Damp proofing a garage floor slab

[pippo]

Hi all

from the pic in the link below, the edge of the concrete slab should extend 150 from the garage structure. Looking at that picture, what is to stop rain from soaking into the slab where it extends past the garage structure?
wouldnt it just saturate the floor ?

http://www.pavingexpert.com/images/concrete/garageBase.gif

Cheers

Pippo

 

[noseall]

Looking at that picture, what is to stop rain from soaking into the slab where it extends past the garage structure?

The slab will not suffer from rain soaking into it but the (mortar, mastic) join betwixt the sectional garage and the slab, will. It will be fine and dandy for a while but as soon as there is any movement whatsoever then the join can and will be broken and rainwater will seep in.

I personally do not subscribe to raft type slabs particularly those that are above the ground and use a pronounced 'toe' edge. Good for a shed only me thinks.

I guess the only answer is a permanently pliable mastic joint - usually industrial and expensive.

 

[pippo]

Oh right I see, forgive me for being daft but if the slab wont absorb rain water why does it need dpm from ground damp etc.

cheers

Pippoi

 

[noseall]

Oh right I see, forgive me for being daft but if the slab wont absorb rain water why does it need dpm from ground damp etc.

cheers

Pippoi

I did not say that the slab will not absorb any moisture i merely said that it will not suffer from rainwater hitting it.

Once the slab has hardened there will be very little absorption from rainfall, practically none. The polythene acts as a protection from moisture ingress, protection from ground gasses and can help deal with condensation.

You are forgiven.