Porch Insulation

Driftwood

Hi there, I am in the process of building a brick porch with a 50mm cavity. I cannot decide whether to put a thin layer of insulation board in the cavity, whilst maintaining a small gap e.g. 25mm (I rang the local the local BCO and they would not offer advice as it is 'except' from BR). The porch is separated from the house by an internal door. Can you help?

Thanks

System

although it is exempt from building warrant it should be built in accordance with the regulations, you must have got a particularly grumpy officer!!
a 50mm air gap is usually the minimum, but i think kingspan or celotex have a product with a bba certificate for 25mm air gap, but it depends on the exposure zone etc etc.
If you are in the process of building why not just have a 75mm cavity with 25mm insulation?

Driftwood

Thanks the_r_sole, the cavity is 50mm. The porch will not be heated and will hopefully be an improvement over the wooden and glass original.

peediedj

why cant you just use 50ml xtratherm or kingspan??

27col

It is pretty pointless to insulate an unheated space. There will be no heat in it for the insulation to conserve.

olias

Why would it need insulating? Are you planning to spend much time in there?

I'm guessing that the most you will be storing in there is coats and shoes. Surely a porch is just a buffer between the house and outside. As said, if unheated, then why insulate? It's just unneccessary expense.

Olias