Why is my house so damp when it never used to be this bad?

[CormorantStrikesBack]

I5s an old Victorian house. I know that damp is generally down a lack of heating and ventilation.

so I have the heating at 19degrees. I admit I’m not great at this time of year about having windows open but I manage ten minutes in the morning in our bedroom before going to work, longer if I’m wfh. But I’ve never been great with the windows so no different to normal.

The house is noticeably damper this year than previously. There are damp patches on all external walls, condensation on the walls. We are getting mould.

i am wiping the walls every day. We use a window vac on the windows every morning. I have a 12ltr Meaco dehumidifier running constantly. So it’s been going in my bedroom with the door shut most of the day, I started it at 8am, went up at 6pm and it was full so had stopped. Started it again and the reading is still 80%. Room feels damp. It never used to be this bad.

i move the dehumidifier downstairs overnight. I probably could do with one in every room but can’t afford the electricity! I’ve ordered some of those non plug in ones, not sure how useful they are.

do I need to get anything structural checked with the house? I asked dh and he just said well it’s cold outside so we’ll have more condensation. But I swear a few years ago it wasn’t like this even when cold.

Do I turn the heating up to 20?

But if the air outside is humid ,like it has been a lot this year then ventilation will have little effect. Ideally you need a humidity monitor inside and out to see the difference. But its damp,raining and miserable outside today so I’m guessing opening the windows is not going be a lot of use.

Id like to see the bucket of air theory tested….. i wonder how many houses in the sahara suffer from damp 😉

Damp proof course needs looking at I'd say. Or you need better drainage around the house itself

Who in there right mind opens the windows when its zero degrees??? Lets get the house down to zero so we can waste energy warming it back up again .
Surely if you want to air your duvet just hang in on the line ?

When its damp outside keep your windows shut , the warmth in and a dehumidifier on to suck any moisture out.

We’ve had very similar issues this year though not quite so bad.
Our house is partly Tudor and it was those walls which were affected. We had an expert out who told us it is several things. One is the weather, it’s been so wet this year many old houses are affected. The other issue is pointing, which needed redoing with lime mortar rather than modern mortar.
He also dug a trench at the base of the affected walls, which almost immediately stopped the damp appearing every day. The repointed has now been done and the problem has completely disappeared!!

What do you think "failed slate" is?

It lasts millions of years.

The bucket of air theory is quite correct. A humidity number of, say, 50% is actually RH 50%. Relative humidity. The amount of water that air is holding, as a percentage of the maximum it can hold at its current temperature. Warm air can hold more. You can easily test it yourself. Fill a glass with ice cubes in the Sahara. It gets covered in condensation which pools on the table. Do the same sitting under your umbrella on a cold rainy day. It hardly changes. On a frosty day, it doesn't change.

That's also why tumble driers work.

You don't keep them open all day. Blast airing... People need to air in winter.

And yes, I put them on line outside.

@PigletJohn maybe not correct terminology. Mine was wet top and bottom.

@PigletJohn not necessarily slate, not sure but we had loads of damp people are surveyor out and they all said that this is happening now as water table so high. Probably made worse by new estate just built over road? Maybe the house wasn’t designed for such a high water table?? Not sure!?

My 1850s house gets terrible if we don't heat the place. We leave it at 21 degrees otherwise it just feels awful. I also have the meaco running constantly. It gets it to 55 humidity then switches itself off. It's worked really well this year.

Just seen the photos, that does not look like it would be fixed with more heating. Is there something going on with a chimney leaking?

Humidity monitoring is a good idea , but if the humidity in your house is for example 55% and you open the windows to air and the humidity outside is 65%. Once the house is warmed again all you are doing is increasing the humidity by 10% from what is was before, which in turn could create more condensation…….. so yes opening windows can be good for fresh air but its not always drier air. Ours is currently 60% …. No idea what it is outside … no windows open. 🙂

My Victorian mid-terraced house doesn't suffer from obvious damp, although I struggle to get the RH below 60. I open the windows for at least two hours per day unless it's pouring with rain, and then put the dehumidifier on. The storms have caused a leak in the roof, however, so I have a wet patch on the bathroom ceiling. I'm still waiting on a roofer - I think they are extra busy this year.

On one occasion (before I acquired the dehumidifier) I saw wet patches similar to the OP's in the second bedroom after I'd washed some towels expecting to dry them outside, but the weather turned and I had no choice but to dry them indoors. The patches disappeared within an hour of removing the towels and opening the window. So I think it's definitely worth the OP seeing if she can dry out the room properly to see if the issue is condensation rather than damp coming through the walls.

I never know what to do about the loft hatch when it gets cold. There's advice from plumbers to keep it open to protect pipes, while damp specialists will tell you to keep it closed to prevent warm air causing condensation on the underside of the roof.

I just wish the rain would stop so our houses could all dry out!

@PigletJohn , that's so interesting about RH. I'd wondered why the humidity can be well over 80% outside and 60% indoors, but the air coming through the windows still feels fresher.

Were these "damp people" hoping to sell you silicone injections?

It's been suddenly very cold in the last week, after a mild wet spell when the air is saturated with damp. That will make the moisture condense out. Normally it gets colder more gradually and the moisture comes out of the air gradually. I think it's just the odd weather these last few weeks.
If your problem is all over, not just in one room or place, I think it's likely to be that. When you get a really cold, sharp, frosty day, open the windows for a good while, that will let cold air in, but that air will be carrying less water, and the damper air in the house will get out. That might sort it out.

If it's cold, dry, and frosty out, there will be less water in the air outside.......

Don't know about the sahara, but having camped out in the desert in Arabia, it can get wringing damp at night-fabrics get positively wet. Paper absorbs the wet and goes crinkly, you can't get a pencil to mark it. That can persist well into the morning, making it misty, dank, and jolly cold too. Even though the days are very hot and dry once the mist has gone.

Yes i know cold air holds less moisture but it was only cold a few days ago and the op has been having problems longer than that. I fully understand how to keep moisture lvls under control in our house and have never suffered mould or condensation issues, but a lot of people dont.

As said before, and by others this year has been a wet,damp even humid year , i work outside and have been in the worst of it. This has been a problem for many with related issues.

give me cold ,dry anyday 🙂

Just got back home after been at work all day. Dehumidifier had been on downstairs in the day so lugged it upstairs to my bedroom. Humidity is 77%. I’ve found a surveyor online, a proper chartered one and emailed them asking for a price.

I nearly booked a company called Peter Cox damp surveys as they came up when I googled chartered surveyors damp and my town name. I thought they were proper surveyors and thankfully I googled them and found all the reports saying they’re a load of fraudsters posing as damp specialists who give out near identical surveyors saying the damp proof course has failed and they can do xyz (injections I think) to fix it.

Its not to do with the heating..........its a structural thing.
Comments such as 19c isnt warm enough to prevent damp, you need the windows open and the heating set to 24c - are completely wrong.

We live in a little terrace. Heating is rarely on, in fact so rarely we've only put it on for 1 hour so far this winter. The temperature is on average 11-14c. No damp issues at all, anywhere in the house.

Second, don't use a "damp specialist". Years ago,we had a purpose built maisonette. Block of just 2,us ground floor, one above. We had black mould, Chrystals and some sort of fungi growing on the outside. We called out "Rentokill" I said by the height of these external problems I felt it was rising damp. He said it wasn't, the building was just drying out (it had been built by a private builder, the client lived upstairs,had no problems,it was left empty for a year to dry out) He told us to put the heating on full and open all the windows. A proper survey then revealed RISING DAMP, the builder had forgotten the DPM under the concrete floor. They all had to be dug up!