Help with white powder on wall

Graceland

I got one of my rooms drylined about 3 years ago, because one of the walls had black on it. Even though it looked damp, it wasn't wet to the touch. Anyway when the man was starting the job, he removed some of the floor boards. The foundations are about 3ft down and on the exterior wall, there was a lot of white powdery stuff. I asked the man would he treat it for me, but I was told that it could just be wiped off, that it wasn't a living fungus. So he just got a brush and wiped it all away. It came off easily enough.
Now 3 years on - after getting it drylined/wallpapered, there is now some patches of damp showing on the wallpaper, but they aren't wet to the touch - it just looks stained. Sometimes there are bits of white powder on the wall and some on the floor. This can be wiped off.
I just need to know what it is so that I can get in contact with someone who could solve it for me.

RKQ

White dust on an external blockwork wall might suggest a leaking flashing or rising damp if seen just about skirting board level. White dust on an insulated dry-lining plasterboard is a bit of a mystery.

It might be worth contacting a reputable Damp proofing Company / expert.
Its very hard to say more on the brief description above. Photo's might be useful. Let us know how you get on, good luck.

sinnerboy

The white stuff is salts . Your walls are damp . The salts are leached to the surface of your wall by water penetration . During warm dry weather they dry out on the wall surface .

"The man" who simply brushed it off ( figuratively and literally ) either did not know or care - what he was doing .

You need an Architectural Technician now inspect your building and diagnose and recommend a remedy .

Keith186

Snort it off

Graceland

Thanks for the reply. The room is downstairs, so if the problem was a leaking flashing, would the room/wall above it not have the same problem as well? This room seems to be ok. Maybe it is rising damp as you said too, although it is more above skirting board level. I'd say it is about 3 or 4 foot high (in patches here and there). I don't know anything about these type of things, but if it was rising damp, is white powder a sign of it.
I'm not sure if this had anything to do with it, but years ago we had a built in wooden press in which lot of paperback books were kept. The main reason this press was taken away was because some of the wood started to crumble. I'm not sure now if the press caused the problem or the problem was already there and that is why the press went like that in the first place.

sinnerboy

Graceland wrote: »

I'm not sure now if the press caused the problem or the problem was already there and that is why the press went like that in the first place.

The problem was already there

Graceland

sinnerboy wrote: »

The white stuff is salts . Your walls are damp . The salts are leached to the surface of your wall by water penetration . During warm dry weather they dry out on the wall surface .

"The man" who simply brushed it off ( figuratively and literally ) either did not know or care - what he was doing .

You need an Architectural Technician now inspect your building and diagnose and recommend a remedy .

Thanks for your reply. Would you have any idea what kind of a job would need to be done. Would it be straight forward or would there be a lot to it, like a big job.
I don't suppose you would happen to know anyone in the Dundalk area who could help me with this.

sinnerboy

PM sent

Graceland

sinnerboy wrote: »

PM sent

Thanks for pm

Mellor

Graceland wrote: »

I'm not sure now if the press caused the problem or the problem was already there and that is why the press went like that in the first place.

sinnerboy wrote: »

The problem was already there

Definitly. The problem was there and caused the press to rot.
Just because its not wet to the touch doesn't mean its not wet.
try to get a moisture content meter to see for yourself.

RKQ

My initial thought would be damp - the salts in the plaster would form on the wall but on a "dry-lined wall - that the mystery?
What sort of drylining was installed?
Was it new plasterboard on timber battens or was the plasterboard fixed directly to the existing wall (without battens)?

Was any aeroboard (white snowy stuff) placed between the battens?

As I said above it could be a leaking flashing if the patch appeared on a chimney breast, on ground & 1st floor.

Rising damp rarely rises more than 3 ft above ground floor level. What are your external walls made of?
Are they Solid blockwork, Cavity construction or stone? (Measure the overall wall thickness at an external window)

Salts on drylining is unusual. The walls would have to be very wet / damp for the battens & slab to get wet.

Unless it was Condensation - poor ventilation was causing damp patches on an uninsulated drylined wall. Are these patches visible mainly in the kitchen or north facing rooms?

sinnerboy

@ Gracleland

There may be missing / defective dpc - lack of sub floor ventilation / problem with adjacent ground levels / defective drains .... you need an expert to have a look .

Re the person whose details I pm'd you .

Ask them to inspect the house and from that outline the required remedial works in drawings and/or specification format .

- then retain them to obtain completive pricing
- then select the best contractor / prepare contract
- then inspect during works to ensure
- payments are made in a manner that is fair to you and the builder
- ensuring works are being executed properly and finally ensuring
- works can be signed off upon completion .

