Designing a weathertight garden room

When you read the Self Build Garden Room Guide and the sample plans in the Complete Guide, you will quickly realise that a garden room is made up of a series of different layers.

This is the case whichever building system you choose – traditional timber frame or (SIP’s) Structural Insulated Panels.

These layers play their part in the structural makeup of the room, but also play a significant part in making a garden room weathertight.

A well-designed garden room is made up from a series of layers which help make a garden room weathertight

On the outer side of your core structure, whether that be traditional timber frame or SIP’s, the layers are designed to stop the ingress of moisture into the building.

A breather membrane plays a key part in this build-up. The membrane wraps around the exterior and prevents moisture entering the core frame, but lets moisture escape from within the structure – in effect acting like a pair of lungs, letting it breathe.

Over the breather membrane treated battens are fixed in the opposite direction to the cladding boards. These battens lift the external cladding away from the breather membrane, which means any moisture in the cladding caused by rain etc. doesn’t penetrate directly into the core structure.

The exterior cladding plays a significant asthetic role, but it is also the first layer that protects your building. Your choice of cladding material and its thickness will play its part in it’s long term performance.