Decking advise, 8.8M x 2.6M.

17 Aug 2017
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United Kingdom
Hello, I am hoping for some advise regarding a decking I am planning.

I had been planning on doing a retaining wall, however this seems too expensive and now looking at a deck and removing the earth from underneath.


The deck will be 8.8M wide (width of garden) and extends 2.6M. The garden is currently steeply slopped.

This is purely in the planning stages to work out costs and feasibility.

The picture shows the post on a anchor although my current plan has them set in 600mm concrete/postcrete.

  • Size of wood is 47 x 150 mm
  • No fixings a planned in yet but would use joist hangers and nails as they are recomended most and decking screws for the deck boards.
  • Deck boards are currently planned as DUAL SIDED TANALISED DECKING 32X125MM GREEN. Although this is likely to change if I can find a similar prices single sided one as I would prefer a smooth side to aid drainage

The hazard box in the middle is a shared sewer access panel.
The light grey area is newer concrete put in a few months ago I am not sure of the depth. the rest is 100mm deep.

I have read many articles and forum posts and watched videos on YouTube. I had a reasonable understanding of what was required but have come across so much conflicting opinions and advice. Too many clearly sponsored by one particular product or another. I now have more questions than when I started and a big headache.


Post set in concrete/postcrete or Concrete with anchor set in with post attached?

Says to set in concrete as does a few videos, others say the latter.

If I set the post in postcrete could the footings rise even if dug below the frost line.

Frame & support beams:

In the thread linked above they have support beams with a frame on top, is this a necessity?

When I first planned my deck I had seen a couple of videos double framing. I am now not sure if that is needed. Does this add strength especially with the length.

Currently looking at JT Atkinson for the most part and they don't have any decking posts. They do have fence posts at 75mm x 75mm or 97mm x 97mm. Is this of suitable strength ot should I find these from somewhere else?

Also a different video used 2 pieces of wood to make a square and used that. would that be better. I would use treated c16/c24 47x50 if that was the case.


Noggins seams to be mentioned a third of the time and are not yet in my plan. Are these recomended

I have included my sketchup file and excell material list.

I think I have explained all I can and asked the questions I need.

Thank you for reading this and any advice offered


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I understand this is a large post and you probable see similar questions all the time. However any help or advice would be appreciated.

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