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Discussion Starter · #1 · (Edited)
I am wondering if anyone might have some suggestions on solving this drainage issue with our vinyl deck.

We used to have 2 separate decks but upon rebuild we have them joined with a narrow walkway. There was previously a downspout where the new walkway currently is. Initially, we were going to redirect this downspout to the other side of our roof gutter as our deck builder didn't think having the hole through the deck would look good. But after having a roofer and a gutter company here, we were told that due to the current slope of our roof, redirecting the downspout to the other side would not work without the risk of having our gutters overflow. We have temporarily attached a piece of downspout across our deck that then drains down into river rock for the time being, but of course, it cannot remain this way.

As a result, I now have to cut a hole in our deck for the downspout to fit through so that it can reach the storm drain below. The deck surface is the Deksmart vinyl product. I want to make sure that I do this as least invasively as possible while also being accurate. The last thing I want is for water to seep under the vinyl and potentially cause bubbling or rotting, so I want to shield the exposed edges in the subfloor once I cut out the hole. Almost all water will be inside of the downspout, but I want to protect the subfloor in case some water on the deck itself runs into the cut-out. I have attached some photos for reference.

Gutter Fix 1 - This is the current layout, as well as the proposed plan outlined in red.

Gutter Fix 2 - An alternative view from under the deck.

Gutter Fix 3 - This is a mock-up of how I was hoping to potentially protect the subfloor edges (the green tape represents vinyl decking that I would heat weld to the existing vinyl.

I have also been searching online for options, but I'm not sure that I have found a viable solution. Our gutters are 2x3" rectangles and the only PVC coated drain openings I could find online are 1.5" or 2" circles.

Could anyone suggest a product or PVC insert that will work with a 2x3" downspout? Or a better way to heat weld the vinyl to protect the cut-out opening? Or any other suggestions or ideas on how to accomplish this?

Any help would be greatly appreciated!
 

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Draw the profile of the downspout on the deck. Then use a Dremmel tool with a small router type bit to carve out a perfect downspout shaped hole. I did it once and it worked. A round hole and a pipe will work but won’t look as nice as a perfect hole with a downspout going through.
 

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Discussion Starter · #3 ·
My concern is not necessarily with how to cut the hole (as I plan on using an oscillating multi-tool to do it), but instead, on how to protect the exposed subfloor and/or the best way to heat weld the vinyl to seal the exposed edges of the subfloor.
 

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retired framer
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Just install a shower drain with plumbers putty



Or you get the decking guy to hot seam a patch on the under side of a shower drain flange then install it and then he seams the patch down.
 

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Would it help to get an adapter to convert it to a round pipe ABOVE the deck? Then you just need a round hole and you have a nice solid PVC pipe instead of that flimsy leader. And you have all kinds of boots and flanges to choose from.

Maybe you could slip aluminum step flashing under the vinyl and bend it down the hole?

I dunno. I'd probably just paint the inside of the hole with some RedGard or something.
 

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I would convert to round PVC at the deck with a fitting:
https://www.amazon.com/Universal-Do...words=Downspout+Adapter&qid=1600444611&sr=8-8
Then pass through the deck with round PVC pipe. You could use another of the same fitting to convert back to rectangular downspout on the underside of the deck. Or, simply run round PVC from that point on. The advantage of this fitting is the uniform lip around it that can be caulked to the top deck surface. Face seals like this are much more likely to stay sealed than a sliding seal like you would have if you simply caulked around a rectangular pipe in a rectangular cutout. Face seals don't experience sliding movement .
 

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Discussion Starter · #13 ·
Just install a shower drain with plumbers putty

Or you get the decking guy to hot seam a patch on the under side of a shower drain flange then install it and then he seams the patch down.
Our deck builder has basically made it clear he won't do any work pertaining to installing a drain or cutting into the deck. Also, I could only seem to find 1.5" or 2" overflow drains and our downspouts are 2x3" rectangular shape
 

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Discussion Starter · #15 ·
Maybe you could slip aluminum step flashing under the vinyl and bend it down the hole?
I'm not sure how difficult it is to peel up the vinyl material since the deck builder used adhesive to glue the vinyl decking to the subfloor.

