Damp on internal wall

[cb1980]

Hi,

Last year I noticed a slight change in colour on the paint of an interior wall, the pattern suggesting it was coming from where it joins the exterior wall. I had assumed that it was just a shadow for a while, but on closer examination the paint felt colder and slightly damp.

Looking outside, I found a drill hole in the brickwork at roughly the corresponding point. So I mixed up some mortar, filled the hole and hoped for the best. In time, the paint seemed to dry out, feeling as dry to the touch as the unaffected areas, so I hoped it was 'job done'.

However, as we approach winter this year, the problem has returned:

So I assume either the hole wasn't the cause of the problem, that I didn't do a good job of filling the hole, the mortar wasn't mixed correctly or you can't just fix it like that.

Here's the outside

and a zoom-in on the hole area

Thoughts?

Other info:
Exterior wall is north-facing, so never gets any sun.
House is a ~1900 terrace, so I assume the wall is solid.

Thanks,

Chris

 

[^woody^]

The darker brickwork above the external boundary wall seems to indicate water running vertically down the wall - which could be saturating the brickwork and tracking across where the wall meets the main house

Could also be to do with the junction of the wall with the main house

A drill hole is not likely the be the cause

 

[catlad]

You can get some water proofer for the brickwork but it may need more than that, what is the small wall is it the party wall

 

[MINDEX]

go with roofers mastic around coping stone and corner where walls joints together, next spray (using ordinary plant sprayer) patch of both walls- 1.5m each way from the center of damage spot- with thompson one coat wall seal- this will solve your problem.
Hole in the brick had nothing to do with damp on your wall- I am sure
Salute
MINDEX

 

[cb1980]

Thanks guys - had suspicion of darker brick but thought perhaps just "old", will inspect my other walls too. The windows are only ~1m away each side, so that'll have to do... How high should I go? I suppose brickwork colour will indicate.

Could this be a guttering issue? The gutters on these houses only run across each individual house, so there's probably a small gap between them. I don't have a long ladder to get up there and see whether there's a blockage. Can go out when it rains next I suppose and see whether there's any obvious problem.

I've not spoken to the neighbours (ever!), they're just renting, assume if they had an internal issue too they'd have got their landlord involved. Can I just spray/seal around the wall when they're out, or do I need to get them involved... any possible issues?

The lower wall with the coping stone is a garden wall between my house and the neighbours, is not in prime condition, I assume it's as old as the houses.

Thanks,

Chris

 

[Graeme]

I would certainly check the slates on your roof. The timing of your posting (severe rain and wind over the past week) suggests that your leak may be entering from a cracked slate which is not a problem in regular rain that goes down your slates but the rain and wind has been so strong recently that rainwater could be blown up the way and enters into the crack. I would take another guess that the leak will now appear to dry-out until another wet westerly gale occurs.

 

[cb1980]

Hi Graeme,

We've not had severe weather here (Northampton), unless I missed something! I know that it has been bad up there in Scotland.

Nevertheless your suggestion may still be valid, although (excuse my ignorance!) if it was a roofing problem, I would expect issues upstairs. The affected area is downstairs, about 2m above ground level. I've just been up into the loft though and can't see anything looking wet up there, although granted any problem could be close to the edge, below the internally-visible area of the roof.

Thanks,

Chris

 

[catlad]

I dont think it will have anything to do with the roof on this occasion as you have solid walls. The reason I asked about the garden wall is it seems to have some marks on it like drill holes

 

[^woody^]

The images clearly show staining to the bricks and a different shade of mortar directly above that boundary wall. Also it looks like the mortar is eroded their too. This is indicative of water running down the wall - normally from defective guttering and this type of defect does make the wall wetter at ground floor level and not at first floor

A roof issue would tend to show in the bedroom

 

[MINDEX]

Untitled

• MINDEX
• 6 Dec 2011
• 1

 

[MINDEX]

I have an idea:
boundary wall has been added some time after your building was ready, so to join the wall with the building bricklayer had to use a type of locks to prevent from falling it down- they drill a hole on the ready wall and when laying additional one they inserting metal rods into them which goes between new bricks (otherwise they can dig out brick from existing wall and insert brick from fresh wall)
Coping stone never let the water seep trough- only joints can do, in this case looks like connection between 2 walls isn't sealed properly so water gets in and next trough the locks into the main wall (see the picture)
even your gutter is leaking and you will do repairs as I have advised in my previous replay/post – this will do the work
My only concerns is- where are from those extra holes on garden wall (with wall plugs?) ? first thought- maybe fixing from the garden trellis? (but too many for that)
wall seal is clear, goes into the bricks as a water, is dry in appx 2h, is not visible till rainy weather- untreated wall will get wet (change the colour to darker) but treated part will remain dry
let me know if that's make any sense for you
after fixing external problem you should hire a dehumidifier and place it in effected room for at least 3 weeks time
Salute
MINDEX

 

[cb1980]

So I picked up some of this today. You mentioned using a plant sprayer to apply it, sounds much easier than a brush or roller. Will this kind of thing do the job, or does it need to be more heavy-duty?

As far as roofer's mastic, there seemed to be a few different ones in B&Q, is it a specific one that I'm after?

Will try to get a pic of the holes in the garden wall up (anytime I'm at home in the daylight...)

Thanks again for the advice so far.

Chris

 

[MINDEX]

I am using sprayer http://www.diy.com/diy/jsp/bq/nav.j...es/specificationsSpecificProductType=sprayers
it does the work for me well, as mentioned water seal from thompson: http://www.diy.com/diy/jsp/bq/nav.j.../specificationsProductType=cleaning___sealing
and mastic: http://www.homebase.co.uk/webapp/wc...ay?langId=110&storeId=10151&partNumber=408049
first cut the nuzzle of the mastic in diameter +/- 8mm, apply on the connection wall/boundary wall and wall/coping stone, when is done squezze with your finger to make sure if sticks well to both surfaces, afterwards spray over with
water seal. To wash out mastic from your hand/fingers you can use this: http://www.diy.com/diy/jsp/bq/nav.j...<{9502022}/specificationsProductType=cleaners
Best of luck
MINDEX