Fluted decking...Up or down?

[DrDread]

I've built about 250 sq.m of decking around our house, about half replacing existing deck which had the fluting facing up. Some tradies I spoke to reckon this is correct.

Advice direct from manufacturers/importers specify the design is to face the fluting down (which I have done) to allow ventillation and prevents rot between the joists and boards and prolongs the life of the deck. My own experience with fluting up is a build up of mildew which becomes slippery.

Is there a definative answer to this or is it just personal preference regarding asthetics?

[Burnsy]

Manufacturers are right, reeding goes down for the reasons they stated.

[DrDread]

Sorry...didn't do a search for "reeding" or "grooving".

Found it.

[Connollys]

Reeds always down

Cheers

[UteMad]

Really simple one ribs DOWN

Ribs are to give ventilation between the top of the joist and the underside of the decking

cheers utemad

[Geebung]

I know of one instance where the deck was being installed with the ribs facing up - the reason the tradie gave was for traction in wet weather. Luckily the person having the deck installed caught him before he had laid too much decking. He told him to rip it up and put it around the other way.

Logic would dictate that ribbing facing up would not only rot the timber underneath where it hits the joists but also it would also allow water to sit on the deck (in between the ribs) for longer (no ability to run off) and hence degrade the wood faster...but then again logic doesn't always come into it.

What reasons did the tradies give for ribbing facing up?

[Dr - 307]

What about all the 140mm decking that is dressed on both sides (no ribbs)?

Dr - 307.

[Brickie]

What about all the 140mm decking that is dressed on both sides (no ribbs)?

Dr - 307.

In that case the timber has to be laid on its edge.....

[DrDread]

In that case the timber has to be laid on its edge.....

.....That would be called dicking...No?

[UteMad]

Gees that'll incrase your lineal to m2 rate to something like 40 lineal / m2...

Might try that as a new selling pitch could be a winner but i would need seriously long screw to fix it down

Food for thought thanks bricki


cheers utemad

[Terrian]

Gees that'll incrase your lineal to m2 rate to something like 40 lineal / m2...

Might try that as a new selling pitch could be a winner but i would need seriously long screw to fix it down

liquad nails FTW

[UteMad]

Never thought of that ... a shot of liquid nails on the joist and a brad driven through on the angle would do the trick.. we definately are onto a winner here.. i can hear the timber merchants getting ecited already


cheers utemad

[Bloss]

Funnily enough I built a deck once with the decking on its edge - the look being sought was for a 'grid with depth' and as client is always right that's what I built.

Just used threaded gal steel rod steel rods hole drilled through face and a nut between each board as a spacer. It was not a huge area (3m x2m) and I used timber of identical lengths. A little fiddly, but simple enough. It was being painted so was primed and painted before assembly then put together. Used brackets underneath to attach to joists which were spaced at 900.

Solid and good looking result, if not my to own liking . . .

BTW - flutes DOWN

[zathras]

Definately flutes down for appearance sake, and least chance to retain water up top.

Now playing devils advocate, would it really matter if you are laying treated pine planks (uggh) over treated pine joists?
Most caravan park cabins I see are done just this way, and everybody assumes it is right for grip.

[UteMad]

Definately flutes down for appearance sake, and least chance to retain water up top.

Now playing devils advocate, would it really matter if you are laying treated pine planks (uggh) over treated pine joists?
Most caravan park cabins I see are done just this way, and everybody assumes it is right for grip.

Yeah it will matter as treated pine grows algae as bad if not worse than hardwood.. Also treated pine dries out worse than hardwood and splits sooner with the little ridges curling up like spikes making the deck unwalkable in bare feet in a not so long time frame if exposed to a lot of sun... Treated pine decking might not rot in the way hardwood does but it deteriorates in its own way which still renders it useles

cheers utemad