Damp and Cavity Walls....Advice Please

SassySaver88

Hi all 
After some advice, we recently realised that our house has damp upstairs, black mould is appearing on the walls. 
We pulled all the furniture away from the walls to let more ventilation into the rooms and open the windows regularly but the mould still comes back
We have had several damp specialists come round who have said different things from: 
We need a fan in the loft 
We need air bricks put in the walls 
We need the walls being taken back to plaster and tanked
I'm not sure what to do next....
We started stripping off some of the wallpaper in the rooms and wiping down the damp and then realised that in the walls little polystyrene balls are coming out...Is this the insulation? 
I wasnt sure if we needed new insulation or can we tank and plaster over it?

Im not even sure what is the best thing to do 

Advice would be appreciated please

troffasky

If I had to guess, I would say that you've got expanded polystyrene bead cavity insulation, which is bridging the cavity and leading to damp inside, but it doesn't make sense that removing wallpaper would lead to the contents of the cavity coming in to the room! Is it definitely loose balls you're talking about and not a thin sheet of expanded polystyrene between the wallpaper and the wall?

FreeBear

SassySaver88 said: We have had several damp specialists come round who have said different things from: 
We need a fan in the loft 
We need air bricks put in the walls 
We need the walls being taken back to plaster and tanked

No to a fan.

No to air bricks.

Definitely No to tanking - What sort of drugs was that 'erbert snorting.....

Damp upstairs would suggest a slipped tile or three and/or a blocked gutter. Get someone with a ladder to take a look at the roof and go from there - I would recommend a roofer and not one of these "damp specialists".

SassySaver88

troffasky said:

If I had to guess, I would say that you've got expanded polystyrene bead cavity insulation, which is bridging the cavity and leading to damp inside, but it doesn't make sense that removing wallpaper would lead to the contents of the cavity coming in to the room! Is it definitely loose balls you're talking about and not a thin sheet of expanded polystyrene between the wallpaper and the wall?

It could be a thin sheet of expanded polystyrene but its becoming visable when I take the wall paper off so i wasnt sure if I could wall paper over that?

SassySaver88

FreeBear said:

SassySaver88 said: We have had several damp specialists come round who have said different things from: 
We need a fan in the loft 
We need air bricks put in the walls 
We need the walls being taken back to plaster and tanked

No to a fan.

No to air bricks.

Definitely No to tanking - What sort of drugs was that 'erbert snorting.....

Damp upstairs would suggest a slipped tile or three and/or a blocked gutter. Get someone with a ladder to take a look at the roof and go from there - I would recommend a roofer and not one of these "damp specialists".

We had a roofer out originally who checked the gutters, or roof is new last year so we know its not that 
We have some pointing issues and the damp is sufficient around the inside chimney breast so maybe something there? 
Would you suggest a roofer again?

RelievedSheff

Damp upstairs would certainly seem to suggest a problem with the roof.

FreeBear

SassySaver88 said: It could be a thin sheet of expanded polystyrene but its becoming visable when I take the wall paper off so i wasnt sure if I could wall paper over that?

If you have some of that "insulating" wallpaper (a thin sheet of polystyrene with a paper top layer), whilst it does provide negligible insulation, it also traps damp in the wall - Get rid of it, run a dehumidifier in the room, and hold off redecorating until August. Three months of hopefully hot summer weather will dry the walls out nicely.

SassySaver88

FreeBear said:

SassySaver88 said: It could be a thin sheet of expanded polystyrene but its becoming visable when I take the wall paper off so i wasnt sure if I could wall paper over that?

If you have some of that "insulating" wallpaper (a thin sheet of polystyrene with a paper top layer), whilst it does provide negligible insulation, it also traps damp in the wall - Get rid of it, run a dehumidifier in the room, and hold off redecorating until August. Three months of hopefully hot summer weather will dry the walls out nicely.

Im not sure how far to go back..there seems a load of it..and then would it suggest that we have no insulation if i take all that away?
In my other daughters bedroom she has no polyestrene but has mould again an air brick was suggested in this room or tanking the walls?

FreeBear

SassySaver88 said: In my other daughters bedroom she has no polyestrene but has mould again an air brick was suggested in this room or tanking the walls?

Tanking an upstairs room will NOT cure any damp issues. It is a waste of money.

If ventilation is an issue, you would be far better off investing in a Mechanical Heat Recovery Ventilation system - This will extract any heat from the air removed from a room and put it back in to the incoming air. An air brick will just give you a cold draught and make the room difficult to heat during the winter. Daughter will not thank you for that.

Unless you have an unconventional build, you should have (from the outside in), brick<->cavity<->brick<->plaster<->wallpaper/paint. You will not cause any irreparable damage by stripping paper & polystyrene off the wall.

troffasky

SassySaver88 said:

Im not sure how far to go back..there seems a load of it

How much is "a load"? It's going to be tricky to non-destructively measure how thick it is, although if you tell me it's 5cm or 10cm it won't make much difference because I wouldn't know what to say next!

What does the wall feel like if you tap on it? A thin sheet commonly used behind wallpaper will sound different to a thicker board that has been applied to a wall.

SassySaver88

troffasky said:

SassySaver88 said:

Im not sure how far to go back..there seems a load of it

How much is "a load"? It's going to be tricky to non-destructively measure how thick it is, although if you tell me it's 5cm or 10cm it won't make much difference because I wouldn't know what to say next!

What does the wall feel like if you tap on it? A thin sheet commonly used behind wallpaper will sound different to a thicker board that has been applied to a wall.

It feels very thin, the wall feels slightly squishy and it doesnt feel like a thick board. 
Im just wondering if the polystrene comes off whilst im stripping off the rest of the wallpaper what do I replace it with?