Graceland

RKQ wrote: »

My initial thought would be damp - the salts in the plaster would form on the wall but on a "dry-lined wall - that the mystery?
What sort of drylining was installed?
Was it new plasterboard on timber battens or was the plasterboard fixed directly to the existing wall (without battens)?

Was any aeroboard (white snowy stuff) placed between the battens?

The bits of salt on the dry lined wall would be very little. It's mostly dark patches on that wall.

The type of drylining was new plasterboard on timber battens but there wasn't anything put between the battens (aeroboard).

RKQ wrote: »

As I said above it could be a leaking flashing if the patch appeared on a chimney breast, on ground & 1st floor.

Rising damp rarely rises more than 3 ft above ground floor level. What are your external walls made of?
Are they Solid blockwork, Cavity construction or stone?

The chimney breast looks ok, there's no damp patch on it.

The external wall are red brick which has been plastered over and painted many times.

Graceland

sinnerboy wrote: »

There may be missing / defective dpc - lack of sub floor ventilation / problem with adjacent ground levels / defective drains .... you need an expert to have a look.

Funny you should mention about the adjacent ground levels. When the man was doing the drylining for me, he said he thought the problem could be caused by the laneway beside the external wall. This laneway is just clay and grass. He was saying that when it rains, even though actual water might not get into my foundations, it could still let the dampness in. He just thought the drylining would solve it. I thought he was just guessing.

Can I ask you what a dpc is. I don't understand about things like this.

RKQ

Graceland wrote: »

The bits of salt on the dry lined wall would be very little. It's mostly dark patches on that wall.

Mostly "dark patches" would suggest condensation If the patches appear in corners of the room, or at the junction of the wall and ceiling, or around windows.

Salts on drylining is unusual.

Graceland wrote: »

The type of drylining was new plasterboard on timber battens but there wasn't anything put between the battens (aeroboard).

The external wall are red brick which has been plastered over and painted many times.

An uninsulated wall might suggest condensation. A solid brick Victorian or Georgian wall is unlikely to have a slate damp-proof-course or DPM.
Rising damp would rise circaft above finished ground level. So if the external wall is higher outside than your floor level, then you will experience severe damp & water penetration problems.

If your floor is below the clay lane, then there is nothing to stop water on the lane flowing down into your home. An untanked wall will allow water to travel across the wall into your room.

Graceland I'm afraid its impossible to state the exact cause of your problem without inspecting it on site or seeing a few photos. It could be rising damp, water penetration, or condensation.

Graceland wrote: »

Can I ask you what a dpc is

Damp-proof-course is a layer of waterproof material that is normally placed in the wall 6 inches above external ground level. Traditionally it was bitumen or even slate but is usually upvc today.


Good luck and let me know how you get on, as its an interesting query.

Graceland

RKQ wrote: »

Rising damp would rise circaft above finished ground level. So if the external wall is higher outside than your floor level, then you will experience severe damp & water penetration problems.

If your floor is below the clay lane, then there is nothing to stop water on the lane flowing down into your home. An untanked wall will allow water to travel across the wall into your room.

I don't know for sure what the problem is but it is making more sense that it could have something to do with this laneway. The ground on this laneway is higher than my floor. The laneway is also on a slope.

Another thing I noticed too was the bottom of my neighbours house. He got it plastered about a year ago, and the wall along the bottom beside the laneway is always damp looking. It's not something I've ever thought to look at, but it is damp along the whole bottom of the wall. I'm now wondering if my neighbour has the same type of problem as me. It's not something I'd like to ask them.

If this was the problem, could I get anything for my wall, either external or internal. Hopefully something can be done to sort it out.

RKQ

Graceland wrote: »

I don't know for sure what the problem is but it is making more sense that it could have something to do with this laneway. The ground on this laneway is higher than my floor. The laneway is also on a slope.

If this was the problem, could I get anything for my wall, either external or internal. Hopefully something can be done to sort it out.

If water penetration is the problem. There are a number of things that can be done.

• A new surface drain could be installed along the side of your house.
• The ground at the wall could be dug away, the wall tanked externally and ground reinstated.
• The wall could be tanked internally.

Get advice from an experienced Arch Tech or Building Surveyor. They will inspect your ground levels, existing drains, existing walls and floor level and advise accordingly.

Graceland

Thanks for all the help. I'll definetly get something sorted out. At the moment I'm getting other work done in the house which will take a while to finish, but as soon as it's done, I'll contact someone to get this sorted.