Another condensation issue

kkelly77

I've searched the forum for a solution to this problem and did find a lot of threads about issues with window condensation.

Following the advice from the other threads I have been making a conscious efforts to ensure bathroom window is open after showers, keeping kitchen door closed when cooking/drying clothes and any other advice to try and eliminate moisture. However, our bedroom window is constantly soaked with condensation. This requires the usual cleaning everyday as well as keeping the window open (brrrrrrrr!). The wall vent is definitely clear. However, I took the cover off today and noticed that the inside of the vent on the exterior wall was very wet, even though there was no rain last night. What could be causing that and could it have something to do with the condensation issue? Or is it just down to poor quality windows/installation methods used?

I've attached a few photos of the window and vent interior.

BryanF

kkelly77 wrote: »

The wall vent is definitely clear. However, I took the cover off today and noticed that the inside of the vent on the exterior wall was very wet, even though there was no rain last night. What could be causing that and could it have something to do with the condensation issue?

this sounds like there is an impenetrable external barrier on the walls (paint? or maybe external insulation?) but it does suggest that there is still more internal moisture being generated and forced out through the building fabric.. so not enough is being dealt with by the vents/windows .mechanical WC and kitchen extracts.

1. is this a recent problem?
2. when was the house built?
3. what work has been done in recent years?
4. what the external walls like? any gutter leaks maybe external vegetation on walls

Or is it just down to poor quality windows/installation methods used?

this is a common occurrence, especially as we put more insulation in our attics and in our walls, as it focuses visible condensation in the weaker areas of our homes, often our windows. (its not the insulation's fault, or problem, its the fact that retro-fitting must be considered in a holistic manner - with input from professionals not salesmen;))

1. Are you opening the windows at night when your sleeping (and essentially creating the water vapour).
2. is there a chance that humid air is migrating from other parts of the house?
3. is the wall also damp/ getting mouldy or is this just the window?

IMO you must start with ventilation. consider the installation of a wall ventilator that has an inbuilt RH sensor (turning itself on when the airs humidity level rises - causing condensation on the windows)


yes your windows are probably part of the problem, the internal surface temp is probably to low in comparison to the room temp and therefore the moist air is condensing on them. BUT whatever you do don't just get crap new windows - you should be looking at DG windows below 1.2wm2k certified if or preferably 0.8 triple glazed certified to ensure that the condensation issues does not re-occur AND these must be fitted with consideration of thermal bridging. something many window installers take no part in discussing with home-owners as they see it as being out side of their remit or just don't care..



I would recommend you get a professional (arch/ arch tech/ surveyor etc) out to assess and recommend solutions to suit your budget before you make any purchases


best of luck

kkelly77

BryanF wrote: »

this sounds like there is an impenetrable external barrier on the walls (paint? or maybe external insulation?) but it does suggest that there is still more internal moisture being generated and forced out through the building fabric.. so not enough is being dealt with by the vents/windows .mechanical WC and kitchen extracts.

1. is this a recent problem?
2. when was the house built?
3. what work has been done in recent years?
4. what the external walls like? any gutter leaks maybe external vegetation on walls

this is a common occurrence, especially as we put more insulation in our attics and in our walls, as it focuses visible condensation in the weaker areas of our homes, often our windows. (its not the insulation's fault, or problem, its the fact that retro-fitting must be considered in a holistic manner - with input from professionals not salesmen;))

1. Are you opening the windows at night when your sleeping (and essentially creating the water vapour).
2. is there a chance that humid air is migrating from other parts of the house?
3. is the wall also damp/ getting mouldy or is this just the window?

IMO you must start with ventilation. consider the installation of a wall ventilator that has an inbuilt RH sensor (turning itself on when the airs humidity level rises - causing condensation on the windows)


yes your windows are probably part of the problem, the internal surface temp is probably to low in comparison to the room temp and therefore the moist air is condensing on them. BUT whatever you do don't just get crap new windows - you should be looking at DG windows below 1.2wm2k certified if or preferably 0.8 triple glazed certified to ensure that the condensation issues does not re-occur AND these must be fitted with consideration of thermal bridging. something many window installers take no part in discussing with home-owners as they see it as being out side of their remit or just don't care..



I would recommend you get a professional (arch/ arch tech/ surveyor etc) out to assess and recommend solutions to suit your budget before you make any purchases


best of luck

First off, great reply Bryan. Very detailed and informative.

The outside of the house has the original, unpainted pebble dash finish on the outside. To answer your questions above -

1.Not a recent issue. Has been happening this time of year since I moved here (approx 6 yrs)
2. 1983
3. Cavity wall insulation, improved attic/attic access insulation, water tanks insulted and bathroom extractor fan recently fitted.
4. External walls in good shape. No leaks or vegetation growing. Front of house gutter was leaking badly about 2 yrs ago but has been sorted.

1. I don't open windows at night because of external noise and temperature. (I did read we produce about a litre of moisture while we sleep)
2. Quite possibly but in the last couple of months I have consciously ensured that moisture from cooking, drying and showering is dealt with ASAP by opening windows, extractors etc. This has had to significant impact on the problem though.
3. It is only the window that is getting damp. No presence of damp or mould on any walls.

Do you have any info on wall ventilators with inbuilt RH sensors? I've never heard of them. I assume they need to be connected to power with an active fan inside them? There isn't a budget for replacement windows unfortunately but thanks for the advice on what to look for if I was to replace them. Perhaps my only option is a dehumidifier but ideally I'd rather tackle the problem rather than treat the symptoms.

