Downdraught prevention chimney cowls

iplogger1 · 10-09-2006 3:09pm #1

I was wondering about these. Pros/cons.
I see there are rotating and stationary versions... the purpose, I assume
being to prevent a downdraught from causing a smoke down situation
at the fireplace.

I've seen the rotating ones occasionally.

Someone mentioned them to me but didn't know much about current
thinking on them. Up until know I assumed I'd just put one of those
standard cast iron cowls which keep crows out,etc.

eg:
http://www.hotline-chimneys.co.uk/cowls_main.htm

rooferPete · 10-09-2006 5:03pm

Hi,

If you have a down draught problem there are a lot of different cowls on the market, each one has purpose so it's best if you know the cause before spending on a cowl.

One of the oldest and in my opinion still the best multi purose cowls is the "H" cowl, maybe not the prettiest but they have always worked for me.

.

iplogger1 · 11-09-2006 11:28am

Thanks for the advice Pete.

We haven't moved into the property yet. In fact they are just plastering
the chimney this week ahead of slating the roof. The topic only came
up when I told my father in-law that I purchased a nice pair of
chimney pots. He asked if I was thinking about putting in a cowl to
avoid "smoked downs". I hadn't even thought about anything other
than the standard inverted cast iron cone shaped cowls.
I guess it is premature for me to be worrying about downdraught
cowls until we've actually lit a few fires and established if there is
a downdraught problem or not.

thx again
~ipl

padraic mchale · 15-12-2006 1:57pm

rooferPete wrote:

Hi,

If you have a down draught problem there are a lot of different cowls on the market, each one has purpose so it's best if you know the cause before spending on a cowl.

One of the oldest and in my opinion still the best multi purose cowls is the "H" cowl, maybe not the prettiest but they have always worked for me.

.

Hi Rooferpete

i have a down draught problem and i had a guy look at it. He also recommended the H Cowl but they seem to be very expensive €290 euro each plus 100 euro installation cost. This is for a terracota cowl. Do you know of anywhere cheaper?

thanks,
Padraic

karltimber · 16-12-2006 11:36pm

rooferPete wrote:

Hi,

tne of the oldest and in my opinion still the best multi purose cowls is the "H" cowl, maybe not the prettiest but they have always worked for me.

.

does anyone have a picture of this type of cowl.

K

serotonin_sam · 17-12-2006 11:50am

karltimber wrote:

does anyone have a picture of this type of cowl.

K

H Cowl

I never use my fireplace and have a chimney balloon placed above the fireplace opening. However, when there are strong winds, I still get the impression that its causing a draft. As well as down-draughting, do cowls play a role in reducing draughts? If so, which one should I get bearing in mind I have no intention whatsoever of using the fireplace over the short/medium term.

padraic mchale · 22-12-2006 1:24pm

ttt

crosstownk · 23-12-2006 9:26pm

I've seen a cowl that has a chain that drops down the chimney so it can be opened and closed depending on whether or not you want to light a fire. I use my fireplace regularly so don't want it to be blocked in any permanent fashion. I'm thinking of getting the chain type. I tried to find the link (without success) to a supplier in Ireland that I've seen before - if I find it I'll post it.

At the moment, when I suffer from downdraught in the chimney I simply light a a sheet of newspaper, and shove the lighted end up the chimney as far as I can. (don't let go of the paper!!) - this heats the chimney and reverses the draught's direction to an updraught. Its a temporary solution but it works.

EDIT: Found link > here.

eddie4 · 23-07-2009 9:52am

as has already been said there are a number of causes of down draught, and many differant cowls, as a chimney sweep i agree that the h pot is an excellent soloution but does present problems when it comes to cleaning and also preventing qour feathered friends from gaining access to the chimney. If the problem is not excessive then a standard static anti downdraught cowl is fine, supplied and fitted 90 euro if a spinning cowl is required the cost should be no more than 150 both are available from heiton buckley.

mrtom · 25-07-2009 11:31am

Eddie4, I need to sort out my downdraught problem caused by a higher neighbours roof. Only happens when the wind is blowing a certain direction.
I like the prices you mentioned for supply & fit. Can you advise me on who I can contact to do the job. I live in the Dunlaoghaire area.

