Internal floor level below ground level

[jamse]

So, you think more like in this second version of the diagram, then?

Untitled

• jamse
• 7 Mar 2013
• 1

One query with that - the guidance I've read online seems to suggest that the part of the cavity wall that is below ground should have its cavity filled with a sand and cement mix up to ground level. (I had shown that as a grey box in my picture.) How should I handle that if I have the DPM crossing the cavity below ground level?

One other query - should I seek to fix the DPM to the inner side of the outer wall, or would it be OK hanging loose in the cavity, where it might flap anywhere between the inside of the outer wall and the outside of the inner wall?

Thanks,
Jamse

 

[stuart45]

Looks a better method. Take the lean mix up to internal DPC level first, then go across with the DPM, and then put more lean mix on top to 225mm below external DPC. The concrete will hold the plastic against the external skin.
The external DPC only needs to be 150mm above ground level.
I've never done this on a job BTW. All the basements or semi basements I worked on had asphalt on the floor and vertical.

 

[damanpunk]

I'm doing something exactly the same at the moment, check out RIW waterproofings brochures/website they have products to suit and typical details.

 

[jamse]

Thanks Stuart. Should I be looking at asphalt as an option? Is that a more 'proper' way of doing what I'm after? Is it within reach of a DIYer who is willing to try most things, or does it need years of practice / expensive equipment to make a decent job? If it is something I should be considering, any pointers on where to start looking (and pitfalls to avoid) would be most welcome.

Thanks for the pointer to RIW, damanpunk. I'll be sure to take a look at the information you mention.

 

[stuart45]

Thanks Stuart. Should I be looking at asphalt as an option? Is that a more 'proper' way of doing what I'm after? Is it within reach of a DIYer who is willing to try most things, or does it need years of practice .

Asphalting is a highly skilled job, especially vertical asphalt and you need the all gear. There are not that many skilled tradesmen around these days that can do a good asphalting job.