RECOMMENDED FIXING GUIDELINES FOR TIMBER DECKING (EXCLUDES COMPOSITE)
This guide will help you when choosing the type of
fixings to use, where to place the fixings and other practical recommendations –
depending on the type of deck board you are using. Click here for Composite
Decking Fixing Instructions.
STEP 1. SPACING BETWEEN JOISTS
When spacing your joist structure, the maximum gap between joists (from
centre to centre) should be no more than 400mm.
Note: spacing recommended is for domestic or light
commercial use, if in any doubt seek further professional help.
STEP 2. MINIMUM GAP AROUND PERIMETER
When decking up to buildings or door sills, install the joist structure and
deck boards so they are clear of the building by at least 10mm and always below
the damp course. This will allow for any expansion.
STEP 3. AVOID WATER POOLING
This is down to your planning and preparation of the joist perimeter
structure. Using a simple spacer acts as an effective guide and a 2mm fall in
gradient of the joist in every metre is sufficient to ensure the rain water runs
away and prevents any pooling, reducing maintenance too.
Note: the fall should run in line with the grooves on the deck boards to aid
STEP 4. DECK BOARD FIXINGS
4.5 x 63mm stainless steel or coated deck screws.
STEP 5. PILOT HOLES
Drilling a pilot hole before screwing down is recommended, alternatively use
a self-countersinking screw.
STEP 6. FIXING DOWN TIMBER DECK BOARDS
Fix the boards down securely with two fixings per joist. Screws will provide
a more secure fixing than nails. To avoid the potential for the timber to split:
A. Position the fixing at least15mm from end of deck board.
the fixing at least 20mm from the edge of the deck board.
STEP 7. SPACING BETWEEN DECK BOARDS
Ensure there is a minimum gap of 5-6mm between each deck board.
STEP 8. JOINING TWO BOARDS IN A RUN
When joining two cut deck boards together in a run, fix with screws 15mm from
the end of each board, at an angle to ensure secure fixing into the joists
NOTE: WHERE MORE THAN TWO BOARDS ARE FIXED IN A RUN, A MINIMUM 6mm GAP IS
REQUIRED FOR ALL OUR TIMBER BOARDS.
STEP 9. PROTECTING YOUR TIMBER DECK
Ensure any cut timber or drilled holes are treated with a suitable,
high-quality timber preservative. A thorough coat of treatment only takes a
moment and will prolong the life of the deck. This procedure is often a
condition reflected in the product’s guarantee, so is worth following.
DECK BOARD INSTALLATION SUMMARY FOR TIMBER DECKING
Max. joist centres: 400
Spacing between boards:
Gap around perimeter: 10mm
Fall: 2 in 1000mm
Fixing type: 4.5
Stainless Steel or coated deck screws
Pilot holes: yes
points: Minimum 15mm from end and minimum 20mm from edge
Fixing detail: 2 per
joist through face of board
Note: where more than two boards are
fixed in a run, a min 6mm gap is required for all our timber boards.