I have a 9m x 3m solid slab base (not a trench foundation), which has had an old Crittall conservatory removed, and I will be putting a new full height upvc one on the same footprint.
It has about 150mm of compacted granite chips, and a concrete slab on top of that about 100mm. No cracks at all in it.
As I'm not having a dwarf wall, if I build one course high of engineering bricks on top of this, will it be strong enough, or do I need to underpin it?
