Under Deck Water Diversion Systems

[Horror Business]

I am debating between installing TimberTech's Dryspace system or CertainTeed's UnderShield system. My main priority is which system will keep the space below drier.

Has anyone used either system? Care to share your thoughts on how well, or poorly, it is working? Thanks.

 

[ItsNemo]

For the price why not just use some corrugated roofing?

 

[jkeyser14]

I am debating between installing TimberTech's Dryspace system or CertainTeed's UnderShield system. My main priority is which system will keep the space below drier.

Has anyone used either system? Care to share your thoughts on how well, or poorly, it is working? Thanks.

These systems are generally very expensive. Watch some youtube videos on DIY systems using corrugate roofing. It is much cheaper.

 

[Higgins]

Past neighboor used the clear curragated roofing in 12ft sections. placed gutter on lower end and piped out to side yard. Worked great. Was quick to install, and was rather reasonable.

 

[jdieter]

I did the corrugated roofing under my elevated deck with gutters. The down side is cleaning the crud out that works through the deck boards. My situation is especially bad as I have an 80' tulip popular overhanging the deck. I use a long piece of 1/2" plastic pipe with a homemade spray nozzle on the end to wash the **** down the corrugation valleys.
The decking is near the end of it's lifespan. I added roofing felt on top of the joists and used an angle fastening system that attaches the deck boards from the underside, so hopefully the joist are still sound. When I re-deck it I'm going to picture frame the deck perimeter because the deck boards are perpendicular to the house and make the boards adjacent and parallel to the house removable so I can flush the crud from the top using a power washer.

 

[SouthLake]

putting down corrugated roofing material i would imagine that turning into a mouse urban development zone?

 

[Higgins]

I'm planning on doing the same under our large deck. Once installed, I'll be able to remove one deck board by the house, so I can clean all the debris that would migrate between the boards!

 

[K'ledgeBldr]

As has been pointed out, the biggest problem with "retro" type systems is the accumulation of debris. And with a very shallow pitch on the material, it's not going to "self-clean".

So, you have two options- create a way to clean out the debris, or install a decking that is water tight to begin with. There is PVC decking that interlocks, as is aluminum. There is also a composite decking that is T&G (the grove has a gasket type material in it that create a water tight seal. Then there are vinyl sheet decking materials also- these require additional substrate buildup but can last upwards of 20yrs.

How much you wanna spend?

 

[Horror Business]

Good conversation. A little more info-the deck is existing, so I am looking for a system that can be installed from underneath. This is a two story deck situation so the aesthetics are important, as the water migration system will also be the visible ceiling for the lower deck.

The CertainTeed system looks a lot better than the TimberTech system, but for some reason I am not sure it will hold back water as well as I want it to.

 

[K'ledgeBldr]

Here's some more details/examples of retro-systems-

http://www.deckmagazine.com/_view-object?id=00000155-0995-df79-abf7-bd9db17c0000

 

[Caddis295]

I used a rubber membrane from http://www.dekdrain.com/products.php

It can be mounted in both top & bottom orientations. It drains into an ordinary rain gutter underneath.

I can attest to the durability of the product, as it has outlasted the decking on top of it.....

I had to replace the decking boards and the material was in great shape once I pulled up all the boards.

I installed soffit material to enclose the bottom of the deck (ceiling) to complete the finished porch area underneath.

 

[rlitman]

If you're using corrugated roofing, why not use white instead of clear? Clear will show all the accumulated debris.

 

[NUTTSGT]

Anybody ever thought of using or tried to use something like aluminum window screen under the decking ? If you're gaps are close, I wouldn't think much could penetrate between the board that the screen couldn't keep out. The vertical area between the decking and roof below could be screened also keeping bird or blowing debris out ?

 

[ItsNemo]

Anybody ever thought of using or tried to use something like aluminum window screen under the decking ? If you're gaps are close, I wouldn't think much could penetrate between the board that the screen couldn't keep out. The vertical area between the decking and roof below could be screened also keeping bird or blowing debris out ?

Good idea but still involves pulling up deck boards for anyone retrofitting this.

I'm in the same boat where there's no way I'm pulling up all the decking to install anything. All of it is hidden fasteners and interlocked all together, easy enough to pull things out, but trying to slide those hidden fasteners back between the boards to put it down would be a nightmare.

But plenty of accessibility underneath (earlier in the build):

 

[rlitman]

Anybody ever thought of using or tried to use something like aluminum window screen under the decking ? If you're gaps are close, I wouldn't think much could penetrate between the board that the screen couldn't keep out. The vertical area between the decking and roof below could be screened also keeping bird or blowing debris out ?

Wouldn't that cause debris to collect in the gaps between the decking. That would cause your decking to rot out if you used wood. And probably isn't good for the joists either.

 

[NUTTSGT]

Good idea but still involves pulling up deck boards for anyone retrofitting this.

I was think more for those that are building new or redecking.

 

[NUTTSGT]

Wouldn't that cause debris to collect in the gaps between the decking. That would cause your decking to rot out if you used wood. And probably isn't good for the joists either.

My thoughts, you could easily power wash the debris out the length of the deck boards. Wouldn't that be easier that to try to get up underneath between the deck and roof below ?


I don't know what the answer is. Just a thought, suggestion or a completely bad idea.

 

[rlitman]

My thoughts, you could easily power wash the debris out the length of the deck boards. Wouldn't that be easier that to try to get up underneath between the deck and roof below ? ...

I suppose. And it would power wash out more easily than trying to spray all the way down to the roofing underneath. It's just not maintenance free (and I'm lazy).

But if there are no overhanging trees, is debris even an issue? Ideally, the slope of the surface will ensure that both the water and debris run away from the structure.

Flashing is also an important detail that the kit systems make easier to work around than a DIY approach. Still, I'd probably use the corrugated roofing on custom cut shims.

 

[drboom]

I installed a layer of corrugated underlay to push the water away under our deck. The main purpose in our case was that the deck sits over a concrete pad we go out of to get to our back yard and the melting snow/ice on the deck would turn the concrete into an icy mess.
Regardless of the product you use - a suggestion from my experience:
Check the joists for leveling and map our your water path in the design phase. I made the mistake of not checking the deck leveling prior to buying materials and getting started. Because of the pitch of the existing deck and the pitch I needed in the underlay to move water in the right direction, I had to substantially lower the underlay in many areas with as much as a foot of bracing versus the spots I could attach directly to the joists.

 

[Horror Business]

I went with the CertainTeed system. It’s been in for a little over a year, and it works well. Looks great too. I have a photo, but I don’t know how to post it.

 

[Horror Business]