Deck floor board spacing

[Jerry Simon]

Is this a new-fangled way of installing cedar deck floor boards - with no spaces in between the boards? Any thoughts?

Click to Enlarge

44.31 KB

[Robert Jones]

There should be gaps between the boards to allow for water runoff. I was always told a 1/4 to1/8" gap between boards. I have also been told that if the boards are wet/swollen, they could be installed flush and that when they dried they would shrink and the gaps would be there.

[RickSab]

For dry boards, the thickness of a carpenters pencil. Wet wood a 16 penny nail will work. To install with the floorboards tight will cause buckling if the wood was even moderately dry.

[Bill Kibbel]

Any thoughts?

You could mention that the Western Red Cedar Lumber Assoc. specifies that decking planks be spaced 1/8" apart to accommodate drainage and expansion.

[gtblum]

I've never laid down a cedar deck but, have always installed treated decking as tight as I could get it. After two days of the sun beating down, it always opens to at least 1/8 to 1/4".

[Jim Morrison]

Yeah, not to mention that when the slider threshold is level with the deck, it becomes the point of entry of much water in snow country.

[kurt]

Treated, I pack it as tight as it can be packed. In a year, there's a space that's just about right.

Cedar, I use a case hardened finish nail, which also happens to be about the diameter of the previously mentioned pencil lead, maybe a tad thinner. That's just about right in a year.

[Brandon Whitmore]

I've noticed that on decks where surface boards are pushed tightly together, there are more problems with premature rot and fungal growth.

It's hard to figure out how much of a gap to leave. I would prefer to install any surface boards when they have a high moisture content, and then leave a decent gap from there. That way, the deck boards can "breathe" and drain better during the wet season.

If I saw a wet deck where boards were tightly butted together, I'd write it up.

Oh yeah, I write up decks all the time that are flush with exterior door thresholds-- bad idea.