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Building a deck

The frame   The key to constructing a good decking area is the frame. If the decking is being built on a low level it should be built of C16 graded treated joists 45 mm by 95mm (4×2 approx.). However if you are building a raised deck you should use 45mm x 145mm joists. Before building the frame you need to decide which way the final decking boards are going to run and build the main joists of the frame in the opposite direction at approx 400mm centres. Also it is good practice to square the deck frame this can be done using the 3-4-5 method.

I.e. if you measure 3′ along one edge and 4′ along the other edge from the corner and mark the two points then measure between the marks it should be 5′ if it is then that corner is square.

If its a smaller deck area measure corner to opposite corner, the measurement should be the same, if so your frame is square.


The frame will need to levelled and supported  every 1.2m in every direction. In general the more support the better as this will help stop the deck from having too much of a spring. Before building the frame it is a good idea to cover the base with a ground sheeting material to stop any weed growth once the decking is finished. Screwing the frame together is the best way to ensure you maintain the strength over a number of years. However on larger decks joist hangers are an option. Level and build the decking so that the frame has a slight fall about 1 in 100, which means for every metre along the joist the change in level, will be 1 cm. The fall should be away from any buildings. Also make sure to add noggins between the joists. These are used to strengthen the frame and stop the joists from twisting over time. how-to-build-a-deck---figure-5 The finished surface The key is to keep the wood in as long a lengths as possible. When laying the surface you need to screw it to the frame starting from the outside edge of the deck area and working backwards. A good tip is to use a small spacing bar to make sure the space between each board is the same. This space should be approximately 5 mm. Using an electric screw driver to secure the decking boards with purpose made decking screws you need to use two screws per board on each joist .Nailing the boards to the frame is a waste of time because the boards will twist pulling the nails out.



Good luck with your project, and remember we are only a phone call away for any advice or help you may need.