Free tool
Put in the size of your deck and we'll work out every board, joist, post and screw you need, with today's prices. It's the same way our team works it out at the counter in Newcastle.
Your deck
For composite boards we recommend 400mm centres. Joists further apart use less timber, but the deck feels less solid underfoot.
Composite boards are best on 400mm centres. Most makers don’t recommend wider spacing, as the boards can sag over time.
You choose how much extra to allow. Most people allow 5% to 10% for cuts and waste.
What you need
| Qty | Item | Price |
|---|
Joists at 600mm centres. Quantities are a guide, so if your deck has steps, corners or an odd shape, call or call in and we'll check it with you.
Please note: These quantities are an estimate only, worked out from the measurements you enter. Every job is different, so please check your own measurements and quantities before you order. The final calculation and order quantity are your responsibility. Abwood can’t be held responsible if you end up short of materials or with materials left over.
How we work it out
What's in your list
Timber: 4.8m reversible boards, 140mm x 28mm, pressure treated, each covering about 145mm with a 5mm gap. Composite: Teranna 3.6m boards, 135mm x 25mm, with an installation kit of hidden clips and screws for your deck area, and end caps for the board ends.
Laid across the boards at 600mm centres for timber decking, or 400mm for composite (600mm if you choose), with a frame all the way round and noggins every 1.2m to keep it stiff. 4x2 for ground level, 6x2 for raised decks.
Raised decks only. 4x4 posts every 1.2m each way under the frame, 1.8m long so there's plenty to go into the ground.
For timber, two 60mm decking screws per board at every joist. For composite, the installation kit. Plus joist hangers for the inner joists, and wall fixers every 600mm if it goes against the house.
Tips from the yard
Before you start
Measure the length the boards will run and the width out from the house. If one side is longer, use the longer one.
Leave about 5mm between boards so rain can drain and the timber can move.
Give the deck a slight slope away from the house so water runs off.
Brush end grain preserver on any cut ends so they last as long as the rest of the board.
Questions
Decking FAQs
How many decking boards do I need per square metre?
With 140mm boards and a 5mm gap, one square metre takes about 6.9 metres of board, so roughly one and a half 4.8m boards. Put your size in the calculator above and it works out the exact number, plus 5% or 10% extra for cuts if you want it.
How far apart should decking joists be?
For our 28mm timber decking, 600mm centres is plenty and that’s what the calculator uses. Composite boards are more flexible, so for composite we recommend 400mm centres to keep the deck solid underfoot. You can choose 600mm for composite, but most makers don’t recommend it.
What size joists do I need?
For a ground level deck, 4x2 (100mm x 44mm) pressure treated joists are plenty. For a raised deck on posts, go up to 6x2 (150mm x 44mm).
How far apart should the posts be?
For a raised deck we put 4x4 posts every 1.2m each way. The calculator adds them automatically when you pick Raised.
Do you deliver decking?
Yes, we deliver timber and decking across Wicklow, Dublin, Wexford, Kildare, Meath, Carlow and Kilkenny. The delivery charge is shown at checkout, or you can collect from our yard in Newcastle, Co. Wicklow.
Not sure about your measurements?
Send us a sketch or call in to the yard and we'll go through it with you.