Decking joist

Discussion in 'Landscaping and Outdoors' started by Agnieszka Walkow, May 8, 2017.

  1. Agnieszka Walkow

    Agnieszka Walkow New Member

    Hi , I'm planning on putting some decking down to cover a concrete "patio".
    Decking will be supported on one side on house wall on the another side on retaining wall.
    There is also few problems:
    1) one of the decking frame (left side of the drawing) will be a base for the shed.
    2) manhole decking.PNG decking 1.PNG
    And the question is what size of joist i should use?
    I was thinking about 100x47 (supported by two beams underneath) but am afraid of bouncing, so maybe 125x47 will be the better option, or maybe 150x47 unsupported will do the job?

    Thanks in advance.
  2. Dr Bodgit

    Dr Bodgit Super Member

    100x47 supported at around 1m intervals will be fine. That isn't going to bounce much if at all. You could add noggins at the mid point to beef it up a bit.
  3. Doall

    Doall Active Member

    I would do the frame running the other way so that there's no joins in the deck boards.
  4. Agnieszka Walkow

    Agnieszka Walkow New Member

    I can't do this other way mostly because of a manhole, also I think that it will be easier this way to put it together. And as part of the deck will bi covered by shed (floor made from plywood) the boards will have less than 5m.
  5. Agnieszka Walkow

    Agnieszka Walkow New Member

    Thank you for reply. I'm planning to buy longer joist so the leftovers I can use as noggins but i just don't include them in the drawing. Do you think that I can use 100x47 under the shed asswell or I shoud go for 150x47 ?
  6. Phil the Paver

    Phil the Paver Screwfix Select

    Is the patio level enough for you to have the support joists??

    If not I would just drop legs down from each joist on to the patio, yes it would be a lot of them but easy enough to do.
  7. Agnieszka Walkow

    Agnieszka Walkow New Member

    The decking will be just under 300 mm high (level of the steps). I'm planning to support main joists by two beams and that will be laying on concrete (or some additional blocks - concrete slightly uneven).
    I can be wrong but this way access point to manhole is better supported.
    Last edited: May 8, 2017
  8. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Are you happy having a timber shed up against the house? Not always recommended(fire-hazard-wise)!
  9. Agnieszka Walkow

    Agnieszka Walkow New Member

    Yes, I have in the same space shed at the moment. It's not lean to shed - there's space between shed and house about 40cm.
  10. Dr Bodgit

    Dr Bodgit Super Member

    If its a shed construction where the floor is laid first and walls on the floor, it should be fine - the load is somewhat spread. I'm building a sub-frame for a log cabin using 95x47 but as the load is around the perimeter, I'm doubling up the perimeter timbers.

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