PigletJohn are you there?! Damp? on internal wall of bungalow

[JMAH]

We are lost for which way to turn next after years of trying to fix our problem. There is damp (?) re paint and some plaster flaking off the base of the wall in the kitchen, it feels damp but not wet. The other side of this internal wall is a bedroom with a long working single radiator attached to the back of the problem wall. The problem wall originally had a big solid fuel burner stove in front of it with a big pipe which went up through the loft and out of the roof - so not attached to the wall as such BUT the stove did sit on a concrete plinth. There is no other chimney involved.

It was removed approx 38 years ago to enable a loft conversion, the concrete plinth was removed with it and the floor was made good. The stove was replaced by a long double radiator. The kitchen floor is the only concrete floor the others are floor boards. The bungalow was built in 1937.
Over the years we have had various trades people in to fix it.
Several years ago my husband did it himself after all failed. He is not a damp expert or plasterer but he researched 'how to' and had a go. He took the plaster off the wall way further than there was any sign of damp - to be on the safe side. He dug a very deep hole in the kitchen floor, grave shaped, probably bigger. He spent hours in this hole injecting a damp proof course in the wall below and above ground level. It was a big job and lasted weeks, drying etc. He re plastered it and it was eventually painted once dried out completely - months later.
This was several years ago. To our dismay it eventually came back again.
We can' help wondering if it is something to do with the old concrete plinth, strange the damp is behind where it was. The damp only goes up the wall approx 60cm/2ft at the most, the plaster looks bubbly, then flakes off.
We want to have a new kitchen fitted which includes using this wall space and so need to have it fixed - we had given up on it.
We removed the radiator about 5 years ago when the problem arose again. We have had two trades people in to give their opinion, one said we used the wrong plaster, we had it replaced by a plasterer. After some time it came back again, it does not come back immediately.
At the beginning of this year we had another tradesman in to assess it. He came to see it and spent some time discussing it with us and gave 3 options. The most drastic was plaster removed, treatment of wall, wall batons attached, something added, some sort of cladding or membrane? Re plastered. This was the most expensive option but we went for it because we wanted it fixing once and for all, especially if we were going to 'cover' the wall. We thought it was very expensive £900+ but decided it would be worth it if it meant it was finally fixed. We accepted his quote and heard nothing from him. I contacted him again and he said he was too busy to do the job. We now think he over priced the job because he didn't want to do it?
Not sure what to do next, where to go, who to seek help from. We are retired now and my husband does not want to tackle it again!
Any ideas?

Is the wall one where a solid concete floor on one side meets a suspended floor on the other? We've just dealt with a problem at such a join. Though the wall above had been removed, the joists on the suspended side were getting damp at the ends ( and not for the first time, they had clearly been patched before). In our case, the concrete kitchen floor was only a thinish layer of concrete, and hardcore and soil from underneath it was touching the ends of the joists, so I consolidated the concrete side with cement to stop that, cleaned it all out, and we set new joists well back from the cement, and sitting on DPC material. Originally, as built 100 years ago, the wall would have protected the joists, but when the house was 'knocked through' the wall was removed to the level the joists sat on, and the soil must have started to spill out. Where there was still a wall at either end, I bricked up the joist 'holes' which also had small soil deposits in them, and set the new joists on hangars which I built into the bricks.
Unless I misunderstand, I just wonder if the damp is coming from the side with the joists, but the rad is concealing it on that side.

Yes, you are right PJ it is getting there from somewhere..... I have checked outside around the drains, down pipes and guttering, there is no sign of any vegetation growing or anything obviously wrong, like a leak. I don't think think it is to connected to the outside as you say, but checked around anyway.

We have not had the floor boards up....yet. The solid fuel stove we removed did not heat the water, it was simply a free standing burner. What is the test for old forgotten pipes?! If you think it is worthwhile it may be worth our doing?

We have purchased a moisture meter and tested the problem wall, it is indicating 30% damp along the bottom of the wall where the paint is bubbling and the plaster coming off. Further up the wall, from about a quarter/third way up to the ceiling it is registering 10% damp as are other walls around the house!

The pipes running across the bottom are disconnected pipes left from when we removed the radiator to 'fix' the wall, the radiator has never been put back, unsure if it will be returned there.

The roof is not that old, complete new roof done around 15 years ago. Today had a check done on it as neighbour was conveniently having his checked! The roof is sound except for one cracked tile at the front which is about to be fixed. It is situated at the front of the bungalow whereas the problem wall is at the back. I think what you can see is pigeon poo!

to test for a slight leak:

it makes a faint hiss. Part of background white noise so you don't notice it

sometimes, a person with good hearing, in the dead of night, will notice when it starts and stops.

this is done by turning the outside stopcock on and off

for ordinary ears, buy an Engineers Stethoscope on ebay for a few pounds. Press the tip against a cold water tap or pipe while an assistant turns the outdoor stopcock off and on. for practice, get them to flush a wc, turn hot and cold taps off and on. when the ballcock in a cistern or tank closes, there will be an abrupt stop.

the noise will be louder in the middle of the night as pressure is higher.

during the leak test, all taps must be off and you must have used no water for long enough for cisterns and tanks to have filled.

if you have an indoor stopcock, try that as well when the outdoor stopcock is open. If the indoor stopcock has no effect, the leak must be between the indoor and the outdoot stopcock.

also, look under nearby floors for signs of water.

