Build ⁄  Decks

Replace Old Decking Boards

A run-down deck with rotten boards might look like it needs to be demolished, but if the damage is localised, you can fix minor issues to avoid total replacement, and still have a safe outdoor area.
By Words: Frank Gardner Main Picture: Chris L Jones


This deck had seen better days, but was still structurally sound. A few simple repairs brought it back to life.

Timber structures like decks, pergolas and balconies have a lot of enemies. Termites feed on timber, while corrosive elements, such as salt-laden coastal air, deteriorate nails, bolts, screws and fixing plates.

Do an annual inspection of timber structures, looking for early warning signs such as corrosion, excessive weathering or movement.

PROTECT the base of posts against rot, and the timber against weathering, by painting, staining or using water-repellent preservatives.

SEAL joints that have opened up.

REPLACE corroded bolts, popped or rusted nails or screws, using stainless steel fixings for longevity.

TIGHTEN loose balustrades.

CONSULT a structural engineer if you have any doubts.

Step 1. Remove old boards

Step 1. Remove old boards

Use a pry bar to lift and remove the section of old boards. Remove any nailgun-driven steel nails that have pulled through the deteriorated decking and remained in the joists using a claw hammer.

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Step 2. Clean up the joists

Step 2. Clean up the joists

Fill splits and nail holes in the top of the joists with a two-part filler. Once the filler has hardened, paint or seal the top of the joists to protect against water penetration and increase the longevity of the timber.

Step 3. Lay out boards

Step 3. Lay out boards

Loosely lay out the new decking boards in a staggered pattern and make sure there are no butt joints side by side on adjacent boards. Mark the position of the cuts using a pencil and try square.


This deck had seen better days, but was still structurally sound. A few simple repairs brought it back to life.

Timber structures like decks, pergolas and balconies have a lot of enemies. Termites feed on timber, while corrosive elements, such as salt-laden coastal air, deteriorate nails, bolts, screws and fixing plates.

Do an annual inspection of timber structures, looking for early warning signs such as corrosion, excessive weathering or movement.

PROTECT the base of posts against rot, and the timber against weathering, by painting, staining or using water-repellent preservatives.

SEAL joints that have opened up.

REPLACE corroded bolts, popped or rusted nails or screws, using stainless steel fixings for longevity.

TIGHTEN loose balustrades.

CONSULT a structural engineer if you have any doubts.

Step 4. Drill pilot holes

Step 4. Drill pilot holes

Use a mitresaw to cut the decking boards to length so all the joints fall on the centre of a joist. Over the centre of each joist, drill two pilot holes with a 2mm twist drill bit through each board.

Step 5. Secure boards

Step 5. Secure boards

Drive in 50 x 2.8mm stainless steel twist nails to secure each board. Check the alignment of the boards with a stringline, using a chisel to space and flex the boards straight before driving in the nails

Step 6. Tidy the ends

Step 6. Tidy the ends

Cut off any overhang so the ends of the decking boards are even. Sand or plane to round the edges and remove any splinters for safety. Apply oil, stain or paint to the new boards to match the original decking.

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