Big condensation problems- any help appreciated

cicfada

Hi . I have serious condensation in my house upstairs. The house is 16 years old but we got the walls pumped with insulation 5 years ago and attic laid with insulation at the same time . Then 2 years ago we got new windows installed in the front ( west) of the house along with a new front door . The house is lovely and warm but all windows upstairs have a lot of water on them still. We got a dehumidifier yesterday and put it on in the landing, last night . All ( 4 ) bedroom doors were closed and while it collected 1.5 pints of water during the night there was still the condensation on all the windows this morning . Very disappointing to say the least. We haven't turned the heating on yet and that may have an effect but it's not cold enough to turn that on yet and why should we have to ? All windows have trickle air vents in them but we have to open them fully now every day as a result of the condensation . We may have to get the device that pushes air from the attic down but you're talking about €1500 then!! I'm at my wits end, we thought when we got the new windows that the era of condensation would be over but it's as bad as ever. Thanks for any advice you could give.

dathi

at it simplest you have a ventilation problem. the moisture produced during the day/night is unable to leave the building and is condensing on the windows as these are the coldest part of the structure. it is most noticeable during autumn as the external air temps drop and you haven't turned on heating yet. the vents on the window must remain open at all times and should only be closed if there is a gale blowing . other than that you have answered your own question in so far as you will need a demand controlled ventilation system . unfortunately what most people dont realize is when you take an old leaky building and start to upgrade parts of with insulation etc, that it has knock on effects on other elements and unintended consequences. and upgrades should be planed holistically for the entire building.

wiz569

Keep the internal doors open,to allow for proper airflow to and from the dehumidifier, plus it will take a few days of running to get the humidity level down anyway

cicfada

dathi wrote: »

at it simplest you have a ventilation problem. the moisture produced during the day/night is unable to leave the building and is condensing on the windows as these are the coldest part of the structure. it is most noticeable during autumn as the external air temps drop and you haven't turned on heating yet. the vents on the window must remain open at all times and should only be closed if there is a gale blowing . other than that you have answered your own question in so far as you will need a demand controlled ventilation system . unfortunately what most people dont realize is when you take an old leaky building and start to upgrade parts of with insulation etc, that it has knock on effects on other elements and unintended consequences. and upgrades should be planed holistically for the entire building.

Thanks for your reply, I'll give the dehumidifier another go with the doors open this time . It probably takes a bit of time to get the humidity under control .

Wearb

Just a thought; Have you been using any sort of stand-alone heater during the transitional period, until you need regular heating later on?

cicfada

Wearb wrote: »

Just a thought; Have you been using any sort of stand-alone heater during the transitional period, until you need regular heating later on?

No stand alone heater in use, the house is warm enough not to need it. I suppose that is the root of the problem, more heat in the house failing to ventilate properly . Better the last few days due to the mild weather and we also have opened the windows for longer through those days as well. Thanks

Dardania

dathi is spot on, and to note that often times the trickle vents in the windows are insufficient (undersized) relative to the actual air exchange required.

A simpler method of improving the situation (compared to the positive pressurisation method you note) might be to have a decentralised constant extract system, that is humidity controlled.

So, for example, you could replace any extract fans in the bathrooms with constant running, quiet ones, controlled by a humidistat. As wiz569 says, you need to have an easy route for the air to travel (so tend to keep the bathroom doors open, or fit door transfer grille)

The dehumidifer idea is a band aid problem that doesn't solve the root cause in my opinion - you would be better off to solve the root cause.

cicfada

Dardania wrote: »

dathi is spot on, and to note that often times the trickle vents in the windows are insufficient (undersized) relative to the actual air exchange required.

A simpler method of improving the situation (compared to the positive pressurisation method you note) might be to have a decentralised constant extract system, that is humidity controlled.

So, for example, you could replace any extract fans in the bathrooms with constant running, quiet ones, controlled by a humidistat. As wiz569 says, you need to have an easy route for the air to travel (so tend to keep the bathroom doors open, or fit door transfer grille)

The dehumidifer idea is a band aid problem that doesn't solve the root cause in my opinion - you would be better off to solve the root cause.

I appreciate your reply . I'm looking at better extractors alright but ideally I would like a solution they could enable us to close bedroom doors at night in an ideal world . Short of bloody knocking holes in walls I'm tempted by the piv system. It seems like the only permanent solution they would enable us to close doors at night . I have three sons entering teenage years who will appreciate privacy, I'm sure. I agree about the trickle vents, they're useless .

Dardania

What I've requested from architects before has been this type of thing:

http://www.waterloo.co.uk/product-models/dsr-acoustic-air-transfer-grilles/

or a simple 20mm undercut under doors (basically a gap between the underside of the door and the top of the floor / saddle board)

both those solutions allow for air transfer, and the first one goes some way to reduce sound transfer. could be an option...

the_pen_turner

Dehumidifier s require a minimum temp to work.
What kind of dehumidifier did you get. The cheap domestic ones a crap.they are OK to keep it down but will take forever to get it down. You should hire a proper one. It will suck gallons in a day.

Open all the windows and blow out the house. Then turn on the heating. Open all the internal doors and leave them open except at night on the bedrooms.

Have you any vents in the walls. You should I still some. . Leave the trickle vents open all the time .

cicfada

I have no vents in the walls and I have often thought about the value of installing some . I did put a vent in the wall between our bedroom and en suite ( 3 years ago) but it made little difference. And in any case, when the window in the end suite is open, the door into the ensuite rattles a bit when closed. We do open the windows during the day now . I am also tempted to hire a bigger dehumidifier as well just to give it a few big "sucking" lashes.!! We will have to see what happens when the weather turns colder, for now it's lovely and mild though you'd expect that to change soon. I'll be updating this thread on an ongoing basis as the weather changes . Thanks again for your kind ideas.