Thank you both for your advice and time.
I think our next move will be to explore the floor boards near by, they meet the concrete floor of the kitchen on two sides/walls, one the reverse of the problem wall which is were we will start and the other into the hall. It will take us a little time as we'll have to move heavy furniture and take the carpet up but I think this is the best move and better to do before the test for small leak!
Thank you BlueMongoose, what happened to you may be a possibility here so worth a look. I have only recently picked up your message as it was on the next page.....doh!
I just hope we come to some conclusion. If the floor boards are in tact I think we will have to do the test for a small leak.......Thanks for telling us about it Piglet John.
I will eventually report back to you!

I'm in a house riddled by damp (every kind! condensation, rising damp, penetrating... we've got the lot). I'm just chipping in to ask about the removed stove - did it have a chimney up through that wall? If so, it's worth checking what happened to that.

(over invested)

I think I'd test for the leak fist TBH- it will be a lot easier, and if there is a leak, it's potentially a lot more urgent! Hope you find the source. Version4needsabitofwork, I feel for you! We've just had all our drains dug out relaid with new plastic pipework throughout as they were 100 years old, and they found a few leaks in the old ceramic pipes (as we expected). I think with older houses you do tend to have to advance on many fronts, as there's rarely one cause (except injecting crap into the walls - or tanking except in VERY exceptional circumstances).

Hello all and thanks again everyone for your input. We have now completed damp testing the wall on both sides and the floorboards, joists and soil below on the bedroom side, the kitchen side is a concrete floor.
We are not sure what the readings actually mean but there are obviously some differences. Any information/advice appreciated. .......

Damp Meter Readings – May 2022

Internal wall with working radiator – this wall divides kitchen and back bedroom and is the other side of the problem damp wall.
Readings taken along wall.
Left Right
Along wall horizontally 3ft up from floor
0 0 0 0 0
Same wall at skirting board level
9 9 12 9 9
Floor boards running along same wall
11 11 13 12
Joists below these floorboards
14 15 17 16
Soil below these joists and floorboards
29 29 29
Other side of the above wall in kitchen – damp problem at base up to about 2/3ft up
Readings taken 3ft up the wall from floor
8 8 10 10 8
Same wall at kitchen floor level
21 29 30 25 23
#Plinth

The kitchen stove, a solid fuel burner was free standing with an iron/metal chimney coming up from the top, going through the loft and the roof out of the house. There is no internal/wall chimney and it did not have a back boiler. It did not provide hot water or central heating, it was just a burner. The base was a concrete plinth and came out from the wall as marked #. When it was removed a membrane was put down before it was back filled with concrete to meet the rest of the concrete floor.
A radiator was installed along the wall and sometime later the problem with damp as described occurred. Please see initial posts also. Thanks so much.

I've noticed the damp meter readings presented differently in the post to my typing. To be clear, all the meter readings were taken in equal gaps right along the wall. I had typed them spread out along the page to indicate this but they did not transfer to the post the same.

Version4needsabitofwork your problem sounds horrendous, I sympathise.
Blue Mongoose, only just picked up your latest message. Well the floorboard checks are done so I suppose the leaks check is next! Our property is 85 years old so it is feasible things need replacing that we can't see as well as those we can.
Looks like your suggestion of testing for leaks is next Piglet John. It is something we were hoping would not be necessary! We will have to tackle it. although neither of us have good hearing!

If I understand you correctly, you have found the wettest part of the wall.

Most likely the source of water is underneath that point (sometimes it is a leak buried in the wall, but you will then find the damp at its worst at and below that point) and will be in or under the floor.

My money is still on a leak, but you can dig in case there is an underground stream or something.

I'm with PigletJohn again re a leak being the first port of call. Our drains are now relaid, and they found a few small leaks in the old pipes we didn't know about, old roots in a couple of places where we suspected there would be, and a weird concrete pit in the drive which none of us know what it was for, as well as confirming my suspicions about where rainwater was running between tarmac and wall and getting into the subfloor, which hopefully is now sorted as well. (That had some damp symptoms in the wall above, though not as evident as yours.)

it would be useful to have the old pipes disconnected prior to their entry into the damp room. They can be capped off or have a valve fitted so you can reinstate them if you ever decide to use a radiator there

presumably you have checked for any sign of drip or leak? wrap kitchen roll tightly round them.