Penetrating Damp? remedy

paintpot

I posted a while ago about a pretty horrendous damp problem in a rental property I refurbished. Linky if you want to see the gory details in photos.

http://forums.moneysavingexpert.com/showthread.html?t=890845

Anyway, I thought the problem had gone away but a note in the inventory returned by a new tenant tells me it has reared its head again :eek: I am yet to see it but I have become convinced it is penetrating damp from my research. I want to know the best remedy so have detailed the problems.

I cannot find any obvious problems with guttering etc etc and have sealed windows around the area etc etc.

A recap:
It's a Victorian property
The wall affected is an external wall
This is an annex at the back of the main terrace
The property's annex is half rendered up to about a meter and the damp is above the render level (hence I don't think it to be rising damp as it is too high.
It has a DPC even in the annex
Above the render the brickwork has been painted with masonry paint which has shown signs of bubbling/deterioration in the area of the damp on the inside.
The plaster inside was all hacked off, bricks taken out to establish there are no old lead pipes leaking within the wall before being replastered in specialist plaster that should not allow damp to penetrate.

The only other hint I can explore further is that there is another flat above with a bathroom directly above the affected wall but I would have expected damage to the ceiling not damp mid way in a wall if the bathroom was contributing so that is probably a red herring.

Hence I am deducing that the brickwork has become porous and it's penetrating damp but I am no expert.

However, to add to the issue, I also manage the property next door which is indentical except that this flat is two story whereas the other flat with the damp downstairs is one storey and above is the bathroom of another flat and no damp. (So identical houses but the layout of the flats is different) The one next door though, the tenants have also now reported damp in their upstairs bedroom which has been described as the size of two dinner plates. They also have had a bad condensation issue causing black mould which has been much improved following a rectification in a badly fitted window but as the weather has changed it is coming back. I had a damp specilaist out to that flat and they said it was purely condensation (I didn't believe that, had some work done to a gutter/roof, the window etc) but again I believe it's penetrating damp due to the dinner plate remark and the fact the brickwork looks crumbly/shot on the outside. Three of the four walls of the bedroom are external and very exposed to the elements.

I don't want to call out another "expert" to tell me it is condensation. I really don't think it is.

Sorry for the long post. So my quesion, what's the best remedy for penetrating damp in these circumstances? Any other thoughts? I've worked really hard to sort these problems including employing "experts" but the problems aren't going away.

If there are any property experts in East Yorks/Humberside who want to take a look give me a shout!

Incisor

I think penetrating damp would have to fall from somewhere. You need to eliminate the bathroom as the problem and also leaking or broken gutters, before looking further [IMHO]

guppy

Does the damp appear/get worse following rain? Is the wall facing the prevailng wind? Is it particularly rainy/windy where you live?

As Incisor says, have you checked the gutters aren't blocked or overflowing?

As I understood it, cavity walls weren't common until at least the 1930s, do you know what sort of bond is used for the brickwork (http://en.wikipedia.org/wiki/Brickwork) and how thick the wall is (say measured through a window?

Who was the "expert" that came round, you could maybe ask a building surveyor specialising in defects to take a look, but that seems a bit extreme for a bit of damp!

paintpot

Incisor wrote: »

I think penetrating damp would have to fall from somewhere. You need to eliminate the bathroom as the problem and also leaking or broken gutters, before looking further [IMHO]

I appreciate what you are saying but I've been down that route with the two flats affected, one upstairs and one downstairs, two separate houses. I can see all the pipes, gutters. I've had a roofer up on the upstairs flat roof who remedied a problem with the roof/gutter where water could have been leaking onto the wall but the downstairs I've filled every crevice, gutters semm fine, I really can't see the problem. The roof isn't old, it's is good shape. I even repainted the masonry paint on the ouside for protection, applied some anti damp brickwork stuff. Hence my thoughts on penetrating damp as the brickwork does seem shot on the outside!

If anyone can explain how water from an upstairs bathroom may get down to the middle of the wall of a bedroom below when there appears to be no pipes running in the walls and no ceiling damage?

However, that doesn't solve the problem next door. I am tired of throwing what seems like good money after bad at the problem.

Sorry, I am just at a loss at the moment. I've thought about tanking the insides, rendering the outside etc but I don't know which is the best way to turn.

real1314

"I am deducing that the brickwork has become porous"

Never heard this one before, sounds like a line from a self appointed damp expert.

Penetrating damp is caused by a source of water. Window lintels, poor roofing, plumbing faults, gutter faults.

Not by "porous bricks". All bricks are fundamentally porous (well, except for engineering bricks) which is how rising damp can occur, however they absorb a small amount of water and then release it out again when things are dry. Unless they are subjected to continuous water, i.e from a source.

paintpot

Yes it does get worse following rain etc and now the weather is getting worse the whole problem is getting worse.

Yes, checked the gutters, been there when it is raining, can't see any cascading of water. They are all exposed walls so the elements will get to them.

I've read and read so I know what to look for, I just can't find a problem.

