Is there a damp/humidity issue in my house??

Alphahedron

Hello,

Looking for some second opinions on a potential problem with damp/humidity I have in my home.

Background is: the home is a 2-bed maisonette, 1970s, ex-local authority, top floor/end-of-block with a pitched roof. The general location is leafy, and at the bottom of a large hill. The property has recently been refurbished by the last owners in previous years. I believe it is brick cavity wall construction, and the previous owners added further loft insulation by the looks. The windows are all recently installed double glazed with trickle vents I keep open.

Situation: since moving in about a month ago (I have just bought), I have really felt that there is an issue with damp/humidity in the place. I have noticed this through:

• An occasionally damp/musty smell in the place.
• A vaguely damp feeling on my bedsheets, which is mostly noticeable at night and which I find really unpleasant and uncomfortable.
• I have now bought two humidity monitors, which seem to suggest the humidity is ranging 60-75% at different times and locations, which I know is on the high side.
• The bathroom has no extractor fan, and so is sometimes a little musty smelling, but I am now in the habit of keeping the window there open and the door fully closed.

As an example yesterday, during a fairly temperate Autumn day, I opened all the windows to ventilate the space well for a few hours, and had the heating on briefly in the evening, which dropped the humidity down to circa 61/62%. By the middle of the night, it had returned to circa +70% despite me having done nothing to increase humidity (no drying clothes, cooking etc). I only got back to sleep by opening the windows again. As I write, the humidity is around 67%. Therefore, I can’t help but feel there is a problem here.

However, I can’t help but doubt myself a little because:

• There are otherwise no obvious visual signs of damp, bar a localised patch near one of the balcony doorways, and a small patch under the sink which I believe is due to a small, intermittent and localised leak under the sink.
• The gutters are I think draining mostly correctly, although they overflow in at least one spot.
• The walls are cool but don’t feel wet to touch.
• There is seldom any condensation on the windows to speak of.
• I’d had a survey done of the property (although not full building survey) which did not pick up on any issues relating to damp.

I’ve got a dehumidifier being delivered, which I am hoping will help manage the issue – ideally, I would like to prevent it from happening. Not really sure where to turn to for advice on this, but also wanting some second opinions about what might be happening. 

Grateful for any thoughts and experiences shared!

grumbler

Cooker - what type? Extractor?

Alphahedron

Cooker is gas hob and oven, with an extractor hood. I have not done all that much cooking with it though in honesty.

FreeBear

Alphahedron said:

• I have now bought two humidity monitors, which seem to suggest the humidity is ranging 60-75% at different times and locations, which I know is on the high side.
  

I have a number of temperature/humidity sensors dotted around the house here and the data is logged. Over the last month

in each room, the humidity has been -

• Unused bedroom - 56-73% (windows & door closed).
• Lounge - 54-72% (door always open)
• Hallway - 52-63%
• Main bedroom - 58-67%
• Small bedroom - 65-76%
• Bathroom - 60-84% (no extractor).

Note - None of these sensors have been calibrated, so there will be some degree of error in the readings.

Despite the high readings, I don't have any condensation issues or problems with mould. Also have a dehumidifier, but it doesn't collect an excessive amount of water. Not that I run the darned thing too often ('orrible, noisy thing).

Alphahedron

Thanks - that's interesting to hear!

I have definitely lived in damp properties before, and in those instances there's been much more obvious problems with wet walls, condensation literally streaming down the windows and the like. This is nothing like that, but the bed sheets are really bugging me. I can't tell how far it is just in my head though, so interesting to see that you get a similar range of humidity without presence of condensation etc.

I've been keeping the place at a decent temperature too - it's been normally in the range of 18-21 degrees, depending on the day and when I've had the heating on.

Bendy_House

Hi Alpha.

I presume you turn your heating right down at night? Do you also crack open your bedroom windows to 'vent' setting? If not, that's worth a try for a few nights. During the day, also ventilate the room on 'cracked open' setting, heating off in there, and shut the internal door. The room 'should' be dry from this. 

I have to say, I'd expect the first indicator of a 'damp' home to be waking up to running window panes. Don't you have any?

If you aren't going to fit an extractor in your bathroom, then def windows open and internal door shut - don't let that warm moist air get to the rest of the house.

Have you changed the type of bed sheets or duvet since your move?

Weird one.

Eldi_Dos

The previous owners might not have kept flat ventilated and may have let a buildup of moisture into the fabric of the flat,especially with gas oven and hob.Not everyone uses extractor while cooking.

I would look into getting a humidistat controlled fan fitted in bathroom and keep trickle vents open as much as possible.

Is there fitted wardrobes in the bedroom?

We use a dehumidifier in the winter and find it very useful but rely on ventilation as first choice for most of the year.

Alphahedron

Hi Bendy,

Yes, the heating goes right down at night. I haven't had windows open at night, but will try this from now on. During the day, the windows are often (but not always) open and I have the trickle vents permanently open.

As for condensation/water running down windows, no I haven't noticed this at all in honestly. One of the reasons I find this so perplexing as I would expect there to be at least some condensation if there's so much water in the air.

I will be installing an extractor fan in the bathroom if I can - just need to figure the logistics of it.

I've changed my bedsheets since moving of course, but it doesn't seem to make much of a difference sadly.

Alphahedron

Eldi - thanks - I do wonder if that's possible and maybe the building just needs 'drying out' (??). There's no fitted wardrobes.

chris_n

Don't know where you are but I doubt it is cold enough for condensation on double glazed windows yet.

Bendy_House

Alphahedron said:

I've changed my bedsheets since moving of course, but it doesn't seem to make much of a difference sadly.

I meant, have you changed the TYPE of bedsheets since moving?! Do they just 'feel' different in any case?

Everything else you report seems fine.

Come winter proper, I would expect you to find condie on your bedroom windows in t'morning if you don't have them venting.