Damp Walls

[Barney12]

Oh bother....damp is sooo annoying. 
 

Just taken out the utility room in the bungalow I’m currently working on to find that behind the units the walls are damp. I had a suspicion they might have had previous issues as there was celotex tucked into the back of the units. 
 

1980’s build, cavity wall (filled with insulation from early 90’s). 
 

My guess is that it’s simply being caused by condensation but I’m not entirely certain. Perhaps the previous owners were a little mean with the heating? 
 

Units going back in the same positions so now I’m trying to decide on the best course of action? 
 

Any wise thoughts?
 

 

[nod]

I would just bleach them Then give them a coat of oil based undercoat 

It does look like condensation 

[Onoff]

Could it be the cavity wall insulation causing the issue? Is the outside wall finish good/intact? No render up over the dpc then damp bridging the insulation?

 

Bleach it all as above. Maybe fit some vents to thd new plinths to get some increased ventilation round the back?

[ProDave]

I would say typical of a 1980's build low insulation house.

 

A kitchen is always going to be a damp room and with poor air circulation behind the units it is always going to be cold there and condensation will form and mould will grow.

 

The fact there is no sign of that above the units where air can circulate and the walls will be warmed much better  suggests it is not a serious problem.

 

If you are going to internally insulate the walls to stop the problem you need to ensure the insulation is sealed to the walls so moisture cannot get behind.  Some loose insulation poked down the back of a kitchen unit before the worktop goes on won't do much.

[Barney12]

26 minutes ago, Onoff said:

Could it be the cavity wall insulation causing the issue? Is the outside wall finish good/intact? No render up over the dpc then damp bridging the insulation?

 

Bleach it all as above. Maybe fit some vents to thd new plinths to get some increased ventilation round the back?

Outside render is all good and dpc appears intact. Suspended floor too and wall vents are unblocked. 
 

vents is a good idea. 

[Barney12]

47 minutes ago, nod said:

I would just bleach them Then give them a coat of oil based undercoat 

It does look like condensation 

Ta. That mirrors my thoughts. 

[Barney12]

1 minute ago, ProDave said:

I would say typical of a 1980's build low insulation house.

 

A kitchen is always going to be a damp room and with poor air circulation behind the units it is always going to be cold there and condensation will form and mould will grow.

 

The fact there is no sign of that above the units where air can circulate and the walls will be warmed much better  suggests it is not a serious problem.

 

If you are going to internally insulate the walls to stop the problem you need to ensure the insulation is sealed to the walls so moisture cannot get behind.  Some loose insulation poked down the back of a kitchen unit before the worktop goes on won't do much.

Good advice. The thin celotex was just shoved behind so not even in contact with the wall. 
 

There’s another cold/condensation point at the other end of the house in one of the bedrooms. I wonder how badly the cavity wall insulation has been pumped in.?

[gravelld]

Are you sure the wall is filled at that point?

[Barney12]

1 minute ago, gravelld said:

Are you sure the wall is filled at that point?

It’s a good question. I guess I could drill out a core lower down and see what it revels?

[Declan52]

I had similar issues in my last house when I removed the old kitchen. It was a 1960s high tech example of housing that had the cavity pumped with beads 20 years on. Over the years these beads moved and left gaps resulting in cold spots. 

My fix was to bleach and clean the inside to sort these issues. On the outside I put a tumble dryer vent to try to get the wall to dry out. 

If it is cold spots in the cavity there ain't really a cheap fix. Your only option is to try to get rid of the damp air by better ventilation. 

[Ed Davies]

2 hours ago, Barney12 said:

The thin celotex was just shoved behind so not even in contact with the wall. 

 

I'd think that was at least part of the problem - making the wall colder but not keeping the water vapour away from it.

[Miek]

10 hours ago, Barney12 said:

It’s a good question. I guess I could drill out a core lower down and see what it revels?

You could possibly (if you have one) look at the house from outside with a thermal camera while the heating is on inside. But you would expect insulation gaps at the top of walls or under cills not at the bottom of the wall.

[tonyshouse]

It looks to me like condensation, the corner has become colder than the other walls in the room so moisture is “pumped” there driven by pvp and can’t evaporate again as there is no air movement 

 

 

[MikeGrahamT21]

be extremely careful with the black mould, wear a good fitting mask when doing anything with it, and cover the whole thing with bleach first before doing anything else to get rid of it. Its extremely toxic, and can give serious health complications to fully fit normal people.

[billt]

Really? Do you have any evidence to support that view?

Which particular type of mould is the toxic one and how do you identify it from its colour?

As mould is ubiquitous it does seem a stretch to claim that a bit more mould than usual is going to kill a normal healthy adult.

[MikeGrahamT21]

One cause of black mould is aspergillus, naturally occuring, and also can be commonly found in buildings, insulation and the like. Its been known to infect healthy adults, though its unlikely to kill a healthy adult it will make you very ill. If the mould spores settle in your lungs, they can grow. If you have any sort of immune deficiency then you are at serious risk.

