Glulams For Exterior Work?

ksensen

Need a little help and advice. Have a customer that owns a furniture store. There's a full wrap around porch @110' long. Porch posts are 6 3/4 square. With a pegged mortise and tenon brace. (purely a decorative detail) Problem is all the posts are rotting out. Upon closer inspection they are all glulams. I would never think of using glulams in an exterior use- but is this something that is common?- They have been painting with a good oil based paint, but they are only 12 years old, the owner has already cut off the bottom 2' on almost every post and replaced them a couple of years ago. My main question is, what would be best to replace them with? We would like to preserve the look of the mortise and tenon brackets. I am afraid that 6X6 treated posts will be prone to splitting. My other thought would be redwood but concerned about the cost. Any other suggestions?

pkp

6x6 is the only thing I would think to use. If the owner does not want to see splits, (minor splits are normal in 6x6 'es but I have never sen one split to the point where it lost structural integrity) then wrap it. It can be a little pain in the butt to wrap it with plywood because then you have to miter and if the 6x6 has the heartwood (which all but the most expensive ones will) then it will be slightly convex due to shrinkage. It's much easier to use dimensional wood and butt the joints, nail on opposite sides, then nail on the other two either slightly proud or slightly recessed from the corners.

...if that makes sense?

dlcj

u dont want to use pt 6x6s on something u what to look nice. they would be fine if they stayed looking new, but they wont. they dont split wide open but some will twist and bow on ya especially if you put them up wet. we started building post up similar to what pkp said. just as strong and dont trist or bow. If you wish to keep the solid post look id use cedar 6x6 or 8x8s and recreate the braces and all. Comparible to the cost of pt and certainly less than redwood. And less work than building all those post. just copy what is aready there.

JustaFramer

Yeah they make glulams for exterior applications. PT'd with no grooves.

karma_carpentry

Comparable price to PT ? Around here it's $50 for an 8' white cedar 6x6. And they check like mad too, just like the PT 6x6.

Maybe you can do something with 4x4 PT and box them, and make some kind of brace detail that looks good. If it's a faux look anyway... not functional.

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karma_carpentry

Here's a link you may want to look at. Concept is to make boxes as posts, giving the illusion of solid wood, including fake pegged braces.

http://www.ronhazelton.com/howto/rus...am_archway.htm

Instead of butt joints, the boxes are mitered & glued. If you get really ambitious and have the budget, I'd suggest routing the edges with a lock-miter bit on a router or shaper table. Much stronger, never come apart. With that construction, I think it would be adequate to support a single roof with no 4x4 inside.

__________________
Build on a good foundation.

WNYcarpenter

Whatever material you use, keep it off the deck with galvanized/cedar/PT bases with channels so the posts arent wicking standing water.

Of course we ALWAYS remember to prime and or seal the end grain before installation