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Fixing a decking joist to your home.
How to fix a deck joist into masonry

If your decking is going to be fixed to your home below your damp proof course (DPC) then you can fix with sleeve anchor bolts.

Many people think you cannot attach a deck to the home above DPC without the risk of causing damp problems. However, done correctly it is possible.

You will need some lengths of threaded bar and anchor resin.

Pick out your best joist (straightest) and cut to size. The length will be the width of your deck minus 2 x thickness of your floor joists. Treat the cut end by painting it with a suitable end cut solution.

6x2 joists won't actually be 6x2 so measure the thickness to get the exact size.

Using a pencil, mark the top of the joist where your joist hangers will be going. Start at the center and then work your way to each end marking at 16" (400mm) gaps until you have less than 16" each at each end.

Lay down the joist and fix the joist hangers in place remembering to use a cut off to ensure the floor joists will sit in the hangers.

Once the hangers are on, drill the correct sized holes in the joist as per the anchor resin instructions. Drill a set of holes 6" in from either end, staggering the top hole from the bottom hole as shown here. This will stop a weak spot developing in the joist.

The amount of holes will depend on the size of deck i.e. the weight the joist will be supporting but 1 between every joist hanger is plenty for a decent sized deck.

Using bricks and wood to prop the joist, position it in place against the wall. Check for level and get it spot on. Remember to allow for your decking when deciding on the height you need to secure the joist.

Make sure the joist is secure and not likely to move while you drill. With a masonry drill sized according to the instructions of your anchor resin carefully go through each pre-drilled hole in the joist and start off the hole in the masonry. Half an inch will do, you are only starting the hole off.

Remove the joist and finish the drilling to the required depth and cut and fix your threaded bar as per the anchor resin  instructions.

Once set, introduce a nut to each bar as well as a couple of galvanized penny washers. Introduce the joist to the threaded bars and carefully fit the joist. Fix with washers and nuts.

Your joist should now be sat approx. half an inch off the wall which will prevent any damp problems appearing in the future.

How to fix a deck joist to a timber frame house

Your joist needs to have a solid fix to your home so its important you find something substantial to screw it to.

The best way is to have the decking joist at the same height as your homes floor joist. That way, the lag screws will find the band joists.

If you need your decking at a different level it will have to be lag screwed to the stud work.

You may need to remove a section of your siding to expose the timber frame and put some blocking behind it so you can bolt the deck joist to that.


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