How important are weep holes?

[WWilts]

If a raised patio is laid above weep hole level, how to let the damp out of the weep holes? And how much does it matter if a section of weepholes is blocked up?

How is this challenge designed out usually?

Edited October 3, 2022 by WWilts

[markc]

Weep holes should be at DPC level so you definitely should not be going above them. Or are these weep holes in a retaining wall, not habitable? Is so then you can add a sort of French drain with pebbles to allow the drainage to continue

[Miek]

My weeps are at dpm not dpc, dpc is 1 block above the bottom of the cavity (I'm in a radon area so the dpm runs over the cavity and into the outer skin) The weeps at ground level are there to release water but in reality they should remain dry if the wall is waterproof.  If they are below grade and draining into porous material I'd say that's fine.

[markc]

23 minutes ago, Miek said:

My weeps are at dpm not dpc, dpc is 1 block above the bottom of the cavity (I'm in a radon area so the dpm runs over the cavity and into the outer skin) The weeps at ground level are there to release water but in reality they should remain dry if the wall is waterproof.  If they are below grade and draining into porous material I'd say that's fine.

Yes, my bad, was supposed to say DPM .. ie to drain the membrane

[WWilts]

So, covering up weepholes with patio hardcore is a no-no.

[markc]

13 minutes ago, WWilts said:

So, covering up weepholes with patio hardcore is a no-no.

If the hardcore will bridge a DPM then it’s a no no or you will get damp walls. You could leave a gap between wall and patio.

if the weep holes are in a retaining wall (damp rising is not a problem) you could use a clean crusher run (concrete,brick,stone pieces) not Type1 which will allow the weep holes to drain. This will create a sort of French drain, type 1 could be used under rest of patio.