floor has lumps and cracks - what to do?

tony6403

techmob wrote: »

do you know if that floor has damp course in it, or would that be below it?

not sure i want to go to the extent of completely removing and relaying a new one.

just wanted to know if it was possible to remove any lumps and fill smoothly with cement. would this affect any damp course etc?

Yes it's possible to remove damaged areas and patch the floor.
You could remove a small test area and check to see what's underneath by way of any damp proofing.
I have to resort to guesswork here , but you might find some sort of bituminous dpc . Or I have seen such floors laid on black ash and seen some laid on shale. None of these are satisfactory. You might be lucky and find a plastic membrane.
I can only reiterate my opinion that , if it were my house , I would lay a new floor - the materials are not expensive and if you want to DIY very few tools are needed.

iamcornholio

Its not clear just from the photo's, but this could be an indication of sulphate attack to the concrete slab

If your property was built between 1930 and 1970 (but not exclusively) then ash or shale used for fill below the concrete could be the issue.

If this is the case, then no repair will work as the reaction will continue, and the whole floor and fill below will need removal

techmob

Hi

the house is 1930's and the black stuff smells like coal if that is any indication?

it looks like concrete underneath.

could this be an expensive repair?

techmob

should i take off all the top black layer and see what condition the underneath is. i.e if it has cracked etc?

iamcornholio

If the surface is heaving (ie moving upwards) as opposed to just cracking, then it is either a sign of a reaction of some sort or is a sign of screed detaching from the slab.

Screed detachment does not normally occur in numerous places and in the same way as indicated in your images and floors of that age tend not to be screeded, so more likely (but not necessarily solely likely) is a reaction, and therefore possible sulphate attack

Best to get this looked at by a suitably qualified structural engineer or surveyor.

Having said that, if the "black stuff" (possibly a bitumen surface treatment or adhesive) is just the thing which is cracked (and not the concrete below) then that's just a simple repair to scrape it off

techmob

would you call the black stuff "Asphalt" ?

it has dents in places where either a workmen has put something heavy on it or over time furniture has caused it. it has cracks in places with the odd raised bits. and that big raised bit being the worst. raised and cracked

it may of been there since the house was built? and i was hopeing it may just need a new coat of the black stuff. i think i need to knock around the section that is raised and see what is underneath and if it looks like that is compromised?

thanks

techmob

this is the stuff on my floor (although not my floor)



i am also hoping the concrete underneath is ok



related link http://www.diynot.com/forums/viewtopic.php?t=237327

techmob

i am very worried now, i have took the top layer of ashpalt from around the affected area to see what was underneath it.

it seems that the concrete is raised/cracked and is very brittle/crumbly. i can break it with my fingers as shown on the pictures.

i have spoken to a builder(who hasn't seen it) and he told me to contact the council's building inspectors and explain my concerns and they should come out and advise.



does anyone know what flooring a 1930's house will have. would it be a top layer of about 1/2 inch of asphalt and then about an inch of concrete underneath?

link to pictures http://img210.imageshack.us/gal.php?g=img0162if.jpg

iamcornholio

If the slab below the surface coating is cracked and crumbly then this is another symptom of sulphate attack. Unless this is a council house, then no-one from the council will come out to advise as it is nothing to do with them, and the building inspectors only deal with new building work - and TBH may building inspectors do not know much about diagnosing existing problems.

However if there are similar council housing locally, then a surveyor from the housing dept may be able to say if their properties have had this problem. Likewise, an estate agent may be able to advise if you pretend that you are looking for properties in your road and that you have "heard" about sulphate attack problems.

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. 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.

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

techmob

The house is an ex council house and there are still council houses on the street. i am going to ask my next door neighbours who also own their house if they know of any problems

would this mean that if the other floors are not showing signs, do they also need replaceing as it would just be a matter of time?

remedial work, would that be based on all ground floors?

thanks