Now that you have planned your deck and know exactly where things are going and that you have all the right materials for the job, lets look at walking you through the main steps to completing your first DIY Decking Project.
If you have not read my guide on pre-installation preparation .. read this garden decking checklist
Ok .. here we go ..
Allow a few clear days to complete this project. Home DIY projects take longer than you think
For deck boards, joists, ledgers and noggins allow around £10 per 3.6m (12ft)
Clear the site and markout
Get rid of any remaining vegetation and mark the area out with pegs and some string. Make sure it is square. Try not to let any slope be more severe than 1:120. Thats a 1cm drop for every 120cm along the length
Level and compact the surface
Lay down some black plastic sheeting and cover with some gravel. This will prevent vegetation from growing underneath and up through your decking at a later stage.
Lay your foundations.
You may want to use old paving slabs for the foundation points. If you do not have anything handy, then make up some concrete and make support pads of around 30cm x 30cm and these should ideally be 45cm deep into the ground. Do not space your support points more than 6′ or 1.8m apart
Lay your decking joists
Once the concrete foundations have set, lay your ledger and joists on top of these. Be sure to use a spirit level as you go, making sure the decking is level and sloping off if you so desire. Position your joists at 40cm intervals and fix using 75mm screws. Noggins (the support beams running at right angles between the joists) must be 40cm apart. Ensure your ledger (this will be load bearing) is spaced slightly away from the wall to allow for ventilation and drainage.
Lay your decking boards
Fit at right angles to the joists. This adds strength to the foundation. Make sure the decking boards and joists are not bowing or sagging under your weight. If they are, do not move on until you have stabilised the foundation. It is important you do not start the next section until you are 100% happy with what you have done so far. If you need to fix a wobbly joist or cut down a deck board that is slightly bigger than you want it .. do it now or it will frustrate you for ever more each time you walk across it 🙁
Spacing & Fixing
Try and stagger any breaks in the boards as this will look a lot better. Use stainless steel countersunk crews or specially made decking screws (usually 50mm) on each board. Galvanised nails can also be used but I wouldn’t recommend them for longevity. Predrill pilot holes for screws to avoid splitting the wood. Try and keep a 3-5mm gap all the way around. 3mm is about the width of a 50mm long nail. Good idea to use this as a guide.
Treatment & Finishing
Using your chosen wood treatment and finishing style, pay particular attention to areas of decking that have been freshly cut. This is where most wood rot will start and needs to be covered well.
# Make sure your deck is at least 6″ below your DPC (Damp proof Course)
# Slightly slope the deck away from any walls or the house
# Lay your decking in a sunny spot
# Make sure your furniture fits the area you are decking
# If boards need joining .. make sure they meet above a joist
# Use an extra deck board or fascia to cover the end cuts
# If using nails, blunt the ends to avoid splitting the wood
Well thats it .. voila .. your first attempt at diy decking.
I hope this has been useful and you enjoy yourself. Love to see some pictures of what you’ve been upto if you have a chance to send them in to us.
Happy Gardening .. Gardener Jack 🙂