Evening, Can i fix PIR insulation to rafters, then drill through it to secure plasterboard? If i use 75mm PIR, that seems like using long screws for plaster board - can they be standard ones, rather than plasterboard ones? Perhaps with washer's to stop the heads pulling through the board? I was hoping to fit large pieces of the insulation to the bottom of the joists, rather than messing around cutting it to fit between them. I was thinking of boarding a ceiling with the combined Plasterboard+PIR products, but both of the (Big Name) Builder's Merchants i went to to get some were astonished. One proposed a full pallet, the other swore that such a thing didn't exist - despite me pointing to it in their catalogue...... Advice appreciated! Crawf
Use insulation washers and screws up to fit the PIR. Use plaster board screws of about 105 length to fix the plaster board over fixing back into joists
Are insulation washer different to penny washers etc? All i can find are amazingly expensive things for cavity walls......
Do a search for Celotex insulation clips. Not cheap however you will not need screws, just some short nails. Quick to install and will save time. http://i.ebayimg.com/images/g/oXAAAOxyLm9TCHEt/s-l300.jpg
Slightly misread your post, you want to fix to rather than between. I used those to hold the insulation between the rafters - two layers of insulation 80mm thick with staggered joints. I would cut them approx to size, quite a quick job with the right tool then use off cuts to force the top one to one side and the under one to the other thus minimising any gaps. It is not a hard job and once you have done a few it becomes easy. As I did, go for two layers of half thickness.