If you look at the photos in my link, you will see how bad it was. I have managed to minimise the problem as the one flat was a grot hole but now it is lovely and this is a thorn in my side. The damp does seem to "move" a little around the corner in the bedroom and into the internal wall as it is in the kitchen and the bedroom both of which are the external wall ground floor and the internal wall separates the bedroom from the kitchen.

I'm not sure how thick the walls are exactly or he bond, not very , maybe 30 cms off the top of my head. It's a rented property, I don't live there, just trying to sort it. The damp expert is "the" expert that everyone in the location seems to recommend. I wil get them out again or someone else but trying to get some other opinions.

guppy wrote: »

Does the damp appear/get worse following rain? Is the wall facing the prevailng wind? Is it particularly rainy/windy where you live?

As Incisor says, have you checked the gutters aren't blocked or overflowing?

As I understood it, cavity walls weren't common until at least the 1930s, do you know what sort of bond is used for the brickwork (http://en.wikipedia.org/wiki/Brickwork) and how thick the wall is (say measured through a window?

Who was the "expert" that came round, you could maybe ask a building surveyor specialising in defects to take a look, but that seems a bit extreme for a bit of damp!

paintpot

I am not trying to be a self appointed damp expert, I've been down numerous routes and put my research hat on that's all

See below. That is what "I" not being an "expert" think is what I am seeing from what I can see of the outside brickwork. The groundfloor flat had masony paint so it's more difficult but the masonry paint has deteriorated, the flat next door doesn't have render or masonry paint and looks cracked, crumbly, breaking down, blown or "shot" as I would describe.

I want to solve it without being taken for a ride. I can't find another problem.
Penetrating Damp

Spalling brickwork, cracked cement render or pebble dash,
face of bricks blown allowing water to soak into brickwork or substrate.
Each brick can hold up to 1.5 pints of water.
Warm air inside and cold air outside causes an osmotic action and the water is drawn through the wall causing internal damp. This is commonly known as penetrating damp .
Penetrating Damp getting into internal walls causes the plaster to break down, surface cracking, flaking and a spongy texture to the surface. These are ideal breeding conditions for black spot mould and mildew which may cause health problems especially to the very young or very old.

real1314 wrote: »

"I am deducing that the brickwork has become porous"

Never heard this one before, sounds like a line from a self appointed damp expert.

Penetrating damp is caused by a source of water. Window lintels, poor roofing, plumbing faults, gutter faults.

Not by "porous bricks". All bricks are fundamentally porous (well, except for engineering bricks) which is how rising damp can occur, however they absorb a small amount of water and then release it out again when things are dry. Unless they are subjected to continuous water, i.e from a source.

guppy

Paintpot,

How thick is the wall? Is it solid or cavity?

If the wall isn't very thick, then driving rain may lead to water getting through the wall.

I'm all in favour of carrying out your own research, a lot of so called experts are just selling their own damp proofing products. Finding the cause of the damp shouldn't be this hard...its getting rid of it that is the hard bit!

I think real means that "I am deducing that the brickwork has become porous" is something a dodgy salesman would say, I don't think he's criticising you!

paintpot

I don't know all the answers, it isn't my house. I don't know how exactly victorian properties are constructed but I don't believe it has a cavity but it might have. If you look in the photo in my link you can see the window so anyone who knows their stuff may be able to tell. I will try and get some more photos downloaded. I don't have any survey reports to go from that mention the construction or cavities.

I am sorry if I appear to be defensive, I'm not, I just don't know where to turn as I keep being told the problems are condensation and they are not. You don't get massive circles of damp that come and go with rain with condensation. Penetrating damp is entirely possible. I've sorted a trillion problems in these houses but I just can't solve this at the moment and it is getting on my nerves. I don't want tenants living with damp. I also don't want to be fobbed off with any more carp! So any help is appreciated. I wouldn't be posting if I didn't want advice.

Sonofa

I'm no bricklayer, but you should be able to determine the type of construction from the outside by looking at the brick pattern. Standard stretcher bond is where the bricks overlap above and below by half the length. This will be a cavity wall construction if the wall has any significant thickness. Should be immediately obvious by looking at the depth of the reveal to the window opening and how far in the window is set into the opening from the outside.

A solid wall construction will look the same with the exception that every fourth course will be bricks end on (headers?) so you are looking at their width by height rather than length by height. I think this tends to be about 9" (225mm) thick.

A third option would be a combination of the two where you don't have a complete course of headers, just one after every three, four (I'm guessing here) stretchers.

tbs624

paintpot wrote: »

I don't know all the answers, it isn't my house. I don't know how exactly victorian properties are constructed but I don't believe it has a cavity but it might have.

Hi Paintpot -cavity wall construction has been around since the 19th century, & became more widespread after the turn of 20th century - many Victorian properties *do* have cavity walls with old iron wall ties in place.You mention the condition of the bricks but what are the mortar joints like? Was the window a replacement and was it the same size as the original? Has there been any other building work that may have left debris in the cavity wall?

Has any cavity wall insulation been pumped in allowing damp to bridge the cavity?

If you need to get someone in you could try Abbey Independent Surveys who have no vested interest in finding damp as they don't flog DPCs etc - see https://www.abbeyis.com