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Hi
We are updating and extending our alfresco by building a deck. We have a pretty good idea with how to deck on the grass but we're struggling to get a definite answer on how to deck under the existing patio (which has pavers, no concrete slab).
So, do we need to remove the pavers and treat the substrate process the same as we would on the grass??
Or if the surface of the pavers is even and solid, can we treat it like a concrete slab??
Any and all advice and tips are welcome.
Area in question, below.
Dog, Dottie.
Good afternoon @291621
Firstly welcome to the Bunnings community 
I am sure you will find lots of information about decking in here!
Couple of questions,
How much clearance between the height of the inside of the door to the pavers outside?
Do you remember seeing water pool anywhere on the pavers?
I havnt heard of treatment to the subsurface before? Could you elaborate?
If the door sill height to the pavers is under 100mm I would probarly think of removing the pavers. Air flow under the timber deck is something that helps prolong the life of the timber. Easiest way to work out how much space you have is to work backwards from the decking timber downwards
Decking Timber 20mm
Joist 70mm - 100 depending
Bearer 100mm depending
Post support ??
These distances can change depending on what type of timber you use and also what type of supports you use for the ground.
Dave
Welcome to the Bunnings Workshop community @291621. It's amazing to have you join us, and many thanks for your question about deck construction.
@Dave-1 has covered a lot of great questions that would be really helpful to know. It really comes down to how much room you have to work with. You'll need to measure from the surface of the pavers to the bottom of the door threshold. Once we have that measurement, we can determine the best construction process for your deck. If there is enough room for your deck height, you can treat the pavers like a concrete slab and use pedestal feet for support.
While waiting for those measurements, check out this helpful guide: How to build a low-level deck. Also, for inspiration, have a look at our Top 10 most popular deck projects.
Please let me know if you have any questions.
Mitchell
Hi @291621,
80mm would typically be considered too small a height to build a deck within, requiring you to remove the paving. Normally, you'd have 90 x 45mm joists with 19mm decking on top, which would require 109mm, even if the joists were sitting on the pavers, which isn't great. Some of our members have gone with turning the 90 x 45mm of its face so it's only 45mm thick. That would be 64mm in total height, leaving 16mm under your joists.
If water pools on the paving, I'd suggest removing it and installing adequate drainage for that area. The last thing you want is pooling water inside a low-level deck frame. Any standing water will send humidity levels through the roof and lead to the early onset of decay. You'd then treat the area like the grassed area and concrete in your posts.
Mitchell
Brillo.
Thank you that confirms that gor us nicely.
A further query, our paving is brick pattern. I am assuming it would be best practice to cut the bricks and replace the halves so that the driveway paving sits flush with the deck?
That would be your best bet @291621.
Please keep us updated and reach out if you need further assistance. Can't wait to see your results!
Mitchell
Evening @291621
Sorry I am having issues seeing any notifications atm 😕
I think @MitchellMc has answered the question tho? If not let me know and I will draw it up
Dave
