Cedar posts for pergola

[mreza Salav]

I am thinking of building a pergola/gazebo out of cedar to be located on our deck. Most 6x6 and 8x8 cedar posts I can find have quite a bit of cracks/checks. I know structurally it is ok but for aesthetic reasons I like to hide the checks/cracks. Is covering the posts on 4 sides with 1x6 cedar glued on a failed attempt? There are hollow 6x6 posts that are made from 2x6 material that look better but I want the solid ones.

[John K Jordan]

I am thinking of building a pergola/gazebo out of cedar to be located on our deck. Most 6x6 and 8x8 cedar posts I can find have quite a bit of cracks/checks. I know structurally it is ok but for aesthetic reasons I like to hide the checks/cracks. Is covering the posts on 4 sides with 1x6 cedar glued on a failed attempt? There are hollow 6x6 posts that are made from 2x6 material that look better but I want the solid ones.

Two posts on one porch on our timber-frame house are made with solid 6x6 posts sheathed with 4/4 rough western cedar to match the house siding. You have to look closely to see they are not made from single timbers. They are 30 years old.

In my last house I used jacks to hold up the roof over the carport to replace a painted 6x6 post, supporting the roof on that corner of the house for 50+ years. I was surprised to find it was made entirely from mitered 4/4 pine, hollow inside. I replaced it with a solid 6x6 PT post.

But if you are willing to cover solid posts with 1x6 cedar, another option might be to just use the hollow posts made from 2x6 cedar "that look better" then slide a solid wood or steel post inside if you want the extra support. I suspect, though, the 2x6 box alone would support a gazebo until well after your grandkids retired and sold the house!

JKJ

[Jim Becker]

I agree with John in that I'd go with something inside the "post" for support and construct a "nice looking" cladding for the corners the reflect the style of the construction you are making. Regardless, be sure that you put proper footings for the supports so that they are stable into the future.

[lowell holmes]

There you go, thinking about the future again.:)

[mreza Salav]

Sorry if I was not clear in my question: I want to buy 6x6 solid posts and then glue on (a thick veneer) out of 1x6 (planed down to 3/4" perhaps) cedar to cover the cracks/checks.
Is this OK or I might be missing something?

[Bill Carey]

Unless your pergola is 3 or 4 stories tall I think 6x6 is overkill. And certainly, if you are covering them with a cedar finish, why pay for cedar when PT would do the trick. If you use PT 4x4 for the structure, you can get the visual "heft" you're looking for by, as you suggest, adding the trim boards to the posts. You could pad the 4x4's as much as you like to get the visual effect you want. Another advantage of using the trim boards is that you can carry them down to the top of your pier, hiding the post anchors.

[Jim Becker]

Sorry if I was not clear in my question: I want to buy 6x6 solid posts and then glue on (a thick veneer) out of 1x6 (planed down to 3/4" perhaps) cedar to cover the cracks/checks.
Is this OK or I might be missing something?
I'd be concerned with glue lasting over time on a "wrap" due to wood movement if the mitered boards are glued directly to the posts.

[John K Jordan]

I'd be concerned with glue lasting over time on a "wrap" due to wood movement if the mitered boards are glued directly to the posts.

I'm concerned about glue too. Maybe construction adhesive - is it flexible? But if the boards are 3/4" thick how about nails (unless you don't want them to show.

6x6 does seem like too big for a pergola or gazebo, both for the strength and the look.

[Victor Robinson]

I'm confused by the responses to Mreza's question or maybe by the goal itself. You can wrap whatever you want, whether it's a cedar post or a PT one - it's just that glue isn't the best way to make the connection for a 4 sided wrap due to movement. How are posts for decks normally wrapped? Just nails or screws, right?

[mreza Salav]

Isn't the board and post move about the same rate both being the same species? It's not a cross-grain joint. I could use construction PL glue. Nails I prefer to avoid for aesthetic reason.

