Laying timber decking

How to guide: Laying timber decking

• Step One Planning and Design

  When choosing where to position your deck, make sure you take into account the sun’s position and the prevailing winds. Then you’ll have to decide whether your deck should be free-standing within your garden or linked to your house.

  Then decide on the shape and size of your deck – the only limit is your imagination since deck boards can be laid in a number of different ways. There are various ways in which you can lay out your deck boards – but make sure you decide this before you start putting together the support joists, as some patterns will affect the spacing and number of joists. For example, if you want a chevron-style layout, you’ll need a double joist.

  Mark out the area where you want your decking using wooden pegs and string: this will help you get a good visual impression of its final size and is essential for preparing your work. If you’re putting your decking on a lawn, it’s a good idea to remove the turf and level the ground. You can stop unwanted vegetation growing under your deck by covering the ground with black plastic sheeting which you then cover with gravel.

• Step Two Creating the frame

  

  There are various ways in which you can lay out your deck boards – but make sure you decide this before you start putting together the support joists, as some patterns will affect the spacing and number of joists. For example, if you want a chevron-style layout, you’ll need a double joist.

  Cut the joists that you want to form the sides of the deck to the right size, then mark their floor position at 400mm intervals. Then cut the deck floor joists to the right length and treat the cut ends with end seal preservative. Place the side and the floor joists in the position where you require the deck, then put together the framework using 75mm screws in pre-drilled holes – use three screws per joist end.

  

• Step Three Fitting posts, rails and spindles

  There are various ways in which you can lay out your deck boards – but make sure you decide this before you start putting together the support joists, as some patterns will affect the spacing and number of joists. For example, if you want a chevron-style layout, you’ll need a double joist.

  You can really smarten the look and enhance the safety of your deck by adding railings. You should fit the railing sections between posts that you fix into position on the framework. You’ll need corner posts at 1200mm intervals on straight sections, fixed directly to the joists of a flat deck.

  
  1. Fix the corner posts first, using coach bolts to fasten them to the inside of each corner.
  2. Mark the position of the posts on the side joists, then bolt the side posts to the inside of the joists.
  3. Measure the length of the spindles to fit between the top and bottom handrails and cut to size to allow the top handrails to be 900mm above the finished deck surface, and bottom rails 75mm above the deck. Fix the spindles at 100mm centres to the top and bottom rails using 50mm screws, fixed from the underside of each rail. To fix the section of railing to a post, first unbolt and remove the posts.
  4. Drill two 12mm diameter holes, 38mm deep in the ends of the top and bottom rails. Drill corresponding holes on the posts, allowing for the bottom rail to be 75mm above the surface of the deck after the deck boards have been fixed.
  5. Join the railing assembly to the posts with glued dowels. For best results, use a concealed dowel fixing. Manoeuvre the finished post and rail section into its position and secure to the joists with bolts. As an alternative, you can create railings without the use of a bottom rail. Posts and top rails are assembled and fixed as before. The spindles are then fixed with screws to t he rail and the deck after the deck boards have been fitted. Make sure that the height of the top rail from the finished deck is exactly that of the spindles you have bought, if you don’t want to cut them. You can also make railings using deck boards and infills.
  6. Finish the posts by adding a screw-on ball top.
  7. When all the post-and-rail assemblies have been fitted, complete your deck by fixing the deck boards. Off-cuts of joists should be used to provide additional support for posts and subsequent decking boards around the posts.

• Step Four Laying the deck boards

  First of all, cut your deck boards to the length you need and brush all the cut ends with sealant. Then place the first board flush with the face of the joist at the front of the deck. Fix it into place using two 50mm screws in pre-drilled holes in each board.

  Install the remaining boards in a similar way, leaving a gap of 3mm between each one (a 50mm nail is approximately 3mm in diameter, so use this as a guide).

  Finish off your deck by fitting deck boards to the side joists. These serve as fascia and conceal the ends of the deck boards. To get the best results, the corners of these fascias can be mitred.