Hi all
As regular posters will know, I am having an extension at the rear of the house re-furb'd. The DIY bit is the electrics, preparation, partition wall etc etc... The builder has started blocking up to cill level (where a patio door was situated previously). He has used (what I think are called) Thermalite blocks for both inner and outer leaves. The extension is going to be rendered on completion, so they won't show, but should these be used on the external leaf of a build, even one that is to be rendered? I have seen blocks used in the modern houses prior to rendering, but assumed these to be more substantial items.
TIA
Phil