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Hi everyone! 
Like many others, I’ve let deck maintenance slide a bit over the years. I built the deck myself (DIY), and during the original sanding, I accidentally went over a few screws—wasn’t thrilled with how that turned out visually.
Now that we’re preparing to sell the house, I’m trying to get everything looking 100%. I'm planning to re-sand the deck, and I’d like to make sure all the screws are properly countersunk so I don’t hit them again with the sander.
Is it practical to replace each screw one at a time?
Do people do this as part of restoring a deck?
I’ve read that if a screw hole is a bit loose, you can glue in a hardwood dowel and re-drill into that—has anyone tried this?
Does it hold up well over time?
Also open to any tips on the best decking screws to use. The decking is Merbau with timber joists underneath.
Cheers!
Gamblor
Welcome to the Bunnings Workshop community @gamblor. It's a pleasure to have you join us, and many thanks for your question about decking.
Could you please show our members some photos of the issue you're looking to resolve? That’ll help us give more targeted advice. Let me know if you need a hand uploading images—I'm happy to assist.
If you're planning to sand the deck and some of the screws aren’t properly countersunk, I'd definitely start by trying to drive them in a little further. As long as the boards don’t split and the screws still have a good grip, that’s often the easiest way to get around the problem without needing to remove each one.
That said, if any screws are sitting proud and can’t be driven in further—or if they’re corroded or loose—then yes, it can be practical to replace them one at a time. Some people do this during deck restorations, especially if the deck is being fully re-sanded and refinished. Just be mindful to use the same type and gauge of screw to avoid alignment issues.
You're absolutely right about the dowel trick—gluing in a hardwood dowel and re-drilling is a great fix for loose screw holes. It can hold up really well over time if done properly. Just be sure to use a good quality exterior wood glue and allow it to dry fully before re-drilling.
Since your decking is Merbau with timber joists, I'd recommend stainless steel decking screws for durability and rust resistance—especially if you're in a coastal area. Look for ones specifically designed for hardwood, with a self-drilling tip and ribs under the head to help countersink cleanly.
Please let me know if you have any questions.
Mitchell
Thanks Mitchell!
Some photo's of the deck, keen to know if you think sanding is a good option still as well
I see what you mean about the screws @gamblor. It would be worth sinking the ones flush with the surface down a few millimetres below it if sanding. Your deck doesn't need the timber sanded down, as only the coating has begun to wear through. In order to get a perfect result, you'd need to sand the coating itself off. No need to aggressively sand the timber.
You could try giving it a good scrub down with Cabot's Deck Clean and coating it with at least two coats of a water-based oil like Cabot's Aquadeck. However, the lighter worn areas might still be slightly visible.
Mitchell
