Deck drainage

[Gez]

I have an outdoor deck with heaps of space under it (its about 7 feet above the ground), which would be great for storage if I could water proof it.

Anyone know if there is a product in Australia like http://www.dryspace.cc./ ???

Or any suggestions on a reasonably simple way I could do this myself.

Thanks

Gez

[silentC]

I've thought about this myself. I reckon it's just an upside down roof. You could fix some battens, gradually getting thicker towards the front giving you a fall, then screw roof sheet to it, putting the screws in the ridges. You'd need flashing on three sides and a gutter at the front.

The only problem I can see with it is if you have trees nearby that drop crap all over the deck, it could block up the valleys and overflow the gutter. It would be a bastard to clean out. Maybe you could work out a way to suspend it leaving clearance to get a broom in there. Have the gutter protruding so it's exposed and hose everything down into it and clear it out by hand.

[Theremin]

Gez

I had exactly the same problem. Our front deck is over part of our garage, and we wanted to retain the timber decking rather than putting down sheeting, waterproofing it and installing tiles which was the other option.

What I did was to install some Laserlight sheeting under the deck, and run it into a custom made gutter (see before and after pics attached). The sheets are attached to the underside of the joists at the front. I had to slope the sheets down from the front because I needed maximum clearance for the roller door. I attached a hanging joist about halfway down the width of the deck, and then the other end of the sheets is resting on a square down-pipe which I cut the top out of, and which is glued to the inside of a 230 PFC beam. I have attached a drainpipe which runs out through the garage wall and connects into the stormwater drain. I also installed some flashing at each side underneath the deck which runs onto the top side of the Laserlight, to catch anything that comes in around the edges.

So far it has been very effective! Our deck has a roof over it, so not a lot of rain gets in, and it is only a garage underneath so if any rain did get through (not that it has) then it wouldn't matter too much.

[sailingamerican]

There are all kinds of rubber sheeting one can glue over the sheeting and then coat it with special deck coatings. Contact an architecet, general contractor or building center. We use a lot of it here in the US. It is used all over the world. Take your bank book. Sheeting and tile needs tarpaper and cement board that needs taping. Then the tile. It will leak if you don't use rubber sheeting under the cement board. Don't know how big an are but it is going to cost a few grand.

[Gez]

Thanks, I like the idea of laserlight because it would be reasonably cheap. Did you need to put much slope on it?

[silentC]

There's no need to spend a few grand. A couple of hundred bucks for some laserlite if he goes with Theremin's suggestion will do what he wants.

[simon c]

Alternatively you could just buy one of those cheap sheds and put that under it.

Or you could use the spot for a rainwater tank or something else that wouldn't mind getting wet.

Simon

[journeyman Mick]

I've done pretty much what SilentC has described for a client. Built a store room under their verandah. Rather than custom orb (corrugated) I used trimdek as the troughs are larger and less likely to block. Metal sheeting is cheaper than polycarbonate (laserlight). You could throw in maybe one clear sheet for every three metal which would give you some light without excessive cost or heat.

Mick

[Theremin]

Can't remember how much the laserlight was now - maybe about $35/sheet? Bunnings carry a good range of it. We went for a fairly dark tint which still lets some light through, but looks solid enough from underneath that you can't really see the joists and decking. The sheets have a slope of about 20cm over their length, which I think is about 2.2m from memory.

[Sturdee]

I've thought about this myself. I reckon it's just an upside down roof. You could fix some battens, gradually getting thicker towards the front giving you a fall, then screw roof sheet to it, putting the screws in the ridges. You'd need flashing on three sides and a gutter at the front.

I did the same under the back verandah a long time ago and use it as part of my workshop.

I used cheap clear corrugated plastic sheets as Laserlite sheets weren't around then. I sealed the edges with the plastic fill in strips and gap filler so that rain water does not run in under the sheets.


Peter.

[Gez]

Thanks everyone for the advice, I think I will try laserlight because I could use a little natural light under there.

Another query: The space under the deck has an outside wall made of hoizontal timber, but it has inch gaps between the timber, which will let a little water in if it rains from the right direction.

What can I use to line the inside of that wall? ie. something that is light in weight and weather proof.

[silentC]

Laserlite!

Or fibro if you want it flat - but it wont let any light in.

[Gez]

good point - laserlite it is!