[brent stanley]

I am thinking of building a pergola/gazebo out of cedar to be located on our deck. Most 6x6 and 8x8 cedar posts I can find have quite a bit of cracks/checks. I know structurally it is ok but for aesthetic reasons I like to hide the checks/cracks. Is covering the posts on 4 sides with 1x6 cedar glued on a failed attempt? There are hollow 6x6 posts that are made from 2x6 material that look better but I want the solid ones.

Hi Mo, I would consider trying to find FOH (free of heart) timbers from a supplier as they will check and split a lot less. Get them a foot or more longer than you need them, and larger than you need and seal the ends up really well, and let them season in the shade somewhere for a year or so. If you are willing to use a different species, select one with lower shrinkage ratios. Then plane them down to the size you want once you've looked them over to determine if checking is not so bad that the planing won't remove it.

These folks offer all kinds of great options and will kiln dry for you too. https://www.westwindhardwood.com/products/timbers/

B

[Mike Henderson]

The only caution I'd offer is to question whether you're going to put a swing in the pergola. If you do, you'll have to make construction "stiff" so it doesn't move when you swing. I built a pergola for a swing and had some problems getting it stiff enough for the swing.

Mike

[Charles Coolidge]

Isn't the board and post move about the same rate both being the same species? It's not a cross-grain joint. I could use construction PL glue. Nails I prefer to avoid for aesthetic reason.

No. Go look at the end grain of those posts most I have seen recently the tree's center pith is dead center of the post and that's some crazy grain. Some of these posts look pretty straight but they are sopping wet, when they dry out they can go BOING in all directions! You could build up your posts out of several pieces of quarter sawn stable properly kiln dried lumber then apply your cedar over that.

[mreza Salav]

Thanks everybody. I'll experiment with laminating the posts.

[Brian Holcombe]

FWIW, you can usually order to spec from a true sawmill, so you could order AYC in clear VG rift sections if you were so inclined, though you will pay $28/linear ft for it in 6 x 6.

[Charles Coolidge]

FWIW, you can usually order to spec from a true sawmill, so you could order AYC in clear VG rift sections if you were so inclined, though you will pay $28/linear ft for it in 6 x 6.

I wonder if they make laminated beams in that size?

[jack forsberg]

here is how i do it .


https://www.youtube.com/watch?v=m_l4mKIcBHU

[Mark Hennebury]

Buy timber without the pith, or buy timber with the pith,but before it has split and run a saw cut down the length to the pith, let it season, then glue in a spline, dress it square and straight, and use it as is or, if you want ,sheath it.

[mreza Salav]

Looks very nice Jack. I don't want to paint it, rather use a transparent top coat (not paint) so that method won't work for my case.

[Mark Bolton]

Can I ask what your drive is to have dead clear, free of any checks, cracks, open knots, and defect? That seems to defy the laws of nature as a general rule and defies every law of commodity sawing of any reasonably affordable material for a lumber producer.

The want for a dead clear, defect free, post/timber would not be unreasonable but buying clear 2x material and boxing a post/timber would seem the smartest course leaving a small hollow core to leave a clear and stable end result.

As has been stated, all the timber material we have ever received from 4x4 to 4x6 to 6x8 and so on is all going to have pith. I would never trust laminating material over a post with pith. Too much potential for cup on the face, twist, wtc to guarantee the corners stay sharp.

I find myself often shootting myself in the foot in a focused pursuit of a single factor.

[mreza Salav]

Mark, as I said in my first post it's only for aesthetic reasons. I know 2x material also develops cracks/checks but my experience has been those are typically much smaller (micro) cracks vs. the much bigger/wider cracks that develop in 6x6 posts.

[Mel Fulks]

I wouldn't trust any thing glued to the posts. I've done a number of columns by building with pressure treated post covered with wood or EXTERA mdf wraps lock mitred. Glued them up in shop with ONE SIDE UnGLUED. All who buy them are happy.

[jim mills]

Around here, there are a couple fence & deck suppliers that carry much higher quality cedar than can be had at the BORG, or even "reputable" lumber yards. I can get 6 x 6 and even larger sizes with NO PITH! That's really the secret.

