Sulphate Attack Survey, concrete floors

[Iara]

Hello, I was wondering if anyone can help me with their expertise and knowledge about getting a survey for sulphate attack on concrete floors. We have been getting quotes from different surveyors for this and one of them has come back at £300, he has good reviews and comes off professional and knowledgable. I'm a bit wary about going with his service as he says he only wants to drill one hole in the middle of the livingroom as a sample, and the price of the job seems a bit too on the low end. I would appreciate any advice, thanks.

 

[JohnD]

it doesn't happen in my area, but in some districts, unsuitable ground conditions, or furnace slag as ground fill, are common.

If this is a local surveyor, he may have seen a thousand houses in your town, like yours, built by the same builders and using the same techniques, so perhaps he easily recognises the problem.

 

[^woody^]

Normally its structural engineer who would carry out the investigation not a surveyor - a contractor takes a single sample of the floor and the fill beneath to a good depth, that goes off to a laboratory, and the structural engineer interprets the results. Whether all that is included for £300, you'll have to ask.

A drain survey should also be done if there is a problem with the floors now.

 

[Iara]

Normally its structural engineer who would carry out the investigation not a surveyor - a contractor takes a single sample of the floor and the fill beneath to a good depth, that goes off to a laboratory, and the structural engineer interprets the results. Whether all that is included for £300, you'll have to ask.

A drain survey should also be done if there is a problem with the floors now.

Thanks, I think I used the wrong terminology. He is a contractor who sends off the sample to a lab. Would you say taking one single sample is common/good practice? I've read in other forums they usually take 3 samples at different points of the floor.

 

[^woody^]

One sample should be enough, but that depends on the person's knowledge and experience - as does interpreting the results. Also it's not just a case of sampling, as there are other factors to consider, so it needs a suitably qualified person to reach the right conclusion

Do you have a floor problem now, or just want to check the likelihood of sulphate attack. If you are in a prone area and have the tell-tale signs then you don't need a test.

 

[Iara]

One sample should be enough, but that depends on the person's knowledge and experience - as does interpreting the results. Also it's not just a case of sampling, as there are other factors to consider, so it needs a suitably qualified person to reach the right conclusion

Do you have a floor problem now, or just want to check the likelihood of sulphate attack. If you are in a prone area and have the tell-tale signs then you don't need a test.

Okay, we might end up going with this contractor then since he's been working in this area for many years and should have the right knowledge and experience. Thank you. We don't have extreme floor issues, we mainly want to make sure that there isn't going to be problems stemming from a possible sulphate attack in the future. We are in a prone area- a postwar neighbourhood in the west midlands, and we have minimal tell tale signs - slightly uneven concrete floors (no cracks).

 

[^woody^]

Okay, we might end up going with this contractor then since he's been working in this area for many years and should have the right knowledge and experience. Thank you. We don't have extreme floor issues, we mainly want to make sure that there isn't going to be problems stemming from a possible sulphate attack in the future. We are in a prone area- a postwar neighbourhood in the west midlands, and we have minimal tell tale signs - slightly uneven concrete floors (no cracks).

The ground or fill below a floor can produce negative, positive or passable results in a test. The problems only arise when the ground water content changes for whatever reason and this causes the reaction.

If you are in a prone area, every single floor will be at risk, but that does not mean that every single floor needs to be replaced.