How to Install Under-Deck Drainage Systems
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- Опубликовано: 7 июл 2024
- In this instructional webinar, FHB editorial adviser Mike Guertin discusses how he uses EPDM roofing or pond liner to drain water under the decking and keep the space beneath the deck dry. Whether you’re thinking of using the space beneath the deck for storage or outdoor living space, Mike’s simple approach is easy to install and cost effective (materials are usually less than $1/sq. ft).
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Thanks for taking the time to make this very informative video! I'm about to install an under deck drainage on my boathouse which has a sundeck on top. The previous owner used plywood (not marine) for decking and obviously it rotted out. So now I'm installing decking boards and needed something to keep the water off of my boat. I had already read your article and this video really helped!
This was very very informative and precisely explained and very well done! The Q & A was awesome! Thank you very much Michael
please include this video to your series on decks. I couldn't find it yesterday and found this by accident today :) thaaaaanks!! this is gold
Great video Mike
Stay safe,
Clemens
don't need to do this project but watched and learned a lot. Thanks Mike!
I couldn't agree with you more! I have always struggled to find FH articles online!!
We're working hard right now to reorganize our website by project type to make it easier to find all of our articles and videos on popular topics. Check out our deck guide, which is organized into chapters based on parts of the project: www.finehomebuilding.com/project-guides/decks
We'll have more guides on drywall, painting, and insulation up in the near future.
Best video on this subject I've come across and I've watched a couple dozen!
Excellent video Mike. Thank you for doing this.
Wow, thanks for posting ! So many questions Answered !!
Great video and great channel. Very thorough and a lot of good sense. Subscribed!
I was just thinking about this topic yesterday.
Very good info and easy to follow
I did this successfully on a 12x16 deck. One large sheet is hard to get just right. I might divide the job into smaller chunks if its your first time. Maybe knock out 5 bays at a time. But otherwise, lots of fun.
Hi William, I am planning to do this when I redo our deck. I wonder though how to fix the railing posts without undoimg the waterproofing in that area again. Did you surface mount? Or maybe fascia mount the posts?
BEST VIDEO ON THE NET👍🏻🇺🇸🇺🇸🇺🇸
Thank you!
Excellent video! Thank you. How would you best clean out the pine needles or debris that falls through between the deck boards? I suppose you would have to take down the gutter and make a long sweep tool. Ideas?
Amazing thank you. Subscribed!
This was fantastic, sorry I missed it live. How do you waterproof around the rail posts or with a ladder box for a double picture frame?
Sorry I missed the webinar. Great information here. My only question is pertaining about sheathing a deck and using a PVC deck flooring. Would a solid floor like that require any structural changes to footings to meet potential uplifting from strong winds?
Using a track saw makes consistently PERFECT wood tapers!!!
you had a very good video on deck quardrails and I was hoping to redo mine with that knowledge, also adding drainage system. How do you handle posts around that EPDM?? Thanks! I'm surprised no one asked that :)
I've got a bizarre setup at my place. The previous owner - builder had truck bed liner sprayed on to sheet plywood. There wasn't much of a pitch put on the system and the bedliner was sprayed on hot, which caused the edges of the plywood to curl every so slightly. It's starting to fail now, after thirty years, and I'm debating redoing it the way he had it, but properly built with a pitch and thicker plywood, or installing scuppers with EDPM roofing the way you have it.
Wow thank you
do you recommend venting of some kind? perhaps a masterflow foundation vent if we do an under deck ceiling under this system? maybe on two sides or facing off of the gutter opening side?
I need to attach this style system to trex metal joists. any thoughts on a stapler that will penetrate 14 gauge?
What is the alternative to EPDM if I want to use IPE decking that requires annual oiling?
Could the joist be insulated to produce a finished space below? or would this cause condensation to build up on the EPDM?
