Page 1 of 1
Posted: Sat Jun 25, 2005 10:52 pm
by paulmillwall
I am in urgent need of help. My current pation already covers my DPC by 3inches. Taking this up is not an option due to time and costs involved 36m2 x depth.
The wall has been rendered covering the DPC.
My new added depth is an extra 50mm of natural slate. This will be falling away well from the wall. Can I get away with butting up against wall or must I expose DPC and create a channel. The new level will be sitting just below air vents.
Main problem is no route to any existing drinage pipes.
have read dainage pages and still need help
Please Help ASAP!!!!!!!!!!!!!!!!!!!!!!!!!
Posted: Mon Jun 27, 2005 2:39 pm
by InfAddict
I'm not an expert, but I believe the reason for the '2 bricks down' rule of thumb is to prevent splash back from falling rain water splashing above your DPC.
I would be a tad concerned if my patio was already 3 inches above the DPC because that means any splashing or idle water could penetrate & rise upwards. I suppose adding another 50mm will not make much difference, as you are already well above the DPC!. Although this may not be causing problems at the moment, I believe the more stringent building surveys would pick up on something like this should you come to sell your property.
In terms of what options you have, I suppose you could dig down and create a channel near the house to expose the DPC (but surely it would have to be about 8 inches deep to get sufficient depth below DPC), and that may look very odd and could be dangerous if someone slips in it etc. It also depends on how the current patio drains? Does it slope away from the house or are there gullies at the house side?
The correct answer is to excavate to correct levels so that the level of top of paving at the house is 2 bricks below DPC. This may not be as big a job as you think because you may be able to slope the patio towards the house rather than away, as long as you deal with the water than will arrive at the house. Tony suggests several ways to do this on the drainage pages, including creating a V shaped channel at the house to channel the water to a suitable draining point.
Good Luck.
Posted: Wed Jun 29, 2005 11:08 am
by Tony McC
There really ought to be a 'dry channel' between patio and DPC. Splashback is not the only problem when a paved surface bridges a DPC - there's a significant risk of damp transmission and any half-decent surveyor would spot this when valuing a property or undertaking a Mortgage Report.
A few simple (ish) solutions to this problem can be found on the Dealing with DPCs page