Very cold wall, high humidity levels, the council strikes again!!

[BigTashJon]

Hi all,
First post in this forum, Ive just moved into an 1812 cottage in north Lincolnshire, loving the Pheasants, Peacocks and Deers that like to keep me awake at night, but i digress.

This house was an ex council house and has had alot of lovely features covered up which are causing issues, my main concern at the moment is one of the exterior brick walls feels cold on the inside and looks wet on the bricks outside, now someone in the past has covered the lime pointing up with a cement mortar, this isnt a particular good job and shouldnt be too hard to remove, the internal wall (full length of house, different rooms) have been plastered in gypsum with something under the plaster which has what looks like lime clumps in it, i dont think its right and i understand these materials do not breathe (obviously not the lime), the bedroom is currently between 8 and 12 degrees c, 86 % humidity, with the windows constantly cracked to deal with the moisture that me and my wife breathe out in the night

I suppose im just wanting some confirmation by people that have has the same issue and removed the gypsum based product and replaced with lime, that it does actually work as its a lot of time and money

 

[DaveG]

Welcome!

In short yes but there’s potentially a lot more going on so tackling the plaster alone may not sort things completely.
Conversely there could be some other things you could do before stripping the wall that will start to reduce moisture levels. You’ve got to tackle things on multiple fronts.
The most important thing is bringing those moisture levels down for better indoor air quality for you and your wife.

Relative humidity while high, would be a lot lower at a higher temperature. Heating is an important part of driving moisture outside. Can I ask why 8 - 12 degrees?
Studies suggest in an older building you should keep temperatures above 14c. Appreciate it’s a bedroom so cooler temps than living areas but at 16 degrees you’ll find the house immediately drier.

Next thing that stands out from what you’ve said is the outside of the wall being visibly wet. What do you think is causing this? Is the guttering in good working order? Some pictures would help.

Last thing is to assess your ventilation in the house. Is it all sealed up? Any air vents? Air bricks? Fireplaces all blocked up? I know you’ve mentioned windows being opened somewhat but if these weren’t open, how much ventilation do you have?

 

[BigTashJon]

Hi Dave, Thanks for the quick reply

The bedroom we sleep in is at the far end of the house there is no fireplace in this room and no air bricks anywhere in the house and the upvc windows do not have vents in them, this is a Georgian solid wall with lathe and plaster flooring except in our bedroom area where the floor has a cavity(Victorian extension).

The heating we have is a log burner (living room)and oil central heating everywhere else, we do run the central heating a few times for a few hours a day, but the temperature dosent seem to stray above 12 degrees, i was hoping the cold walls are caused because they cant breathe and if i was to allow them to breathe they would dry out and the temperature would go up and become toasty
Ive read that as the mortar has been covered up the moisture seeps into the brickwork instead and tries to dry out that way.

I will post a picture up, noticeably damp from the subtle colour difference, the wall in question dosent have any guttering as its a gable end, theres no leaks i know about and that i believe would cause this issue

Pictures attached one of the substance under the gypsum plaster and i will resize one of the damp which only seems to be located outside

 

[BigTashJon]

This was taken in summer, notice the bottom part looks damp, the inside wall is dry under the plaster, but now the cold weather is here it all looks abit moist

 

[DaveG]

Lovely looking brickwork. It’s a shame it’s causing you so much trouble!
I see the wet patch. What room is on the other side of that patch? Assuming the bedroom is upstairs and not on the ground floor?
Looking at that lower window is that a cellar kind of room where your inside ground level is lower than the outside?
Do you get much in the way of traffic along that road? The wet patch to me looks like it’s caused by splash. It could be traffic but even just rain hitting the concrete pavement can splash up against the wall.
When you have this kind of situation where you can’t address outside ground levels to help the wall breath outwards more, you are only left with the option of the moisture coming in, turning to a gas (provided temperatures are high enough) and then being carried away by good ventilation.
You’ll definitely need to look at getting temperatures up higher to help with this process though I’m afraid. Obviously you also need to allow the moisture out as you’ve done by opening up that hole. Taking it off does look like it’s necessary but can appreciate it’s not for the faint hearted! Perhaps you can just take it a section at a time but it’s difficult to know without seeing the full wall inside and the living situation as in, is it a room you need regular use of or do you have space to gut it while living in other areas of the house.
Going back to the bedroom specifically, assuming this is upstairs and not next to that damp patch, I would expect you to be able to better manage the moisture levels in that room unless water is coming in from another source. Any signs of damp in that room?
If it’s just a case of the moisture being carried around the house you can look to start zoning areas off, keeping certain doors closed, others open and trying to get some more heat and air circulation at least in the room you’re sleeping in

 

[paulc]

Relative humidity while high, would be a lot lower at a higher temperature. Heating is an important part of driving moisture outside. Can I ask why 8 - 12 degrees?
Studies suggest in an older building you should keep temperatures above 14c. Appreciate it’s a bedroom so cooler temps than living areas but at 16 degrees you’ll find the house immediately drier.

I've been trying to maintain a temperature upstairs in the 16-18°C range. This has helped to push relative humidity levels down to 45-50% in the bedrooms and has cleared up much of the problems with condensation. Its taken me a while to get to this stage (years, not months) by way of improving insulation levels, cutting draughts, and installing a new heating system.
Like BigTashJon, the bedrooms had always been difficult to heat even after fitting new windows, but that has been solved by fitting much bigger radiators.

One point to remember - A damp wall is a cold wall, and will attract condensation making the problem even worse. Ventilation will help a little, but does nothing in getting the temperature up. I don't have trickle vents, nor do I open the windows - Maybe the wrong strategy, but it is working for me.

 

[DaveG]

I thought I had it tough with a poorly insulated attic room as my sleeping quarters which typically hovers around 15 - 16c when the rest of the house is 18 - 19c. I had no idea some people had that much difficulty heating bedrooms (assuming CH was in place obviously).
Reminds me of my dads stories of waking up in his childhood room and having frost on the INSIDE of his window

 

[BigTashJon]

Thanks Dave and Paul, on the picture showing the damp behind the wall starting from left to right is a halway with staircase curving round, followed by a bathroom, celler below and kitchen on the far right, all are terrible if i put any object in front of them (mould appears), the kitchen thats fitted at the moment has mould behind the units and its creeping into the cupboards, at some point someone has tried to fix the problem with a damp course, on the topic of splashing from the road, water dosent pool in this area and the road is a fairly quiet one(only used if you live in this part)

In the celler when i arrived was a small dryer, ventilated outside, this is now gone and what small amount of moisture has now gone, there is a manhole cover thats been put in at somepoint which had me question has something being disturbed, but im trying to stay positive and tackle years of council addons that have made things worse