aujopimur · 25-07-2009 11:45am

Wait until you have your fire lighting in all weather conditions before you decide on a cowl.
Most fluing problems are caused by poor constuction or flue location.
With regard to draughts from fireplaces most people are under the impression that air is coming down the chimney when in fact its the opposit .

eddie4 · 25-07-2009 7:03pm

hi mrtom we cover your area, not sure on the ethics of posting contact details on here but if you would like to contact me my number is 085 1665807.

mrtom · 25-07-2009 10:28pm

Thanks, will be in touch.

sooty_soupy · 29-07-2009 9:02pm

Just be very careful guys that it is actually a blowdown problem. For over 20 years I have been a registered chimney technician in the North and have trained many people over the years. I am Chairman of the Northern Ireland Association of Chimney Sweeps and am a technical advisor to Building Control here in the north.

Blowdown is often a term used freely when smoke is spilling back into the room. This can be caused by a number of issues. I agree that higher properties, trees or hills can pose a serious problem, but would also suggest that some cowls are significantly better than others. Blowdowns often are when the wind is coming from the direction of higher obstrctions placing the termination point in the pressure zone of the roof. This can be helped by putting a permanent vent on the wall to equlaise the pressures.

Smoke could also be coming back into the room by something as simple as an extractor fan in the property creating a negative pressure in the home, or air tight construction leading to air starvation, effectively smothering the draught required to vent the flue gasses correctly. Finally it could be a ratio problem, where the fireplace is too large in dimension for the diameter of flue. If it of any use to you, the solution to ALL of the problems above is to fit an electric fan, if your finances allow, otherwise expect a lot of headaches and expense trying to cure it with cowls. The art of chimney building has unfortunatly been lost through the years.

Hope this helps.

David

DougB · 04-08-2009 3:03am

serotonin_sam wrote: »

H Cowl

I never use my fireplace and have a chimney balloon placed above the fireplace opening. However, when there are strong winds, I still get the impression that its causing a draft. As well as down-draughting, do cowls play a role in reducing draughts? If so, which one should I get bearing in mind I have no intention whatsoever of using the fireplace over the short/medium term.

I always thought that if you stop up the flue that you lose ventilation for the house, especially if its an older house with now window vents etc.

Eurorunner · 04-08-2009 5:47am

DougB wrote: »

I always thought that if you stop up the flue that you lose ventilation for the house, especially if its an older house with now window vents etc.

The chimney ballloon is designed to allow some ventilation of the chimney. The purpose of this ventilation is solely to make sure that there are no damp issues with the chimney itself. Ventilation of the house itself should be achieved by other means. If its an older house, chances are that its not airtight anyways. Most ventilation issues have arisen as house builds have improved - and become more airtight.

nick 56 · 04-08-2009 8:32pm

As a retired heating fitter I would agree with sooty soupy (above ) and suggest that if you have a problem you contact a real Qualified sweep for advice. As gas fitters will tell you the issue of extractor fans and sealed draft proofed houses can indeed create problems (boiler flues and gas fires).
Another issue is the strain that the fitted device puts on the chimney and the pot especially in this age of high winds.
When I worked in Dublin’s inner city fitting back boilers the locals told me that how you set a fire and the dampness of the fuel (coal / anthracite) was a big factor.

Bumbleybeebee · 09-08-2009 1:08pm

To all who have chimney problems. I supply the best thing to stop these problems.
Its been mentioned before and its called a Chimney Closure.
It works for many different problems
: stops moisture coming down
: regulates the up-draught so therefor regulates how much fuel you burn in your open fire
: stops heat escaping up your chimney while the fire is not on simply by pulling the chain and the closing the cap at the top
And the best advantage is that it saves heating costs by up to 66%, in this financial environment we are all trying to do that...it is not expensive and is a good investment that you could get back over 1-2 years after fitting.
Its fitted and working in 45-60 mins depending on the roof, simple to use and comes with a guarantee.
This is not an advertisement. I genuinely believe this is the only solution you need and it is tried and tested with amazing results. I am not aware of anyone who has not been happy with the Chimney Closure and most of my customers are so delighted with it they have passed on other people who are interested.
If you need any more information just give me an IM and I can go over the details with you.
Good Luck