Before adding the decking boards: I think I could strategically pre-bolt Joist hangers to the top 4'x8' of corrugated fiberglass sheets (get at big box stores) on the up curve, where they lineup with joists (top and bottom centerline and one on each side of the centerline at nearest joist which leaving an edge for adjacent sheets to slightly overlap, and halfway down: the sides; x8); building a solid suspended-hanging/sloping Lean-to kind of roof underneath the Decks frame. The degree of slope varies and is secured by how much of the joist hanger is positioned up the Joists" and water will flow off the ends to a gutter, like a roof on a structure does, eh! No calculus is needed to figure out progressive curved channels.
How would you do this with an existing deck? Don't want to tear off the deck surface boards. Also, same concerns as Waya Hedia expressed earlier comment about cleaning out debris build up. Even leaves will find their way between deck boards and build up on the liner...eventually clogging drainage...just like traditional gutters.
I live in an area where TONS of fir needles fall and we have quite a bit of green moss in shaded areas. Is this type of EPDM rain drainage system "cleanable" to wash out the accumulation of stuff between the deck and membrane? I would LOVE it if this system worked with that purpose also in mind. Thanks for your time!
Can the blocking for lateral restraint be placed as high as possible so that the liner can run underneath it this maintaining a decent slope?
My deck has 2x6 braces staggered between each joist. These are near the center. Do you simply cut a trough in those (down a few inches) to allow this to be installed? I've yet to see others have them in these installation vids.
I am picture framing with Trex plus attaching posts inside of framing...how do you block using this system
I discussed this system as well as Trex RainEscape with one roof/decking company guy and his criticism is that there will always be some water penetration, getting trapped below the system. That water will pool and be less likely to escape via run-off (especially on a flat roof), which will create a mold and mosquito breeding ground. Is that valid and is there a solution for that?
my house's front has (upper) deck on 2nd floor, under which is the ceiling over lower deck, there is no gutter or a good draining system, except the low spot on 1 side. A contractor said he'd add open gutter around outside the siding. i dont think it is a good design. What do you recommend as for the design?
Buddy, you are amazing. Thank you for all of the information. I am about to remove all of the nasty cracked tile and subfloor from my deck and replace it with composite deck boards. I will use your under deck drainage system. Is there a particular brand that you recommend? We are located in Orlando FL.
Once again thank you for sharing your knowledge.
Do you provide consulting? I would like to share with you the pictures or live video of the issue we have at hand at my house.
Looking forward to hearing from you.
Just buy 45 mil pond liner. Buy it on a roll so that you don't have creases in the material from it being folded. G -tape now makes a butyl tape designed to adhere to EPDM to go over the top of any place where there is a seam. Jason, aka Dr. Decks, also uses a sealant between every piece but I'm not sure he's using the correct product. Hope that helps.
Great video, thanks! My deck sits in a corner, so one of the joists will run flush to the wall. I was planning on picture framing but am thinking that would create a small gap between the edge deck board and wall without a drainage path. Do I need to eliminate the edge piece along the wall and butt the decking to the wall to allow drainage between boards, or is there another way? I want to avoid water running down the wall. I'm planning on running the EPDM up the wall under the flashing in the same way you're doing it over the ledger.
I am doing the same and instead of doing ladder blocking I put a 2x4 flat on top between the joists
Would 45 mil be good enough in Florida’s heat and humidity?
Can we put advantech on top of the joists, use the epdm on top of it and then the Trex boards?
Does it matter if the epdm is reinforced or non-reinforced?
What do you to if you cannot make a trough? Like when you picture frame the deck. The outside two joist will have blocking for the picture frame. Also, this makes it hard to not hit your bracket that secures your post with the trough.
How do you clean all the plants material cumulating between the lines and under de deck ?
Michael, In our application we actually have a golf cart barn under a 32' x 43' floor system that previously had a concrete slab patio poured over top of 2x10 non treated framing and subfloor with no waterproofing. The slab has failed and the framing has been getting wet. We are exploring options to renovate. One such option is to remove the concrete slab and subfloor. Repair/replace water damaged framing and reinforce structure by sistering additional floor joist as called for by structural engineer. Once that is completed how would you feel about installing your system over non-treated framing and then covering with composite decking? Would the addition of peel and stick flashing over the epdm covering the joist be a wise addition, or does the presence of non-treated framing make the system questionable?
As long as you keep the joists dry, there wouldn't be an issue.
