DPC and Weep Vent Location

[Barney12]

So I have a timber frame with an outer block and render skin. 

Our external finished ground is going to be level with the slab (including channel drains at every opening).

MBC have installed their DPC under the sole plate and lapped it down to the ring beam that supports the blockwork (see image below).

 

I think I've gleaned that standard practice is then to add a second DPC 100-150mm above the external ground level and lap it down onto the frame DPC. Does that sound right?

 

However, where I'm confused is where to put the weep vents? If they go at the bottom then they will be blocked by the external ground. If they go at the higher level then the lower section could just fill up with water.

 

I'm beginning to to think I've got this detail all wrong? 

 

[Oz07]

Your going to need a dpc all around at 150 above ground level. Not bridging cavity. I'd probably leave a few perps out in the first course of brickwork externally sitting on ring beam. Free drawing gravel with no fines to let any trapped water/moisture drain from cavity. 

[Russell griffiths]

We built with a very similar build up, we added another damp course sealed to the outside of the timber frame,fitted over the sarking  board but under the weather membrane, this then crossed the cavity with weep holes fitted above

 

any moisture falling down the cavity was ejected outwards. 

[Barney12]

9 minutes ago, Russell griffiths said:

We built with a very similar build up, we added another damp course sealed to the outside of the timber frame,fitted over the sarking  board but under the weather membrane, this then crossed the cavity with weep holes fitted above

 

any moisture falling down the cavity was ejected outwards. 

 

This was a thought I had but it's now going to be a pain to implement as MBC have gas nailed numerous ground tie straps (im not sure what theyre actually called. It's a strap that's nailed to the frame and sits under the blockwork) around the perimeter. They are at exactly the wrong height to allow the detail you describe. 

 

[Barney12]

55 minutes ago, Oz07 said:

Your going to need a dpc all around at 150 above ground level. Not bridging cavity. I'd probably leave a few perps out in the first course of brickwork externally sitting on ring beam. Free drawing gravel with no fines to let any trapped water/moisture drain from cavity. 

 

That's sounds doable! 

[Russell griffiths]

Need a pic really. 

If the strap is nailed to the frame on the outside of the membrane that will be a pain. 

I would think you would need to cut around them, poke your new Dpc up fold cut membrane back down and repair membrane with appropriate tape

[Barney12]

1 minute ago, Russell griffiths said:

Need a pic really. 

If the strap is nailed to the frame on the outside of the membrane that will be a pain. 

I would think you would need to cut around them, poke your new Dpc up fold cut membrane back down and repair membrane with appropriate tape

 

Yes nailed to outside of membrane  

I'm off to site shortly and I'll take a picture. 

[Brickie]

https://www.travisperkins.co.uk/Visqueen-Pro-Single-Sided-Jointing-Tape-75mm-x-25m-RS020777/p/171762?gclid=EAIaIQobChMIxsKy7f7l1QIVRrXtCh1aeABOEAQYAiABEgJokfD_BwE

You could lay the continuous Dpc tray,cutting either side of your straps as tight as is practicable & cover with this product. 

If you really wanted to go to town there's a double sided version that you could cover the strap with first,lay the Dpc onto it and then cover with the single sided stuff. 

[Barney12]

I'm beginning to think the easier option is going to be to remove the ties and place them above the second DPC. 

Ill talk to the TF guys tommorow. 

My young nephew will just LOVE pulling all those rink shank nails out