hillviewfarm · 31-08-2009 3:23pm

I have a solid fuel stove installed. There is no chimney just some insulated double wall stainless steel liner. Anyway this liner exits the house and ends just below the roof. We live in a very windy place. There is a down draught a lot of the time. We do not have a vent installed.
Any ideas what we can do? Extending the flue is an option but feel that the wind may blow same down.

Bumbleybeebee · 01-09-2009 2:00pm

hillviewfarm wrote: »

I have a solid fuel stove installed. There is no chimney just some insulated double wall stainless steel liner.

The units I install are only for chimneys as they need a Flu to sit into but you have other simple options that would be suitable for a stove chimney.
A spinning cowl could be one of them as they move with the direction of the wind. They can be purchased in a DIY store the problem is you have to either fit them yourself or hire someone with the correct equipment to fit it for you.
Do not attempt to get on the roof if you have not already got experience with working on roofs.

Hope this helps
BB

ttm · 01-09-2009 8:09pm

Appologies for my dumb post here earlier (now deleted) excuse is I had two reply windows open and picked the wrong one.

In reply to hillviewfarm the top of chimney must be higher than the ridge of the roof (add on about 3 feet but less will do) othewise wind blowing over the roof will blow straight down the chimney. Top the lot with an H Cowl. If the top of the chimney is well away from the centre of the ridge then you can get away with a chimney that is not as high as the ridge even so the more height the better provided you can support it on your outside wall.

hillviewfarm · 06-09-2009 5:51pm

Thanks for the advice. Is it possible to have more than 2 s bends in the piping ? To extend the twin wall and get the stove working I need to manipulate it with more bends (there are 2 already in use), and add more to have it reach the roof. It is the roof of the sunroom so its not as high as the roof of the house proper. Also what could I use to secure same. I am slow to secure the pipe into the rafters.

ttm · 06-09-2009 6:28pm

No bends are good

but I get away with 2 right angles and a 3 foot horizontal section. The draw is still OK but I also put in T sections at the joints so I can easliy sweep the whole thing. If I had to put in another 30 - 45 degree section it wouldn't bother me to much just make sure it doesn't stop you sweeping the chimney properly.

PeteHeat · 06-09-2009 8:35pm

hillviewfarm wrote: »

I have a solid fuel stove installed. There is no chimney just some insulated double wall stainless steel liner. Anyway this liner exits the house and ends just below the roof. We live in a very windy place. There is a down draught a lot of the time. We do not have a vent installed.
Any ideas what we can do? Extending the flue is an option but feel that the wind may blow same down.

Hi,

I strongly recommend that you stop trying to use the stove in its present set up, reading the above you run a serious risk of setting your house on fire.

Be thankful that you have what appears to be a down draught problem because the flue gasses (smoke) is exiting just below your soffit / facia, if the flue gasses get hot enough everything above the flue could catch fire.

The above is not taking smoke damage to the wall and possibly through vents into the house.

I recommend that you try to employ someone who understands chimneys, flues and stoves, how they work and why there are minimum standards in place.

.

sooty_soupy · 07-09-2009 9:39am

Have any of you guys ever heard of the silent killer?

ttm, I don't mean to be rude sir, but I would delete the post you have on this page as well as the other dumb one you claim to have left. ARE YOU SERIOUSLY ADVISING TWO RIGHT ANGLE BENDS AND A HORIZONTAL RUN. Do you have any idea how dangerous this is when the horizontal begins to clog up and the flue diameter is reduced. I can see where you are coming from using the "t" sections but they are normally used to create a sump below a vertical run in a flue and double up to be being an acceptable sweeping point, but what happens if the rogue retailer doesn't supply the "t" to the unsuspecting public, and uses a 90 degree bend instead....and poor joe bloggs remembers you saying you are using a 3ft Horizontal run in a flue system.

