How to build a decking area

2014-02-03 13:35:21

How to build a deck

This example shows you how to build and maintain a decking area for your garden. You will require some basic DIY skills but no element is difficult. Depending on the size of your deck it can be finished in a couple of days.

1: Plan your decking area

• As with any landscaping project, the best way to start is to draw the finished project or to lay out battens to mark the edge of the area you wish to deck to see how it will look.

• Remember that decking laid at right angles to your house draw the eye to the garden, decking laid parallel to the wall emphasise the width of the deck.

• Once you have decided on the extent of your deck, don’t forget to take in to consideration obstacles in your garden such as, waste water pipes, air bricks, manhole covers, door openings etc and draw a plan with these in mind. Also you must make sure that the top level of any deck that is to be attached to your house wall is at least 150mm below the damp-proof course in order to meet the current building regulations.

2: Measuring up

• Now you have drawn you plan you need to calculate your deck in m². Generally each pack of decking has the area it covers on it. If you divide the area of you want to deck by the area the pack covers this will tell you how many pack you require.

• You will also need posts and rails so will need to work out how many you require. If you have queries about the amount of packs you will need or the amount of posts and rails ask a member of staff and they will be able to help you (take your plan with you just incase).

3: Preparing the ground

• You will need to peg and string the area that you want to deck and clear all the turf and vegetation and make sure you firm down the ground.

• You will need to lay some type of weed membrane on the ground you have prepared and weigh it down with pegs or slabs.

• Now you can think about the frame work, this should be laid on concrete foundations not directly onto soil. Your foundations can either be concrete slabs or mixed concrete. If you use concrete slabs you will need to lay them in a grid pattern and position them at least 1400 apart this will support the timber joists.

• If you have bad soil conditions or poor drainage you will need to support the joists on a stronger base of concrete instead of slabs. You can do this by digging 300mm square holes and making them 300mm deep and then fill them with concrete and allow to dry before continuing with the project.

• You will need to lay some bitumen membrane over the slabs you have laid or the concrete bases you have done before you start laying the decking timers

• It is an idea to have a spirit level handy to make sure that the deck gently slopes away from the house and for every 1 meter of decking there should be a 10mm slope.

4: Building the framework

• To start the framework you will need to form the outer framework with joists which need to be 150mm high and 50mm wide. You need to rest this on the levelled slabs or concrete.

• You will need to fix the joists together with 100mm rustproof screws and external wood glue to ensure secure fixing. Ideally you should use one screw on the top edge of the joist and two screws on the sides.

• If you are attaching the decking to the house you must make sure you leave a gap of at least 10mm, you can do this by using stainless steel washers between the joist and the wall.

• Once the outer framework is finished you then need to fill it with long joists making sure they are spaced at 400mm intervals and screwed to the frame. You should fit these joists at right angles to the finished decking just like you would an internal floor.

• To add strength to the framework you should fix short lengths of deckboards ‘noggins’ at right angles between joists.

• It is advised that you treat any new cuts in the wood with a preservative.

5: Fixing the deck boards

• When you have finished placing all the joists the framework should be completely rigid.

• You can now start to lay the decking, start next to the house and lay around 6 boards each time making sure you leave approximately 5mm gap between each board. This is for ventilation and expansion.

• Stainless steel or galvanised screws will be needed to fix the boards in place (use these so as no to get rust stains). It is advisable to pre-drill your screw hole to reduce the chance of splitting the wood. Once you have laid the deck boards fix each end first then the rest making sure you screw it to every joist.

• If the area you are decking is longer/wider than the deck boards you will need to stagger the boards and make sure you join the boards over a joist and cutting to size where needed.


6: Variations

• When you are fitting you decking you do not have to stick to straight lines, the boards can be fitted diagonally or cut to make herringbone patters (although this is generally more wasteful than using straight boards)

• If you have a raised deck and it is over 60 cm high then you will need to put a deck surround or railings on the edge to form a safety barrier.

7: Finishes

• There is no need to treat your decking as the boards are pressure treated with a long lasting preservative but the colour will fade after a few months. If you decide you want to treat your decking boards an exterior penetrating oil that soaks into the wood rather than sitting on the surface will be best. The oil can be brushed rollered or sprayed on to the boards.

8: Maintaining your decking

• Ideally once a year you should check and repair any loose boards or missing screws. You should also clean the decking with cleaning solution to remove algae, moss and all dirt. Once you have cleaned the decking you will need to re-treat the boards with deck oil (if you choose to treat initially).


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