Worried!

[Steve]

I'm aware my house ground floor is suffering with sulphate attack (which expands the slab and can cause damage to external walls). However I have followed suit with my next door neighbours. They filled in the cracks in the living room and hall. I did the same last year. I've currently got 2 men with jigger picks in my kitchen replacing the slab. My neighbours did the same about 10yrs ago.

I've discovered something worrying the last couple of Days. The front corner of the house appears to have new cracks in it. I had noticed cracks before but not thought anything of it, they weren't bad. It appears to have got worse. This corner adjoins the hallway. I'm getting more worried about it. Should I bite the bullet and have the whole house slab replaced and the pointing made good? In my view this movement is something pushing the brickwork out at floor level.

 

[HERTS P&D]

Leaking gully/drains. Get a cctv survey of your drains.

Andy

 

[Blagard]

That gully on the corner and the drain to it would be suspect. While a CCTV is very useful it may not reveal if the branch to the gully if there is one is the issue and unless the survey is cheap enough you may be better digging up the corner to do a visual inspection followed by repair if anything is found.

 

[^woody^]

Sulphate attack is most often brought on by a leaking drain. The same leaking drain is often the cause of subsidence on house corners, rather than the floor pushing the walls.

You do know that you should not just be replacing the slab, but removing the affected fill below it too?

 

[KenGMac]

Steve, good evening.

Question? how long and high is the affected wall? and is there an expansion joint in the wall. is the wall South facing

Not easy to see, but it looks as if the wall has had the mortar raked out and re-pointed as some time in the past?

Does the drainage system in and around this corner have a history of blocking up? or overflowing Etc? any external ponding of rain water?

Is there any internal crack [or other damage] at the same area as the external cracking?

Ken.

 

[Blagard]

SteveNot easy to see, but it looks as if the wall has had the mortar raked out and re-pointed as some time in the past?

Looks like someone has just faced up the old pointing - I seriously doubt any raking out was done except to dust off the old surface!!