FLUE GASES RISE. Vertical chimneys around Mainland Europe, America and Canada are built for a reason....they know how a chimney works. Your Document J will tell you a flue should have no bends in, but if there are bends to be used they should be no greater than 37.5 degrees

IT'S HERE IN BLACK AND WHITE

2.5 Direction - Flues should be vertical
wherever possible and where a bend is necessary, it
should not make an angle of more than 37.5° with
the vertical. Horizontal flue runs should be avoided
except in the case of a back outlet appliance, when
the length of the horizontal section should not
exceed 150 mm.

and here

Note:
Should an offset be necessary in a metal or similar flue of minimum
dimensions serving a closed appliance, then the flue size should be
increased by 25 mm on each dimension (diameter or each side of
square flue).

Why is that someone from the North is needed and is being bombarded with questions from the Republic, with dozens of people coming up to the showroom to show me catalogues of cock up installations. JUST FOLLOW YOUR BUILDING REGULATIONS. If you want a stove...fine we'll sell you it..but seriously folks someone is going to loose a life if you don't get a grip. Do you want to know what concerns me...it will have to be the life of a child before someone sits up and takes notice. If an old wrinkly dies in some quiet village and Carbon Monoxide is found to be the cause...it will be a tragic accident and a box will be used to get rid of the remains and nothing will be done about it....if it is a child, the media will crawl all over it....remember the two kids in Corfu and the gas boiler....

WHY WAIT FOR SOMEONE'S CHILD TO DIE...DO THE BLOODY THING PROPERLY OR DON'T DO IT AT ALL.

sooty_soupy · 07-09-2009 10:35am

Hillview Farm.

Here is a paragraph from Document J covering England Scotland and Wales, and has been adopted by Irish government.

Provisions should be made to enable
flues to be swept and inspected. A way of
making reasonable provision would be to limit
the number of changes of direction between
the combustion appliance outlet and the flue
outlet to not more than four 45° bends with not
more than two of these being between an
intended point of access for sweeping and
either another point of access for sweeping or
the flue outlet. (90° factory made bends,
elbows or Tee pieces in fluepipes may be
treated as being equal to two 45° bends

I would also query just what is supporting your flue if you have not used ceiling supports and roof supports while ensuring you have you minimum clearances from combustibles as you pass through the roof. If this is installed wrongly, and not compliant with fire regulations and manufacturers instructions, you will find your insurance company will walk away from you when you burn the house down.

Solid fuel heating is not a DIY job no matter what advice you get from these forums. You only have to read some of these posts with my background to see how ludicrous some of the advice is...but to the unsuspecting...how do you know what is right and wrong...Read the building regulations or speak to your local building inspector...or better still, get the flue manufacturers instructions for installation and follow them to the letter...then if things go wrong...they are answerable..not you.

Have a good day...and stay safe

David

eddie4 · 18-09-2009 6:36pm

hi David
i tried ti pm you but doesnt seem to be working, can you advise if you run or know of a sove installing course available in the north, i have looked into HETAS in the uk but the north would be much handier

Many Thanks
Eddie

Omron1 · 11-10-2009 3:20pm

Hi All,
New board member here
In relation to down draught problems I have a bungalow in Wexford with 2 chimneys back to back and the flues are side by side. Bought the house about 3 years ago and never lit the front room fire. We had both chimneys swept after we moved in. When we light the backroom fire I have a serious problem with smoke coming out of the front room fireplace so bad that I ended up sealing the fireplace in the front room. I was convinced the smoke was being sucked down the chimney however I was advised by my father who knows everything that this was not possible.I rang a chimey specialist company to try and get someone to come out to inspect the flue however it was quite expensive to get a flue inspection and after a long conversation with him and reading a few posts I am now again convinced it is a down draught problem. Last night I sealed the top of the flue of the front room and lit the fire in the back room and no smoke came out.
In terms of ventilation there are no vents in any of the walls in the house. House was built 1989 approx.
House is surrounded by Lelandi Trees approximately same height as ridge line.
Questions:
Does my test last night prove that the problem is a downdraught problem if not what else can I do to prove the problem?
Is there anything other than the H Cowl that will do the trick I have seen something called the Eurocowl which might look a little better?
Will I need a an anti downdraught device on both pots if I want to use both chimneys?

