Patio Fire Pit

[desperate]

Ok not exactly green, but it is construction. I am doing a patio job, concrete paviours on sharp sand with haunched edges all standard stuff, but the punter wants a fire pit to satisfy his pyromaniac tendencies. I was wondering about the best way to keep it all from cracking up. my thoughts were to lay a base for the pit with a weak crete mix, then bring some concrete blockwork up to the haunching level for the edge of the paving. Then build a brick liner inside the blockwork using a loose rubble fill between the brick and the block, just like a fireback is built into a breast, finally I will lay a brick hearth on top of the base to create the bottom of the pit.

This should mean that the blockwork does the structural stuff and the brickwork does the hot stuff, and if the brickwork falls to bits the paving wont follow it.

I doubt any serious smelting will be going on but, will standard facers handle the heat?

Whaddaya reckon, will it work??

Thanks

Desperate

[Billy]

Hi Desp

My only experience with fire and concrete was that it exploded, the ballast blew out and girt lumps of hot stuff descended on me.  It were a big fire and it spread embers everywhere.

billy

 

[clockmanFR]

desp,

For fire brick cement i use 1 part hydrated lime mixed with 1 part normal cement mixed with 4 part sand. This was told to me by several of the 'Old School' tradesmen.
Worked for me for the last 20 years in all my fireplaces.
However, every 10 years or so you will need to re-point as the mortar joint eventually turns to dust.
Good luck.

[Baz]

It is the pebbles in concrete that explode. I would think that a base that is able to absorb water ie brick will be rather deadening to the fire. Hence the availability of steel liners for such things.

[Stuart]

i found bricks tend to explode too, +1 on clockmanFR fire cement mix I've been told that one too. You not get firebricks these days?

[AlanM]

Why not sink a steel wheel rim into the ground,  various sizes available , have used one for years.

Alan

[Contadino]

I've just built a recessed/sunken firepit into a patio. I had to do some of the work twice because I forgot to put a soakaway underneath to get rid of rainwater.

I used lime, crushed terracotta (old plant pots, roof tiles, etc..) and sand - no cement.  That's what they use for mortar in pizza ovens, so I figured the temperatures in a pit shouldn't be a problem.  It seems to be holding together, although it's only had about 6 firings and now the weather's broken so now it won't get used until first green next year.

ETA: Sorry, should have emphasised that the mortar mix (cocciopesto) is a structural render, applied to sandstone (tufo) blocks.

[MR GUS]

 

dESP, GET THEE DOWN TO THE TIP & RECYCLE A STAINLESS STEEL DRUM FROMA LARGE WASHING MACHINE, WE'VE COVERED FIREPITS HERE BEFORE, (caps off) then you can design around it with something inbetween, looks flash & lasts well, cheap to replace, should deflect heat from your brickwork too.

linky

http://www.navitron.org.uk/forum/index.php/topic,10699.0.html

[MR GUS]

for your brickying i'd show him what they look like & sell the ventilation, removal aspect (raised dais) improved combustion so theoretically less smoke, cosmetic appeal, all them holes, easy to replace if it looks raged rather than shiny in a few years, proven to last! etc.

 guess if you make it slightly elevates so its got good air draw you can desugn it to keep heat off the bricks in the main, say bar 3 or four contact & stability points?

big enough to stick a grille over & bbq too or as an overflow bbq, you could probablty jetwash the firepit drum if that floats your boat! 

[desperate]

Thanks for all the ideas guys, will certainly consider drainage and steel/drum liners and etc, I will have to consult with the punter and Mrs Punter first, but I like the idea of a washing mc drum..................like the idea of explosions too, best not go there though


Thanks again,

Desperate

[docka]

I'll second the washing machine drum. Lots of the caterers and traders at festivals use them, with feet welded on as they leave very little mess and are reasonably light to carry around.

[KLD]

Desp,

I would guess anything that takes up some water will not withstand the heat: once the water is soaked in, heating it rapidly in a fire will lead to shattering or explosion. We've got a makeshift bbq with a few old bricks dotted around the fire. They last no longer than one season before they return to dust. (Makeshift, you see, put a few blocks, slates and bricks together when the old cheapo metal bbq fell apart. Was thought to be there for just one eve, now three years later ...)

Klaus

[desperate]

Ha ha ha I know what you mean about temporary setups Klaus, I have the same problem at Cactusville, some of my temporaries last for years. This barbie has seen 2 winters now...........

Desp

[garethpuk]

Klaus has got it right, anything that soaks up water will possibly explode. The water turns to steam and expands in the material which in turn bursts, the intensity of the burst depends on the material, some will have little bits drop off and some will shoot hot bits all over the place! I would use some sort of metal insert with a small air gap round it, if it can lift out it'll be easy to empty the ash, the washing machine drum is a great idea.

[desperate]

Thanks Klaus, Gareth, and all.

Maybe I should use a semi engineering brick and then as you say line with a machine drum or similar, I'll run it past the punter, maybe I'll post a piccy or two if anyones interested.


Desp