New concrete floor - old terrace house with flagged flooring

[ToMMY2ooo]

Hi all,

I have a few questions. Im in my first house and after ripping all the carpets up Ive discovered that the floor is flagged (with some rather nice stone flags actually). Im not sure whats underneath but Im 100% sure whatever it is is not waterproof. We have a terrible problem with damp so Im on a mission to sort it.

I dont want to lay down a wooden floor so Im resolved to ripping up the flags, digging out whatever is needed, laying some plastic, filling it with concrete and putting a self levelling floor down.

Ill make this easy to answer...

1) How much should I dig out and how thick should the concrete be?
2) Does anyone have any recommendations for the plastic to lay down and is there any special sort I should look into?
3) What sort of concrete can I use, is there a cheaper concrete used for foundations that can be used successfully (I was told there was)?
4) Finally, what would people recommend for the self levelling floor? Any brands or types that would particually suit a DIY application?

Thanks for taking the time to read

Cheers,
Tom

PS Ill post photos and my progress when I start the job.

 

[Beans-on-Toast]

This is a big job your taking on, why not get a couple of quotes and ask a few questions whilst they are on site.

 

[ToMMY2ooo]

Big job yes, but its more manual labour than anything else.

Anyone got any ideas on my questions?