Sorry for the long post but I just want to get it sorted out soon.
Thanks to anyone who has read to this far.

ttm · 11-10-2009 3:29pm

Omron1 wrote: »

Hi All,
New board member here
In relation to down draught problems I have a bungalow in Wexford with 2 chimneys back to back and the flues are side by side. Bought the house about 3 years ago and never lit the front room fire. We had both chimneys swept after we moved in. When we light the backroom fire I have a serious problem with smoke coming out of the front room fireplace so bad that I ended up sealing the fireplace in the front room. I was convinced the smoke was being sucked down the chimney however I was advised by my father who knows everything that this was not possible.I rang a chimey specialist company to try and get someone to come out to inspect the flue however it was quite expensive to get a flue inspection and after a long conversation with him and reading a few posts I am now again convinced it is a down draught problem. Last night I sealed the top of the flue of the front room and lit the fire in the back room and no smoke came out.
In terms of ventilation there are no vents in any of the walls in the house. House was built 1989 approx.
House is surrounded by Lelandi Trees approximately same height as ridge line.
Questions:
Does my test last night prove that the problem is a downdraught problem if not what else can I do to prove the problem?
Is there anything other than the H Cowl that will do the trick I have seen something called the Eurocowl which might look a little better?
Will I need a an anti downdraught device on both pots if I want to use both chimneys?

Sorry for the long post but I just want to get it sorted out soon.
Thanks to anyone who has read to this far.

Is it possible to check if you've had a chimney fire that has burnt out the lining so one flue is connected to the other before they reach the outside world. Not seen that on newer houses but have on older ones.

Thats just one possiblity there are many others as I''m sure you'll read.

sooty_soupy · 12-10-2009 11:36am

Hi Omron, welcome to the forum. The condition you have is almost definitely siphonage. The condition arises where one flue chamber is cooler, therefore at an unequal pressure to that of the one being used. On calm days especially you will run into a problem where the colder flue can actually suck the smoke into the room, so your suspicions were almost correct. I would be hesitant to spend money on anti down draught cowls etc, as I don't believe this is actually the case. You have tried what I would have suggested in that if a plastic bag temporarily is used to block the offending flue and there was no problem, the simple cure is remove the bag and replace the LIVE chimney pot with a taller pot, which staggers the termination points, thus curing the problem and not affecting the performance of either.

Hope this helps.

best regards

David

Omron1 · 17-10-2009 9:51am

Hi ttm & sooty soupy,
Thanks for the responses. ttm I don't see any evidence of a chimney fire and prior to us buying the house it was used mostly as a holiday home so the fires would not have been used much I would guess and we got both chimneys swept when we moved in. Is there anything other than getting a camera survey done that can confirm your suspicions.
Sooty soupy since my last post I have been speaking to a neighbour up the road who had a similar problem with smoke coming down the chimney and he cut one of the flue pots down to the chimney cap and it solved the problem. I have checked and the chimney pots on the top of my chimney are both approximately 60cm from the chimney cap so if I cut one pot down by half would you think this should be a sufficient offset of the pots.

Thanks again for your posts.

ttm · 17-10-2009 11:18am

Omron1 wrote: »

Hi ttm & sooty soupy,
Thanks for the responses. ttm I don't see any evidence of a chimney fire and prior to us buying the house it was used mostly as a holiday home so the fires would not have been used much I would guess and we got both chimneys swept when we moved in. Is there anything other than getting a camera survey done that can confirm your suspicions.
Sooty soupy since my last post I have been speaking to a neighbour up the road who had a similar problem with smoke coming down the chimney and he cut one of the flue pots down to the chimney cap and it solved the problem. I have checked and the chimney pots on the top of my chimney are both approximately 60cm from the chimney cap so if I cut one pot down by half would you think this should be a sufficient offset of the pots.

Thanks again for your posts.

