Opening up fireplace to builders opening

wxy

We wanted to put a wood/multi-fuel burner in our 1930's house and have removed the fire surround and plaster of the open fire today. This is where we've ended up

http://www.flickr.com/photos/94449415@N02/9050661150/

It does not seem like there is a lintel in place. :eek:

However we think we can tell where the builders opening is - by the colours of the bricks (the original appeared paler looking) and the fact that the new inserts were slightly further forward from the other bricks.

Can you see the arch-shape and where the natural line is?

The next step would be to take the new inserts out. However, in the absence of the lintel, I'm not sure that the arch shape would be sufficient in supporting the weight of the chimney. As the consequences would be severe (!), I am inclined to insert a lintel if there's any doubt at all..

Is anyone familiar with the arch shape (I was hoping for a horizontal lintel or some vertically laid bricks as the support) and know whether it would be safe to take out the new inserts without needing a lintel? Any help would be much appreciated!

Leif

I had the stone surround and hearth removed from my fireplace, and then I removed the fire brick and the rubble behind it to open out the builder's opening. They had filled the sides and back with old bricks and dollops of mortar, and then shaped cement to create the flue shape above. However, I was careful to confirm the presence of a lintel above the opening before removing the fire brick. In your case it looks as if the fire brick is helping support the wall above, and removal could cause the bricks to cave in. There is a special term for the way they collapse which eludes me at the moment. As you say, it does look as if there are some bricks either side that are not part of the wall. You might find the width of the suspected opening matches a standard size. I am simply an amateur, so I cannot advise you. If you don't get help here, try UltimateHandyMan.co.uk DiyNot.co.uk.

Leif

Incidentally this is the fireplace before I removed the fire brick and rubble:



In this case the lintel was concrete and just above the fire brick. There was a half brick wide gap either side.

tony6403

Whilst you do need to be careful when disturbing the brickwork around the fire opening the bricks are self-corbelling and very few are liable to fall when you open it up. Your chimney would not be at risk of collapse - provided of course that you don't try to make it too wide.
The bricks at risk of falling are roughly in the shape of an equilateral triangle from the top of the new opening. You will see this if you look at how each brick is held by the one below along half its length.
Unless you are going to construct an arch you will need a lintel inserting over the new opening in order to build/retain the new brickwork. A concrete lintel would be ok.

wxy

Thank you very much both for the helpful input and reassurance!

We had a stove installation person come round yesterday who recommended inserting a lintel. We have bought a concrete lintel and will have it inserted shortly :T

Leif

tony6403 wrote: »

the bricks are self-corbelling

That's the term I was searching for.