Type of ply
Marine ply was the obvious choice for the floor. After some investigation I learnt that Marine ply is AA quality ply that has no imperfections or defects, such as knots in the timber, that can compromise any sealer or waterproofing applied to the timber. The wiki definition is ‘Marine plywood is manufactured from durable face and core veneers, with few defects so it performs longer in both humid and wet conditions and resists delaminating and fungal attack. Its construction is such that it can be used in environments where it is exposed to moisture for long periods’.
Where to buy
I looked around when buying and found a wide variation in price without much variation in quality. In the end I bought from two places Bunnings and Barrenjoey Timber. Bunnings was great as they could cut it down to a manageable size to get it home without paying for delivery, however, their stock was low. The boys as Barrenjoey Timber were also kind enough to allow me to take down my saw and cut down the ply myself.
The size I bought was 12mm 1220×2440 for around $88 a sheet (much better than the $220 some places were charging). I went with 12mm as I found the 9mm a bit too flexible for my liking. At 27kg per sheet the extra weight of the 12mm was not ideal but in the end I am really happy I went with the 12mm.
Before cutting I created a template with cardboard from some packing boxes. This method worked really well. The one thing I had to account for was
the thickness of the carpet after glued. This was a bit tricky and I will cover more about this in the section on carpet. In short the gap required for marine carpet is between 4mm and 5mm. On average I aimed for 4.5mm. So if two pieces were butted against each other (carpet to carpet) the gap was 18mm as each piece had carpet on each side.
Cutting the timber was nothing special other than to say the edges that butted up against the hull were the trickiest and required an angle equal to, or greater than, the angle of the hull. To do this I used a jigsaw at maximum angle.
Contrary to many opinions marine ply must be sealed. I used a two part Norseal epoxy wood treatment. This is a great sealant that really gets into the
timber. My biggest tip is to watch the underside for running drips that harden into lumps. The simplest way to manage this is by lightly rubbing a cloth round the edges about ten mins after application. Keep an eye on the drips as they really do sneak up on you.
In the end I’m really happy with the floor. Its firm, sealed really well and is a really snug fit after the carpet was glued.
Here are my top tips for timber:
- Buy marine ply
- The cheaper AA marine ply is just as good as more expensive stuff, especially seeing it will be sealed
- Seal the ply well with an epoxy sealant
- Watch out for the sealant drips that can harden into lumps on the underside.
- 12mm ply felt the best too me but you could get away with 9mm if your happy to have a bit of movement under foot as 9mm is more flexible
- Create a template with cardboard before cutting
- The gap for carpet is around 4.5mm per side.
- Remember two carpeted pieces butted up against each other will need a gap of 18mm (4.5mm x 4 sides)