Options to stop penetrating damp

[Bens_Dad]

Hi, I’d be really grateful for some advice on how to deal with a penetrating damp problem on my property. It’s a solid brick 1930s semi with what I think was originally a scullery sticking out the back of the kitchen. The walls of this are brick but thinner than those of the rest of the house. I’m getting damp coming through these walls in various places. Quite a lot of this is next to uPVC windows / door but also happening on plain wall (see photos). I originally thought the problem was due to condensation so have had extractors and radiator installed – the damage shown is since new plaster and paint in Oct last year.

The outside has at some point been given a layer of what I think is Spar. I suspect this is probably over the top of the original pebble dash. I can’t see any signs of significant cracking in the spar in the areas affected (although the paint might hide them if they’re there) but I don’t know what condition the pebble dash underneath is in. The brickwork mortar throughout the house is really soft and we’ve found plenty of gaps in it as we’ve done other work – I expect the same is true of the scullery. I’ve recently put sealant along the joint between Spar and window/door frames, but no sign yet that this is making any difference.

The longer term plan is to take this all down as part of an extension so I need a cost-effective solution that keeps it watertight in the meantime. The two options I see at the moment are either (a) to have the spar / pebble dash removed, the walls repointed and a new render coating applied and painted or (b) to clad the walls with uPVC planks to keep the water off (yes I know it’ll probably be ugly!). Either way I might look to add some external insulation.

I’d really value comments on whether these options are likely to solve the problem, are there others I should be considering and any pro’s and con’s I should be thinking about. Should a decent render coat keep a wall like this dry on the inside? Is there a risk that removing the existing spar / pebble dash damage the walls?

Many thanks.

 

[JohnD]

there are some pictures that look like skirting level. Please stand back and take a pic of the entire wall to put them into context.

Are all the damp patches near the window and patio door? Are any of them near the drain?

Does the gutter overflow?

Does the damp appear after rain?

How and when do you ventilate the room? Is there any wet washing indoors?

What is the height of the DPC relative to ground level?

Is the floor concrete? Is it wet? Did the scullery have water or drain pipes in or under the floor?

to check if it is condensation, tape cling film tightly to the wall. If water droplets form behind it, the wall is wet. If they form on the room side, it is condensation.

 

[Bens_Dad]

Hi John, thanks v much for for replying.

Attached a couple of pano pics that show most of the external walls (not the tops) I've marked up where there is evidence of damp. Hope these are clear. As you can see, issues both at low and higher level. There is also a damp area at the base of the wall to the left of the door.

Its difficult to access the wall right next to the drain but it looks likely that there is damp there too.

Gutter doesn't overflow to my knowledge but will check next time we get heavy rain (should have to wait too long for that this year!)

The damage has been gradually getting worse since early January - there is no clear worsening with rain, but then its been wet most of the time since then with few long dry spells to be able to tell a difference.

Room is ventilated using hood extractor and windows (above door) open when cooking etc. We do dry washing indoors during the winter, in another room with a dehumidifier.

DPC - not sure on this part of the house as the wall below the dash is covered with render (which is not in great condition). If its continuous with elsewhere in the house then its probably between external ground level and floor level, prob closer to ground level. We had the plain (left hand in the external photos) wall section injected as part of rising damp work to the adjacent house wall, but not the rest.

Floor for this section is concrete - its covered by tiles then lino so don't have access directly to it. No evidence of damage to those, or of any drain pipes in/under, although these could have been covered.

I'll try the condensation test over next couple of days and report back.....

 

[JohnD]

in your first pic all the damp patches look window-related. External pics of the detailing round the frames might help.

the other ones might have a different cause. Possibly steam from cooking, or splashing from the sink, or perhaps a sink-related leak unseen behind the cabinets. Can you have a look behind? A plumbing leak making the floor wet will soak into the wall, but will also cause a pocket of damp and humidity behind the cabinet.

while waiting for rain, look in the gutters for leaves, look at the joints for gaps, and pour some water into them with a hosepipe. Look at the tiles to make sure they discharge into the gutter.

If Aldi has a garden sale on, try to get some side sheets for their polyester shelters. Pergolas? They are big and cheap, and if you hang one over a wall, using vine eyes, it will keep rain off the render for a trial period. But I doubt the render is the problem,

 

[Bens_Dad]

I've attached some pics of the detailing around the door and window frames - hope these are close in enough. The sealant is all new (nothing there before).
Steam from cooking etc was definitely an issue before we had the recent work done but since then I'd hope much less so - the windows certainly don't fog up etc now even in middle of winter.
So now I have a list of things to investigate - I'll report back when I have some answers.
Thanks again John.

 

[Bens_Dad]

Hi @John D , I've made some progress although not as much as would have liked as have been ill.

From the questions you've asked this is what I've found so far:
- Gutter doesn't overflow or drip, and the tiles discharge into the gutter.
- Tried the cling film on a sample of each type of damp area (all 3 walls) but didn't get any condensation on either side. Most areas seemed to get worse while the cling film was in place (without any rain)
- The damp around at the windows / doors does seem to get worse after rain.

I've not managed to get behind the units / washing machine yet, will do this when I'm a bit stronger. There's no evidence of leakage under the sink but have measured humidity, using a garden variety temp/humidity meter so not massively accurate but this showed quite high humidity in that cupboard. More generally also higher humidity around the scullery relative to kitchen and rest of the house, and especially nearer the floor and on the worktop next to the cooker (all >60% overnight). I guess this in itself could lead to the damage on the wall next to the cooker which is north facing?

I've been thinking about the floor slab. I've not managed to get under the lino yet but there is damage to the render under the door (see pic) which could allow rain splashing off the adjacent concrete through? The ground level on the other (north) side is higher than DPC. We had it injected as a precaution when doing similar on the main house and have a shallow French drain against the bottom of the scullery wall below this, but I guess this could also be making the slab wet.

In poking around I've also noticed that there is damp on the main house wall that divides the scullery from the rest of the kitchen next to the door. There is evidence of this below the line in the second picture - only on the scullery side of the wall. The render is not tight against the doorframe in a couple of places here and it also lines up pretty well with the bottom of the chimney coming down the corner of the house shown in the 3rd pic (the top of the chimney was removed and covered by new tiled roof about 3 years ago). There does appear to be a crack in the render on the chimney at the bottom of the access hatch, which so far I've not managed to budge!

Sorry, bit of a download. It feels like I'm surrounded by problems here and grateful for any thoughts on where to go next e.g. what type of work would be needed to stop any leakage around windows / doors, deal with a potentially wet slab and fix to the chimney...