Exposed DPM in concrete floor

[masaru]

Hi

I plan to put new wooden flooring down in the near future but have a problem with my concrete floor. The photo is of the concrete floor by my front door, as you can see the previous owners have knocked out some of the floor and exposed the DPM and brick wall.

http://i306.photobucket.com/albums/nn270/masaru_album/concreteDPM.jpg

I am worried about what will happen if I just fill this with concrete; will the DPM be breached?

What do you advise? Thanks.

 

[JerryM]

i'd use mortar (5:1 sharp sand: cement) not concrete (concrete being for >1 to 2" depth).

i'd ideally knock/chisel out the previous "repair" then butter the area with mortar "thin scrap all over", then put a sheet of plastic dpm down and cover over with mortar. try to lap the dpm up the edges and mortar underneath to avoid any gaps/voids.

if the dpm sheet is not practical then would put a liquid paint on dpm down 1st something like bitumen (check what your local builders merchant has).

 

[masaru]

Jerry, thanks for your reply.
The depth of the work id about 1.5" (would that change the advice to cement?).
I think the DPM sheet may be a little beyond be; would it be essentially creating come sort of DPM bucket that the new mortar would lie in?
As for the liquid DPM option, should I put down something like this http://www.screwfix.com/prods/29359/Building/Building-Chemicals/Hyprufe-5Ltr be sufficient? if so would the steps be liquid DPM all over the cavity area and wait to dry then mortar?
thank you very much for your help

 

[JerryM]

the depth at 1.5" makes it ok for concrete or screed (whatever is easiest)

the idea of the dpm sheet is to effectively create a bath for the new mortar/concrete to sit in. the trick is to get good buttering so that there are no voids ie any extra mortar/concrete is squeezed up the sides when the mortar/concrete is added over the dpm sheet.

i use the aquaseal myself - it's pretty spot on except that it dries pretty quickly and very little will then adhere to it. u need to spread (by hand) some sharp sand over it before it dries to provide a key for the mortar/cement. i don't think u can put the mortar/cement on whilst it's still tacky. the instructions on the tin will say.