Fireplace rebuilding in 1930s house

[MarkBeharrell]

Our new house has a multitude of fireplaces but the lounge one is the worst in terms of hidden construction 'issues'.

So I'm now rebuilding it to try and meet current regs as close as the property will allow.

The fireplace will eventually have a stove in there so it wont be an open naked flame fireplace.

Im at the point where I need to replace the bricks that were once removed to allow the original tiled concrete surround to fit. But I need to know what bricks to use. The ones that make up the walls don't appear to be firebricks as they are normal brick size. Attached is a photo. Also how do I cope with the cavity. Make brick same levels then face it with stone?



The photo shows the hearths have been removed (there was three superimposed hearths? and a not very think constructional). Now the facing wall brick work has been redone - it wasn't mortared at all and the rubble infill is level ready for a concrete pour.



Thanks in advance

Mark

 

[Ashful]

Looks like they were using an airspace between the inner and outer masonry to provide insulation. I have a similar setup on one of my 1773 fireplaces. It seems mine had only the outer masonry, and someone later added a brick firebox within the original with a 2" air gap, similar to yours.

If you're installing a wood stove, the requirements are much reduced, versus using this as an open hearth.

 

[begreen]

If the intent is to install a stove, be sure that the poured hearth is specced correctly for it both in size and R value requirements.

 

[MarkBeharrell]

Looks like they were using an airspace between the inner and outer masonry to provide insulation. I have a similar setup on one of my 1773 fireplaces. It seems mine had only the outer masonry, and someone later added a brick firebox within the original with a 2" air gap, similar to yours.

If you're installing a wood stove, the requirements are much reduced, versus using this as an open hearth.

Does have that feel to it although it seems to have been built all in one go as the bricks are the same both external and interneal. Just cant match them...

 

[MarkBeharrell]

If the intent is to install a stove, be sure that the poured hearth is specced correctly for it both in size and R value requirements.

I cant seem to get the height requirement of 125mm for the constructional hearth - I can get at least 100mm then its flush with the floorboards. So I was possibly going to go with a much thicker superimposed hearth to make up the deficit.

Considering what was there originally which was a tiled concrete superimposed hearth then approx 2-4cm poured concrete over a tiled superimposed hearth over another concrete substrate of 1cm ish then the non mortared brick and rubble!

 

[Ashful]

Does have that feel to it although it seems to have been built all in one go as the bricks are the same both external and interneal. Just cant match them...

Yep... didn't mean to imply otherwise. I think the modification to mine was probably done within 20 years of yours being built. Likely just the mentality of the time, and surely not a bad way to go. In my case they were also full 8.0" x 4.0" x 2.0" bricks, laid on a 8.75" x 2.5" spacing. They're clay brick, which may have been all they used at the time.