How to add steps & railing to decking


Unless your deck is at ground level, you'll need steps to give you easy access to your garden or link different levels of the deck. If you add a handrail and balustrades they'll turn a functional stairway into an attractive feature as well as helping to prevent slips and falls.

A basic open stair is all that’s necessary on a low deck, but for higher ones you’ll need handrails. Be sure to check the most up-to-date Building Regulations.

The easiest way to build steps is to buy pre-formed kits that include two stair risers (side panels) and step treads. They're available in three, four and six step options.

Alternatively, build your own with two risers (side panels) and as many separate step treads as you require. We're going to take you through this process for timber deck boards. If looking to lay solid composite decking steps, follow steps one and two below and then jump to the section 'How to fit solid composite stair treads'.


If building your own steps, we suggest:

  • A step tread width (the width of the steps) of 900mm - it should not be less than 760mm.
  • Stairs wider than 900mm will need to add a central step riser to support the steps and prevent them buckling.
  • A step depth (the vertical distance between each step) of between 150 and 180mm if building your own riser. This ensures the steps are a comfortable depth and not so deep that they're an effort to climb, but not so shallow that you trip on them. This is especially important for the bottom step - between the step support pad (the step's foundation) and the first riser.

Top tip: Layered timber decking

Consider using a layered surface deck board, such as the Walksure or Grassedeck deck boards, for your steps. The extra layer improves the grip, making it a safer step.


Step 1

Check that the site for your steps is level and firm - anything uneven or too soft and the steps won't be secure enough and might sink into soft ground.

If no hard landscaping exists there already, consider laying an area of concrete or paving slabs (British Standard Paving is a very strong and durable option). For more on paving options, head to our buyer's guide.


Step 2

Cut two sections of joist off-cut to the same width as the step treads.

Attach them to the step risers at the top and bottom using two countersunk coach screws on each side.


Step 3

Position the assembled steps against the sub-frame of the deck and in the centre of the step support pad.

Ensure you have the longest edge of the stair riser on the paving slab and the short edge against the deck.

Drill pilot holes through the step assembly and the sub-frame joist. Screw the step assembly securely to the sub-frame with four more countersunk coach screws.


Step 4

Drill pilot holes and then screw the treads into the riser supports at either end with two 50mm deck screws to make a sturdy step.

To fit solid composite stair treads, see 'How to fit solid composite stair treads'.


Step 5

If you would prefer a solid stairway to an open stair, fill the gaps with joist off-cuts or deck boards.

Simply measure the height and depth of the gap and screw the timber into the step riser with two screws at either end.


In order to fit handrails to your steps, you’ll first need to fix notched deck posts at the top and bottom. Notched (or rebated) deck posts have had a section of the post removed in order that it butts up to the steps better.

Step 1

Measure and mark the post accurately with a square prior to making any cuts.

Use a reciprocating saw or jigsaw to score the post. Remove the weakened sections with a chisel making sure not to remove more than half the post or you’ll significantly weaken its structural integrity.

Smooth down any rough or cut edges with sandpaper and treat with an end grain protector.

Step 2

Drive two coach bolts through each post into the step riser.

Position a length of hand rail on the outside face of the posts parallel with the angle of the steps.

Mark with a pencil the line of the outer edges of the posts and cut along this line with a jigsaw.

Bolt the hand rail to the posts and check that the edges are neatly flush.

Step 3

To attach spindles, fit a base rail in the same way as the hand rail. Then cut the spindles to length and screw them in place.

Hand and baserails with upright balusters won't just help prevent falls. They'll also instantly transform your basic deck into a more elegant feature. Notched posts are specially profiled at the bottom so you can attach them to an existing deck.


Step 1

Start by deciding how far to space your deck posts (they shouldn't be any more than 1.2m apart) and fix the first notched post to the sub-frame with coach screws. Measure out lengths of joist to sit on the outer face of the sub-frame between the deck posts, and attach these with deck screws as you fix the posts. When you reach a corner, measure and cut the length of joist to the outer edge of the sub-frame. Then position the corner post on the adjacent side overlapping this joist - this will keep the posts inline.


Step 2

Measure and cut lengths of handrail, then mitre the corners for a neat finish. Next, clamp a length of handrail into position with its grooved edge facing down. After checking its level with a spirit level, drill in countersunk pilot holes and screw it into the deck posts.


Step 3

Use a baluster lined up with the groove in the handrail to work out the position of the baserail. Make sure that any gap between the baserail and the decking boards isn't more than 75mm. Clamp the baserail in place, and fix it to the deck posts with countersunk screws.


Step 4

Position the first baluster, checking it's straight with a spirit level. Then fix it to the handrail and baserail with countersunk screws. Use a wood off-cut or a length of base rail as a spacer to keep an even distance between the balusters. Remember that the maximum gap by law between railings is 100mm, and make sure you space your balusters and deck posts so they're even.