Wet in morning- dry at night.... Vent or extractor fan ????? SOS wet bedroom wall to sort !

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If someone can help me sort this problem out I will be eternally grateful .... I own an old stone cottage terrace and I rent it out..... Every tenant ends up leaving because of damp .... We have had loads of workmen look at the problem and all conclude ( after checking roof etc etc) that it is an internal moisture condensation issue not damp.... Our current tenant is really good and we don't want to lose her but although she does not dry laundry indoors and ventilates and cover boiling pans etc etc we have a hard core problem wall in a bedroom upstairs which is always wet ( and it is wet!!!) in the morning but dry by the evening after heating on..... How can we address this ? I will get a dehumidifier for her but would a vent help or an extractor fan???? It can't be noisy during the night or will disrupt sleep.... And want to trust it is on and not put all responsibility on tenant in case she does not turn it on ??!!! Want a good quality one if anyone can recommend something ??? Also, can condensation really be this bad ?????? It is a small bedroom and it dripping wet! Never seen anything like it ! I would not want to sleep like that ! Should I get yet another professional in.....? Sos

could it be the very cold wall, given it is stone?

you can insulate these walls inside or outside. We have dry lined one of our bedroom walls and voila, no more condensation on it. But of course the condensation from breathing has to go somewhere. Usually on the windows, which need wiping. The wet cloth then needs to be squeezed out and go OUTSIDE to dry.

is she wiping up the condensation?

but an old cottage will always have this kind of problem to some extent.

When cold walls are causing condensation, venting just makes it worse, as it makes the wall even colder. We just use dehumidifiers to keep it under control, in winter, but we're the ones paying the electric bill. You do need some way of taking out the moist air, so an extractor fan is probably the way to go.

it isn't true that ventilation makes it worse. You are getting condensation because there is a lot of water vapour in the room, probably because the occupant insists on breathing all night. Ventilation takes the water vapour outside.

if it has a solid stone wall it is doubtless very cold. You could as special suggested line it. Kingspan and others make a special phenolic insulating board with a plasterboard face (this rigid foam is a better insulator than the same thickness of mineral wool). It has to be sealed to prevent moist air getting past and reaching the wall. The old plaster can be hacked off.

External insulation is a lot more expensive and will change the appearance of the building. It will usually be rendered afterwards, but could be slate-hung.

If the room is full of water vapour, and you prevent it condensing on the walls, it will instead condense on the windows, so you still need ventilation. however the improved insulation will make the room warmer. Verify that the loft is also well insulated and ventilated.

Trickle vents in the windows will help get the water vapour out.

Oil and gas heaters make a lot of water vapour if they have no flue.

The stuff we used is called moisture board, plaster-board-ish on one side, rigid foam on the other. Himself is a skilled DIY-er and worked VERY hard to get it cut right. It is HEAVY and too big to fit in cars.

it sticks on with special cement, we've also added some screws higher up - then it is filled and sanded. The gaps need to be filled, taped, sanded, filled again, re-sanded - and he's done such a good job you really can't see the join.

you lose a few cm of room size and have to consider matching up cornices and skirtings.

this is a room which is definitely condensation, not damp. Still thinking about downstairs where it is damp. :-(

Thank you everyone .... Laughing at comment about tenant insisting on breathing !!!!!!

Some of these things sound expensive and messy !!! But worth it if successful .... Should I try for cheaper vent option first ????

Think will try dehumidifier and vent or extractor first ( money rubbish at moment ) then if still have problems I will go with the other above ideas ! What would work best ? Vent or extractor fan ??? Needs to be quiet !

a vent near the floor, and one near the ceiling. If you rely on a fan the occupier will turn it off. Fit a plastic or brass hit-and-miss vent on the inside of each. As far away from the head end of the bed to avoid draughts.

If the low one is under a radiator it will combat the cool air coming in.

A vent or grille in the door would also help, it will allow warmish air into the room from the rest of the house. A very small room will have a higher concentration of water vapour as there is less air for it to mix with.

Thanks pigletjohn ! Thanks very much !

Would it be worth suggesting window is left a tiny bit open overnight to vent while it's milder this weekend? Then you would know for certain if venting will solve the problem or not.

good idea

she could also try leaving the bedroom door slightly open

experimentally, try one thing at a time.

also the windows in the room below, just in case water vapour is rising up from there. How is the house heated?

Thanks I will ask our tenant to do that. The house is centrally heated and she does have it on a lot. The room below does not have any windows. Originally it probably did , it is a small two up two down stone cottage terrace ( in Ramsbottom , old mill worker houses)but the previous owner built a kitchen extension so the dining room is below with no windows and that leads into the kitchen extension ... There are no doors downstairs so the living room, dining room and kitchen are all ' open plan '..... I have ordered an ebac dehumidifier for the tenant to help but since she may not use it, or open windows, I do like the vent idea that pigletjohn suggested since it will help without her having to control it and me trust her and it will still work if she is away ....

It originally had a chimney / fire places in that bedroom and other rooms ... They have all been professionally changed and you would not know they had ever been there .... Wonder if the property had these problems when it was originally built ?!

Dehumidifier and she needs to open the windows for a little bit every day. Also what's the decor like? If wallpaper is not breathes le could be adding to the problem.

Presume you have already had a plumber look for a leak?

e.g. radiator pipe in that or adjacent room, possibly under the floor, or a pipe, waste or shower tray if bathroom is adjacent? You have already had builders in so will be confident that it is not spillage from a gutter or a leaking downpipe, or steam from a condensing boiler, or rain penetration round a window. Experienced local builders will be familiar with these cottages so should know what to look for.

Next time it is empty, live in it for a week and experience it for yourself so you have a better understanding of what does and doesn't help.

If it was just due to nocturnal breathing, it would not occur after nights when that room was unoccupied, but it could take a few days for the bedding to dry out, and actually months for the fabric of the wall to dry.

p.s. you mention it used to have a fireplace.

Each old chimney of flue, unless demolished below the roof line, needs to be ventilated top and bottom with an air brick or similar. Even that, in a small room, will help with ventilation, especially if there is a bit of a gap under the door.

Remember that in terraced houses, there might be a plumbing leak in the adjoining house.

This must be a very worrying problem, but unless there is an extra source of water, ventilation, plus internal insulation of the external wall, should fix it.

Thanks for all of that ...I have just spoken to the tenant and she said she has the heating on loads and always sleeps with the bedroom window open ....... She is going to try tonight with the window open as usual but with door as well ...

Following advice on this thread I am Waiting for quote re couple of air bricks in room so can vent .....fingers crossed... Next step if that is not enough .... Trickle fan in bathroom next door ... Last straw ( more money )the insulation to wall ....