Damp or mould

dahac

I have a mid terraced house and have problem with damp or mould in the living room corner. I have had this problem for sometime so I thought it was the cavity blocked so I cleaned it out which had a lot of stones and next doors cavity wall insulation, hoovered out and but air brick back. Cleaned the whole wall inside with hot water and bleach and it didn't return until I noticed it today which killed it for 6 months. Wallpaper the wall and not it's started to have dark 1cm round spots just above the skirting board. I have peeled back some paper from the bottome corner and it has large black patches on it. I'm not sure if I have damp or condensation problem as I have notice the floor beam seconded in from the outside one is soft and you can put your finger right through it. This beam is joining to the next door house.

I need some help as I have spent a lot on wallpaper and now it might have to come off and it's driving me mad.:mad:

muckybutt

If you have a wooden joist you can put your finger through then you have a damp problem !

Could well be the damp proof course has either failed or has been breached thus letting damp in from the ground below.

I would for starters get in touch with a couple of trusted builders for quotes and get one of them to investigate it and repiar the problem. Not really a lot you can do in the meantime until you find the cause of the damp its just going to keep coming back, and now its got into the woodwork it need sorting sooner rather than later.

dahac

I'm not sure how long the joist has been like this for as it's only in the corner were it connects with next door which is internal . If it was damp wouldn't we get it right the way along the outside wall. The damp proof course has been injected from outside as this is a mid terraced house which is over 100 years old

ariba10

Could it be Condensation?

dahac

I'm not sure. The joist has gone on the joining wall, and we are getting the mould growth on the outside wall and none on the joining wall.

Confused.com

cyclonebri1

Dahac wrote: »

I'm not sure. The joist has gone on the joining wall, and we are getting the mould growth on the outside wall and none on the joining wall.

Confused.com

You need to talk to the neighbour too as they are likely to have the same issue if it's a continuous joist, and access may be necessary next door.;)

cyclonebri1

Dahac wrote: »

I'm not sure how long the joist has been like this for as it's only in the corner were it connects with next door which is internal . If it was damp wouldn't we get it right the way along the outside wall. The damp proof course has been injected from outside as this is a mid terraced house which is over 100 years old

And it has cavity walls?????

The wallpaper cost sounds like the least of your worries to be honest, exposing the joist's may show more than 1 is in need of repair or replacement:(:(:(, sorry, but it's likely in a 100 year old property.

dahac

Yes we have a cavity wall, so the inside wall isn't touching the outside wall as I have cleaned the stone away which is what I first thought was the problem.

Had a look and it's only the one that's like this, as the one closest to the outside wall has already been replaced. Is this down to damp, if so how would the damp course sort out the problem on the inside wall as there is a cavity between them.

Yes cannot workout why we get the mould growth on the outside wall.

muckybutt

dahac wrote: »

Yes we have a cavity wall, so the inside wall isn't touching the outside wall as I have cleaned the stone away which is what I first thought was the problem.

Had a look and it's only the one that's like this, as the one closest to the outside wall has already been replaced. Is this down to damp, if so how would the damp course sort out the problem on the inside wall as there is a cavity between them.

Yes cannot workout why we get the mould growth on the outside wall.

That sounds like damp if one joist has already been replaced.

As I said it does sound like the dpc is breached somewhere ie there is a break in the chemical dpc or if it is a cavity wall as you say, there may well be something like insulation that has bridged the dpc thus allowing damp to penetrate through.

What ever the cause you will need to rip a good section of flooring up for starters to replace the rotten joist, and you may also need to redo the dpc which will mean hacking the plaster off in the affected areas. Your wall paper is the least of your worries i'm afraid to say.

dahac

The gas metre is in this corner as well so it might have something to do with it in the cavity. The cavity is the only problem I can see.

cyclonebri1

OK, you have a cavity wall, unusual in a property that old. Both the inner and outer walls have ther own dpc, or that is they should have.
I will bet my bottom dollar that the original inner skin doesn't.

Building technology wasn't what it is today back then, you have possibly one of the earliest examples of cavity wall construction, they didn't tray out at dpc level as we do today.

What form of DPC is it, I'd guess slate or maybe lead going back that far, neither of which would provide a drip towards the outside skin.

Right, just re read, and I guess as it has a chemical dpc, it had no form of dpc originally?

Now chemical dpc is ussually only applied to solid walls, 4" or 9".
The practise for a solid 9"wall is to drill in say 3", inject the chemical, then drill in a further 4" and inject again.

I don't know if you can apply that method to a cavity wall. In fact I doubt you can.

I suggest that you have a dpc to the outer brick skin only, hence the rotting of the floor joists, again, sorry to be the harbinger of bad news,:o:o:o