If theres no sign of a past chimney fire and its not been used much, on a newer house then don't take too much notice of what I said. I'm used to living in 200yo houses/cottages with all sorts of previous chimney disasters often from tenants that would have a chimney fire as soon as sweep the chimney.

I'm sure sooty soupy has the answer here, but I'd check how the air is getting to the used fire. If both rooms are well sealed from the outside its always possible the only place that fresh air can come into the house is down the unused chimney. Another one of my extreme theories but if you've had double glazing put in and sealed everything up on a house with no room vents its vaguely possible.

I'm not sure I'd want to cut a chimney pot down by half? I think I'd prefer to add on a new taller pot?

If you ever want to inspect something, pipe or chimney its quite easy to rig up a cheap USB camera on a 4m USB cable and tie it on the end of a drain/sweep rod to take a look at whats going on. 4m is about the limit of the USB cable length without buying a fancy cable. A laptop obviously better as you can easily get it near to the base of the chimney and you may need a second pair of hands to hod the rods and a tourch (up chimney) while you check the picture.

sooty_soupy · 17-10-2009 1:12pm

I too would avoid cutting the chimney pot to be honest. It is so much easier to take off the old pot serving the live applaince and replace it with a taller one.

Air starvation is very much a problem with chimneys in the modern home, as ttf has said, however I feel that air starvation is more a problem with a lack of negative pressure rather than positive. If I was a betting man...but I'm not as my old man is a bookmaker and he is never short of money funnily enough, I would say siphonage is more than likely the issue. Another way to temporarily determine if it is the long term solution to raise the pot, would be a very big jubilee clip, and a sheet of thin aluminium or stainless steel. Wrap the sheet steel around the pot and secure it with the jubilee clip and see if it helps.

As far as the CCTV inspection is concerned, I would imagine the idea of USB cameras might work, but it seems a lot of hassle for an imperfect view of the flue. A CCTV inspection would probably cost less than what is being proposed, unless you have the gear already. A crack in the flue will only give problems if the chimney is blocked. I would be inclined to sort out the chimney heights and see how things perform. If you still get smoke, then look at a proper survey on the chimney with a view to flue lining. We have a system that coats the chimney with a resin based ceramic which will seal any cracks should it be the case, but I don't believe this is your problem.

Best regards

David

PeteHeat · 17-10-2009 1:15pm

Hi,

Cutting a pot in place can be both dangerous and counter productive as you may end up with a pot that is not straight and it can catch wind causing a real downdraught.

I suggest go the opposite way, get a piece of stainless steel and add to the height of one of the flues.

That said your problem may be added to by the trees surrounding the property or even the angle (pitch) of the roof.

Trying to diagnose a problem without seeing it seeing it can be very difficult, it is also possible to be sending the person in the wrong direction.

Looks like we both posted at the same time and appear to be in general agreement.

.

mad m · 17-10-2009 5:35pm

I want to block off a fireplace altogether, whats the best way to do this up top? I dont want to put a vent where fireplace was either....Cut a template in ply and shove down cowl and fill in with sand&cement??

ttm · 17-10-2009 5:54pm

NO if your blocking off a chimney you really need to keep it open at the top and bottom even if you do cap off the top you can get vented plugs and brick up the bottom were you put in at least an air brick. You should keep an air flow through the old chimeny.

Fill it in and you could get all sorts of damp problems.

PeteHeat · 17-10-2009 7:31pm

Hi mad m,

I'm in full agreement with ttm you can get a vented cap for the chimney pot and fit a vent in the skirting board.

It doesn't have to intrude on any decorating plans you may have for the room.

.

mad m · 17-10-2009 9:42pm

PeteHeat wrote: »

Hi mad m,

I'm in full agreement with ttm you can get a vented cap for the chimney pot and fit a vent in the skirting board.

It doesn't have to intrude on any decorating plans you may have for the room.

.

I know what your saying and in theory dampness could happen but in practice would it happen....What would be the long term problems...

ttm · 17-10-2009 10:09pm

mad m wrote: »

I know what your saying and in theory dampness could happen but in practice would it happen....What would be the long term problems...

