I have been experimenting with forming an opening through a simple insulated cavity wall such as is found in many modern dwellings in England that are built down to being commonly affordable.

This consists of:
1] 110mm Outer Brickwork Skin
2] 50mm cavity,
3] 75mm insulation
4] 140mm Blockwork inner skin

However forming openings through this specification is proving onerously impossible or nearly so. I have successfully formed and opening treating each layer as a separate entity by drawing the opening onto each face and extruding each singularly. This proves to be not easy and not accurate.

I have attempted to form the opening using solid leaf entities and a plug to pass through the wall to be negated. but that doesn't seem to work even though each leaf and the plug are 'Solid Groups'.

In short how do we do this please in such a way, that say, 10 doors and twenty windows are not two weeks work and that are accurately formed? HELP!

ChrisPSR