Deck framing help

Discussion in 'Landscaping and Outdoors' started by Gary Fletcher, Jul 15, 2021.

  1. Gary Fletcher

    Gary Fletcher New Member


    Im going to build a deck in the space you see on the picture between the house and the wall. I am very good at DIY as ive been a gas engineer for 20 years done bathrooms joinery etc . The issue is knowing how to support it and how often etc . I dont want to sit it directly on the floor as ive read thats not best but i have limited room beneath as you can see

    My current plan is to to board each of the 4 sides with 6x2 and then span joists across left to right and support them directly with 4x4 concreted in the ground. Just not sure how often to put the supports in etc . Not sure if i have the room to sit them on top either so would have to be screwed to the side. Also what screws bolts spacers etc to use would be useful thanks . Id rather give it the belt and braces so if for example we have people over it can support us rather than risk it not being enough.

    any advice would be much appreciated
    thanks in advance

    decking 2.0.jpg
  2. Abbadon2001

    Abbadon2001 Screwfix Select

    Looks like your wall is level with the DPC in your house, which will be a possible first issue? might be better to have ledger type boards on the inner side of that wall, and the house below the DPC, and then joists between the two using hangers. With 6x2 you can span about 2.5m, potentially more depending on joist centers you choose and predicted load. How far from house to wall?
  3. Gary Fletcher

    Gary Fletcher New Member

    it s not going as high as the wall mate there will be step up onto the wall section which will be tiled. Yeah i plan to board the wall at a fall mate, But i want my boards to run from house to wall so my joists would have to be left to right as you look at picture. joist centre i was going to do 400mm but wasnt sure if every single joist had to be supported and how far along. around 4.5 m from house to wall pal
  4. Severntrent

    Severntrent Screwfix Select

    Put decking in search engine and Severntrent in Posted by Member, read past posts and come back with any queries
  5. Gary Fletcher

    Gary Fletcher New Member

    Hi mate, yeah just gone through quite a few of yours, sorry to be a pain but any chance you can give me some specific advice for mine mate, ive drawn a rough sketch on what my plan is , its a 7m span and i want to put joists left to right so i can put my deckiing back to front. so im going to put a piece of wood in middle . measurements are on there pal can you advise on spacings for joists and how many and where i need the supports please pal . i would like it to be strong enough if the mrs wants a party etc.

    cheers in advance decking drawing 3.jpg
  6. Abbadon2001

    Abbadon2001 Screwfix Select

    Might be worth looking over this thread - (not my thread)

    you may be better off using sub-beams to support the joists half way accross the span, as otherwise youll need quite a few posts.

    I'm doing a 4x5m deck, and one end is supported from a ledger board, and im using a double beam 2m from wall, and a double beam at 4m from wall, with a small overhang at end of joists past the last beam. saves noggins and quite a few posts in the ground. main reason for me was some problem areas in the ground below due to pipes etc... that I need to put the posts where I can fit them, and the beams help do this for my layout.
  7. Severntrent

    Severntrent Screwfix Select

    Assuming Class C24 joists spaced at 400 centres, joists span from side ledgers to centre support joist OK, Your centre support joist will require post supports at 1/4,1/2 and 3/4 spacing
  8. Gary Fletcher

    Gary Fletcher New Member

    On every single 400mm joist ?

    So 3 posts per joist that’s a lot of posts hahah but great thanks for the help pal
  9. Gary Fletcher

    Gary Fletcher New Member

    cheers mate . I can only have one level of joist so I can’t put beams beneath them you see not enough clearance .
  10. Severntrent

    Severntrent Screwfix Select

    No, just on the central support joist .i.e the one in themiddle of your sketch, i.e. 3 posts in total, are you sure you can do this job?
  11. Gary Fletcher

    Gary Fletcher New Member

    thanks for the help . Yes mate I’m sure I’m very handy just don’t have the knowledge !
  12. Abbadon2001

    Abbadon2001 Screwfix Select

    So basically, put 3 equispaced posts on that beam you are showing across the middle. If you haven't got clearance then you'll either have to make that beam at joist height, and cut all joists half way, mount to hangers both sides etc... and then support that center beam with 3 spaced posts OR you'll have to dig out a trench under the beam, and put it under all the joists, which would be a bit of digging, but save a load of cutting, save a load of extra joist hangers, and you still need 3 posts, but they will be really short as they will just hold up the beam that's under the middle of all the joists... I went for the latter option, dig a bit of extra clearance for the under beam.
  13. Abbadon2001

    Abbadon2001 Screwfix Select

    One other thing, in the photo, there is a concrete fence, I assume you arent supporting it off that, as I dont think thats going to be the best idea, so youll need posts over there too for the rim joist that side?
  14. Gary Fletcher

    Gary Fletcher New Member

    Cheers for the info pal. To be honest my plan was to fasten the ledger to it but only with a single screw on each post then it would dig and put some post in front of it screw it to them and cement them in then all the weights on them . Just a good way to get them bang on.

    on your previous point mate , I don’t fancy doing that much digging to I plan to put two middle joists across and put 3 post in between them and fasten together and then hangers each side from there pal. Don’t mind about the price of hangers just want a spiked job that won’t move or creak or fall apart after 5 years .

    what you think . Like I said I’m new to this but you have to learn somewhere so don’t think it’s hurting anyone Ey
  15. Abbadon2001

    Abbadon2001 Screwfix Select

    Id avoid the fence, from experience they will be rock hard (I tried drilling concrete garage panels once...) and you'll likely hit rebar in them before you get any real depth to get a fixing in thats big enough to offer any benefit to the deck (should be using an m12 hammer in bolt type fixing), better off just going with independent posts on that side. Just less hassle.
  16. furious_customer

    furious_customer Screwfix Select

    I had a horrendous time trying to build my decking frame and eventually gave up and got a pro in.
    My issue was that all the 6x2 joists had twisted and were impossible to fit straight.

    I'm not sure if 4x2's would be as prone to twisting, but if I was starting over I would design it with enough supports to allow me to use 4x2s.
  17. Gary Fletcher

    Gary Fletcher New Member

    that’s not good. I thought smaller the wood the more prone to twists it would be.

    I’m gunna give it a whirl mate I wanna say at least I tried
  18. Abbadon2001

    Abbadon2001 Screwfix Select

    To deal with twisted joists you just need to persuade them to be straight using a screw driven in on the face an a claw hammer to twist while driving structural screws in to the end or skewed. or thats how I do it anyway...
  19. Gary Fletcher

    Gary Fletcher New Member

    Ok mate give that a whirl if I get any twisted.

    next question.

    screws bolts etc can you give me what’s best to use.

    to screw ledgers to brickwork

    joist to posts (gunna sit them next to them not on top )

    joist to joist (using brackets)

    Cheers in advance
  20. Abbadon2001

    Abbadon2001 Screwfix Select

    youll need joist hangers at the end of every joist here it meets a perpendicular joist,

    m12 fixings to the bricks, something like 140mm long , half in the brick half through the ledgers, and space them off the walls with stainless washers by 10mm.

    the choice for posts to joist is endless, but itsll need to be structural, either coach bolts or coach screws or timber drive structural screws. Just need to make sure its structurally rated.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice