DIY Doctor UK DIY Forums

Hi,

I'm planning on building a summer house. I want to know the best way of insulating the walls. I'm currently planning to make the external walls from external shiplap - to be painted - fixed onto a studwork wall, with internal shiplap. What would be the best way of insulating this? My first thoughts are polythene between external wood and studwork, and then mineral wool.

Any help is appreciated.

Many thanks

If you build using ship lap, the summerhouse will be full of holes and impossible to keep warm as, the passing wind will suck all the heat out.
A plastic membrane will not stop heat escaping.
To create a warm summerhouse you need to cover the frame in waterproof plywood making sure to avoid leaving any holes, then fit the ship lap as a cosmetic finish.
The best insulation is polystyrene or similar, as this is composed of masses of tiny balls of air each surrounded by a thin plastic skin. It is the size of the plastic balls and the air inside that provide the insulation.
The insulation needs to be fitted carefully as once again holes equal heat loss.
The thicker the polystyrene the better the insulation - you should not need to exceed five inches.