Condensation on inside of bedroom windows - new extension

aidanodr

Hi Guys,

I REMOVED A RANT

We built an extension onto our existing house. Finished about may 2015.

The house itself ( built in mid 90s ) is a bungalow and is c2. However the new extension was well insulated to high A. The insulation behind the plasterboard on the inside is anywhere between 30mm to 60mm ( I think, as far as I can remember ).

In our case the bedroom in question is in the new extension. The room has no wall vents - we were told they are not allowed anymore ( engineer etc ). Only vent is a window trickle vent that can open and close on the PVC of the small window ( images below in another post ). Its meant to allow a little air to circulate. When the extension was finished a guy came around to add these window trickle vents to all new windows.

Looks like this is not enough. Every morning when we wake up in this colder weather the inside of the windows, around the edges ON THE GLASS have condensation and now beginnings of mold. I clean this regularly. It seems only to be an issue on very cold mornings. No condensation otherwise.

We have a blackout blind & also a full length curtain ( as seen in images below in another post ). We have tried leaving one or the other open with no real effect.

During the day while in the house I open the windows and doors to let air flow through.

So - I am wondering is this a common problem in newly built extensions and houses .. with all this extra insulation and no vents, in comparison to older builds? OR do we have a hidden damp problem somewhere else? I dont suspect the latter because this condensation only occurs in very cold mornings?

The condensation is NOT between the panes, it is on the inside ..

Fiery mutant

I don't understand this whole no fireplaces thing, absolutely baffling. I couldn't live in a house with no fireplace. We have a stove instead of an open fire, and if you keep all the doors open inside for the day, it heat upstairs as well.

If you're worried about lack of ventilation, put in some vents yourself. Keep doors open so the temperature is even throughout the house.

Metric Tensor

aidanodr wrote: »

I think this condensation thing is as a result of recent pre occupation wth BER ratings and the like. Houses now are too insulated??

No such thing. Some might be poorly ventilated though - which is a different thing to insulation.

As an aside I have now heard fireplaces are going to be banned in new builds. No more chimneys.

This is a half truth. It is very very difficult to meet the new energy conservation rules if you have an open fireplace in the house because an open fire is so inefficient. No problems whatsoever with stoves though.

In our case the bedroom in question has no wall vents - apparently not allowed anymore.

This is totally wrong. The wall vent is mandatory unless you have alternative mechanical ventilation - which I'm fairly sure you don't in a 1990s house. Also you'd know if you did!

Only vent is a sort of vent strip one can open and close on the PVC of the small window. Its meant to allow a little air to circulate. When the extension was finished a guy came around to add these t all new windows.

This sounds like it was done because they forgot the wall vent. It is not sufficient though.


Now - to your actual problem:

Common causes are:
1. Poor ventilation - as you mention but it you open the windows regularly in most of the house it should help. You should have a proper vent though.
2. No extractor in your bathroom combined with lots of hot showers.
3. Drying clothes in the house.
4. A large number of occupants.
5. Thermally unbroken window frames. What are your window frames made from?
6. Possibly a leak.

I'd look for the easy things first like showers and clothes drying.

Calahonda52

OP, would be useful if you stick to the knitting here and separate out the issues you need advice on from the rants about extraneous stuff.

Its not evident if the bedroom is in the old or new part of the house.
Like wise you post is silent on what ventilation there is throughout the house.

When the extension was done was it signed off for compliance with Part F?
http://www.housing.gov.ie/sites/default/files/migrated-files/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad%2C1647%2Cen.pdf

Also can you be more specific on what you mean by around the edges..
of the
glass
frame
reveal
?

Before I sign off, the black out blind and the full length curtain will help to almost eliminate air flow, they will also help to insulate the window from the warmed air in the room, hence dropping the temperature lower than the dew point.

http://www.dpcalc.org/

However, eliminating the airflow will not stop the moisture, contained in the air as water vapour, finding the colder spots due to the differential vapour pressures present, hence the Tina Turner effect.

Good luck and keep well.

Metric Tensor

A P.S. to the above. When I say no such thing as too much insulation I mean ideally no heat should escape through the building elements:

Obviously:
1. This is impossible unless outside is warmer than inside.
2. There's a point at which spending extra money on insulation is very poor value for money.

aidanodr

Ok. Apologies for the rants.

