Raised Decking

cloughy513 · 13 May 2018

Good Evening everyone

I have a few questions for any decking experts out there, i am about to start a decking project in the trees, it will be raised of the floor 2.5 meters and measure 3 x 6m. I am planning on sinking the posts 1 meter into the ground and concreting them, and maybe bracing a couple to the floor also.

looking at using 8 3.6m 12.5x 1.25cm posts 3 on each side and 2 in the middle with joists at 40cm gaps

My question is does anyone have any advice or ideas that will make this experience smooth and not a disaster

how can i calculate the max load that the deck will be able to take as there will be potential for lots of guests to want to get on and have a look.

any pointer or help will be great received

all the best

cloughy

Phil Pascoe · 13 May 2018

Welcome. I built mine on the rear of my house years ago, it was about the same size as yours but with a solid wall on on end and three pairs of posts. I had stainless brackets made by a neighbour which mounted to bolts set in concrete so the posts never actually touched the ground, so I can't speak for how far to sink them, although as long as the structure is good and stable I'd have thought a metre overkill - every joist, handrail etc. will keep it rigid. My posts were 200mm x 200mm - which looked good - I think aesthetically 125mm x 125mm might look spindly even if perfectly adequate.

Woody2Shoes · 13 May 2018

I think that the safest and most sensible thing would be to find a structural engineer to advise - if the thing collapsed with lots of people onboard the consequences don't bear thinking about. Personally, I'd avoid concreting posts - in fact I'd avoid any timber in contact with the ground in this situation - IME concrete traps moisture and accelerates rotting of timber.

Cross-bracing will be a key to success as well.

Good luck, WS

Turnr77 · 13 May 2018

Do bear in mnd any decking higher than 30cm above ground level requires planning permission.

cloughy513 · 17 May 2018

Thanks for all the replies I will certainly look into other options about sinking the posts to see what’s out there.

With regards planning, this isn’t a issue as the decking and all out buildings do not cover more than 50% of the garden so no planning required.

Woody2Shoes · 17 May 2018

cloughy513":bbv02fui said:
Thanks for all the replies I will certainly look into other options about sinking the posts to see what’s out there.

With regards planning, this isn’t a issue as the decking and all out buildings do not cover more than 50% of the garden so no planning required.

I think that at 2.5m off the ground, you will need PP regardless of the area:

https://www.planningportal.co.uk/info/2 ... 11/decking

Cheers, W2S

Turnr77 · 17 May 2018

I think you'll find planning is required if eitherof the conditions are exceeded i.e over 30cm or covering more than 50% of garden regardless of height.