Hearth extension - suspended timber floor

12 Nov 2012
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United Kingdom
I have a 1930's house with a suspended timber floor and i am looking to extend the concrete/screeded hearth. Can anybody give me an idea of how this may have been constructed before i get intrusive at the weekend (brick pier from underneath with the floor joist cut around perhaps?) I need to extend the hearth 250mm into the room but hoping I won't need to bring additional support up from the ground beneath the suspended floor (taking a big wood burning stove)
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Depends on the direction the joists are running in relation the the hearth. If you could provide a sketch showing how the floorboards are running, that would be helpful!...pinenot :)
It really depends on what the hearth extension is for. If its to satisfy the requirement of a fireproof floor in front of the stove, then you could put a paving slab (or slate) on the joists and seal it to the existing hearth with fire cement. If it has to support the stove then you have no choice but to build up from the sub floor.
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View media item 61044 As you can see from the alt diagram, blue marks the location I would expect the dwarf walls
supporting the joists to be at present. Red marks the hearth joists which can either be bridled, or on a dwarf wall, which I've marked in blue. Now depending on the existing arrangement (which I think you should copy) the yellow depicts either the position for a new dwarf wall or a bridle. Once exposed, can you post a pic of these joists, I can then advise you further to the next step, which will be cutting the existing, a shutter (if required) to cast the concrete extention. In the meantime if you have to hand, some separation membrane strips (Visqueen), sand - cement - and stone pebbles and various lengths of suitable timber etc. that will get the job going forward...pinenot

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