Yes the bedroom is in the new part of the extension.

The condensation is on the inside of the windows on the glass itself around the edges.

The vents on the windows are along the pvc at top of small window. Going through to outside. They click open and closed.

Otherwise no other vents in wall.

In old house all rooms have a square plastic vent through to outside.

We were told these vents were not allowed anymore?? Only the ones in the windows

Will take pic when back in house.

Thanking you all

BryanF

Sounds like a lack of ventilation and mediocre windows.

Just leave the window slightly open at night.

the rest of the OP rant about too much insulation and no more chimneys is nonsense.

aidanodr

OK guys .. I got you about the rant already .. Now removed from the OP ..

aidanodr

As promised .. here are photos of the window and then the window trickle vent at top:





The window trickle vent is in the pvc at the top of the small window. In the large image it is covered by the roller blind over right ..

If we have condensation tomorrow again I will take a pic of that and post here too ..

aidanodr

Guys,

Should we really have had something like this in th bedroom?? In the older part of the house all the rooms have these ..



In fact should we go about getting something like this installed now ???

Metric Tensor

aidanodr wrote: »

Should we really have had something like this in th bedroom??

Yes

In fact should we go about getting something like this installed now ???

Possibly/probably.

There should 100% be one in any room with a combustion appliance - fire/stove/boiler, etc. There should by rights be one in each bedroom too but it's possible you can solve the moisture by other means and it's still well worth identifying the source. Also if you are leaving the window ajar each night you are doing the same job as a vent.

aidanodr

Metric Tensor wrote: »

Yes


Possibly/probably.

There should 100% be one in any room with a combustion appliance - fire/stove/boiler, etc. There should by rights be one in each bedroom too but it's possible you can solve the moisture by other means and it's still well worth identifying the source. Also if you are leaving the window ajar each night you are doing the same job as a vent.

Thats the thing .. could their be a source other than the two of us in the room sleeping at night? We tend to not have the rad on over night.Like cooler room to sleep in.

A small hallway from the extended kitchen leads into this bedroom - door at either end. Through the bedroom into a small walk through wardrobe type room into the ensuite bathroom ( door here too ) that has a shower unit, small window facing out the back. Extractor fan.

As i mentioned the condensation only happens on very cold nights.

BorneTobyWilde

The way I look at it is you probably don't have enough heat in room in morning. It's like condensation on inside of car window, when car warms up and heat is on it disappears.
WHat is heating this room , I see no radiator under window.

aidanodr

BorneTobyWilde wrote: »

The way I look at it is you probably don't have enough heat in room in morning. It's like condensation on inside of car window, when car warms up and heat is on it disappears.
WHat is heating this room , I see no radiator under window.

The radiator is not under the window based on Wife decision .. she wanted full length drapes as you can see.

The rad .. as you view the image is on the wall to the right out of shot. Next to that is the door into the ensuite wardrobe room, then bathroom.

Sleeper12

aidanodr wrote:

In fact should we go about getting something like this installed now ???

Yes definitely.
I've never been a fan of trickle vents. When curtains are closed its restricts the air flow.

aidanodr

Maybe you guys could answer something .. Though we finished the extension which sort of doubled the house size ( bungalow ) last may 2015 .. Could the new concrete / plaster keep on "sweating" for months, years? Even from May 2015 to now? Could this cause condensation?

As mentioned elsewhere ( extracts ):

"As others have mentioned a new build that has a concrete base and a plastered interiors will take a long time to dry out properly, add in the moisture from the occupants and suddenly it can become a big problem.

... a person produces about 1.5 ltrs per night apparently

... it is just one of the joys of a new build property, partly brought about by the modern insistence of virtually hermetically sealed housing.

... You have to get the moisture out of the air, so if you can't or won't open the windows in cold weather or when people are at work, the only option is a dehumidifier."

AND when I say it only happens when the weather is very cold outside .. does that point to anything? Other than on real cold nights their is zero condensation. Would this take out OTHER MORE SERIOUS REASONS? If their were other reasons would this condensation happen under other weather circumstances? .. sorry if a dumb question ..

Metric Tensor

Does it only happen on the bedroom window? If it is only on this window it would "probably" rule out bigger problems. If it's happening elsewhere in the house it's definitely a wider issue!