I was also considering hiring a moisture reader from the local tool hire company to test the walls in the bedroom. Do you know is there a particular moisture limit for internal walls?

meercat

is the problem caused by the heat from the radiator ,when the curtains are closed?

kkelly77

meercat wrote: »

is the problem caused by the heat from the radiator ,when the curtains are closed?

I don't think so.

For example, when I was heading to bed last night, the curtains were open and the heating had been on. Condensation was already starting to appear at the bottom of the window. It looked like a very cold night last night too. The car looked like an ice block.

meercat

when you close the curtains you trap the moist air against the window which cools overnight causing condensation
if possible allow airflow top and bottom of curtains

kkelly77

meercat wrote: »

when you close the curtains you trap the moist air against the window which cools overnight causing condensation
if possible allow airflow top and bottom of curtains

Curtains are full length (curtain rail to about 2" from the floor) and cover the rad when closed.

meercat

kkelly77 wrote: »

Curtains are full length (curtain rail to about 2" from the floor) and cover the rad when closed.

think by closing the curtain you are causing the problem so
others might give more insight as im no expert
try leaving curtains open for few nights
or else shorter curtains

kkelly77

meercat wrote: »

try leaving curtains open for few nights
or else shorter curtains

Probably go for shorter curtains. I need it dark to sleep

meercat

kkelly77 wrote: »

Probably go for shorter curtains. I need it dark to sleep

dont do anything drastic until you get a more informed opinion though;)

kkelly77

meercat wrote: »

dont do anything drastic until you get a more informed opinion though;)

*moves scissors away from curtain*

Carlow52

link

kkelly77 wrote: »

.... The wall vent is definitely clear. .

Well well well I beg to differ: lets have a pic from the out side at an angle to show the gap between the alu vanes on the external wall grill.

This vent is really giving no real ventilation

This vent needs to be cleaned up, internally and ideally replace the alu grill with a proper one, will look for a pic/link and post it.

The curtains are keeping the air still/trapped against the window and the moisture vapour moves through the curtain and condenses on the window.

Try putting a chair or 2 behind the curtain to keep it out from the window and still give u privacy. also leave bedroom door open if u can

U need to get the air moving, there are intelligent wall units around, dont have a link now but the key here is controlled air movement

IMO u are a long way from needing new windows

http://www.dorseyconstructionmaterials.co.uk/gifs/catalog/fullsize/Through_Wall_Vent_Sets_vset93r.jpg

the orange bit

ps a 1983 build with cavity wall build: are you sure?

kkelly77

Carlow52 wrote: »

http://www.dorseyconstructionmaterials.co.uk/gifs/catalog/fullsize/Through_Wall_Vent_Sets_vset93r.jpg

the orange bit

ps a 1983 build with cavity wall build: are you sure?

Thanks for the link. Do those vents come in different sizes? That particular one doesn't look like the right size/shape. This looks like it might do.

I'll have to check the build year again but I have that year in my head from what I remember of the engineers report I got prior to purchase. What are you thinking? Older than '83?

BryanF

so basically the problem is that the rest of us who have crap windows open them a bit at night but you cant because of noise issues

here's a non-mechanical one, but more suitable where drafts are the problem

the issue is, many of the Rh sensor vents are sold as WC of kitchen extracts, as its generally the intakes that are placed in the bedrooms - so when you search for them, companies want to sell you a whole house MEV system (which are great but your talking €'s maybe a grand or so) or MVHR which is more €'s more like 3-5g + a good level of air-tightness - their issue is that if you mechanical extract from a bedroom there must be an intake elsewhere for the air-pressure to equalise + some units may be noisy

here's one company that provides these units but again they will probably try to sell you a centralised fan system. here's another

here's an RH sensor, i don't think its a moisture reader you need, unless the walls feel damp.

about your question on moisture limit (I'm not sure what you mean but here goes) the reason its known as relative humidity(RH) is that the point where the moisture laden air (the litres coming out of you & family) condenses is 'relative' to the tempetaure of the room and the surface of the window where its condensing (in other-words the external temp). this is made worse at night because as the room temp drops the air holds less moisture.
again ventilation and as Carlow says air-movement is key, but where theres a surface (in this case the window) that is cold, condensation will form on it so I disagree Carlow that the windows are no part of the problem

here's the science here's the external rh levels and the SEAI say:

Research has shown that if relative humidity levels exceed 70% for prolonged periods, there is a high probability that the condensation occurring on cold surfaces will lead to mould growth. A ventilation rate of between 0.5 and 1.5 air changes per hour (ach) for the whole dwelling will usually be sufficient to control condensation.

from here

Spread

I imagine that too much of the radiator heat is going up behind the curtain and causing the condensation. If you cut the curtains to just touch the window cill, then cut the nosing off the window board and added a few inches to widen it (so the rising heat from the rad is kicked into the room) ........ that should lessen the problem. The alternative is a dehumidifier.

Carlow52

kkelly77 wrote: »

Thanks for the link. Do those vents come in different sizes? That particular one doesn't look like the right size/shape. This looks like it might do.

I'll have to check the build year again but I have that year in my head from what I remember of the engineers report I got prior to purchase. What are you thinking? Older than '83?

I was just showing you the idea of what u need, there are round ones also whcih I regularly use for retro vent work with a 4" core drill.

The question re the year was that in '83 it may have been cavity block and not cavity wall

Bryan,

I disagree Carlow that the windows are not part of the problem

Not arguing here, poor writing on my part, the op needs to do the other stuff before deciding new windows are it as the condensation will look for the next available spot unless, to use ur own words, its a holistic approach [ 'doze and start again, you know the drill ]

ps great links.

kkelly77

Carlow52 wrote: »

The question re the year was that in '83 it may have been cavity block and not cavity wall

Bryan,

Not 100% sure TBH