I'd probably just paint the inside of the hole with some RedGard or something.
I briefly looked into that RedGuard product you suggested, and if everything they claim is true, it sounds pretty amazing. Would you happen to know if RedGuard would help adhere a flange to the vinyl decking material or would I need to use an additional adhesive or silicone caulking? Also, would it make it even more watertight if I applied some wood waterproofing sealer to the exposed plywood before applying RedGuard? Or would that inhibit RedGuard's ability to properly seal the wood?

Would it help to get an adapter to convert it to a round pipe ABOVE the deck? Then you just need a round hole and you have a nice solid PVC pipe instead of that flimsy leader. And you have all kinds of boots and flanges to choose from.
I would convert to round PVC at the deck with a fitting:
https://www.amazon.com/Universal-Do...words=Downspout+Adapter&qid=1600444611&sr=8-8
Then pass through the deck with round PVC pipe. You could use another of the same fitting to convert back to rectangular downspout on the underside of the deck. Or, simply run round PVC from that point on. The advantage of this fitting is the uniform lip around it that can be caulked to the top deck surface. Face seals like this are much more likely to stay sealed than a sliding seal like you would have if you simply caulked around a rectangular pipe in a rectangular cutout. Face seals don't experience sliding movement .
I am tempted to convert it to a round hole, which would make it much easier to get a nice, clean cut and also make it more secure like you mentioned. One minor inconvenience is that I already have all the 2x3" rectangular downspouts.

In terms of using 2 of the adapters to turn it back into a rectangular downspout....would you happen to know if the 2 adapters would connect to each other directly or would I need a small intermediate section of round pipe between them? That way I can still put my 2x3" downspout pieces to use.
 

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Discussion Starter · #16 ·
This what the do on a roof top drain for draining the deck.
Oddly enough, this is one of the videos I also ran into when searching Youtube for a solution. But when I went to look for a PVC coated drain that can be heat-welded to vinyl, I was only able to find 1.5" or 2" diameter drains which won't work with my 2x3" downspouts.
 

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In the first post you say the deck builder said he wouldn’t cut a hole because it wouldn’t look good. In post 13 you say he “basically” refuses to cut a hole in the deck. Does he have information from the manufacturers spec sheets that say it should not be done? Do they offer any suggestions?
It sounds like the deck builder designed the deck thinking the drain could be rerouted, but then when he consulted the roof guy, which he should have done before finalizing the design, he discovered that wasn't an option.
Sounds to me like your deck builder screwed the pooch and is trying to avoid responsibility. I would tell him to fix it or meet you in court.
 

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Our deck builder has basically made it clear he won't do any work pertaining to installing a drain or cutting into the deck. Also, I could only seem to find 1.5" or 2" overflow drains and our downspouts are 2x3" rectangular shape
It was a plumber that put one in while I was working inside the house, I am not sure which shower fitting he used but he had an adapter for the rectangle to 2" pvc that just sat in the drain with out the screen.

It was he that explained how he had worked with a deck guy on his own house.
Might have to wonder around a box store and see what you can put together
 

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retired framer
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In the first post you say the deck builder said he wouldn’t cut a hole because it wouldn’t look good. In post 13 you say he “basically” refuses to cut a hole in the deck. Does he have information from the manufacturers spec sheets that say it should not be done? Do they offer any suggestions?
It sounds like the deck builder designed the deck thinking the drain could be rerouted, but then when he consulted the roof guy, which he should have done before finalizing the design, he discovered that wasn't an option.
Sounds to me like your deck builder screwed the pooch and is trying to avoid responsibility. I would tell him to fix it or meet you in court.
The normal is the have the downspout some where else, but when you build the deck after the fact things happen. I don't think any of the decking suppliers have anything for this but the roof drain his guy should have offered that in but they are bigger.
 
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