Why wont my chimney draw properly?

[Agent L]

I recently removed the old nasty gas fire that was in situ when we bought the house. This left a nice open fireplace that we had planned to put a wood burner in. Due to the angle of the existing clay chimney liner however that doesn't look like being possible. While we work out what to do I thought I'd just use the old basket we bought from the last house to have some 'normal' fires. I'm not having any luck getting the smoke to go up the chimney though but am being particularly successful at filling the lounge with smoke.

Does anyone know what the problem may be? The fireplace is pretty tall compared to the basket and was swept after I removed all the backfill for the gas fire. The pot on top was changed from a gas one to a bird guard too.

On the terrible picture I've attached, the yellow lines are the approximate position of the clay liner, it then goes vertical around the edge of the image, the red is roughly what the fireplace does behind the brick.

Does anyone have any tricks for starting to get the chimney to draw?

I was wondering if installing a piece of fireboard inside the top of the fireplace to funnel the smoke up to the clay lining would help at all?

[Agent L]

shakotan said:

I know the yellow lines are 'approximate', but would you say the actual angle of the flue is at 45 degrees or greater.

I only ask, as less than 45 degrees and it's never going to work properly.

What is the ventilation into the room like?

You are only going to get a good draw if the ventilation is equal to, or greater than, the natural draw of the flue, otherwise you'd be creating a vacuum!

Angle of the flue is too shallow I think, it's not 45 degrees anyway.

Ventilation is pretty good, there's a vent in the floor on the right that you can see by the clock. Opening windows/doors didn't make much difference.

[Agent L]

Grandad Gaz said:

What size is the existing clay liner? It could be too small.

First thing to try is to open the windows and see if that helps. Second is to temporary fit a board over the top 6" or so of the opening. it could be the opening is to big for the flue.

Liner is 6 or 7 inch I think, not 'small' but not a full size chimney of course. I'll try the board over the opening. I did wonder if it all needs raising up a bit from the floor, it will be when we do it properly but only 2 inches I'd guess. What material should I use? And where would I buy it?

[Agent L]

David58 said:

I had the same problem,
Same kinda bend and clay lining etc...

It was all down to the pot on top of the chimney. Try it without one I get the odd drop of rain very very rarely and thats about it. Otherwise it made all the difference works a treat now..
Oh and set the cast grate as far back as possible.

We've had a proper bird guard fitted that is basically 4 inches of nothing but wire and then a flat metal 'lid'. Can't imagine that stopping it from drawing, could it?

[Agent L]

Thanks for all the advice so far The chimney was swept less than a week before I first tried a fire.

TooLateForAName said:

If the original chimney opening has been partly blocked for the clay liner to be installed you have no chance (zero, null, none) of getting a decent draw. All you'll do is fill the room with smoke.

Woodburner.

I'm assuming that the house was built with the liner in place. The sweep has done another house in the close and it was the same. There are also signs of a fire being used previous to the gas one being installed so I think it 'should' work. Do you mean blocked as in filled in around the clay liner? That has been done but I think it was done when the house was built.

We've had two quotes for burner installation, the first involved breaking open the chimney breast to remove a section where the liner rounds the corner. The second said it would be almost impossible and they wouldn't take it on. I'm not keen to break into the chimney breast as that will condemn the chimney for any future use that doesn't involve a steel liner.

Edited by Agent L on Sunday 21st February 20:06

[Agent L]

TooLateForAName said:

An open fire needs quite a big chimney. If you have a restricted opening (which you have) then you'll not get it to draw.

How big is the flue diameter?

You can put a gather in but tbh if the flue is 5 or 6 inches it wont help. How old is the house?

Flue is 6" at least I think but not bigger than 7". It's in a very hard place to measure. House is mid 60's.

[Agent L]

Thanks for all the advice. I'm going to start by making a fake floor out of bricks to see if raising the basket up a couple of inches improves things. Then I'll start exploring other avenues.

[Agent L]

Like the sound of that, thank you Tuna.

[Agent L]

Yesterday I raised the floor height within the fireplace by 2 bricks, heated the chimney as best I could before lighting the fire, then did the newspaper over the front thing to really restrict the opening as it got going. The result was still a lounge full of smoke

I don't think it's going to be possible. I managed to track down a stove fitter though who should come to take a look next week and see what's possible regarding fitting a stove just using the existing clay liner. If that's not possible then it looks like we wont be having a fire at all for the time being.

[Agent L]

Engineer1 said:

Try burning something that will produce a good smoke, so oily rag or similar, only a small bit and see if the smoke even heads up the chimney, then try again with a window open.

I did open the window yesterday too and it made no difference.