I'm looking for some advice, hope this is the right place ;O)
I have recently bought an old pre 1930's bungalow with nine inch solid brick walls and an appalling condensation /mildew problem due mainly to the fact that what with double glazing which has no vents or night latch, draughtproofing and oil as the only heat source, the place is vacuum packed!
I want to build on an external chimney and install an open solid fuel (coal) fire. What I am wondering is, will this help with the condensation problem by giving the moist air an escape route, or will it make it worse?
I'm looking for some advice, hope this is the right place ;O)
I have recently bought an old pre 1930's bungalow with nine inch solid brick walls and an appalling condensation /mildew problem due mainly to the fact that what with double glazing which has no vents or night latch, draughtproofing and oil as the only heat source, the place is vacuum packed!
I understand from reading this group on deja that leaving my heating on 24-7 is the best way to prevent the condensation but thats just not affordable in the long run. At the moment I am using 500 litres every six weeks or so and thats running it at 65 degrees in the evening only.
I have the place as well insulated as possible and even priced inner insulation for the outer walls using a polyurethane sheeting faced with plasterboard and that worked out at over £500 per wall! Multiply that by ten walls and its just insane!
Anyway...getting to my point.
I want to build on an external chimney and install an open solid fuel (coal) fire with an all night burner which will keep it ticking over all night. What I am wondering is, will this help with the condensation problem by giving the moist air an escape route, or will it make it worse?
I'm looking for some advice, hope this is the right place ;O)
I have recently bought an old pre 1930's bungalow with nine inch solid brick walls and an appalling condensation /mildew problem due mainly to the fact that what with double glazing which has no vents or night latch, draughtproofing and oil as the only heat source, the place is vacuum packed!
I understand from reading this group on deja that leaving my heating on 24-7 is the best way to prevent the condensation but thats just not affordable in the long run. At the moment I am using 500 litres every six weeks or so and thats running it at 65 degrees in the evening only.
I have the place as well insulated as possible and even priced inner insulation for the outer walls using a polyurethane sheeting faced with plasterboard and that worked out at over £500 per wall! Multiply that by ten walls and its just insane!
Anyway...getting to my point.
I want to build on an external chimney and install an open solid fuel (coal) fire with an all night burner which will keep it ticking over all night. What I am wondering is, will this help with the condensation problem by giving the moist air an escape route, or will it make it worse?
This is a real classic, Susan. Your predecessor has created exactly the right conditions for mould and condensation. Why people are so stupid, I don't know.
The problem is that the heatloss through the walls is huge in comparison to the windows and they will be comparatively cold. No ventilation plus cold walls creates the problem. If by oil, you mean paraffin portable heaters, then they are releasing loads of water vapour into the rooms. If you meant a central oil boiler, then the water is going through the flue.
There are a number of solutions which you can use slectively or combined:
- The chimney idea will help because it will create some ventilation. You could look at adding some vents in the walls as well. In any case, you will need some air inlet into the house of some sort or the fire won't draw properly.
- A better ventilation solution would be a whole house heat recovery ventilation system. Basically this is a small central fan unit which goes in the loft and then has flexible ducts running to each room ceiling to deliver air. You have other ducts in other places like bathrooms and toilets which remove air. There is a heat exchange within the unit to recover some of the heat rather than just venting it outside. In a bunglaow, this would be quite easy to implement.
- You could use a dehumidifier in the house. That would be a pretty effective way of taking water out of the air.
- Longer term, you could consider insulating the walls. In places where you could afford to lose, say 40mm depth, you could insulate the walls with sheets of 25mm Celotex and plasterboard over the top. In rooms with lots of outside wall, this would make a large difference.
How do you know what the cause is? You may well be right, or it may be a contributory factor, but don't pre-judge the issue. You are unlikely to suffer condensation if the heating operates morning and evening, and the damp may be coming through the walls from outside. Is it worse on one side of the house or the same all over?
If the place were that tightly sealed, your heating bills shouldn't be high. I think for starters you need to find out where you're losing all this heat. Is the loft/roof insulated?
You MUST provide appropiate venyilation to replace air drawn up teh chimney tho.
Building regs are quite good in this area.
What you need is wall insulation behind a vapour barrier to keep walls warmn and reduce condenstaion there, plus damp courses if not already installed to reduce mositure ingress.
Then any stove or fire will naturally draw in cold air from outside, heat it, and echaust loads of atwer vapour up the chimbly.
The chimnet stack itself will help heat uptairs.
The cfact tyhat the fire produces vast quantites of water itself is not a problem. This goes right up the chimney anyway, or you will soon have a smoke filled room.
The key is adequate ventilation, reduce moisture ingress, incease local temp of cold surfaces (walls) and add kilowtts (light fire)
You must allow air in, for it to get back out, or you will really be living in a vacuum packed house. Keep cold air in takes way down low to the floor, and hot exhaust gasses way up high above the roof. Doing that causes the air to circulate around the house and draw any excessive moisture and dust out the forced flue of the chimney.
Any sealed room with a heater is a potential death trap because of carbon by-products, and not only from the heaters but from people breathing, so please allow an air circulation path if you're thinking of using any heaters, especially solid or fossil fuels.
Wall insulation, although expoensive, is the other secret.
It doesn't need to be that thick. The U value of a single glazed window is what - about 5? A DG unit of some age is probably only 3. Yet DG units solve window condensation quite well.
All you need is to get wall temperatures up above dewpoint. I have done that in the past in a kitchen using nothing more than 3mm of cork.
Of cousrse this does not affect the heatloss all that much, but enough to get the wlls up past teh criticakl dewpoint.
You complained about te nsulation cost, AND the fuel bills. Do the sums. You might save 500 quid a year on heating by dry lining the walls with some kind of insulation backed plasterboard.
My new house has no ventialtion as such to a huge space - so much so that I may still have a tussle with te BCO, but in fact, with tow chineys, and underfloor vents for the fire, there is virtually NO condesnation on teh single glazed windows. The walls are of course up to spec insulation wise.
Building regulations specify ventilation in rooms these days. Add some. BUT insulate as much of the walls as you can. The fire will take care of teh rest.
In addition to the sound advice already given. If you are installing a solid fuel fire it might be worth considering a fully controllable firebox that will also supply heat to your CH/HW. More expensive to buy & install but it could (a) solve your condensation problems and (b) vastly reduce your heating costs. All my heating is provided by a woodburner. The only costs I have are 3 days labour per year preparing logs and the cost of running motorised valves.
If you really must use the email address provided with my newsreader please be aware that the email is processed with spamcop. As a result your email to me might be treated as spam!
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.