Brick barbecue Chimney

[Alessandrotvf]

Hello everyone

Hopefully this is in the right place.

Recently I had a brick barbecue built and my idea is to get an Argentinian style grill in it.

I had it built as per the photos and the guy making the grill said it would be too bad for the smoke to escape and a lot would roll out into my face.

The top of it is currently 3 holes for smoke and the builder assumed this would be enough for smoke to escape as per photos. But I do notice it not drawing it all out even though I haven't given it a very smokey test run.

I have this old chimney pot as per the photos. If I widen the hole underneath it and brick shut the other holes will this solve the problem do you think?

 

[aveatry]

I can only see 1 square hole in the top - is that a slab ? I dont think making the hole bigger - just smaller than the pot will make much difference. Why did you add the slab on the top, also are you having made a bespoke arg grill to fit the space - do you mean one with a wheel for height on the side.
Also I am not sure on the wisdom of using a slab for the coals I think the slab may crack. Unless you plan to line it with fire bricks or BBQ ceramic tiles.

 

[Alessandrotvf]

Hi Mate

Thanks for the reply. If you look on top there is the single hole in the middle then there is 2 rectangular holes on either side where the bricks are.

What I am saying is if I was to brick those up and make the small square hole the size of the chimney pot, will that make all of the smoke go this way?

I am getting basically a Parilla grill without a height adjustment bespoke make and one of the log burning boxes for the coal at the side.

The builder believes the slabs are fine up to 600 degrees but I am going to get some fire bricks I think

 

[aveatry]

Ah I see what I am looking at now in the pictures. I am surprised that the side openings are not enough but I think the hole on the slab is doing nothing and it will be far worse if you block the sides and try to widen the slab hole as the pot is not big enough. instead ov the slab the hole needs to start as wide as the slab and then you can taper it to a pot sise. The nature of the flat slab the smoke will hit that and roll sideways.
What was the reason for the top slab - keep it dry or keep the heat in.
I think you can use piza stones as a base - square ones but may be cheaper to get fire bricks.

 

[Alessandrotvf]

Thanks mate. To be fair I'm going to wait for the grill to come and try it properly.

The guy making the grill was adamant it's no good and we need to make an angled chimney or something which is why I thought focusing it all up that chimney pot would work. Maybe it needed more or an ascending roof?

To be fair it wasn't my design I sent the builder photos of what I wanted and he decided this was the way to go so I'm trying to think of a way to improve it without making a mess of it

 

[Harry Bloomfield]

Just like a kitchen hob extractor, it needs a 'collector', either a sloping hood, leading to the way up and out, or you might be able to add a strip of steel vertically, as a lip, under the front edge that slab, to help encourage the smoke to go where intended.

 

[Alessandrotvf]

Thanks a lot. So basically the grill maker was right and it should have had a sloping chimney.

Do you know if there's something I can buy that can be attached to the top? Or maybe do you think if we opened the hole in the centre some more, added some bricks to the central slab to elevate the chimney pot then added it on top it would extract everything?

Sorry I am so clueless with brick work. Really appreciate the help

 

[Harry Bloomfield]

Thanks a lot. So basically the grill maker was right and it should have had a sloping chimney.

Do you know if there's something I can buy that can be attached to the top? Or maybe do you think if we opened the hole in the centre some more, added some bricks to the central slab to elevate the chimney pot then added it on top it would extract everything?

Sorry I am so clueless with brick work. Really appreciate the help

Warm smoke, behaves very much like water (except it rises, instead of falling) - it always takes the easiest way up and out, In this case it will spill out from under the slab, into your face, which is the easiest way out for it.

The way a chimney works is - warm air is less dense than cold, so it rises. If the easiest way for it to rise, is up a chimney, that's where it will go, drawing more warm air (and smoke) behind it. The taller the chimney, the more effective it becomes.

I would look to add a strip or lip, along the front edge. To that, you could try adding your chimney pot, which should help, it might also be worth blocking the other two holes.

