Wooden Decking in Great Missenden

• Paving slabs – old or cheap ones are fine
• Timber for the frame and legs
• Type 1 MOT hardcore

1. Mark out the area as we explain in ‘How to lay decking’. Then, dig to 200mm below where you want to surface of the decking to be.
2. Add a 50mm layer of hardcore and make sure it’s compact.
3. Build the decking sub-frame as we describe in ‘How to build a deck frame’.
4. Lay out paving slabs along the edges and in the centre of the area. This will help to spread the weight of the decking.
5. Set the decking frame on the slabs, checking for high or low points and adding off-cuts of timber where needed. Don’t forget to sand and seal these off-cuts with decking preservative.
6. Add your joists and then the deck boards, leaving the recommended gaps of expansion of between 5-8mm.

1. If you’ve not got an overhang or it’s a fixed deck, fit starter clips along the outside edge of the frame and secure with screws provided with the composite decking. If you are working with an overhang, put the first board into position not exceeding 25mm. If you’re adding a fascia, put an off-cut of board under the overhang so you know it’ll be flush with the fascia.
2. Pre-drill all fixing points, measuring in 30mm from the edge of the board. Secure the board to the joist below with composite decking screws.
3. Slide a hidden fastener clip in so it sits within the groove of the deck board. It needs to be in the centre of the joist to keep the boards secure and ensure an expansion gap of 6mm. Tighten the clips until just tight, and repeat so there’s a clip at every joist.
4. Add the next board, ensuring that the fastener clips sit within the groove – make sure you don’t force it. Repeat step 3.
5. Continue steps 3 and 4 until you’re at the final board, which you should secure in the same way as you did the first.

If your deck isn’t going to be flat to the ground, it’s a good idea to have some kind of balustrade to avoid any tripping. If the gap between the deck and the ground is less than 600mm, use a 900mm balustrade. If it’s higher than 600mm, the balustrade should be 1100mm tall.

1. Place a post in the corner of the frame you created with the pegs and string. Measure and mark out 100mm from each side.
2. Dig out this soil to a depth of 700mm (watch out for cables or pipes). You should have a 300 x 300mm hole. Repeat for the other 3 corners.
3. Using a brick bolster, split a concrete block in two. Put a section of the block in each hole.
4. Get a length of post longer than you need and place one in each hole. You can cut it down later.
5. Create props on each post to hold them in place until you’re ready to add a cement mix. Check that they’re level. When you’re happy that they are, secure them in place with a concrete mix, making sure you create a slope in the concrete so that rainwater runs away from each post. When the concrete is set, remove the props.
6. Create a string line around each corner post and find the centre point between each. Place a timber batten at each point, ensuring that they’re not spaced any more than 1500mm apart.

1. Working from the corner where the deck will be at its highest above ground level, measure and mark on the post where the highest part of the frame will be.
2. Measure from the far side of one post to the opposite and cut sections of joist to size. Line up a piece of joist with the mark you made and temporarily secure it. Factor in a 2mm fall for every metre of decking so rainwater can run off.
3. Secure the frame to the other corner post, ensuring it’s at the right level. Do this for every side of the outer frame.
4. Using 100mm coach screws with washers hanging on the end, secure each end of the four sections of frame.
5. Mark out where the centre of the support posts will be and secure all of these posts to the frame, except the centre post.
6. Add your central support joists. These should run in the same direction as the deck boards will run. You’ll need to measure from the inside of the frame on one side to the inside of the frame on the opposite side. Attach the joist in the same way as you did for the other posts. Repeat so the centre post is in between two sections of frame and secure the posts with concrete.
7. Trim down all the posts to the correct height using a saw.
8. Add your weed-control fabric and weigh down with gravel across the entire area.

1. Measure 400mm from the centre of the outer frame and mark a line. This will be where the first joist is positioned. Repeat at 400mm intervals down the length of the frame – if the last one will be more than 400mm, add another joist to create enough support.
2. Attach a joist hanger to each end of the joist.
3. Place the joist in position so the centre lines up with the 400mm spacer mark.
4. Secure using external grade screws once you’re happy that the joist is flush with the frame.