What cavity insulation for my extension?

[noseall]

I have personally witnessed cavity batts permanently submerged in water for 3 months with no wicking.

In fact, they recommend that you can actually install their product below the dpc within the drip trough.

 

[stuart45]

. There really isn't that much to choose between the two methods these days. I just prefer a cavity.

The idea of building the blockwork first does not sit at all well with me and many brickies feel the same.

I would definitely agree with that point. Before insulation was put in to half filled cavities the face brickwork was always erected first.