crumbly concrete under floor

[jonathanwilliamwright]

Just lifted my tiles off floor in back reception. Underneath the concrete is very soft and crumbly and you can press your fingers right in.


spoke to a builder and he in forms me i have two options i can either take all concrete out and reconcrete installing a dpm.

or

I can leave the concrete and tiles down and just put k11 sovereign damp proof system on top.

any advice

 

[^woody^]

It could be anything from that description

However, one of the possibilities may be sulphate attack (search here or Google), and if that is your problem then its a much bigger job than your builder thinks

You need to determine the cause first before deciding on a repair

 

[jonathanwilliamwright]

It could be anything from that description

What other thing could cause this woody other than sulphate?

However, one of the possibilities may be sulphate attack (search here or Google), and if that is your problem then its a much bigger job than your builder thinks

You need to determine the cause first before deciding on a repair

Ive got eflorescence in one corner so maybe. I think ive messed up here big style.

Been reading this thread on subject interesting

http://www.ebuild.co.uk/community/topic/3874-sulphate-attack-in-concrete-floors-how-much/

 

[ConcreteDrBill]

Only absolute way to tell if it's sulphate attack is to get some of the concrete tested (measure sulphate content and get it looked at under a microscope)- Try Sandbergs !

If it is sulphate attack, the concrete needs to removed , a dpm put in place and new concrete put in. If you use hardcore, blind it with sand and then put the dpm over it. Pour the new concrete over the dpm. For 'belt and braces' use a sulphate resisting cement in the concrete.

 

[jonathanwilliamwright]

Only absolute way to tell if it's sulphate attack is to get some of the concrete tested (measure sulphate content and get it looked at under a microscope)- Try Sandbergs !

If it is sulphate attack, the concrete needs to removed , a dpm put in place and new concrete put in. If you use hardcore, blind it with sand and then put the dpm over it. Pour the new concrete over the dpm. For 'belt and braces' use a sulphate resisting cement in the concrete.

My builder told me if the concrete is crumbly and there are signs of eeflorecence on the tiles then its sulphate attack. Maybe hes trying a fast one.

How much does the test cost ? just that im nearly skint after the mortgage is paid.
What else makes the concrete turn to pieces?

How far down in theory would you have to dig down to remove all the concrete?

Im thinking off removing all the concrete myself it may make the job come down in price because theres no way i can afford it for next few years.

Thanks for advice. Because im in a right mess cant sleep with worrying.

 

[^woody^]

Only absolute way to tell if it's sulphate attack is to get some of the concrete tested
If it is sulphate attack, the concrete needs to removed , a dpm put in place and new concrete put in. If you use hardcore, blind it with sand and then put the dpm over it. Pour the new concrete over the dpm. For 'belt and braces' use a sulphate resisting cement in the concrete.

If the floor cracks in an indicative way, then a test wont be needed, as it will be obvious

As for the repair, you forgot to mention that the work has to be done via a building regulations application and will require insulation to current standards

There is no need for SR cement

 

[^woody^]

How far down in theory would you have to dig down to remove all the concrete?

Normally you would remove all the fill (ie the hardcore) and some soil so you could be looking at 900mm or to the house footings. It depends, but its not just the concrete which should be removed as the actual reaction is coming from the fill material.

I've posted a few times on this with more detail if you do a search.

Also, you may need your drains checking as a leak may be a cause of all this to start in the first place.

Either get someone who knows what they are looking for to have a look and advise, or you could just leave it and see if it gets any worse in the short term. You can just do a temp repair to level any patch to tied you over.

It may or may not be sulphate attack, and efflorescence is not a sign that it is

 

[jonathanwilliamwright]

Only absolute way to tell if it's sulphate attack is to get some of the concrete tested
If it is sulphate attack, the concrete needs to removed , a dpm put in place and new concrete put in. If you use hardcore, blind it with sand and then put the dpm over it. Pour the new concrete over the dpm. For 'belt and braces' use a sulphate resisting cement in the concrete.

If the floor cracks in an indicative way, then a test wont be needed, as it will be obvious

As for the repair, you forgot to mention that the work has to be done via a building regulations application and will require insulation to current standards

There is no need for SR cement

How much wwill this cost? im nearly skint and going to end up losing the house because there no way im going to be able to afford the 10 grand.

On the sellers questionaire they said there was no structural damage is there anyway of seeking compensation on this because they obviously lied also the front room they have concreted over and the sulphate attack may still be there.

Im on the verge of losing everything its took me 8 years to save deposit to buy this house and get out of council estate now i may find my way back there.

 

[^woody^]

Why would you lose the house? Is it yours, are you buying it or what?

 

[jonathanwilliamwright]

Why would you lose the house? Is it yours, are you buying it or what?

Because i cant afford to have the work done. I can afford the mortgage but my builder says if i dont get the work done in a couple of years time the sulphate attack is going to effect my next door neighbors on both sides and they could put in compensation claims.

Not to sure if hes just trying to pull fast one but i aint got the ten grand to sort it out.


Just feeling very negative at moment was thinking of maybe patch it up myself take all concrete out and refill and fit a dpm got a mate who used to work as a labourer so he knows what to do. Not ideal but if i patch it up i could get lodgers in and then save up and get work done properly.

Thanks for advice woody

 

[joe-90]

I'd just patch it up like you say. By the time it becomes a problem you'll be long gone into another place.

 

[jonathanwilliamwright]

I'd just patch it up like you say. By the time it becomes a problem you'll be long gone into another place.

Yes this is what im going to do, the problem is I couldnt sell this on without telling the person whos buying the problem { I know im soft like this}

What would you need to do in theory dig out 900mm put the sand cement etc dpm down .

 

[joe-90]

You don't know it's a problem. Concrete often goes crumbly as it ages, patch it up and sell it on - why disclose a fault that might not be fault? Are you crazy?

 

[jonathanwilliamwright]

You don't know it's a problem. Concrete often goes crumbly as it ages, patch it up and sell it on - why disclose a fault that might not be fault? Are you crazy?

Im going to patch it up for now the walls are not bulging and the floor has not got any big lumps in so just going to take up concrete down 900mm and fill it and concrete again over a good dpm. I intend to stay in this house for abit.

It was my builder who scared me abit he was more or less saying my house will be destroyed if i dont pay to get it fixed and you cant pay if you dont have. The cement has been there since 1950 so a lot of years.

Whats the best way to insulate the floor when i do it?

thanks for advice joe

 

[jonathanwilliamwright]

Only absolute way to tell if it's sulphate attack is to get some of the concrete tested
If it is sulphate attack, the concrete needs to removed , a dpm put in place and new concrete put in. If you use hardcore, blind it with sand and then put the dpm over it. Pour the new concrete over the dpm. For 'belt and braces' use a sulphate resisting cement in the concrete.

If the floor cracks in an indicative way, then a test wont be needed, as it will be obvious

As for the repair, you forgot to mention that the work has to be done via a building regulations application and will require insulation to current standards

There is no need for SR cement

What is insulating to current standards woody?

thanks for advice buddy