How to build a large, low deck over pavers?

[blt]

Hi,
I'm looking to build a large, low deck over some old and tired pavers.

The rough dimensions are:

- 10.5m x 5.7m at the widest point, other sections are about 4.7m wide

- Height varies between 10cm and about 21cm at the door to the house

There's not enough room for joists over bearers and I have seen various posts using pedestal feet with joists only.

I'm thinking of using the Ekodeck composite boards and running these perpendicular to the windows in the photo with a picture frame. This would allow for full length 5.4m boards over the widest point of the deck.

Some of the initial design questions that I have are:

- For the framing: the joists would run the full 10+ meters. If I use 6m + 4m lengths of 90x45mm joists for these 10m, can I put them end to end on the same pedestal (butt joint)? Or should the joist ends be on separate pedestals or the joists side by side (lap joint)?

- For drainage: should I put down a membrane and drainage gravel over the pavers or is it okay to let the natural fall drain the water? The pavers look uneven as they were removed to install a french drain.

- Any tips for keeping things square? Other than using good old pythagoras?

[MikeTNZ]

Hi @blt,

Thanks for asking a very serious question.

I've installed a few decks in my time and my advice first off, would be to get rid of all them pavers, they are only going to cause issues

with the initial set-out of your deck.

What you need is finished soil under your deck, so that you can mark out your positions for your posts that will be concreted into the ground,

this is a requirement, no matter how low your deck is and saves problems later on.

The biggest thing with any deck is getting your "ledger board" in place, where it connects to the house side of things and having everything square and plumb throughout the process

Invest in some builders string lines, you will need these and timber for the "profile boards" that you will be measuring distances off to keep everything square, yes pythagoras does come into it, but if you can use a measuring tape off a string line, you shouldn't ever have to worry about that 3/4/5 rule.

There are any number of tutorials on the net that you can follow, but, make sure they are Australian.

Hearing people bash on about inches and 3/16's gets pretty tiresome.

If you require any further help (which you will with a deck), by all means, let us know with a post,

We are more than willing to help here.

Cheers,

Mike T.

[EricL]

Hello @blt 

One of the most important things you'll need to address before you begin is drainage. If the area forms puddles, I recommend installing draincoil so that the water drains away from the area. Because you have weeds growing between the pavers it would be prudent to put weedmat on it to prevent further growth. I suggest having a quick look at this guide - How to build a low-level deck by @Adam_W.

If the pavers are in good shape and are not shifting in their position, it is possible to put pedestal feet on the pavers. 

Putting in a lap joint on is one way of linking timbre together. However, I suggest having a think about splitting the frame so that you have more control over the level of the timber. I also propose building it as a floating frame system, this will save you from having to anchor the deck frame to your house.   

Keeping your cuts square and true will save you a lot of heartache. I recommend using a builder's line or laser level to always check your position. Just keep in mind that a small amount of compromise on one end could end up being a few centimetres at the other. 

Please remember to use personal protection such as gloves, goggles and a dust mask when working on your timber deck.

Here is a handy link for ideas and inspiration: Inspiring low-level deck builds.

I also suggest having a look at the Bunnings deck building guide:

• how to plan out your deck
   
• How to set out a deck
   
• How to install stumps
   
• How to install bearers
   
• How to install joists
   
• How to lay decking
   
• How to add a step to your deck.

If you have any other questions we can help with, please let us know.

Eric

[blt]

Thanks @MikeTNZ , @EricL 

I'm leaning towards a free standing deck using pedestals.

There are still a couple of spots where water pools which I can address with some left over draincoil.

I'll also have a think about potential ways of building the frame from the links you have attached.