 

Clearly it is difficult to know whether it is or isn't aspergillus, which is why you should take serious precautions regardless.

 

My wife suffered from an aspergillus infection, she was immune deficient, she developed an aspergiloma (a bit like a tumour) in her lung, they successfully treated it over the course of a year, but unfortunately not long after she suffered from respiratory failure from the damaged caused by the fungus. Its really not worth not taking precautions.

 

If it infects your body, it releases a chemical called aflatoxin, which is both toxic and carcinogenic.

Edited January 28, 2020 by MikeGrahamT21

[Cpd]

2 hours ago, billt said:

Really? Do you have any evidence to support that view?

Which particular type of mould is the toxic one and how do you identify it from its colour?

As mould is ubiquitous it does seem a stretch to claim that a bit more mould than usual is going to kill a normal healthy adult.

having suffered from Chronic fatigue syndrome (not mould related in my case ...) I did a lot of reading and I was amazed at how many people with M.E / CFS found that either sorting the mould problem out or moving house resulted in a big improvement in there health. I live in an old uninsulated house that is a prime candidate for mould and it’s something I am always aware of and try to make sure it does not get the chance to form.  

[Barney12]

13 hours ago, tonyshouse said:

driven by pvp

You’ve got me? pvp?

[DavidFrancis]

Partial vapour pressure?

[tonyshouse]

yes pvp

[tonyshouse]

the bad news about mould spores is that thy grow well at 37C in moist environs like inside lungs ?

[Onoff]

Search "black mould dementia".

 

Mycotoxins etc are implicated in forms of Alzheimers/dementia from various studies.

 

Close to home I see my own parents, Mum has mixed dementia (let's not mention the diabetes and double incontinence ? ). Up by the wall / ceiling junctions, in corners and behind hoarded stuff in various rooms are black spots. None of it helped by her obsession with closing and locking windows and doors then drawing curtains(again mouldy) and barricading everything. What little cleaning my father pays for (he has the means), doesn't touch the problem. 

 

I'm 100% certain that fitting housing with MVHR as a standard would alleviate a lot of this and very likely improve the occupants overall and long term health.

 

To say nothing of improving the smell...

[MaryM]

currently having a row with builder over a few things, including insulation he has put in my integral garage

 

the external wall is single brick with damp course, the floor has no damp protection

 

he has built a timber stud frame, connected direct to the floor & wall, the spaces between are filled with Knauf cavity slabs, no vapour barriers or sheathing to protect the timber

 

then plasterboarded over and the joint sealed

 

I am alarmed to find this might cause mould growth and at my advanced age, although many people would say I am already somewhat demented, could put me at increased risk of the genuine article

 

looking at the photo at the top of this thread, is it likely my garage will end up like that?  it's used as utility/garden workshop space and visited frequently, the washer & utility sink are in there (or will be if it's ever finished)

 

photo of unfinished insulation, I've already been advised on another thread this is not good, what do people think about the specific mould risk?

Edited January 29, 2020 by MaryM

[ProDave]

33 minutes ago, MaryM said:

currently having a row with builder over a few things, including insulation he has put in my integral garage

 

the external wall is single brick with damp course, the floor has no damp protection

 

he has built a timber stud frame, connected direct to the floor & wall, the spaces between are filled with Knauf cavity slabs, no vapour barriers or sheathing to protect the timber

 

then plasterboarded over and the joint sealed

 

I am alarmed to find this might cause mould growth and at my advanced age, although many people would say I am already somewhat demented, could put me at increased risk of the genuine article

 

looking at the photo at the top of this thread, is it likely my garage will end up like that?  it's used as utility/garden workshop space and visited frequently, the washer & utility sink are in there (or will be if it's ever finished)

 

photo of unfinished insulation, I've already been advised on another thread this is not good, what do people think about the specific mould risk?

But that is easy to put right. Cover with a vapour barrier before plasterboarding. The hardest part will be sealing up the cable entries into the back boxes.

 

But in the real world I see hundreds of houses like that with no vapour barrier and no mould problems either.

[MaryM]

8 hours ago, ProDave said:

But that is easy to put right. Cover with a vapour barrier before plasterboarding. The hardest part will be sealing up the cable entries into the back boxes.

 

But in the real world I see hundreds of houses like that with no vapour barrier and no mould problems either.

thanks @ProDave I've been in touch with Knauf Technical and they said the same, I just didn't understand what 'lining the boxes' meant

 

the trouble is a lot of the plasterboarding has been done and my builder isn't willing to take it down to put in a vapour barrier

 

I have an unheated conservatory that gets filthy with black mould every winter, it's easy to clean off, I've just done some of it and ended up with a bucket of filthy black water

 

but if it was plasterboarded over I wouldn't be able to do that

 

could I expect to get this from cold brickwork under plasterboard?