Hearth-ache (n.) /hɑːθ eɪk/
The pain and stresses of trying to work out where to place your stove and constructional hearth in order to comply with impenetrable building standards documents and reams of technical sheets from the stove company.
The first decision, of course, is whether you actually need a constructional hearth in the first place. This depends on the stove, and the temperature that the area under the stove will reach. The stove manufacturer will indicate whether you need a constructional hearth and, for our inset stove, we did. More about choosing the stove here.
The size of the constructional hearth and the superimposed hearth was the other puzzle. The question of using the manufacturers instructions (generally German building standards for a German stove) or Scottish Building Standards. And to confuse event further, the area of the superimposed hearth is not the same as the area and position of the constructional hearth.
I could write reams of utterly boring blurb on calculating the size of the various hearths so I’ll spare you that (there a bit more in this blog). But I’ll tell you that I did read the building standards documents, and the stove technical documents, to within an inch of their lives (I even had to call the German offices of the stove manufacturer to get the answer to a couple of my questions that the stove retailer couldn’t answer) and eventually managed to get my head around them.
In the end I had a plan. It was all a bit time-dependent, as usual, as Builder#1 was about to put the underfloor heating and screed floor in. But, of course, nothing is simple when you are piecing together lots of different builders to do different bits of the build. Builder#3 was to put in the masonry wall that would be behind the stove and mortar down the Foamglas before the floor came in. I called him a few times just to be sure it was all go.
I arrived on site one Monday morning at the very moment that the insulation was going down with a membrane on top, ready for the screed coming in the next day. The first thing I noticed was that the masonry wall was in, with the Foamglas Perinsul underneath, but the Foamglas for the hearth wasn’t there and the Kingspan insulation had already been laid down. The plastic sheet was just being laid down and stapled up the walls ready for the underfloor heating and the screed to come in.
Fortunately it was just in time and they took a saw to the Kingspan and the Foamglas and put it in (phew). The screed came in over the top and then a 50mm concrete slab cut to size went directly under the stove.
That was bit was not without mishap (what isn’t) but it all went in well and now the stove is in and fits and I am glad I went through all the Hearth-ache of working it all out. If anyone else wants to put in a constructional Hearth, I’m your woman to ask…..well perhaps not.
Here’s the definitive blog on the stove