condensation damp in home opening windows isn't helping

PollySouthend

hello,

i have a 50's built house in a coastal exposed area. it was empty last winter and I moved in in the summer. I was aware of a damp problem but assumed it was just condensation from the old lady that lived here before and not opening the windows and using a gas fire. it did not smell of damp in the summer, but now does.

however now its got cold there is a considerable amount of water on the windows and walls and fabric are getting mold. i cant even use a salt mill as it just clogs up and my pepper mill has gold moldy on the bottom .

im pretty sure it isnt rising damp or horizontal damp as no plaster is cracking away.

could this be a problem with the caverty wall insulation? it was done in 2010 and I have the guarantee but it is not in my name.

any advice is welcomed, i have purchased a dehumidifier that should arrive today.

nickcc

Have the same problem especially behind any furniture where air circulation is restricted. We are fully double glazed with cavity wall and loft fully insulated and we also live in a coastal area. All the window vents are left open but, like you, everything gets damp. We now use a dehumidifier for about 8 hours per day which helps but doesn't solve the problem, we have to empty about 5 litres of water out after about 3 days use. One cause of damp is over insulation and lack of air circulation, condensation from cooking, clothes drying and breathing also doesn't help.

PollySouthend

nickcc wrote: »

Have the same problem especially behind any furniture where air circulation is restricted. We are fully double glazed with cavity wall and loft fully insulated and we also live in a coastal area. All the window vents are left open but, like you, everything gets damp. We now use a dehumidifier for about 8 hours per day which helps but doesn't solve the problem, we have to empty about 5 litres of water out after about 3 days use. One cause of damp is over insulation and lack of air circulation, condensation from cooking, clothes drying and breathing also doesn't help.

Thanks, yes I'm in the same situation as you double glazed fully insulated apart from under the floor boards. How do you heat your house? At the moment my heating is off and dont put it on until it is under 15 degrees.

It's often misty where I live and i'm ontop of a hill, could that be a reason?

Mine only seams to happen most on the north facing rooms in the corners, the south facing ones including the kitchen and the bathroom are damp but no mold on the walls.

I open the windows and doors to vent the house for an hour or so every morning.

Getting a log burner put in, any idea if that help / hinder?

PollySouthend

a dehumidifier on for 8 hours a day will work out 60p a day and rising, could easily cost over 100 just for the cold months to run

WestonDave

Polly - your lack of heating will be making the situation worse. Humidity is a relative concept - air at 20C with a certain amount of water vapour in it will be a lower relative humidity than air at 15C, so be letting the temperature drop you are automatically increasing humidity. This is a problem because it will start dumping water as condensation on cold surfaces such as your north facing walls.

Conversely, increasing the internal temperature will allow the air to hold more water without issue and will help dry the damp surfaces. However that is obviously at a cost of heating so its possible that the dehumidifier and no heating option is more cost effective.

The holy grail solution is something called a MVHR (Mechanical Ventilation and Heat Recovery) which is a ducting system which sucks warm wet air out of the house, passing through a heat exchanger which transfers most of the heat to incoming dry air from outside - the by product being water which is drained off. However they are hard to retro fit because of the ducting needed through the house.

nickcc

We have central heating and damp/black mold even on the new extension which is south facing. Would have thought the wood burner would be better than an open fire as it's completely sealed when in use, much the same as central heating. We use the dehumidifier in the clothes storage area as we were ending up with mouldy shoes, leather bags and clothing, I can't think of any other way we can help to prevent the damp so looks like 60p per day is a small price to pay. Some local people have even installed fixed dehumidifiers with extractor vents in all the rooms, goodness knows what their running costs will be.

EwloeFM

We had something similar in our property last winter where the water would build up on the angled sides of the ceiling and upper walls, opening the windows seemed to fix the issue, our long term solution was to fit an airbrick at the top of the apex of the house to improve circulation and reduce the condensation build up.

Our house also has cavity & loft insulation etc ( believe it or not a house can be too well insulated!)

This has definately worked and now I can sleep soundly without being woken by an unexpected early morning shower! :j
A qualified builder could install an air brick for you in a few hours and for under £100 in most cases - surely worth a try!

PollySouthend

Thanks for all the advice, sounds like my house is just like many others.

I bought quite an expensive dehumidifier and on the low setting will cost 10p a day, guess i will just leave it on low most of the time and see how i go.

hopefully it will resolve some of the issues for now, like all my paper going floppy.

airbrick sounds like a good idea to try, im hoping it wont get any worse but its still double figures and its already an issue lol

nickj_2

some useful info and ideas here

Matt_Pug_106

PollySouthend wrote: »

Thanks for all the advice, sounds like my house is just like many others.

I bought quite an expensive dehumidifier and on the low setting will cost 10p a day, guess i will just leave it on low most of the time and see how i go.

hopefully it will resolve some of the issues for now, like all my paper going floppy.

airbrick sounds like a good idea to try, im hoping it wont get any worse but its still double figures and its already an issue lol

Out of interest which model did you buy? I'm in the same sort of situation however it mainly seems to be the hall and bathroom that's the issue.

GwylimT

I used to live on the Welsh coast, the air is more humid and so you are more likely to have damp/condensation issues compared to areas in land.

When you are drying clothes and cooking what sort of ventilation are you using?

You will suffer with more condensation if your house is cold, where do you live? Just wondering as it is yet to go below 15 in the day or at night yet, it has been horrid here.