Which EPDM mill would you recommend for the underdeck drainage the 45 mil or the 60 mil and also I'm having a hard time finding it especially for less than a dollar a square foot
45 mil is fine. Check your local Menards. Also, make sure you give your deck boards a first coat of sealer on all sides before install, then a second coat after installation.
If you have the room underneath, just waterproof the joists, and install full length colourbond under the deck slanting away to gutter. Takes a day
Can you use PVC Pond liner?
At 45:45 you mention using a certain type of staple. The video is unclear due to internet connection. Preferably, you mention using 'stainless steel' staples. My cap stapler uses 7/16" 18GA staples and nowhere can I find stainless options; only electro galvanized. Will electro galvanized cause an issue over time? I plan on taping and caulking w/ butyl based products to ensure water tight seals around punctures. Also, can I flash using metal based flashing on ledger; I only have 3.5" of EPDM flashing due to window and door placement. Please advise... Great video!
The cap staples are more of a temporary fastener. Once the deck boards are installed, their fasteners will "clamp down" on the EPDM. So electro-galvanized should be fine.
Tongue and groove azek would stop debris and help protect the fastener puncture
At 15:44 you talk about the cantilever method, but what if the blocks between joists are at the same height as the joists ... how do you cantilever from the front to the dropped beam?
You can cut them down to a height no less than 60% of the joist.
What about this design: Attach 2" x 2" spacers ripped from dimension lumber every 2' or so from the house to the far side of the deck on the bottom of each joist. Each spacer would be a little taller than the previous so that the first may be 1" in height, but the final row of spacers are about 3" in height, creating a slope. This would allow you to use a rigid piece of plastic on the underside of the deck and avoid the drooping/folding/cutting/butterflying of the EPDM.
Or is there a reason this would not make a good solution?
It's retro-active and not pro-active. Water will run down the side of the joists. Much better to have a membrane on top (imho). If you do use an under deck system, you should still tape your joists, ledger, etc.
Look like this is applied if there isn't any Joist Blocking....
Can someone please let me know what type/name for the clamps with the long handle that are being used to position the deck boards tight together?
How do you prevent moss, leaves, dirt, needles etc from collecting in these drains?
Or a tear. This makes me cringe, if/when there is ever a problem. Probably problems won't occur in at least 5 years so... out of scope?
the decking videos demonstrate the best of the best practices .... none come close.
Anyone use LPDE pond liner instead of EPDM? I'd created a similar idea on my own and already ordered a bunch of pond liner.
What about mounting that correlated plastic under the deck (at a slope). Seems easier and cheaper
I'm trying to figure out the best way to determine the size of EPDM I need and how to cut it. Do you have a pattern or formula for determining the shape of epdm based on the size of the deck? For example, my deck is 15x22.
I'm have 12 inch joists, so my understanding is the droop should be about 28 inches between each set of joists.
how do I flash ledger against brick ?
If you're talking about brick veneer, you need to use spacial hardware to bypass the brick and fasten directly to the framing. Otherwise a good alternative is to build a free-standing deck. Here's some good info on the topic in our Deck Project Guide: www.finehomebuilding.com/project-guides/decks/deck-ledger-mounting-system-masonry-veneer-challenging-cladding
What if….
One simply [multiple] coated the joists with Redgard?.
doesn't that system make the area under deck to be counted as impervious then?
This if you want deck boards. Then there is the tile method.
Jeepers, gotta know calculus to install this, eh!!!
Woodglut has very good designs and plans.
Your thickness dimensions needs another zero after the period. .045” and .06”
He stated that already
I don’t think he comes to this site to answer any questions.Kinda makes sense not his site as he is a guest.
Hopefully he reposts this to his own domain site
Come to think of it.. FHB should include a courtesy link for this man.Unbelievable
Has anyone tried using TyPar wrap or their new reinforced rapid drain version of the original TyPar fabric wrap?
Some may say it’s not UV rated,well okay,But how much uV radiation is getting through that little gap.
I am going to order some and use it to drain my re planking deck project.
rollover blocks?? mid span blocking?? fail