Lintel - prop boys at different heights??

[diysos101]

Hello. I have the attached fireplace. I want to add a lintel just above the new brick hole level. The double arch has a crumbled layer and one layer ok. I’m thinking of inserting props above the arch either side of the safe using prop boys. Taking out the bricks below functioning arch to lintel level, adding lintel then bricking back up to it arch. Then take out new nicked up builders hole. Question: Does it matter if the boys are on different brick courses? I want to avoid too much hanging brick below and avoid disturbing the good arch. Also want to have a small gap between props. Builders hole is 900mm planning lintel at approx 900mm. Purely for aesthetic purposes as no roof level chimney anymore but another room of breast above.

[wine~o]

shouldn't be a problem

[diysos101]

Thank you Wine~o.
Here is progress so far. Do you think I should remove the remaining arch for ease of bricking up? And what do I do where I’ve less than a brick height. I read currying brick length wise makes them weak and that thick mortar is also weaker. But then again the rest of the wall has all kinds of random sh*t filling it …so….!!!!

[dewaltdisney]

When I saw this originally I wondered why the arch support was off centre, was the original breast much wider? Was the breast chopped back to facilitate that apparent built in cupboard? I think you have to get an understanding of the original wall dynamics as although it no longer supports a stack there may well be collateral issues like ceiling joist supports to conside higher up the wall. It is always difficult to advise from pictures.

DWD