90mm building framework with 50mm silver backed solid foam insulation boards and a cavity (which is also a great insulation layer) where the building wiring and recessed electrical back boxes are fitted

  • 18mm OSB (Oriented Strand Board) which is a structural wood panel, providing strength, additional insulation and security

  • Breathable membrane to allow moisture away from the building, whilst keeping external moisture away

  • External cladding in a range of options


  • From the inside, the ceiling is plain MDF board with the benefits of being a warmer, more insulative board in comparison to cold to touch mineral based plasterboard

  • Minimum of 100mm rockwool insulation in the roof framework

  • 18mm OSB boarding on the outside

  • EDPM rubber roof

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