Decking on my existing patio

14 Jan 2008
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United Kingdom
Hello everyone,

I want to deck over our existing patio by laying the foundation joists over the patio. However, after browsing around on the net it looks like I might have to lift the patio and concrete posts in to support the foundation joists. My questions are:

- Is it best to lift the existing patio or can I just lay the foundation grid over the top?

- If I lift the patio can I use wooden posts that are concreted in to the ground, is this the best way to support the frame?

Here's what I'm on about:

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you're awfully tight on to the bottom of that patio door... 1 brick course to the bottom of the sil, and maybe 2 if you put the decking level with it?
Yeah I know it's tight, I've seen another post where Thermo has actually built a lower platform for access to a door which I could do but would rather not if I can help it.

I really want to attach timber to the walls and then attach the frame to that with a few supports under the frame at the opposite end.

What do you reckon?
IMO use 2by2 tanalised timbers laid onto the patio, wedged up to make level and allowing some drainage to take place, and screw decking onto this. The weight of the boards will hold it flat. If you want to be ultrasure of preventing warping, screw the 2by2s into the current concrete flags.
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I did a small-ish deck outside the back of my house by screwing deck boards laid flat directly to the patio flags using concrete screws, to form a supporting frame. I then screwed the surface boards to this.

I probably went overboard on the frame and kept the spacing fairly close - partly because I knew I was laying the surface boards at 45 degrees. I was also careful to make sure that the framing boards were positioned and orientated so as not to obstruct drainage under the deck. It's below the DPC and there's also a small gap between the deck and the house - so no problems on that front.

2 years on, it's still rock solid and doesn't bounce or anything.


The trickiest bit was scribing all of the boards into the curved wall!
She loves sleeping on top of the hot tub in the sunroom in the background.

Only cat in Cheshire with a bloody heated water bed!
Thanks for the replies, so you think the best thing would be to fix the foundation boards to the concrete patio? In that case would I still need to attach a leger board to the house? Also how would you recommend fixing the foundation boards to the concrete - do I use brackets or just screw directly through the wood?
The weight of the frame + the decking will be ample enough weight to hold it down, fixing to the slabs is a waste of money and energy. I did this with my deck 9 years ago, I can't lift it if even if I try, even in the summer when its bone dry. The frame is made up of 75x50's. If there's any uneveness with the exiting slabs you can easily pack it out.
Guys, it took us 2 days but we've finished the first part of the decking. It's all supported by a decent framework underneath and has a weed membrane underneath. It was tough graft but we're pleased with the results. What do you think?


very nice..

now all you need it some lights on the walls and some plants in puts and your good to go..
The damp proof course? I wasn't aware you could breach it?

And from what other posts say from people who have done lots of decking it isn't even an issue.

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