Brick fireplace - squaring the arch

[scaryfast]

I've knocked out the old fireplace and fireback to the original brick built arch, as follows:

Untitled

• scaryfast
• 27 Oct 2008
• 2

I'm going to install a wood burning stove and intend to render the inside of the recess (like this).

How would you recommend squaring off the arch?

I was thinking about a length of mild steel flat bar (4" x 1/2") hammered into the mortar course at each side with the void above filled with mortar.

Will the steel likely crack the render/plaster when it gets hot?

I'm reluctant to replace the arch with a lintel as it's essentially sound (though could do with stiffening as it has a small amount of give when pushed).

Suggestions are greatly appreciated.[/url]

 

[Symptoms]

scary - traditionally these were supported by a length of iron strap, often 3" x 3/8", in the way you describe. 4" x ½" will work but maybe remove some mortar before you hammer the steel in, gently does it 'cos of your movement. Also it ain't going to get that hot so as to cause probs to the render.

 

[scaryfast]

Thanks for the reply.

Would it be better to prop, knock out the arch and install a concrete lintel?

I've removed the plaster/render from the chimney breast now as it was blown, so I've got a better view of the thing.

Cheers.

 

[^woody^]

Why can't you just plasterboard it?

 

[scaryfast]

Erm... I can't get 8' x 4' in the car

I'd rather render and pay for it skimmed as that matches the rest of the house.

I'm going to have to render the recess anyway, so being able to use metal bead saves me fiddling about with the edges (I think).

 

[^woody^]

In that case, why can't you use Masterboard or similar and render it?

 

[Symptoms]

scary - disturb as little of the brickwork as possible, insert the strap, infill the void with masonry, fit your plaster/render beads then render/plaster. I can guarantee if you attempt to fit a concrete lintel (why bother - there are no loads) you'll loosen more than you bargined for.

 

[scaryfast]

OK, thanks for the advice.

I'm going to keep the arch and render the brickwork.

The strap (probably 3" x 3/8") will have to go straight across with mortar filled in above it - I'm not going to be able to bend the it into the arch.

 

[gday2uk]

Sorry to hijack this thread.
I'm doing the same sort of thing except I am putting a concrete lintel in and taking the arch out, do I need to support the chimney breast with strongboys and acrows before taking out a course of bricks or will it be ok? Or is there a better way of supporting things while working?
Thanks for any help.......

 

[Symptoms]

scary - it was my understanding that you always wanted to square off and infill with masonry (as per pic of stove). Try to introduce some bits of brick into the void to support the mortar infill.

gday - depends how wide the chimney breast is. Bear in mind that the face of the breast is likely only to be one brick thick. A small/narrow fire opening (often found in Victorian bedrooms) might mean you could remove some of the stuff without support, but medium to large openings would require some support. If the plaster is off, chalk a triangle on the brickwork; base of the triangle = lintel length, then follow upwards with the staggered sloping lines, which follow the mortar lines, to the apex of the triangle. The area of the triangle is potentially the amount of unsupported masonry. You then need to make a judgement about support; strongboy/prop is good.

 

[gday2uk]

gday - depends how wide the chimney breast is. Bear in mind that the face of the breast is likely only to be one brick thick. A small/narrow fire opening (often found in Victorian bedrooms) might mean you could remove some of the stuff without support, but medium to large openings would require some support. If the plaster is off, chalk a triangle on the brickwork; base of the triangle = lintel length, then follow upwards with the staggered sloping lines, which follow the mortar lines, to the apex of the triangle. The area of the triangle is potentially the amount of unsupported masonry. You then need to make a judgement about support; strongboy/prop is good.

Good idea, many thanks!

 

[pmkur]

I have a very similar looking chimney breast in a 1930s house.

Photo: http://ubuntuone.com/p/WCi/

As you can see from my photo I have a second arch under the top arch which is supported (?) by two curved steel bars.

I would like remove the steel bars and lower arch in order to open the fireplace as shown in the scaryfast's photo. Any idea if these are original and structural?