Assuming it's only in the bedroom - how would you feel about leaving the extractor in the en-suite on overnight - that should give a nice flow of air through the room.

It takes a long time to dry out floor screeds and plaster but not 20 months unless there's a mitigating factor. If there was a lot of moisture around the house timber work would probably be warping and distorting too.

aidanodr

Metric Tensor wrote: »

Does it only happen on the bedroom window? If it is only on this window it would "probably" rule out bigger problems. If it's happening elsewhere in the house it's definitely a wider issue!

Assuming it's only in the bedroom - how would you feel about leaving the extractor in the en-suite on overnight - that should give a nice flow of air through the room.

It takes a long time to dry out floor screeds and plaster but not 20 months unless there's a mitigating factor. If there was a lot of moisture around the house timber work would probably be warping and distorting too.

Yip - The new bedroom window & a small bit on the small window in the ensuite bathroom. Up to now the door from the hallway into the bedroom, and the door from the bedroom into the ensuite would have been closed while in bed to keep the room dark ..

Metric Tensor

Sorry - just re reading my post.

When I suggested leaving the fan on overnight I meant for one night only as a test. It is obviously not a long term solution!!!

BryanF

aidanodr wrote: »

Maybe you guys could answer something .. Though we finished the extension which sort of doubled the house size ( bungalow ) last may 2015 .. Could the new concrete / plaster keep on "sweating" for months, years? Even from May 2015 to now? Could this cause condensation?

As mentioned elsewhere ( extracts ):

"As others have mentioned a new build that has a concrete base and a plastered interiors will take a long time to dry out properly, add in the moisture from the occupants and suddenly it can become a big problem.

... a person produces about 1.5 ltrs per night apparently

... it is just one of the joys of a new build property, partly brought about by the modern insistence of virtually hermetically sealed housing.

... You have to get the moisture out of the air, so if you can't or won't open the windows in cold weather or when people are at work, the only option is a dehumidifier."

AND when I say it only happens when the weather is very cold outside .. does that point to anything? Other than on real cold nights their is zero condensation. Would this take out OTHER MORE SERIOUS REASONS? If their were other reasons would this condensation happen under other weather circumstances? .. sorry if a dumb question ..

Please use the quotation function in future .


You have two adults producing 2 x 1litres of water vapour over a night

You have cheap pvc windows that have a cold internal surface allowing this vapour to condense.

Open the window!

On really cold nights, don't bother opening the window.

Next time you have the builders in, buy bettter windows and a ventilation system.

hatchman

BryanF wrote:

Next time you have the builders in, buy bettter windows and a ventilation system.

That's a bit harsh ! Not everyone can afford better windows !

BryanF

hatchman wrote: »

That's a bit harsh ! Not everyone can afford better windows !

True. But, this thread has brought up all the 'old wives tales': talk of dehumidifiers, Too much insulation blah blah blah,

the op was set straight by many of the regular posters, but is still looking a mythical source of condensation, when it's just caused by two adults sleeping in a bedroom,

The windows that are the weakest link in the buildings thermal envelope.

The options are as stated:

BryanF wrote: »

Open the window!

..

Next time you have the builders in, buy bettter windows and a ventilation system.

Sleeper12

hatchman wrote:

That's a bit harsh ! Not everyone can afford better windows !

A simple 4 inch vent can be done for 100 to 200 euro depending on the builder. It would take 2 hours to do properly. There will be no curtain to restrict the air flow

multisport

Would this work as a solution
http://munsterhrv.com/shop/index.php?main_page=product_info&products_id=56

There's previously a boards thread on single room heat recovery units http://www.boards.ie/vbulletin/showthread.php?t=2055606229

Some units seem to be suitable to leave running overnight as they have a lower noise setting.

Calahonda52

multisport wrote: »

Would this work as a solution
http://munsterhrv.com/shop/index.php?main_page=product_info&products_id=56

There's previously a boards thread on single room heat recovery units http://www.boards.ie/vbulletin/showthread.php?t=2055606229

Some units seem to be suitable to leave running overnight as they have a lower noise setting.

The noise level is a recurring issue, despite the claims.
The other issue about SR-HRVs is the technology.
They are essentially a suck and blow fan so the full room rarely gets a full air change.
Likewise the location chosen is usually the existing vent in the wall, which in many cases is contra-indicated as a suitable location