[Mark Bolton]

Mark, as I said in my first post it's only for aesthetic reasons. I know 2x material also develops cracks/checks but my experience has been those are typically much smaller (micro) cracks vs. the much bigger/wider cracks that develop in 6x6 posts.

Right? So why wouldn't you just miter 2x6 (or even 4/4) material. I haven't read back but it seems I recall you dont want a hollow post and would rather solid. And my question is when even the post perfectly sawn and dried 6xy may not meet the standard (perhaps $50/bd ft if it were ever even available in the market) why would a hollow post be objectionable?

A 6x6 free of defect rarely if ever occurs in nature. So the only option is to box it. So box it?

[Charles Coolidge]

Maybe a lamination could also be aesthetic, a laminated post of 1 or 2 inch cedar with some flush, exposed large wood dowels through it for aesthetics?

[mreza Salav]

Mark, I'm unsure if a hollow post will be structurally acceptable to carry the load of snow around here. It will be a 18'x14' structure with 6 posts and will require a permit and inspected by the city.
My thinking was to start with 4x4 cedar and laminate on 4 sides 5/4" cedar boards to "build" it up to a 6x6.

[Brian Holcombe]

Here are some resources for you in this decision:

https://thecarpentryway.blogspot.com/2015/01/gateway-27.html

https://fabulalignarius.wordpress.com/2016/05/17/black-forest-zendo/

[Wayne Cannon]

I have some questions about gluing the wrap to the internal post. I just did something similar around interior 6x6 posts. The problem is in achieving nice "invisible" joints in the wrap due to minor irregularities in the inner post. I sized the inside of my 3/4" wrap slightly larger (1/8" each side) than the inside post, and anchored the wrap to the post with glued shims and non-expanding foam so there was no hollow sound -- probably superfluous for a solid 2" wrap.

[Glen Gunderson]

I've used the same technique as Wayne where you make the interior of the wrap slightly larger than the outside of the solid post which protects against most irregularities you'd run into with normal wood movement. In my case I was doing a sort of frame and panel covering with rails and stiles, so allowing room for movement was absolutely necessary because the wrap wasn't going to expand across its width at all. But the same logic could be used with a solid lumber wrap as well.

Both the interior and exterior posts I did like that have held up well for over 10 years now so I think it's a viable method as long as the design allows for it.

[Mel Fulks]

Yes. Agree with Glen. We just blocked the structural posts nice and plumb. People love them! Like anything they can be poorly done,I've seen some wraps that just rattled around ...mostly on commercial buildings like grocery stores.

[Mark Bolton]

Mark, I'm unsure if a hollow post will be structurally acceptable to carry the load of snow around here. It will be a 18'x14' structure with 6 posts and will require a permit and inspected by the city.
My thinking was to start with 4x4 cedar and laminate on 4 sides 5/4" cedar boards to "build" it up to a 6x6.

I hear you. I would however ask the building department. Hollow columns are very common in every climate. I would personally be concerned with keeping nice tight joints over time wrapping a boxed heart post. A lot will be dependent on what you have access to with regards to grade, MC, and so on. If they required a solid post for structural support I would go with a 4x4 and simply fabricate the 4/4 box to drop over top with some blocking to center the hollow box and then if the post were to move at all you'd be left with your dead tight box. Just my 0.02. We recently built pergola for a job that incorporated large brackets and we brought in a bunch of dead clean/clear 6x8 material. May take some hunting.

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[mreza Salav]

I guess I didn't mention this: I don't intend to glue the wrap directly to "not so straight/square" inner post. I thought of actually dimensioning (i.e. join/plane) the post and the 2x material and then glue them. Basically build up a bigger but straight/check free (for now!) post. The idea of having a gap between the inner post and outer shell is also something I have done int he past (the following post you see has an inner 2x material that is load bearing but the outer shell was built separately and then slide over the inner structural post:
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