Porch renovation insulation/condensation problem

[dirtmatt]

Hi

I'm hoping to renovate our very small porch. It's single skin brick to window height then uPVC windows to roof level. Internally, the brick has been rendered which is looking very chatty. I was thinking of chipping away enough render to make space for a 2*2 frame to fit some tongue'n'groove panels to and finishing with a varnish but I'm concerned about the condensation forming on the render. Should I be filling the space between the remaining render and the t'n'g with insulation of some kind or is that just going to let damp bridge across? Should I treat all surfaces of the timber with an external varnish (or something else) before construction.

Thanks in advance

Matt

 

[noseall]

Adding insulation to the single brick wall will help deal with condensation internally provided it is thick enough (100mm or so).

This will deal with any internal issues.

However there is always the risk with single skin structures from penetrating damp externally.

This can be countered by building an internal framework inset by 50mm+ from the external masonry thus forming a cavity. This allows the external wall to become wet and eventually dry out without effecting the internal structure.

All of the above is very well if you are creating a heated habitable space out of the porch.

If not then leave it as a porch and ventilate it. After all it is just a porch and porches are not meant to be warm/humid.