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Building a charcoal barbeque advice |
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| message from BIGEYE on 25 May 2004 |
I am looking at building a charcoal bbq from either brick or concrete
blocks. The price of bricks is very expensive so I am swaying towards the
blocks.
Has anyone built a bbq with concrete blocks and has there been any problems
with concrete due to heat?
TIA
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| Ian Stirling replied to BIGEYE on 25 May 2004 |
Concrete will be fairly rapidly destroyed at somewhere over 100C, the
water used to make it "boils off", and it disintegrates into a pile of
dust.
If it's not exposed to actual flame, it'll probably be OK.
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| Scott replied to Ian Stirling on 25 May 2004 |
Below 300 C
No appreciable damage done
300 to 500 C
Damage to concrete requires careful assessment (especially above 400C).
Concrete will be weakened and some loss of modulus will have occurred.
Prestressing will be down to 50% of its strength above 400C and cold worked
steel will be affected above 450C.
Above 500 C
At these temperature significant loss of strength occurs in the concrete and
the modulus of the concrete is significantly reduced.
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| Ian Stirling replied to Ian Stirling on 25 May 2004 |
In some ways it's the other way round.
The act of boiling off absorbs an enormous amount of energy.
I don't know the exact temperature, it's not 100C, but significantly
higher, as the water has reacted with the cement and is largely bound
into the structure.
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| nightjar replied to BIGEYE on 25 May 2004 |
I have a barbeque and pizza oven built of concrete building blocks. They
came with the house and I've never used them, but they appear to have seen
plenty of use with no obvious signs of problems.
Colin Bignell
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| Jeremy Collins replied to nightjar on 25 May 2004 |
Outdoor pizza oven? What a *fantastic* idea! Are you
able to post a picture?
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| Mary Fisher replied to Jeremy Collins on 25 May 2004 |
When we have time we're going to build an outdoor bread oven - an 'earth
oven'. It will cook anything, including pizzas.
Mary
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| sPoNiX replied to BIGEYE on 25 May 2004 |
Make most of the bbq out of concrete and use a couple of courses of
proper bricks near the hot part.
sPoNIX
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| Nick Brooks replied to sPoNiX on 25 May 2004 |
I used the bricks out of an old night storage heater. (Often free, look
in local paper) they have cracked a bit but hold the heat in well
Nick Brooks
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| Christian McArdle replied to BIGEYE on 25 May 2004 |
At university we built ourselves a barbecue.
4 aerated concrete blocks from a nearby retaining wall as legs (two blocks
on end per leg). Then the fire surface was a cracked concrete paving flag.
The back and sides of the surface were windproofed using several old grade B
bricks found semi-submerged into some flower bed. The grille was formed by a
chrome wire shelf rescued from our fridge which had fortuituously exploded
some weeks earlier and been replaced.
It was the best barbecue I've ever used. Easy to light, and excellent at
keeping a nice medium heat for long periods, much better than any
commercially bought one.
The next best barbecue I've used was built entirely from concrete decorative
buff walling blocks from B&Q with their built in barbecue kit (grille + fire
pan). The hot concrete goes a little pink, which is soon unnoticeable due to
the pleasing carbon patina that develops over the season.
I'd be a little concerned about using aerated concrete for this, but dense
concrete would be fine.
Christian.
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Archived message: Building a charcoal barbeque advice (UK DIY House Decoration)
