B&Q Online: From Kitchens & Bathrooms to Sheds & Paving; plus planning tools

How to build a basic deck and walkway

Build a basic deck and walkway

Use decking to transform your garden and bring the freedom of outdoor living to your home.

The natural warm colour and texture of wood will compliment any garden design and even the smallest of decks can change how the area is used.

Designing a deck

Decking

A place for barbecues with friends and family, a safe play area, a relaxing spot for morning coffee, or a romantic outdoor dining room. There are endless reasons why a deck will enhance your home and how you use it.

Decking

There's a great range of wood and finishes to choose from and designing your deck doesn't stop there. Balustrade, steps, a gate, skirting and a wealth of project finishers give plenty of scope for creating a very personal space which reflects your lifestyle.

First decide on the best position. Consider whether you prefer a sunny or shady site and think about which direction the prevailing wind comes from. Decide on the most convenient way to access the deck. If you are building away from the house, is there a path or walkway? Don't forget that you can extend and add to it at a later date, so keep it simple to start with. Imagine the view you will be obscuring as well as the deck you will be constructing. Check for manhole covers or drains as a trapdoor may be needed. It's a good idea to mark out the position with some wooden pegs so you can see exactly what space it will occupy. Keep the size of the deck in proportion to the size of the surrounding house and garden. A very large deck might need planning permission so if in doubt check this with your local authority.

What's in a deck?

Decking

Simple ground level deck

Decking

Ground level deck with balustrade

Which deck board?

Decking

Softwood

Classic decking style, warm colour tones and soft to touch. Softwood blends comfortably into the surrounding landscape.

Decking

Hardwood

For a quality finish, hardwood is hard to beat. Extremely durable, easy to maintain and weather resistant.

Decking

Composite

Made from recycled timber and PVC, tough, durable and almost maintenance free. Special screws and fixing clips making them easy to lay.

Decking

Thermodeck

Heat treated Scandinavian softwood sourced from sustainable forests. An environmentally friendly process produces a tough, water resistant finish which will last for at least fifteen years.

Decking

Grassedeck

A deck in sympathy with it's green surroundings, soft enough for sunbathing and tough enough for children to play. A funky new look but practical too.

back to top

Prepare the site

Decking

1 Using a tape measure, mark out the dimensions of the deck. Tap wooden pegs into the ground and stretch string between them to give you a line to work to. Measure across the diagonals to make certain the corners are square.

Decking

2 If you are working on a lawn remove the turf making sure you cut a neat edge along the outside of the string line. If it's a rough site, remove stones and debris and firm the ground. Be careful you don't disturb any underground pipes or cables. Roughly level the area and then use a length of wood as a straight edge, with a spirit level resting on it, to level the area accurately.

Decking

3 Cut a piece of building membrane a little larger than the size of the deck and lay it over the prepared area. Spread gravel over the membrane to a depth of about 40mm. This will prevent any unwanted vegetation from growing under the deck.

What if the ground is wet?

If you are working on a potentially wet site, then you should raise the deck off the ground using concrete pads.

1 Clear and prepare the site as in steps 1 & 2 above. Dig a series of small holes 150mm square by 150mm deep at 1.2m intervals around the outer edge of the deck.

Decking

2 Fill each hole with concrete leaving it to stand proud of the hole by about 60mm. Before the concrete is fully dry, use a spirit level resting on a straight edge to get each concrete pad level with the next.

3 When dry, cover the area with building membrane. Rest some stones on the membrane to keep it in place whilst you cut holes to allow the concrete pads to push through. Cover the membrane with about 40mm of gravel. Cut squares of building membrane to cover the top of each concrete pad. These will fit under the decking sub frame, so keep them nearby until you are ready to put them in place.

back to top

Assembling

Making the sub-frame

If you are working on a potentially wet site, then you should raise the deck off the ground using concrete pads.

Decking

1 Cut the outer joists to the correct length, remembering to allow for the timber overlap at the corners. Arrange them in position on the ground. Cut the inner joists to length. Decide which direction you want the decking boards to run, then lay the inner joists in place inside the frame, running in the opposite direction.

2 To comply with building regulations the gap between inner joists must be no greater than 400mm. Lay a tape measure along the length of the outside edge of the frame and mark with a pencil at 400mm intervals. Do the same on the opposite side of the frame and adjust the position of the inner joists so they line up with the marks.

3 Check the frame is square by measuring across the diagonal and make sure the timbers are level. Secure each corner of the frame using two countersunk coach screws. Then fix the inner joists using two countersunk coach screws through the outer frame and into the end of the inner joist.

4 A very long or wide deck should have noggins fitted between the inner joists. These are pieces of in-fill timber which fit between the cross joists to provide extra strength.

Extending joists

If your deck is longer than the standard 2.4m timber length, then you will need to extend the length of the joists.

