Decking Advice

Discussion in 'Carpenters' Talk' started by TreeField, Sep 21, 2021.

  1. TreeField

    TreeField New Member

    Hi we are looking to get quotes for decking along the back of the house. Some people have talked about drilling into the brickwork of the house / using something like joist hangers and have also heard of small brick walls being built to put joists onto. Do people have opinions on whether one way is better than the other. Not sure I like the idea of connecting it to the house, always thought there should be separation/ gap to avoid damp. No idea what is the norm though. Thanks
     
  2. CGN

    CGN Screwfix Select

    I don’t do loads of decking, but when I have, I fix a timber wall plate to the wall but sit it off with rectangles of 18mm ply or similar where the fixings go.
     
  3. TreeField

    TreeField New Member

    And do you just fix it / drill into the brick or mortar joints?
     
  4. Roys

    Roys Active Member

    Drill into the brick, drilling into mortar is doomed to failure as it has a tendency to lose its grip after a while.
    As above I have only done a couple of deckings, fixing a timber to the wall, usually with resin bolts. Also I put spacers in to hold timber of wall.
     
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  5. CGN

    CGN Screwfix Select

    What Roy’s said... into the brick. Concrete bolts would be my choice. I fix the packers to the wall plate. Offer it up and level it. Perhaps put a couple of temporary screws/plugs through to hold it, then drill through to size to fit the concrete bolts. No plugs. Often a 10/12mn hole and a ratchet to tighten the bolts into the brickwork.
     
  6. Roys

    Roys Active Member

    I just remembered something after reading CGNs post, I used two trolley jacks to hold the timber level while the resin went hard, didn’t take long 30 mins maybe.
     
  7. TreeField

    TreeField New Member

    ok so the packers create the gap to stop damp? Only problem with going into the bricks is that the faces of the bricks we have seem to blow easily when drilled into. Happened withoutside tap and few other things. New bricks were for extension. Has anyone done decking without attached to house?
     
  8. Astrochicken1980

    Astrochicken1980 New Member

    I've only done a couple of sections of decking, and in one case it was next to a large outdoor garden room. I built a concrete slab for the base and screwed batons into the top of the slab to make pseudo-joists for the decking to be screwed to. I then used large timber to hide the concrete sides and it's really solid. The whole area was covered by a porch to reduce rain ingress, and whilst the slab and batons will eventually degrade this should be years into the future. The air-gap under the decking between the 'joists' should help reduce rot in the decking too. Could you make a mini slab by the house end, keeping it independent of the house? This wouldn't need to be right by the wall, as you could set it away enough for any damp concerns, and run the decking planks past this to hide the gap (depending on which way you're running the decking). It might not be as quick and easy as using the wall, but it should leave your brick-work intact.
     
  9. TreeField

    TreeField New Member

    Thanks for the advice. Appreciate those who responded would reccomend attached to house, though for completeness, what is the alternative option? I mean what would be done if the decking was not near a house? And what is advantage of attaching it to house? Thanks
     
  10. savage

    savage New Member

    Joists and noggins all made up , joist near the wall 50mm gap away from the wall .Decking laid on top of joist 45 mm overhang , rain should run away from the wall so you need a fall .Decking end or edge 5 mm away from the wall to allow for expansion and contraction .The weight of all this timber will be enough to keep in place and no need to attach to the wall of the house . If its in shaded spot you will need to clean it every year as it gets very slippery due to algae .
     
  11. TreeField

    TreeField New Member

    ok. What do the joists sit on? Direct on to the ground or some sort of piers made of bricks? Or do the joists need pinnig to the ground.
     
  12. Offshore

    Offshore Active Member

    I've installed a fair bit of decking in a DIY capacity, it's very satisfying and worth considering if you are at all "handy". Bolting a joist/ledger board to the wall and then hanging the joists off it perpendicularly works well. However, if you are not happy drilling into the wall then it is possible to hang your supporting joist/ledger on posts, effectively disconnecting it from the house altogether. I dug holes along the front of the house wall, about 600mm apart, breeze block in the bottom of the hole, drop in a 100mm post (or 150mm if you prefer) and then back fill it with postcrete. Once the post is squared up and cut to height and the postcrete has hardened then bolt your main joist to the posts, fit your joist hangers and hang your other joints perpendicularly. Repeat the process at the other end and you will have a completely stand alone decking (depending on the length of the span, you may need interim supports on the joists to stop it springing). This method might be impractical if the decking is high up, works best for low level decking otherwise the hole depth becomes an issue.
     

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