Any experts? Home ventilation & condensation.
Discussion
I seem to have a minor damp problem at home and as I cannot find a leak anywhere it all points to condensation.
I have a 1960's semi bungalow and in the past 18 months have had full double glazing fitted (sealed type with no 'trickle' vents). I have also had the loft insulated and the wall cavities blown with rock-wool. The ceilings are of plasterboard with 'vapour lock' backing. Floors are suspended, tounge and groove boards. I only have elecrtic storage heating, with no source of heat in the two affected rooms.
The problem is occuring especially in the bedrooms, so I suspect general moisture from breathing is sticking to the walls and ceilings, leading to minor outbreaks of black mould and a 'musty' smell.
I'm guessing that ventilation is the key here, but would should I be looking to do? Anyone have any useful advice?
I have a 1960's semi bungalow and in the past 18 months have had full double glazing fitted (sealed type with no 'trickle' vents). I have also had the loft insulated and the wall cavities blown with rock-wool. The ceilings are of plasterboard with 'vapour lock' backing. Floors are suspended, tounge and groove boards. I only have elecrtic storage heating, with no source of heat in the two affected rooms.
The problem is occuring especially in the bedrooms, so I suspect general moisture from breathing is sticking to the walls and ceilings, leading to minor outbreaks of black mould and a 'musty' smell.
I'm guessing that ventilation is the key here, but would should I be looking to do? Anyone have any useful advice?
Silly person! 
If you have blocked off the top of your cavities with insulation, that will cause condensation(but, then again you've filled them). Seen it before on a job where somebody had put kingspan between the joists too low and it covered the cavity.
>> Edited by groucho on Monday 14th November 18:20
>> Edited by groucho on Monday 14th November 18:20
Lack of ventilation.
Solved by putting a couple of airbricks in, upstairs and downstairs. Also, if your chimney is capped and sealed, uncap it - and install a chimney breast vent.
Why did you fill the cavity with rockwool? Who recommended that?
>> Edited by Parrot of doom on Monday 14th November 18:29
Solved by putting a couple of airbricks in, upstairs and downstairs. Also, if your chimney is capped and sealed, uncap it - and install a chimney breast vent.
Why did you fill the cavity with rockwool? Who recommended that?
>> Edited by Parrot of doom on Monday 14th November 18:29
pstruck said:
I seem to have a minor damp problem at home and as I cannot find a leak anywhere it all points to condensation.
I have a 1960's semi bungalow and in the past 18 months have had full double glazing fitted (sealed type with no 'trickle' vents). I have also had the loft insulated and the wall cavities blown with rock-wool. The ceilings are of plasterboard with 'vapour lock' backing. Floors are suspended, tounge and groove boards. I only have elecrtic storage heating, with no source of heat in the two affected rooms.
The problem is occuring especially in the bedrooms, so I suspect general moisture from breathing is sticking to the walls and ceilings, leading to minor outbreaks of black mould and a 'musty' smell.
I'm guessing that ventilation is the key here, but would should I be looking to do? Anyone have any useful advice?
When studying as an architect I learnt about this.
You have answered the question yourself, you used to have a set of leaky windows, no loft or wall insulation so the air was able to circulate. Now with the changes made that cannot happen.
If you look at a modern house the cavities have air bricks for cross ventilation, the roof has gaps all around the edges formed by plastic spacers which lets the wind ventilate the roof, the windows have vents, plus kitchens and bathrooms have automated fans for expelling damp air.
You need to open the windows of the house on a daily basis and check air bricks and roof cavity ventilation. Dont leave this too long as the mould will grow plus you could damage the walls and roof timbers otherwise.
Bennno
pstruck said:That's probably contributing to the problem too. As the rooms are cold the moisture in the air is condensing. The other rooms are warmer and therefore can support the volume of moisture in the air.
I only have elecrtic storage heating, with no source of heat in the two affected rooms.
How about heating these rooms?
All very sound advice guys. Most of it I suspected was the case.
I plan to put in some circular soffit vents all round the outside of the house as a start. Yes, heating those two rooms is on my list to do, especially as the cold weather is approaching - hopefully just a small panel heater in each will suffice.
I considered a small vent somewhere in each room, but it seems a shame to let cold air into a room I'm trying to heat, but I see the sense. Would an air brick be the answer then? Should it be set high up, or low down?
Any ideas how to get treat this mould, as it seems fairly stubborn?
I plan to put in some circular soffit vents all round the outside of the house as a start. Yes, heating those two rooms is on my list to do, especially as the cold weather is approaching - hopefully just a small panel heater in each will suffice.
I considered a small vent somewhere in each room, but it seems a shame to let cold air into a room I'm trying to heat, but I see the sense. Would an air brick be the answer then? Should it be set high up, or low down?
Any ideas how to get treat this mould, as it seems fairly stubborn?
Suppose as I am a surveyor i should know what to do 
Firstly you have answered your own question, the whole problem is down to lack of ventilation and lack of heating. The vents which are usually installed in the soffits are only to ventilate the roof space, preventing condensation in the roofspace. You should of had trickle vents installed in the windows, I know you are trying to heat the rooms but I would recommend having them retrospectivley (spelling) installed. As this is the best form of background vetilation. Closing off your cavities is not a problem as all modern houses have all of the cavities closed, at the top and around all windows and doors
If you need any further advice PM me
Edited for spelling
>> Edited by spdpug98 on Monday 14th November 19:39
Firstly you have answered your own question, the whole problem is down to lack of ventilation and lack of heating. The vents which are usually installed in the soffits are only to ventilate the roof space, preventing condensation in the roofspace. You should of had trickle vents installed in the windows, I know you are trying to heat the rooms but I would recommend having them retrospectivley (spelling) installed. As this is the best form of background vetilation. Closing off your cavities is not a problem as all modern houses have all of the cavities closed, at the top and around all windows and doors
If you need any further advice PM me
Edited for spelling
>> Edited by spdpug98 on Monday 14th November 19:39
If you're worried about wasting the heat then how about installing a heat recovery and ventilation system. Would be relatively easy to do in a Bungalow, and it solves your ventilation and condensation probs, and reuses the heat.
You’ve basically created the kind of sealed house that they have in Scandinavia, and heat recovery is widely used there (might even be mandatory).
You’ve basically created the kind of sealed house that they have in Scandinavia, and heat recovery is widely used there (might even be mandatory).
another surveyor here. most of the above points pretty much cover it but....
www.nuaireforhomes.co.uk/piv.shtml
have a look at these. Probably a more mid to long term solution but they do sort the condensation problem and also recirculate the warm air from the roof space back into th ehouse, cuting the fuel bills a bit.
Another thing, you may have a type of trickle vent installed on your windows. There are types that allow you to partially open the window and then lock it off so you get a small gap around the edge of the window whilst still making it secure. Try opening the window a few mm and then try to turn the handle.
>> Edited by a2z on Monday 14th November 21:17
>> Edited by a2z on Monday 14th November 21:18
www.nuaireforhomes.co.uk/piv.shtml
have a look at these. Probably a more mid to long term solution but they do sort the condensation problem and also recirculate the warm air from the roof space back into th ehouse, cuting the fuel bills a bit.
Another thing, you may have a type of trickle vent installed on your windows. There are types that allow you to partially open the window and then lock it off so you get a small gap around the edge of the window whilst still making it secure. Try opening the window a few mm and then try to turn the handle.
>> Edited by a2z on Monday 14th November 21:17
>> Edited by a2z on Monday 14th November 21:18
a2z said:
Another thing, you may have a type of trickle vent installed on your windows. There are types that allow you to partially open the window and then lock it off so you get a small gap around the edge of the window whilst still making it secure. Try opening the window a few mm and then try to turn the handle.
Yes I do have these, but I'm not keen on leaving the open all the time. They do latch into position, as you rightly say, but all the security bolts do not engage. These do allow that little bit of ventilation while we're at home, but security is compromised if left open.
The outside air is ALWAYS drier that inside a house even on an apparently damp day outside. Hence ventilation is the key, even if at the expense of heat loss. Warm air holds larger quantities of moisture in suspension too.
Opening the windows especially at night in the bedrooms will result in a much drier room, get thicker duvets if needed.
We keep our windows open all year, it makes for a much more comfortble climate, leave them closed & the effect is noticeable within a day or so.
Opening the windows especially at night in the bedrooms will result in a much drier room, get thicker duvets if needed.
We keep our windows open all year, it makes for a much more comfortble climate, leave them closed & the effect is noticeable within a day or so.
Gassing Station | The Pie & Piston Archive | Top of Page | What's New | My Stuff