Sulphate attack - advice please

[kateb901]

Hi, desperately need advice please!

We've had an offer accepted on a house but we've been advised by friends to check for sulphate attack owing to problems in houses in nearby roads. I've read up on the problem but not sure what to do next - are there companies out there who can survey for this, can you get indeminity insurance?

It's a 50s/60s build - not sure of exact date. Don't want to walk away from it unless we have to - we really like the house.

Any advice appreciated. Thanks

 

[joe-90]

It's s job for a structural engineer.

 

[diane1]

excellent advice Joe!!.....

and just because they accepted your offer....doesnt mean you have to buy it.....if you really like the place....get the survey done, then change your offer to reflect the cost involved in sorting out the problem....!

ps...welcome to DIYnot!..... ....and good luck!

 

[malcolmX]

Hi, desperately need advice please!

We've had an offer accepted on a house but we've been advised by friends to check for sulphate attack owing to problems in houses in nearby roads. I've read up on the problem but not sure what to do next - are there companies out there who can survey for this, can you get indeminity insurance?

It's a 50s/60s build - not sure of exact date. Don't want to walk away from it unless we have to - we really like the house.

Any advice appreciated. Thanks

What exactly do you mean by "sulphate attack" are you talking about sulphate penetrating a chimney breast that has been used in the past for burning coal? a house built in the 50's or 60's has more than likely been used for burning coal.

 

[dazdel]

Do you mean salt damp ?, what type of plaster is on the walls , sand and cement and skim, lime and sand. Or is the house all concrete walls ?, some pics might help. Salt damp is rare in the uk, but there are some areas where it is found, and can be a real problem to sort out if there is no dpc, more info mate

 

[0000]

I think he means sulphate attack. From preliminary on-line reserch you need to make sure that the hardcore containing suflates is not exposed directly to the concrete, and the condition.

This is something that can only be done by a structural/civil engineer.

If it is something tat is happening in that area a lot you might ask what is the procedure. Just because it is near by doesn't mean the conditions apply to you.

 

[^woody^]

Generally, you may not get a mortgage on a property which is in an area prone to sulphate attack, unless the floors have been replaced previously and a certificate from an engineer validates the work. This tends to get picked up by the valuer on the mortgage valuation

Sulphate attack can occur at any time, and could be slight or major - we've seen floors crack and rise by 40mm within 4 months after being generally flat for 50 years or so. Other floors can just remain a bit uneven for many years

A test involves drilling the floor and taking samples of the concrete and ground below. The seller may not want you to do this. However this only tells you the condition at time of test. A wet winter or broken drain can set off susceptible fill under the floor at any time.

Hollow sounding floors, general humps and unevenness or cracks and ridges are a sign - you can tend to detect problems just by walking around on the floor. But there is no guarantee that a nice floor today wont develop problems tomorrow.

Remedial work is about £10-15k and requires all the floor and about 1m of fill below it to be removed and replaced

 

[malcolmX]

About 20 years ago I sold a house and the surveyor said that the disused back chimney breast was affected by sulphates, something I had never heard of till then, the plaster was the original sand/lime mixture.
He said it was acids from the coal tar and smoke penetrating the breast, I just hacked it off and replastered with Carlite browning, the surveyor passed the job, asked loads of guys in the trade had they ever heard of this problem, no one had.

 

[joe-90]

Woody has just told you what it is.