How To Build A Raised Deck

A raised deck can look great but it can also be practical. Sloping sites can be difficult to use, but raised decking can create a flat area perfect for relaxing, entertaining or as a childrens play area. You can build your raised deck beside your house, beside a pond or as part of your landscaped garden. Use different heights in your design as a feature to add interest and lift you garden above the run of the mill.

Designing A Raised Deck

If you plan to build your raised deck adjoining your house ensure its proportions are in keeping with the building. Draw a plan of the raised deck marking the position, height and dimensions. You will need this decking plan to help mark out the foundations. 

If you intend to build a very substantial structure you may need to get planning permission before you begin.

Preparing A Site For The Raised Deck

Mark out the postion of the deck using a tape measure and check that the corners are square. Remove turf, loose material and any stones or debris from the marked out plot. If part of the plot is concrete it can be left intact as metal posts bolted to the concrete can be used as part of the raised deck construction.

Preparing Firm Foundations

Good foundations are essential. Mark the positions of the joist support posts. Dig holes 600mm deep and put a piece of concrete at the bottom of each hole for extra support. Cut the posts to the correct length and treat the ends with preserver, then set the posts in their holes using concrete. Make sure the posts are vertical and the ends are level.

Fixing To A Building

If you building next to a house then you must attach the sub-frame to the wall. Drill holes in the joist to be fixed to the wall. Use a spirit level to get the joist level, then mark the wall with a pencil through the holes. Drill holes into the wall and fix the joist bto mthe wall using expanding masonry bolts and washers.

Making The Sub-Frame

Cut the outer joists to the correct length allowing for timber overlap at the corners. Attach the frame to the wall using metal joist hangers. For the other two corners use two countersunk coach screws through the joist and into the post. Decide which way the deck boards will lay. Cut the inner joists to length running the opposite way and fix each one to the frame using two countersunk coach screws. Drill pilot holes first. Inner joists should be no more than 400mm apart.

Fixing The Balustrade - An Essential Safety Feature

Railings are an essential safety feature. The handrail should be 1m above the deckand the base rail no more than 75mm above the deck board surface. You must attach the railings before laying the deck boards.

Laying The Decking Boards

lay the deck boards at right angles to the sub-frame inner joists, working from the outer edge of the frame inwards. Cut the first board to length, mark the outline of the post and cut out the unwanted piece. Lay the board in position and fix it to the sub-frame using two 50mm deck screws into each joist. Fix all the deck boards to the sub-frame leaving a 3mm gap between boards.

Building Steps For Access

A raised deck may need steps for access, or two link different heights of decking. The easiest option is to buy ready made risers and treads that can be adapted to fit