Using chimney bricks for extension

[xdrive]

Hi.

I'm planning on getting a rear extension 4.5m X 4m wide.

I've got quite a bit of bricks from removing chimney.

They are red bricks with frog.

Would these be ok to reuse or would it not be worth it (time consuming, better building material, etc)?

The mortar comes away easy enough.

 

[bernardgreen]

I recall that sooty bricks have acidic ( or is it alkali ? ) residues which compromises the strength of mortar when the bricks are re-used.

 

[bobasd]

any soot on any part of the brick will eventually leach through to the interior or exterior surface of the brick .

if the bricks are dead clean - no soot at all - then they can be re-used.
any doubts then skip them.

 

[xdrive]

I can give them a pressure wash.

Or Maybe good for building garden wall and building wall at top in loft where chimney stack was.

 

[bobasd]

you've been given a suggestion and the reason why - why not follow the suggestion?

 

[^woody^]

Will you be paying the poor bricklayer one shilling and thrupence too?

 

[xdrive]

Will you be paying the poor bricklayer one shilling and thrupence too?

Not at all sir. Just don't like to waste stuff if it can be reused in anyway. I've put most my money in to my first property so a bit cash strapped.

 

[catlad]

Use them for hard core.

 

[xdrive]

Whilst we are on subject of soot would this need cleaning off the wall or is there a way to board over it by applying a sealer first?

Cheers

 

[bobasd]

dont even use them as hardcore - the soot will leach through and the wetter the brick the more the contamination.

vacuum, respirator, glasses, overalls and gloves - scrub the soot off with wire brushes - dont use any liquids.
your remaining flue seems to have been parged ie. S&C rendered - just hack it off back to brickwork.
after wire brushing use a stiff bristle dry scrubbing brush.
any remaining flue or flues have swept.

blind the cleaned off brickwork with two coats of SBR - with second coat tacky then apply a 3:1 mix of sand and lime render. two 10mm - 15mm coats of render best.
then build out the rendered opening to match the wall plane.

check any outside wall surface for signs of soot penetration.

 

[^woody^]

You could use the bricks externally, with or without soot (although brush the loose stuff off) but you must use sulphate resistant cement in the mortar.

 

[xdrive]

Thanks guys.

You are legends

 

[bobasd]

i've seen sooted up bricks used as hardcore below a 2" to 3" screed of S&C - the soot came through 5-10yrs later.

sooted flue bricks were re-used on a different house - a 1980's grant jobber had economised and used them for bricking up redundant frame openings in cavity walls.
20yrs later we were asked to take a look.
according to the householder, the soot chemicals showed first on the pointing of the outside skin, and later showed on the bricks.
on the plastered interior skin of the wall the contaminated grid of the pointing pattern was to be clearly seen grinning through the paint decorated surface of gypsum plaster.

i've also noticed a few garden, sooty brick pathways with sooty chemicals blooming.
and neat, soaking piles of redundant flue and chimney stack bricks waiting for a second use.