Did I make a mistake?(wood choice for outdoor pavilion)

[tnbison]

Good morning, 

I joined a couple years ago when I was thinking about building a timber pergola.  Although that project never happened(went with a shad sail instead), I have ordered timbers to build an 18'x25' pavilion.  This was ordered through a log home building in Missouri.  8x8 posts, 6x12 header beams across posts, 8x12 collar ties between header beams, 4x10 ridgebeam, and 4x7-1/2 rafters.

The posts are white oak but everything else is red oak.  I had asked about wood preservation when I spoke with the company and he said they used oak to build ships.  I didn't really give it another thought.  Now it's my understanding that red oak has very little decay resistance.

Being as the red oak will mostly be protected from rain except maybe the gable ends and rafter tails, do you think this will be ok?  Obviously with the money I'm spending, I want this thing to last a very long time.  I have put a deposit down on my timbers and now I'm just a bit nervous. 

The instructions from the log home company are not comprehensive at all.  Basically placing beams with timberloks.  I will need to figure out how I want to put it all together. 

I have attached any approximation of what I'm trying to accomplish.



 

[tnbison]

I am located outside of Memphis, TN.

[Don P]

Not at all. I'd borate the timbers well and then use a water repellant finish. A number of folks here like the Heritage line of finishes, basically something that will repel the majority of liquid water while letting any that does get in dry back out as vapor, the borate provides a level of decay resistance but is leachable so it is protected by the water repellant finish. Look up Bora-care, Timbor and Solubor. Since the timbers will probably be partially air dried I'd lean towards something with glycol to help penetration like the BoraCare. Was it Gastineau in MO?

[tnbison]

Thank you for the reply Don.  It wasn't Gastineau.  It was Schutt log homes.  Patrick was very helpful with any questions I had.  I priced them up from some mills in TN and they were still a better deal.

The "manual" for assembly isn't very detailed at all.  I need to figure out where I need mortise and tenon joints and where timberloks will suffice.  No engineering done on this one.  My experience level is pretty low.  I'm competent in woodworking and general construction but timber framing is new.  I did do a mock mortise and tenon knee/wind brace out of 4x4 stock a few years back and everything worked out.  Just took me a while.  I think my understanding has gotten better.  I've been watching a lot of Jim's videos at TheTradesmanChannel on youtube.  

[kantuckid]

If the white oak is the posts and the rest in red oak has more shelter from weather, once finished I see no issue?
The same question could apply to thousands of log buildings not made from white oak-it's all about staying above the splash zone down low and keeping a good finish on the rest.

[Brad_bb]

As long as wood can dry out adequately after it gets wet, you won't have rot issues.  Look at the old barns.  They used pine, oak, doug fir etc for siding and it lasted 100+ years because it could dry out properly.  Rot only occurs when wood holds moisture. 

White oak heartwood is more rot resistant than most because of it's vascular structure, it does not take in water readily once it's left.  You don't want sapwood because it's not rot resistant at all.  If you find sapwood on your posts, put that end away from the  ground.  Down low is where you'd have the most problems.  So how are you attaching the posts to the ground?  You need separation so they are not in direct contact with the ground because you don't want constant moisture contact.  You can install them on knife plates, or have pilasters coming up a foot above the ground and installing the posts with a lexan plate between the concrete and the wood.  You need to anchor them to the piers and there are several ways.  Timberlinx connector or knife plate would be my choice.

[cabindoc]

Good morning,

I joined a couple years ago when I was thinking about building a timber pergola.  Although that project never happened(went with a shad sail instead), I have ordered timbers to build an 18'x25' pavilion.  This was ordered through a log home building in Missouri.  8x8 posts, 6x12 header beams across posts, 8x12 collar ties between header beams, 4x10 ridgebeam, and 4x7-1/2 rafters.

The posts are white oak but everything else is red oak.  I had asked about wood preservation when I spoke with the company and he said they used oak to build ships.  I didn't really give it another thought.  Now it's my understanding that red oak has very little decay resistance.

Being as the red oak will mostly be protected from rain except maybe the gable ends and rafter tails, do you think this will be ok?  Obviously with the money I'm spending, I want this thing to last a very long time.  I have put a deposit down on my timbers and now I'm just a bit nervous.

The instructions from the log home company are not comprehensive at all.  Basically placing beams with timberloks.  I will need to figure out how I want to put it all together.

I have attached any approximation of what I'm trying to accomplish.


(Image hidden from quote, click to view.)

You have one of the premier water based latex stain companies located near Knoxville.  Perm-A-Chink.  Borate products for pre treatment to post treatment and as I said, water based latex stains to apply once the moisture content drops down below 12% or so.  And as others have said, keep moisture aware, off the ground, seal end grains, barrier between concrete and wood.