Recommendation for a slightly damp room in an otherwise dry and warm house

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SumBodi

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#232106 29-Mar-2018 21:02

Hi guys

We're moving into a new house which is two storey and very sunny, so is dry throughout except for one medium size bedroom on the lower level which doesn't get much sun. It's not mouldy and we haven't seen any condensation (but we haven't seen it in winter yet), but in that room I can immediately sense some moisture in the air and being an allergic sort, I start coughing a bit.

There's a heat pump downstairs which makes a little difference but not much as it's located at the other end of the corridor. Upstairs there's a fireplace and a fan.

The house is insulated but not double glazed, in Auckland.

Just wondering from those with experience - what do you think the best solution is as the problem appears isolated to just this one room. A dehumidifier? a heat pump in that room? HRV system for the whole place?

Thanks for any advice :)

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#1985688 29-Mar-2018 21:05

I would look for the source of the moisture. If you can't find it you might find ventilation effective, and cheaper than other options. You can get small fans that pull air out of a room, or push it in, including one fancy one I saw a while back that has a heat exchanger.

jonb

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#1985731 29-Mar-2018 21:49

A good quality Mitsubishi dehumidifier just outside in the hallway should be enough, and roll it into the bedroom during the day when the room is empty, that controls the humidity in the rear bedrooms well during the winter in my house. Also handy for drying the washing sometimes if you don't have a tumble dryer.

JayADee

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#1985733 29-Mar-2018 21:52

I'm with timmmay- why is it damp is what I would want to know. And if it is damp now, winter is sure not going to help.

SumBodi

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#1985738 29-Mar-2018 22:04

Thanks all for replies.

The house is in Laingholm, on top of a hill with lots of sun exposure, but the downstairs is built "into" the hill so to speak. It's not a problem except for that one room that is a bit isolated from sunlight. The tree canopy limits light into that room. Even if we cleared the trees (which we're not allowed to do) there still would be a problem with that room as the hill blocks much of the sun.

It's not that bad, certainly not compared to similar houses in the area, and there is no visible mould anywhere in the house, even the bathrooms have been kept in great condition. The structure itself is pretty dry including what is visible of the wooden frame. It has recently been renovated, and as far as I know this particular room has lived through one winter after renovation. I just want to get on top of the dampness before mould does become a problem.

I appreciate the replies, and any further advice is gratefully received :)

nickb800

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#1985777 29-Mar-2018 22:28

Sounds like there is no moisture source, just a lack of heat. I say just heat the room - the warmer it is, the harder it is for the humidity to condense and cause problems

Aredwood

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#1985802 30-Mar-2018 01:45

nickb800:
Sounds like there is no moisture source, just a lack of heat. I say just heat the room - the warmer it is, the harder it is for the humidity to condense and cause problems

Exactly this.

The small bedroom on the SE corner of my house suffers exactly the same problem. It is simply due to not enough heating. The other bedrooms get lots of free heating from the sun.

Although running a dehumidifier will almost certainly be cheaper than heating the room. Unless there is another reason to heat the room.

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timmmay

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#1985807 30-Mar-2018 06:40

Sounds like it could be either moisture seeping from the hill through the wall into the room, or a cooler room that you're percieving as damp. First step is to identify what the problem is. Is there a moisture meter / test available?

Once you know the problem you can start looking at solutions.

SumBodi

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#1985835 30-Mar-2018 09:30

No moisture reader but I think I will get one after Easter.

In the meantime will test with a heater in the room and report back.

Cheers :)

Dingbatt

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#1985854 30-Mar-2018 10:02

Is the door to this room usually open or closed?
If it is normally left open, then the 'dampness' due to the room being cooler should even out with other rooms on that level. If there is a dampness source particular to that room then it will always be slightly damper than the rest, even with the door open. Cold walls and cold windows will naturally attract condensation.
As in the posts above, the first thing to eliminate, or at least minimise, is the source of the moisture.

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

richms

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#1985859 30-Mar-2018 10:16

Sensing dampness in the air yourself isnt going to work. Get a humity meter and see if it really is considerably more humid or just cooler so you perceve the cooling as you go in there as damp. Most of them take a few 10s of mins to update so you cant really go walking around the house with them looking at numbers change like with themometers.

Richard rich.ms

PeterQ

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#1985871 30-Mar-2018 10:31

So I gather it is on piles, could be rising damp? if it is and low to the ground you could lay polythene on the ground to alleviate the issue

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1101

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#1987474 3-Apr-2018 10:30

SumBodi:

but the downstairs is built "into" the hill so to speak.

and there's the cause of the issue
Just buy a dehumidifier for that one room. Keep the door closed, except for occasional airing out .

gzt

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#1987625 3-Apr-2018 13:51

Is that a timber wall or concrete block? Makes a difference for the potential problems and the quick fixes if any.

SumBodi

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#1987728 3-Apr-2018 15:51

Thanks all for the advice.

It is a timber wall.

I don't think there is a problem with the structure, just that the particular room gets less sun. The rest of the house feels very dry.

I bought a dehumidifer (the "desiccant" model Goldair GD330 as it should work at all temperatures). It took about one hour to get to 58% humidity and two hours to get to 48% (if the settings and manual are to be believed). There was definitely an improvement in the room. Leaving the window open works well enough at the moment but won't be a great option for winter.

Appreciate the help and advice, the dehumidifier was the way to go.. hopefully it will perform well in winter!

gzt

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#1987776 3-Apr-2018 17:17

Go have a look underneath if you can. A few things I've seen in this scenario:
-blocked/inadequate gutter leading to runoff soaking the joists
-unpiped gutter randomly running off underneath house

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