Decking

For an outer joist, cut a piece of joist timber about 600mm long, use an off-cut if possible. Fix it across the join on the inside of the frame using eight evenly spaced bolts. Where the inner joists need to be extended, use two 600mm off-cuts fixed across the join on both sides. Use four evenly spaced bolts for a secure join.

Alternative patterns

The simplest way to lay the boards is at right angles to the inner joists. For the more ambitious, why not try laying the deck boards in a pattern, however, you need to plan this before making the subframe. The inner joists for both these patterns should be spaced at 300mm.

Decking

Diagonal decking - mark 900mm from the corner of the sub-frame and fix the first board in line with the marked position. Screw the board to the outer joist and to the inner supporting joists.

Decking

Chevron decking requires double joists where the boards meet at right angles. They should be locked together securely with coach screws.

Laying the deck boards

Reversible deck boards can be laid with either the smooth or ridged side up. If you intend adding a balustrade then you should fit the supporting deck posts, before laying the boards.

Decking

1 Lay the deck boards onto the sub-frame so that they overlap the edge and then trim to fit once fixed into position. Alternatively you can cut them to the correct length as you lay them. Deck boards are usually 2.4m long, so if your deck is bigger than this you will need more than one board end to end. Make sure that joins are positioned half way across a joist.

2 Adjacent boards should have the join staggered, this looks more attractive and increases strength. Leave a gap between boards of 3mm to allow for drainage and movement. A simple way to achieve accurate spacing is to use deck screws as a guide. Wedge a screw into the gaps as you lay the boards. Check the boards line up perfectly and adjust the gaps as necessary.

Decking

3 Fix each board to the sub-frame at every joist, using two 50mm deck screws spaced evenly. If you have not cut the boards to length before fitting them then you should carefully cut off the surplus using a power jigsaw or hand saw. Treat the newly cut wood with an end-grain preserver.

back to top

Deck or walkway

Deck tiles - the easy option

Reversible deck boards can be laid with either the smooth or ridged side up. If you intend adding a balustrade then you should fit the supporting deck posts, before laying the boards.

Decking

For a ground floor deck, path or walkway, deck tiles are quick to lay and easy to use. They are produced in hard and softwood, and in a variety of different patterns and sizes. Kits are available which are simple to assemble and can easily be adapted to suit your project.

Create a walkway

Use a deck kit to make a garden walkway.

Decking

1 Mark out and clear the site. Spread building membrane over the area and cover with a 40mm bed of gravel.

Decking

2 Fix the outside edges of the frame together, using deck screws and a drill driver.

Decking

3 Fit the crossbars to the frame, keeping the recess, where the tiles locate, uppermost. Move the frame into position, onto the gravel. Fit the deck tiles into the frame and secure with a deck screw in each corner.

PEFC & FSC® logo

At B&Q, we work hard to ensure, wherever possible, we only use wood that comes from sources that are backed by schemes which certify that the forests are well-managed. The FSC® or PEFC symbols give you that assurance. Look out for them on our products.

back to top

How many deck boards do I need?

To work out how many linear metres of board you need, use the appropriate table below. Divide the number of metres required, by the board length, to find out how many boards you should buy. These tables calculate the quantity using figures which include the gaps.

Example:

For a deck measuring 4mx4m you will need 112m of 150mm wide deck board. If the deck boards you want come in 2.4m lengths, divide 112 by 2.4 = 46.7 so you should buy 47 boards.

Using 144mm (150mm nominal size) deck boards

Metres 1 2 3 4 5 6 7 8 9 10
1 7 14 21 28 35 42 49 56 63 70
2 14 28 42 56 70 84 98 112 126 140
3 21 42 63 84 105 126 147 168 189 210
4 28 56 84 112 140 168 196 224 252 280
5 35 70 105 140 175 210 245 280 315 350
6 42 84 126 168 210 252 294 336 378 420
7 49 98 147 196 245 294 343 392 441 490
8 56 112 168 224 280 336 392 448 504 560
9 63 126 189 252 315 378 441 504 567 630
10 70 140 210 280 350 420 490 560 630 700

Using 118mm (125mm nominal size) deck boards

Metres 1 2 3 4 5 6 7 8 9 10
1 8 16 24 32 40 48 56 64 72 80
2 16 32 48 64 80 96 112 128 144 160
3 24 48 72 96 120 144 168 192 216 240
4 32 64 96 128 160 192 224 256 288 320
5 40 80 120 160 200 240 280 320 360 400
6 48 96 144 192 240 288 336 384 432 480
7 56 112 168 224 280 336 392 448 504 560
8 64 128 192 256 320 384 448 512 576 640
9 72 144 216 288 360 432 504 576 648 720
10 80 160 240 320 400 480 560 640 720 800

back to top