Blocking up chimney?

[babydays]

I can't find the thread (it's not the chimney one) but I seem to remember seeing a discussion about possible problems about completely closing off a chimney.

I think there was something about condensation or I just don't know what exactly.

Does anyone know if/why there might be a problem doing this?

tks!

 

[Sue Ellen]

Have you had a look thru these?

 

[BillK]

Hi,

Yes, it can cause a problem, but the solution is very simple. Just put an air vent at the bottom. If the flue is ventilated there will be no problem.

 

[babydays]

Hi BillK,
could you tell me what problem could arise from closing it over.
We intended putting a sheet of wood over the fireplace and paint it on the outside.

My father-in-law wants to just block it and scoffs at my worry that there might be 'some problem'.

Any light on the matter much appreciated!

 

[ClubMan]

could you tell me what problem could arise from closing it over.

Damp for one.

We intended putting a sheet of wood over the fireplace and paint it on the outside.

You need to leave ventilation holes or fit one of those sliding plastic vent covers on any cover fitted to the fireplace. Might be simpler to use one of the suggestions in the other thread linked above for fitting draught excluder (with ventilation) to the chimney.

My father-in-law wants to just block it and scoffs at my worry that there might be 'some problem'.

I guess he has never worked in construction so?

 

[z102]

I blocked my chimneys as well, totally, had no problems with "damp"(why,where?) and worked in the building industry myself. It's a homeowner's duty by continental laws to block ALL chimneys that are not in use i. e. regularly supervised by a specialist.
That is for fire safety reasons, cabonmonoxide poisoning is a fire caused problem b.t.w.,fire can be set from outside in the chimney. For example by sparks from a neighbouring chimney falling into another chimney that is filled with dry lichen, moss, bird nests, flying debris and who knows what.This would cause a smouldering fire, one that might produce "cold" smoke falling down esp. when the weather situation enhances a down blow.The advice to leave holes in a blocked chimney flue -one that is not in use or at least checked regulary- is dangerous and irresponsible. Please check your sources of knowledge and correct your advice.
My advice ( and that of the professionals) is to close the chimney with fire proof material, like mortar, concrete blocks or a "red" piece of gipsum board. Well sealed AND NO HOLES IN IT!
And for energy conservation and fire safety: if closing a chimney then close all openings, the top as well. A chimney can be calculated as an outside wall in the energy calculation sheet, though that is not done in Eire due to ignorance of basic physical laws. I don't know if that has something to do with the "nod and agree" culture or just basic ignorance. But it is a matter of fact that any surface (like for example the inside of a chimney !) in contact with the outside environment is a source of energy emission- a heat loss.
Think logical.

 

[ClubMan]

[broken link removed].

Unused chimneys may be blocked with baffles or closed up,
but a small opening should be left to air the chimney.

Ensure adequate ventilation

The ventilation rate should be high enough to prevent the
build-up of moisture (and pollutants) in the indoor air, but
should not be so high that it causes excessive heat loss.
The optimum ventilation rate will vary depending on
what activity is going on and the weather conditions on
the day. In well-sealed houses (e.g. those with draughtstripped
doors and windows, blocked-off chimneys, etc.),
ventilation should be provided through controllable
openings such as trickle vents or windows that can be
secured in a marginally open position. These can be
adjusted by occupants in response to ventilation
requirements. For example, they might be opened on
calm days when large amounts of moisture are being
generated in the house, and closed on windy days when
little moisture is being produced. Signs such as misting up
of windows indicate the need for increased ventilation.

 

[X-Man]

in my new home(built 1950's) all bedrooms and rooms had a fire.when i got the keys to this home a few months ago i reopened the blocked up fireplaces and found nothing.i closed them back up again and plastered over while renovating the entire house.i honestly don't see no reason why i should vent the chimney.

 

[z102]

Sorry for may be apearing unfriendly. But using a chimney as a ventilation source is idiotic, it might kill you. See my previous post.You could as well smoke a cigarette and think that you're ventilating your lungs. But don't try that whilest asleep....
The professionals advise to block and seal all chimneys that are not in use, for safety reasons. To your quote:the draft of a chimney flue is not controlable.Full stop.That is a physicall law. Controll means in our case that the amount of air expelled is acounted for.As with the engine of a car. When driving a car at a certain speed then a certain amount of CO2 is emitted. But with a chimney - either there is a draft or there is none. No controll.
Depending on St. Peter to stay alive might have been an idea of Columbus's crew, but in our modern world we want results depending on action.
What has a calm day got to do with the amount of moisture created in a house ?
Is the source of your quote reputeable ( I got only the general google page with 140 something sources when clicking on the provided link) ?