Crack in Wall Letting Moisture in

tcs

On stripping wallpaper in one of the bedrooms in a mid-terraced house, I discovered a couple of cracks in the wall to the left of the window. The walls are mass concrete and the house is about 60 years old.

Both cracks were patched up with skimcoat at some point by the previous owners but the plaster was falling out of the top crack so I just knocked it out to see what the damage underneath entailed (see attached photo where skimcoat 'patch' job knocked out). The top crack comes down diagonally to the window like "\" and the bottom crack goes up to the window like "/" (but a bit steeper than that).

The top crack runs through the wall (cannot see it on outer side of the wall because of pebble dash but I can see the crack running through on the smoother plaster on the window jamb - is that what you call the upright side of a window?).

Was curious to see what was happening in damp weather so after a downpour a couple of days ago, I'd a look at it and sure enough there was a damp patch at the bottom of the upper crack - you can see that in attached photo. There's also a damp patch around the skimmed area on the lower crack.

There's mould on the walls and I reckon it could easily be attributable to 1 or more of 3 factors.
1) the cracks,
2) a leak in roof that I got repaired a few months ago (this wall is to the front of house where there's an apex in the roof & the leak was in one of valleys just above the mouldy wall)
3) condensation - fireplace had been blocked up and no other ventilation was in room - have removed the blockage and intend to put something with a vent into the chimney area.

Given that the house has been standing for 60 years, I guess it's unlikely to fall down around me in the morning but I can't just do like the previous owners did and put skimcoat over it to fall out again. Figuring I need to get the cracks sealed for starters.

On discussion with someone who doesn't work in the building trade, he suggested that this is probably a fairly common occurrence where the existence of a window weakens a wall and he mentioned to me that if there was risk of danger to the structure, the plaster would be knocked off and metal used to brace across the crack before replastering. As I said, he doesn't work in the trade so not sure if he's seen this done somewhere or just heard others talking about it.

Any thoughts on this and/or suggestions on who I could get to sort it out?

mad m

Well if its coming through from outside you will have to sort that out first before doing any other work on inside first.

I had a crack under window sill inside/out.I got an engineer to have a look at it as I thought I would have to under pin the foundations as it kept coming back after repair.He suggested that I knock out atleast two inchs either side of crack inside and out.

I went a bit OTT when doing it and could see out to drive from sitting room.Filled the crack with some concrete and put expanding metal over it and then bonding then skim coat to finish.Also done same outside but finished in dry dash.Crack never came back(Yet).Anyway you will have to sort out where the water is getting in first....

Goodluck

mad m

Just looking at pic again,is the crack on the jack wall between neighbours house and is that the old fireplace beside it?

tcs

The crack is to the left of the window inside in the bedroom or to the right of the window from outside, fireplace is nowhere near (it's over on wall between my house and neighbours).

Just found a pic of a house in same style as mine on myhome.ie and edited it to mark rough position of cracks on it. Am fairly sure of position of the top crack (in red) but not so sure about lower one (in blue) - would have to look at that again.

BTW - what do you mean by expanding metal? And what's a jack wall? I ain't no builder!

mad m

Expanding metal is a mesh which you cut to size and nail to wall using masonary nails with a washer attached(cant remember name off hand)Its to strenghten the patch work .A jack wall is wall between you and neighbour.

In the pic those type of cracks are fairly common,especially where I live.Most of my neighbours seem to have had same problem as me and like yours. I can see how they tried to fix it in past.

From the picture though there seems to be a lot of dampness getting through,are you sure the leak on the Apex is fixed? Have you actually got up on a ladder and looked at the cracks on outside?

rooferPete

Hi,

The problem is not as unusual as it may appear, most of that type of house were built using mass concrete and when something had to give it took the easiest route.

There are a couple of different types of valleys in those houses, some are lead while others are valley tiles, what I have seen happen are contractors (?) patching the valleys when they should have been replaced, others have patched the centre valley between the houses to avoid involving the neighbours.

If I am right and the house is poured concrete it can be prone to condensation and can benefit from dry lining the walls, of course you are right open a vent in the old fireplace and make sure the chimney is not blocked.

The piece around the window is called the reveal, the good news is they are very sturdy houses, so sturdy that opening the crack and repairing it properly can be very labour intensive but well worth the effort.

.

tcs

Thanks for that mad m & rooferPete!

mad m - Re.

From the picture though there seems to be a lot of dampness getting through,are you sure the leak on the Apex is fixed? Have you actually got up on a ladder and looked at the cracks on outside?

Do you say this based on the circle of damp at bottom of crack or based on mould? Haven't been up to look at cracks on outside yet - will probably have to hack off a bit of pebble dash & I do need to get a longer ladder as don't wanna be doing anything from top rung of my ladder! I should hack off the rest of the skimcoat that the previous owners used to cover cracks so I can see the full extent of it too. The pic I attached just shows the crack where I already hacked it out. Burying my head in the sand for a while longer though as am working on some other stuff!

Roof leak was over on opposite side of window to where cracks are.

rooferPete - Re.

There are a couple of different types of valleys in those houses, some are lead while others are valley tiles, what I have seen happen are contractors (?) patching the valleys when they should have been replaced,

If I am right and the house is poured concrete it can be prone to condensation and can benefit from dry lining the walls, of course you are right open a vent in the old fireplace and make sure the chimney is not blocked.

It was a crack in lead in valley. My uncle who has tall ladders came up to patch it for me warning me that I should really plan to get valley replaced as I'll only have more problems if I don't. Some other muppets who did a previous repair job had poured gunk all over it making it pretty hard to find where the problem was this time.

Yup, it's poured concrete. Neighbour said that equivalent wall in their house was always prone to damp (she's lived there since it was built). The wall's pretty exposed because of the apex & takes full brunt of weather. Sounds like dry lining could be on the cards once I sort the crack out - around when I'm putting in new window. Removed tacky brick wall that they'd built at opening of fireplace to find a few dead birds so the fireplace has its own set of dramas.

Looks like I've a lot more fun ahead of me :rolleyes:

Victor

Its an odd crack - you usually expect the crack to form from the corner of the window, but maybe they expected this and reinforced just arounf the window and it cracked instead at the end of the the reinforcement.

I don't think it'll make your house fall down - it has survived this long. However, I do think there is some risk (especially if there are cracks on the other side of the window also) of you losing that small gable and it taking part of the roof with it. I would strongly suggest you get someone to look at it professionally, possibly an engineer.

It could possibly be repaired with steel straps, grouting and sealing.

rooferPete

Hi Victor,

I have come across this type of cracking before in similar houses, the cause in the ones I dealt with was the valley leaked into the wall causing the re-bar to expand and spall.

An Engineers opinion would be a good idea especially when making good the crack yourself, if the steel has started to rust it might mean opening a larger area and treating it instead of covering up what could be a bigger problem.

.