Delta Membrane For Outside Waterproofing

Question Icon
Posted by: from Granton
3/13/2013 at 8:36:42 PM

Is the delta membrane for waterproofing suppose to go to about 1 inch below grade?

We had membrane installed last year but contractor put it one foot below grade and we are still getting leaking through that one foot. He told us it had to be that way due to ultraviolet light damaging the membrane. Every where I look it states it should be 1 inch below and overlap atleast six inches with second strip if foundation wall is higer then the membrane.

Could really use some info from some other contractors experience in such Delta waterproof membrane.

User Icon
Date/Time3/13/2013 at 9:59:30 PM

Delta dimple membrane IS NOT a waterproofing material. It is only for proper drainage thats all. Usually this membrane goes on top of a damp proofing material (bitumen material-black stuff). Using this setup (delta membrane + damproofing) is not enough for a leak proof basement. You need to use a waterproofing agent applied directly on a clean, no holes or crack concrete surface then apply the damproofing system.

It is right to have the delta membrane 1" below the ground to protect it from UV rays as it will get brittle but not a foot deep. Eitherway the problem is the untreated exposed concrete and maybe poor sealing of the membrane.

User Icon
Caesar from Ernesto Voss Inc in Toronto
Date/Time3/13/2013 at 10:16:47 PM

I am a general contractor and it should always be about 1-2 inches below grade.

The reason you still getting water inside is probably because the ends and overlapping wasn't sealed properly, that tend to happen when the parging is dried properly.

I hope this helps.

User Icon
Date/Time3/13/2013 at 11:33:42 PM

Your contractor was lazy and cheap that he didn't want to put another row of membrane in. That being said, if the rest of it was installed properly WITH some kind of waterproofing underneath the delta you shouldn't have water leaking in just because he's a foot short.

Have you checked the grading around your house? That is the first step to a dry basement and solves most water problems. If that's not it, then the contractor did something wrong, and you need to call him back in.

User Icon
Date/Time3/14/2013 at 4:36:15 AM

All foundation water proofing systems must be done to above grade to allow ground water no opportunity to enter and flow behind the waterproofing system. Slightly above grade or better is acceptable

User Icon
Kelly in Granton
Date/Time3/14/2013 at 7:23:49 AM

The guy that put the membrane in told me he was going to fill the cracks with hydrolic cement and then tar over that. This is a house that has been leaking water like crazy for 40 years before we moved in. So the cracks in some areas are quite large. My concern with the membrane being a foot below grade is what happens to the standing water at that level where there is no membrane or waterproofing tar during the spring when the ground under that is still frozen.

Is the membrane just suppose to sit losely down on your footings? Can we just go ahead and add another row of membrane now with the seal sitting at the top of his current row?

I appreciate all responses as this will help when I have the guy back to fix it.

User Icon
Date/Time3/14/2013 at 11:32:34 AM

1) First off, the membrane should be higher BUT it's highly unlikely there's a leak that high up. (If UV attacks the visible part of the membrane, so what? It's above grade anyway.)

2) Are you sure the water is entering via the basement wall or is it coming in higher up and running down?

3) You should have a warranty so start there. Presumably the job was to stop the leak, not install the membrane. The leak's still there so the job is not done properly.

4) Assuming it is a foundation leak, it's more likely the weeping tile was not put in properly and/or the membrane not applied properly because usually, it's the pressure build-up by the water not draining away that forces the water through any available cracks.

5) If water is coming through the floor, than it's likely a weeping tile problem - or worse!

6) With block wall (as distinct from poured concrete) construction, water can flow a long way from where it enters to where it leaks out because the blocks are hollow. Unless the water is released from the blocks, leaking will continue after the outside repair until all the water in the blocks has gone.

I hope this helps send you in the right direction.

User Icon
Date/Time3/28/2013 at 10:03:37 AM

Common sense would be to put the membrane above grade. If you're worried about UV rays just place some 3/4" gravel to cover it.

The first things to look for if you have a basement leak is the grade sloping away from the house in that area and is the downspouts expelling rain water significantly away from house.

Having a clean eavestrough and enough downspouts on that eavestrough is a good idea. Too many homes don't have enough downspouts and when it rain heavy it overflows. Simple common sense.

Search the TrustedPros directory and discover the best contractors in your area.

Find your home service pro
Great renovations start with a great contractor.

Since 2004, TrustedPros has been helping homeowners find the right contractor for their home improvements and repairs.

Post Your Project

Within hours you'll be comparing offers from top-rated professionals. It's free to post and you're under no obligation to hire.

Trustedpros Inc. does not warrant the accuracy, completeness, safety, legality or usefulness of any Content, or Whether Content is Current and up-to-date, and TrustedPros Inc. Shall have no liability whatsoever with respect to your use or reliance upon any content or for content being removed or otherwise ceasing to be available. Please refer to the terms and conditions of use of this websites for more details.

Get quotes from top-rated contractors