Good evening,
I'm about to embark on a garage conversion with a small extension to the rear of the garage to match an existing rear single storey extension across the back of my house.
My current conundrum is around the garage floor and meeting the required U values for BC, the garage has an existing concrete slab floor which falls to the front of the property by around 100mm over the 8m.
To meet a u value of 0.18 kingspan advise a DPM then a 90mm PIR with a T&G floating floor. This would give a total thickness of around 108mm above the slab, unfortunately the step down into the garage from the kitchen is only 90mm and there's even less at the very back of the garage (~70mm).
I really would like to avoid digging up the whole slab if possible, any insights would be much appreciated.
Thanks