Firstly the house was designed with the chimney so part (if not all) of the ventilation of that room is via the chimney.

If you block it then any moisture from the chimney stack will sit there and eventually build up and have to come out somewhere. Any blocking up is likely to channel the water in a way you'll have no control over if damp does become a problem. Its also likely that floor and roof timbers are supported by parts of the chimney and you don't really want dry rot in those. Even if you were to remove the top of the stack and roof it over I'd still vent it to the roof space and put a vent in the room as a matter of good practice.

I can't really see any point in going to the effort of filling up an old chimney if you dont need to. At most all it needs is the pot taking off if its loose and replacing with a vented cap plus pointing up. Inside block off the old fire place any way you like just pop in a air brick sized vent somewhere. Theres no need for a howling gale to have to go up the chimney just a flow of air.

Is there some reason for wanting to block it off completely?

mad m · 17-10-2009 11:48pm

Ah i wasnt hypothetically speaking, bought house over 10years ago,one open fireplace in front room and there was one in back room and now its only dawning on me there's no vent where fireplace was. Not upstairs either or in attic......Could it be possible that that the other fireplace in front is venting the other one in some way?

ttm · 18-10-2009 11:19am

mad m wrote: »

Ah i wasnt hypothetically speaking, bought house over 10years ago,one open fireplace in front room and there was one in back room and now its only dawning on me there's no vent where fireplace was. Not upstairs either or in attic......Could it be possible that that the other fireplace in front is venting the other one in some way?

Just as I wouldn't be rushing to fill a chimney with concrete neither would I rush to unblock one and fit vents.

If they are in the same stack then the air going up the open chimney will help stop the stack retaining to much damp. So if you've had no problems so far I wouldn't worry.

My guess is that you chimney isn't blocked up completely just capped off and in many cases no will have bothered to even go on the roof let a lone climb up with bucket loads of a cement mix. If the location of the original fireplace is still obvious then you can see if you can drill a long thin hole through into it (10mm SDS?) to see whats the other side and if there is any air movement into or out of the hole (hold up a match or candle - incense sticks are good) if there is an air flow you could simpley drill a matrix of holes and put a screw on vent facia over it to cover it up.

I'd be more worried about not having a ventilation through an unused chimney on an old house with no DPC or a poor DPC as in that case the ventilation really could be doing some good keeping damp at bay.

And don't forget having been challenged I was making a point in my previous post

mad m · 18-10-2009 2:09pm

No different stacks on top of house. Had roofers check out chimney when I was getting extension to see if it was ok. Not blocked up top. Guess I'll get a 10mm long drill bit so...Thanks...

ttm · 18-10-2009 2:56pm

mad m wrote: »

No different stacks on top of house. Had roofers check out chimney when I was getting extension to see if it was ok. Not blocked up top. Guess I'll get a 10mm long drill bit so...Thanks...

Might have the wrong nomenclature when I said "stacks" as what I meant was the brickwork that supported the chimneys were the two chimneys supported by the same brickwork or were they seperate? Any size long drill bit will do I just happen to have a couple of 10mm hilti ones that I use for everything. You could also try lower down on the skirting board if that would be more convienitent just at that point the brickwork might be thicker, still best place for a vent.

loup · 27-10-2009 9:00pm

hi everyone, have a problem also with smoke coming into the room when fire is lit and the weather is windy (tonight). We are end of terrace so presumably this is why as we are the last chimney pot in the row! We already have a cowl to stop birds getting down chimney so what would we need to get fitted..a rotating cowl? Thanks!!

miltown britton · 28-10-2009 7:12pm

i own a stove with a boiler and the glass smokes up severly also when the doors are opened the smoke comes out and sets off the smoke alarm, its at its worst when the weather is calm, the flue comes out at the back horizontally for one foot approx and goes up in a 45 degree angle and sits within an existing straight up flue lined chimney for 4 feet, the chimney and stove are regularly cleaned and maintained properly, when there was an ordinary fire there , there was no problem with smoke coming down, there seemed to be a good draw. The stove was installed by a certified plumber and i have asked numberous people but haven't been able to solve the problem, when the wind is high the stove works well with only a small amount of smoke on the glass and is easier to refuel. Any suggestions?

