Damp wall/damp proof paint question

david75 · 19-02-2014 4:18pm #1

Hey
So basically we have two walls that are not just damp but wet. I've bought two tins of johnstones damp proof paint.
My question is, this isn't my house so I can't go too far, but if I wire brush this, I've a feeling the plaster will all flake away down to the brick(it's a really really old house) and I am no plasterer nor do I know any.
So is there another way to remove the dead/flaking paint without getting down to plaster? Or something else entirely? Any advice is greatly appreciated.
Here's a pic

sky6 · 19-02-2014 4:55pm

That seems like it could be a Chimney Problem and could be an easy fix with a Chimney inspection on the Roof.
Otherwise any remedial work will be only temporary as the problem will quickly return.
A better short term solution might be to stud and slab the Wall, it won't cure the problem but would leave it looking nice clean while your there.

I'd start with trying to identify the root cause of the problem, and I'd start on the Roof at the Chimney.
It could be a cracked pot or flashing around the pot.

david75 · 19-02-2014 5:20pm

Thanks for the reply!
Thing is the house is so old. It's literally sitting on mud, no foundations and its sucking the water up directly.
The floorboards are sitting on lengths of wood barely above the muck. Mice infested under there. I can't even contemplate the remedy you suggested as I'm doing this on a shoe string. If the damp proof paint even works for a year ill be happy.
The landlord knows about it but couldn't give a fudge. I just don't want me or my other half having to deal with getting sick. My dog does be licking the water off the walls some days! Screw that!

sky6 · 19-02-2014 5:32pm

It sounds as if it's not fit for Habitation. surely you could find somewhere better as there's plenty of decent properties idle throughout the Country.
I don't want to appear alarmist but you will surely end up sick with lasting Chest and Lung problems living in that environment.

WilyCoyote · 19-02-2014 5:57pm

Why are you still living there?

Nu Look · 19-02-2014 8:27pm

Move move move

david75 · 19-02-2014 10:30pm

It's a long long story. I can't move. I don't want to move.
It's such a brilliant house and perfect for everything I need and need to do. It's just old and needs some TLC

oisinbutler · 19-02-2014 10:48pm

david75 wrote: »

Hey
So basically we have two walls that are not just damp but wet. I've bought two tins of johnstones damp proof paint.
My question is, this isn't my house so I can't go too far, but if I wire brush this, I've a feeling the plaster will all flake away down to the brick(it's a really really old house) and I am no plasterer nor do I know any.
So is there another way to remove the dead/flaking paint without getting down to plaster? Or something else entirely? Any advice is greatly appreciated.
Here's a pic

If the house is really old theres a fair chance that wall has been plastered with lime in which case its trying to breath. If this is the case then scrape off as much loose paint as you can and then paint the wall with a breathable paint. Your local paint shop will tell you which one to use. Once the wall has been painted you will find moisture coming through the paint but the paint won't peel away. The damp block that you mentioned should stop water coming through the paint but that just means the water will find somewhere else to appear

david75 · 20-02-2014 12:06am

Yeah the paint in the other room seems to do that. Meaning letting it through but without flaking

WilyCoyote · 20-02-2014 4:23am

OK then ........ if you can't move.

Batten out the wall vertically with 2" X 1"s at 16" centres ....... keeping them a couple of inches from the ceiling and 1" up from the floor. Mark the centres on ceiling and floor with pencil

Redirect any electrics if necessary

Screw on the 1/2" foilback or polythene backed plasterboard ......staggering the joints and starting at the top. Keep the bottom board 1" off the floor

Tape & joint or scrim & skim the wall

When fully dry - fit the skirting

Drill 2" holes through the finished plasterboard near the top corners (1' in and 1' down approx)

Ditto at the bottom corners - 1' in and 1' up. You can then fit a 2" round vent in each hole

This is not a long term solution but it will help.

oisinbutler · 20-02-2014 8:37am

david75 wrote: »

Yeah the paint in the other room seems to do that. Meaning letting it through but without flaking

Right, then its lime based plaster on the wall and the way forward is to use the breathable paint. The walls need to let moisture through. It can look a bit funny when you see the water running down the wall but thats what its supposed to do.

You can find out more about lime plaster here http://www.jackinthegreenlime.co.uk/paint.html

WilyCoyote · 21-02-2014 5:21pm

oisinbutler wrote: »

Right, then its lime based plaster on the wall and the way forward is to use the breathable paint. The walls need to let moisture through. It can look a bit funny when you see the water running down the wall but thats what its supposed to do.

You can find out more about lime plaster here http://www.jackinthegreenlime.co.uk/paint.html

You are giving out wrong info here. As a plasterer I work with both hydrated and hydraulic lime and hydraulic and Portland cement. One of the uses of plaster is to keep out dampness. If dampness appears on an inside wall, then the plastering system used has broken down.

Hydraulic lime plaster on the outside of external walls will allow the wall to breathe - not act as a strainer.

OP, are you sure that this isn't condensation? Does the wall weep in dry but cold weather?

oisinbutler · 21-02-2014 9:41pm

WilyCoyote wrote: »

You are giving out wrong info here. As a plasterer I work with both hydrated and hydraulic lime and hydraulic and Portland cement. One of the uses of plaster is to keep out dampness. If dampness appears on an inside wall, then the plastering system used has broken down.

Hydraulic lime plaster on the outside of external walls will allow the wall to breathe - not act as a strainer.

OP, are you sure that this isn't condensation? Does the wall weep in dry but cold weather?

If theres moisture coming throught other walls in the house as the OP mentioned and the paint isn't flaking away from them would you agree that they have been plastered with a lime plaster and painted with a breathable paint?
Would you agree that if moisture forms on a lime plastered wall that its simply the plaster breathing?
The problem as I see it is that somebody used a modern paint on a lime plastered wall and it's causing the paint to peal and all the moisture to flow from that area.
The OP wrote "Thing is the house is so old. It's literally sitting on mud, no foundations and its sucking the water up directly"
This again sounds to me like a lime plaster, which is porous, sucking the moisture up and then trying to release it.

Or have I got this all wrong?

Damp wall/damp proof paint question

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