1. Installation - two types of hearth; xxxbuilding up to a suspended floor Building Regulations recognise two types of hearth;- A Structural Hearth takes the weight of the stove. A Superimposed Hearth is a fireproof barrier that protects the floor from embers etc that might fall out of the stove. If your home has a solid concrete floor life is simple, since it fulfills both functions. If you have a raised timber floor, things get more complicated (see illustration at right.) XXThe normal approach is to cut a hole in the floor and build up a brick foundation from ground level. This is essentially an open "box" which is then filled with rubble and smoothed off with a concrete screed. You will obviously weaken your floor by cutting through the joists so Building Control will want to see a timber frame bolted to the bricks to support the ends of the joists you have cut so that the end result has all the strength of the original.