ttm · 28-10-2009 8:16pm

miltown britton wrote: »

i own a stove with a boiler and the glass smokes up severly also when the doors are opened the smoke comes out and sets off the smoke alarm, its at its worst when the weather is calm, the flue comes out at the back horizontally for one foot approx and goes up in a 45 degree angle and sits within an existing straight up flue lined chimney for 4 feet, the chimney and stove are regularly cleaned and maintained properly, when there was an ordinary fire there , there was no problem with smoke coming down, there seemed to be a good draw. The stove was installed by a certified plumber and i have asked numberous people but haven't been able to solve the problem, when the wind is high the stove works well with only a small amount of smoke on the glass and is easier to refuel. Any suggestions?

While trying not to say whether your stove is set up correctly or not I'd check if the short horizontal section at the back of the stove is clear (also check and sweep the flu attached to the stove) and check that the pipe that goes up the chimney is sealed in chimney with no major air gaps.

miltown britton · 29-10-2009 7:34pm

hi yeah,thanks for your reply,i check and clean that pipe on a regular basis,it does help a little,but thats all,i have checked all the pipes at the rear stove for air leaks and put fire cement around all joints to be extra cautious,any other suggestions,thanks

ttm · 29-10-2009 8:03pm

miltown britton wrote: »

hi yeah,thanks for your reply,i check and clean that pipe on a regular basis,it does help a little,but thats all,i have checked all the pipes at the rear stove for air leaks and put fire cement around all joints to be extra cautious,any other suggestions,thanks

Not a lot more I can say, if you can I'd experiment a bit and try putting another pipe section up the chimney to see if that helps other than that I'm sure others would say the only way would be to line it but I'm not sure it that would fully solve the problem?

What stove is it?

Edit> Another question what are the flue sizes? Its not always a good idea to go straight from the stove in a flue size bigger than the stove outlet.

googled eyes · 29-10-2009 10:23pm

Hi all , sorry if I'm asking a question again but I'm only coming onto this thread today .
My problem is that I have two chimneys in the one stack , my living room and the front bedroom ( typical Dublin Corpo house ) and when I light a fire downstairs the smoke is pulled by a down draught into the bedroom. I have to open the window which seems to right the down draught problem ?

Would one of these spinning cowls put onto the bedroom chimney pot fix my problem or will i have to drill a vent hole in the external wall of the bedroom (which i dont fancy doing as its gonna mean a cold bedroom )

NutleyAFC · 30-10-2009 4:28pm

First time posting - anywhere, so please excuse me if I'm duplicating a previous question.

We built an extension with a new chimney. The builder started constructing a standard flue and heart opening. We needed a larger fireplace so I assume he just widened/heightened the opening without doing anything to the flue.

I now know there is some flue/opening ratio.

The room fills with smoke.

When I go to buy a cowl and explain my problem I'm advised to buy an electric cowl. Then when I went to buy an electric cowl I was recommended to start with a standard cowl.

So far I haven't had any luck getting a chimney expert to come out and diagnose the problem.

Any advice? Is there someone/a company that will fix this problem?

Thanks.

loup · 12-11-2009 8:15pm

NutleyAFC wrote: »

First time posting - anywhere, so please excuse me if I'm duplicating a previous question.

We built an extension with a new chimney. The builder started constructing a standard flue and heart opening. We needed a larger fireplace so I assume he just widened/heightened the opening without doing anything to the flue.

I now know there is some flue/opening ratio.

The room fills with smoke.

When I go to buy a cowl and explain my problem I'm advised to buy an electric cowl. Then when I went to buy an electric cowl I was recommended to start with a standard cowl.

So far I haven't had any luck getting a chimney expert to come out and diagnose the problem.

Any advice? Is there someone/a company that will fix this problem?

Thanks.

I was just coming on to say that eddie4 (above posts) is great, he came out and fitted a cowl to our chimney last week and really knows his stuff! PLus he was reasonably priced too..I would contact him and see if he can help you?

Downdraught prevention chimney cowls

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