Vinyl deck leaking

My builder used a vinyl deck covering on a southern exposed 2nd floor balcony. The problem is the deck leaked badly into the room below. It appears the leak occured in one of the corners of the balcony and poured from this point into the room below. He has repaired this 2 times before and is now attempting a 3rd time.

I have also noticed that along the wall were the vinyl siding meets vinyl deck sheeting there is tar coming & leaking out from were the 2 products meet. Several questions come to mind that I hope you can help me to resolve.

1. Is the vinyl deck sheeting the right product for my balcony? It is summer and the temperatures are extremely hot. Someone mentioned perhaps fiberglass is a better option.

2. Is this builder applying the vinyl deck sheeting properly for it not to leak from the corners?

3. If the vinyl product used is okay for this application what is the proper way to fix this (detail needed) so I can make sure he is going to fix this issue the correct way?

4. Why is this tar coming out:

Please know I reside in central New Jersey near the coast. This information could be helpful in your advise.

I really appreciate your help in this situation. The builder is not very helpful in this matter and Im not sure if we can trust what he is telling us.

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Aug 02, 2010
Leaking vinyl deck thoughts
by: Matt Whale

My answers are numbered to correspond with your questions...

1. PVC materials are use in an exposed environment (roof and deck application) all over the world for over 60 years which leads me to say it is.

2. I would think not but siding above can cause the leak if siding seals are not proper. The water flows down hill so if the PVC detail terminates 6? to 8? above the deck surface, behind the siding and the welds at there corners are sealed then look higher. If not then locate the manufacture?s installation detail for exterior corners and ask the contract to comply.

3. This is where company and product?s differ; a good product installed by an untrained installer can be installed in such a way it will never perform where a poor product can be watertight if installed by a trained installer. Therefore if the company is trained by the manufacture and under contract with them then require him to fix it via the manufacturer but if the manufacture has no knowledge of the installer, contract or any such training program then you have the task of enforcing your own contract.

5. My quest is a asphalt seal take incompatible with the membrane is drawing the fluids (plasticizers) out of the PVC membrane causing it to become unstable and drip. PVC membranes should not contact asphalt peal and stick tapes, there are other better option.

Aug 01, 2010
An expert is Matt Whale
by: Editor - Rich Bergman

Great question which deserves an absolute expert in the field to respond to you. Matt Whale has done podcasts on the site and is a trainer with decades of experience in waterproofing vinyl decks.

He is at:

Duradek Northwest
18715 SE Aub-Bk Diamond Rd
Auburn, WA 98092


I suggest you give him a quick call and he might even respond directly to this question because a lot folks would benefit from his response on this issue.

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