Dry Storage under Decking?

[frusc]

I have a smallish rear garden ~9m/9m which is significantly below the ground floor of the house (slope from front to back of property). Due to other building developments around my property I've managed to get planning permission to deck the entire rear garden to my properties ground floor height.

A large part of the area under the deck will be head height, therefore I'm contemplating adding some dry storage here. I had thought I could wall off a section of the head height area, use corrugated roofing material under the deck and send the water into a soak away (opposite end of deck).

My builder has raised some concerns, as he feels:

- dirt/debris falling through the deck will eventually block the roof and water will sit there. This will eventually cause the roof to fail.

- Since the entire deck will also be enclosed by two boundary walls, one boundary fence and my properties rear wall, he feels it will be damp under there and that will eventually work its way into the enclosed area. (Total under deck area will be 81 sq/m, enclosed area about 10-12 sq/m).

It's going to be a costly project, as the rear boundary wall will end up almost 4m high (fortunately the side wall is mostly already that height as the neighbour has a raised deck already). Therefore if possible I would like to get some extra storage out of it as well if possible. The additional cost of building the storage area is negligible compared to the overall project cost, so I think its worth a try. But I'd appreciate any advice to give it the best chance of success. Or should I heed his advice and just drop the idea :/

Appreciate any thoughts, thanks.

 

[OwainDIYer]

can you drop in some shipping containers and build the deck over them?

 

[frusc]

can you drop in some shipping containers and build the deck over them?

Thanks for the suggestion. But definitely not, unless I knock down one of the neighbours houses to gain access, but I expect they may object to that

 

[rsgaz]

Something like this PVC channel/gutter?

http://wahoodecks.com/dryjoistez-structural-waterproof-decking/

Dirt/debris falling through could be flushed out easier than if you put corrugated plastic up tight against the underside of the decking joists.

Gaz

 

[frusc]

Something like this PVC channel/gutter?

http://wahoodecks.com/dryjoistez-structural-waterproof-decking/

Dirt/debris falling through could be flushed out easier than if you put corrigated plastic up tight against the underside of the decking joists.

Gaz

Wow, that looks ideal.

If I understand it correctly thats the joist and roof/guttering all in one profile.

Now to find someone that stocks it in the uk and hope the prices aren't eye watering. If its economical I could use it for the whole deck possibly and chuck all the water in a soak away. I'd still only use a small part as dry storage but hopefully that would keep everything dry under there.

Thanks, really appreciate it

 

[frusc]

I have emailed them to ask for pricing.

Did some googling and found an American forum where someone stated $12-16$ sq ft, may be a bit too expensive to do whole deck in that case. But would be ok for just the sheltered storage area. I'll update the thread when I get pricing back from them.

 

[ladylola]

Could you perhaps hinge the decking to allow for cleaning of any debris that may fall through?

 

[frusc]

Could you perhaps hinge the decking to allow for cleaning of any debris that may fall through?

That would be a possibility, but i'd need to be sure its very secure. The drop underneath would be 6ft.

I've found some information on US forums (after being led to them by rsgaz's suggestion of dry joist), where "dry deck systems" as they call them are more popular. There seem to be a couple of options, the following site details the main options:

http://www.hometips.com/diy-how-to/create-waterproof-dry-space-under-deck.html

Some people have also gone the corrugated roof route I was considering.

All the under deck roof systems suggest an annual clean with a jet wash to remove debris is required. The best solution is dryjoist, but it also looks the most costly and unless they have a UK stockist it will likely be very expensive.

The Waterproof decking flanges are the only ones that don't require regular maintenance of the roof below as they prevent debris and water falling through. But they will increase maintenance requirements of the decking itself, as water will sit on it rather then drain through.

 

[frusc]

Well I got a response back for DryJoist. Equates to approx $130 sq meter, no UK supplier so theres going to be shipping and possibly DUTY/VAT on top of that.

I'm going to get a final cost and consider possibly using it for a smaller portion of the deck.