Maintaining moisture content when planking

[George Emmanuel]

I live in Florida and am restoring a 1955 Sportsman. The decks were done previously and incorrectly so I'm replacing them. Some days we have very low humidity in the Spring followed by damp days, then dry again. It drives me nuts trying to anticipate a day when the humidity is low so I can fasten the planks for tight fit. If I do it on a "normal" day here, the day when the humidity drops the planks shrink and then the next day they're back tight. I understand planks respond to the humidity but how can I get them to remain stable enough to keep the seams tight? I do not want to use a plywood skin and glue the planks to the skin. Is there a suggested procedure prior to applying finish that will help? I spoke with Seth Katz at Tavares and he indicated they don't have issues with that and he doesn't use 5200 to bed them. I don't use 5200 on the deck planks. I might add that when fastening the planks I did clamp them tight to each other.

[DennyDowning]

Your asking some good questions about redecking your boat. I noticed you did not say what type of wood you are using. Yes wood will expand and contract and there is very little you can do about it other then keeping the boards in a controled environment. Boat builders are very aware of these charistics in wood. In fact they must plan on the wood expanding. Again not sure the type of deck you are doing either but there should be space left between boards. Clamping them tight while you are fitting the pieces is fine but, again, you will not stop them from moving. On my boat the decking is mahogany and looks like 2" mahogany strips with a white line between them. Ya know why the white lines are there. Yep, there is a good caulking between the boards to expand and contract with the wood. Just fit the boards snugly. Clamp them only to hold them in position while fitting the next piece and yes I agree to stay away from 5200. I used a good non silicone exterior caulking and seams get filled and stained, with a filler stain, or painted. Either way my friend the gaps will not show when you get it done. And for goodness sake stop waiting on the humidity - I say just rough out your pieces get them all kinda close but oversize. And then start fitting them in place. Working one piece at a time may be where your getting into trouble. Get all the pieces roughly laid out. Match up the color and grain if you will be staining so there are no great variations in the grain for piece to piece. Then pick a nice day or stretch of days and fit them all in. Also I recommend after you rough out all the pieces for the deck and before you start fitting them that you should pre-paint or seal the underside and edges of the boards. It is an extra step but pays off bigtime. Then the painted surfaces can be bedded down with boatyard bedding compound for a strong and solid feel.

Best of luck with your project.

[boat_art]

Yup, what Denny said.