 

[aveatry]

Try looking for a second hand stainless steel kitchen extractor hood with a broken motor ( take out the motor ) and do away with the slab and replace with the hood. My kitchen hood is 900mm wide by 500mm deep it that helps -- but you cant have it

 

[Alessandrotvf]

Thanks a lot everyone. I will speak to the brick layer. Hopefully there's a decent way to make it look good and also get the smoke extracting

 

[aveatry]

Thanks a lot everyone. I will speak to the brick layer. Hopefully there's a decent way to make it look good and also get the smoke extracting

I think you need to speak less to the bricky and more to the BBQ metal work man who gave you some good advice in the first place. Ask the bricky how many BBQs he has a year personally and you will have your answer as to who to ask for advice.
Harry's tip may help - use wood or anything just to test and add a 5 inch curtain at the slab front edge and the smoke should bounce off that and reduce the amount going into your face. But again I say that hole in the slab is doing nothing. you need to funnel.

 

[JohnD]

I am looking at a video of an Italian pizza oven built into a (brick) garden shed sent to me by an Italian friend.

The oven opening is about working height, with a tiled worktop in front. The oven is arched over, and there is a brick chimney rising to about three foot above the shed (flat) roof, so chimney top is about ten foot above the ground. It was extended by a couple of feet after build because it was not high enough to draw well. I think they used hollow clay roman "pot" type blocks for the oven and chimney, not solid bricks, which heat quicker. It is on a wooded hillside and has a flat slab spaced off the top in Italian style, or it might be Roman tiles.

So I think you need at least a metre of chimney. Once it is hot it will draw well. I believe it is possible to start the chimney drawing by stuffing a ball of scrunched newspaper in it and lighting it when you start the fire.

Compared to your one, your opening needs an arch starting about half way up, filled in with brick, for the hot smoke to collect behind instead of drifting out the front.

I bought a scrap stainless chimney cooker hood for a similar project, but a garden barbie, and am looking for sections of stainless flue, I think they are usually 150mm diameter.

You could do it in brick, but it will not draw well until the brickwork is hot.

 

[Alessandrotvf]

I think you need to speak less to the bricky and more to the BBQ metal work man who gave you some good advice in the first place. Ask the bricky how many BBQs he has a year personally and you will have your answer as to who to ask for advice.
Harry's tip may help - use wood or anything just to test and add a 5 inch curtain at the slab front edge and the smoke should bounce off that and reduce the amount going into your face. But again I say that hole in the slab is doing nothing. you need to funnel.

I'm in no way ignoring the Metal Work guy mate he's overall correct, however it's the Bricky I have to use to get it fixed. The Metal work guy has gone out of his way to help however his solutions have basically been to angle grind a ton off and start fresh and as you can imagine I don't really want to do that.

In hindsight I should have looked for a bricklayer with more experience in this but this is where I am at.

I will get a strip of some kind, I do notice you can buy 'Fireplace canopies' or something like that for this specific reason.

As for the Funnel aspect - so am I understanding right that there needs to be a gradual increase rather than the vertical chimney pot, and also that there needs to just be one exit hole on the top?

So I think you need at least a metre of chimney. Once it is hot it will draw well. I believe it is possible to start the chimney drawing by stuffing a ball of scrunched newspaper in it and lighting it when you start the fire.

Compared to your one, your opening needs an arch starting about half way up, filled in with brick, for the hot smoke to collect behind instead of drifting out the front.

I bought a scrap stainless chimney cooker hood for a similar project, but a garden barbie, and am looking for sections of stainless flue, I think they are usually 150mm diameter.

Thanks for the reply mate - so close up the opening a bit so the smoke can pool upwards and give it one exit basically?

 

[SFK]

My suggestion would would be to get your metal man to make a metal plate to drop down off front of that top concreate slab by about 1 brick height.

That will form a collection area under the slab that directs more smoke and heat up chimney.

Sfk

 

[aveatry]

I will get a strip of some kind, I do notice you can buy 'Fireplace canopies' or something like that for this specific reason.

As for the Funnel aspect - so am I understanding right that there needs to be a gradual increase rather than the vertical chimney pot, and also that there needs to just be one exit hole on the top?

How wide is the internal, I am thinking take off the slab and insert an old kitchen hood and you have a ready made sloping 3 sides