Western Red Cedar 5/4 x 6 Deck Board Fastening & Finishing

by Van G
(Toronto)

I've got my two decks all framed up and I'm ready to lay down the boards. When I started out we had planned to use Ipe, but then we added a second deck, post and beam features...... You get the idea.

Job Specs: Location = Toronto, Boards = 5/4x6 Western Red Cedar #2 or Better Knotty, Two Decks = 640 sqft, Finish = UV Seal

I hope to get some consensus on best practices for the following:

Fastening: How should I fasten the boards? Top or Hidden

Which hidden fastener system works well with WRC?

If face screwing, which screws should I use and do I need to pre-drill?

Protecting:

I would like to preserve the warmth and natural tone of the finished deck. I plan to use a UV sealant like Cabot. I realize this will involve washing the deck semi-annually and hopefully seal every other (or more).

If this was your deck and you had plenty of hands to help, would you pre-finish boards: sand, seal, cut & end seal?

What is best practice?

Board Pattern:

I picked up a FHB deck magazine a couple weeks back which showed a nice board detail on an Ipe deck. Can't remember the specific pattern name, but it was a picture frame border, 3 courses wide, butt joints which used a biscuit joint for strength.

Can I still attempt this pattern with WRC, or is it too soft?

Comments for Western Red Cedar 5/4 x 6 Deck Board Fastening & Finishing

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Jul 21, 2010
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Using cedar
by: Editor - Rich Bergman

If you really want a great look and longer lasting deck boards, the hidden fasteners, either underneath or side mount are nice. I am thinking of Shadow Track and Tiger Claw to name a couple but there are other good products too. There are no holes in the deck surface for water or dirt to accumulate.

But using side fasteners is not as strong for the overall stiffness of the deck as compared to using screws from the top side. As a result you may wish to consider adding blocking between joists at a fairly close interval. Yes, this is extra work and material but if you are going for the high end look it is worth it.

Additionally many builders try to address this by using a construction adhesive like PL Premium undereach board. But if you use joist sealing strip like Grace ice and water shield then you would be gluing to the top of the water shield not the joist. Something to think about.

But the glue in combination with the joist blocking is your best bet when using side mount fasteners if you want a low chance of squeaking or moving deck boards over the long haul as they expand and contract, which cedar is known to do.

Top side screws in cedar usually don't need to be predrilled except when you get close to the end of a board to prevent splitting. But Splitstop makes a great fasteners designed to greatly reduce the chances of this. The composite screws - intended for composite material - have a thread near the top of the fastener head to pull down fiber to prevent mushrooming. Works great for composite but don't know if it will work the same for cedar which is quite soft.

A sealant like the Cabot stain will require annual sealing at a minimum but if you keep the deck clean should be fairly quick to do. Sanding, sealing and sealing the end cuts is great but more time consuming. Sealing the ends is always a great idea because that is where moisture is wicked into the board.

I know the FHB article you are referring to. That is a great look but requires planning to design your joist layout to accommodate it. I would recommend using a sealing tape like ice and water shield adhesive to go over the joists and reduce water damage over the long term. There are also extruded joist caps for that purpose and you could also use a heavy felt paper. There should be no reason why it won't work with cedar. Just ensure the framing is stiff.

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