Concrete Floor

[sunburyashes]

My cottage was built in the 1800's and has what appears to be damp coming up from the concrete floor into the surrounding walls, the top has what looks like asphalt on it, I want to completely dig out my concrete floor and replace properly.

What layers, depth, insulation etc would I need to do a proper job?

Your advice would be appreciated

 

[PrenticeBoyofDerry]

you would need some structural calcs of an engineer

 

[sunburyashes]

Sorry to ask but why would I need calcs for a floor?

 

[gday2uk]

Generally -
100mm hardcore
50mm sand
DPM (to spec)
Insulation (to spec)
100m concrete
25-50mm screed.

Can't see the need for an engineer either.

 

[PrenticeBoyofDerry]

Sorry to ask but why would I need calcs for a floor?

so when you start to dig out, you do not disturb foundation and the way the walls are supported.
If you dig too deep it will collapse!

Proper Job you said not a blind bodge!

 

[stuart45]

The problem that you have is that even if you replace the floor, because of the DPM the damp will still be sent up the walls.
I've got this problem in the kitchen, and this is a common problem with the old cottages round here. The old flagstone floors allowed the damp to breathe out through them.
An option is to replaster the walls with lime to allow them to breathe better.

 

[freddiemercurystwin]

Sorry to ask but why would I need calcs for a floor?

so when you start to dig out, you do not disturb foundation and the way the walls are supported.
If you dig too deep it will collapse!

Proper Job you said not a blind bodge!

That doesn't need cals just investigation beforehand.

 

[PrenticeBoyofDerry]

you would need some structural calcs of an engineer

maybe it had been best substituting the word would for could,
but you never know, who's to say the previous occupant has not dug down at some stage to give them a greater ceiling height.

 

[jm2000]

I agree, we have been asked before to help with problems like your own, digging down and replacing could be very risky as old properties were not built on foundations like todays, depending on your location it could be built on sand or clay. if the sand has eroded or the clay had dried you will now have shrinkage around your stepped footing. Removing any concrete, may let the footing move.

As was said earlier. you may want to have a reputable damp company take a look, a quote is usually free unless a survey is required.

Jason

 

[mointainwalker]

And which damp companies have a good reputation ?

How many people requesting a survey have ever been told it's a leaky gutter or cracked rendering repairing rather than 3K of damp-proofing they need ?

 

[jm2000]

Well if you dont trust any company then its time to call in an independent surveyor

 

[PrenticeBoyofDerry]

And which damp companies have a good reputation ?

ne risquez pas le frenchones

 

[sunburyashes]

I have not dug out anything yet and the internal brick supporting walls do look dodgy to say the least, the bricks are spalling badly

The property has not got a DPM anywhere in the building and where I
have replaced bricks at ground level it appears it has no footings either and has been built on solid clay!

What steps would I need to take or is it a bigger job than I thought?

 

[PrenticeBoyofDerry]

sounds like you need a surveyor to see whet needs doing.