Pressure Treated vs Oak

[Justin Edmonds]

Ok, quick question for barn repair. The original structure is made of oak. Since I am having to replace parts of it, including flour joists wall studs, and a post or two, which would be better, pressure treated or oak? Is there a difference? Is one better?

[Mike Henderson]

Ok, quick question for barn repair. The original structure is made of oak. Since I am having to replace parts of it, including flour joists wall studs, and a post or two, which would be better, pressure treated or oak? Is there a difference? Is one better?
In this area, oak will be more expensive than pressure treated. I'd use pressure treated.

Mike

[Justin Edmonds]

Ok. Can I use the same dimensions or would I need larger pieces of lumber?

[Rich Enders]

Justin,

If you use pressure treated make sure it is hidden/covered/protected. I stored half dozen cut-offs of the new (brownish) PT outdoors and in six months of sun (lots) and rain (little) it is worthless. It has all twisted and split. I don't know if the old (greenish) PT was better in weathering, but this stuff is terrible.

[Art Mann]

There are different grades of pressure treated lumber. The material rated for earth contact will last as well or better than heart white oak and is quite a bit cheaper (still pretty expensive though).

[Justin Edmonds]

Glad I asked. I didn't know that.

[Kevin Bourque]

I'm a building contractor, and I live on a farm full of old barns so I've done this before.

White oak is very resistant to rot and has been used for centuries on barns for that reason.
Pressure treated lumber is fine for most applications, but if it touches the ground you'll need to use ground contact rated material.
Oak is also much stronger than PT lumber so you'll need larger pieces of PT to get the same load rating.

Personally, I would use the white oak for the floor joists and the posts.( I'd also use black locust for the posts if I could find it in large enough pieces)
Treated would work for wall studs.

[lowell holmes]

+1 for white oak.

It is one of the best species for weather exposure and it won't poison the earth.

[Justin Edmonds]

The hard part is finding someone with the sizes I'm needing.

[peter gagliardi]

The hard part is finding someone with the sizes I'm needing.
Depending on where you are located??? You should be able to find a smallish sawmill within about 30-50 miles, and have them custom cut the sizes you provide. Rough sawn green, white oak should be quite reasonably priced. I get it all the time for little more than pressure treated in price.

[Aleks Hunter]

+1 on that sentiment. If you limit the "cost" calculation of a project to dollars, you have no idea how expensive it really is. White oak is far superior in every way. Buy logs and hire someone with a portable bandmill to cut exactly what you need. The dollar cost will be not a lot more than using the copper arsenide pressure treated pine.

[Justin Edmonds]

I'm in East TN. I'll look around and see some time.

[Rick Moyer]

Any livestock in the barn? What about feed, hay, etc.? Possible concern about pressure treated then, but I'm not sure.

[Mike Cutler]

Oak

I can show you 200+ year old barns as straight and true as they day were built. PT has a long way to go before it proves itself to equal oak.
I've torn down quite a few decks built of PT, and was stunned at how fragile PT gets over time, exposed to the elements. Especially the posts.

PT in a barn with livestock may be a no go based on local codes.

[Sid Matheny]

In East Tennessee you should be able to find several small sawmills willing to supply what you need but you may need to dry it yourself.


Sid

[Justin Edmonds]

Thanks for the input. Right now, no. There isn't any livestock or hay. However, that could change. The only problem is, I need at least a 20-22' 6x6 before it snows. It completely rotted out at the base and isn't holding anything. Thank you crazy great-uncle who never fixed anything...

[Jim Andrew]

If this is a post, could you not splice it at the floor joist line? You could cut off the old one centering on the floor joists and plate over the splice for strength.

[Justin Edmonds]

That may work on some of the posts in question, I have 12 to deal with on this shed of the barn. However, 1 is completely shot. The reason I'm considering replacing them is, the posts in there now, appear to be pine or something that's really kinda old and are rotten at the bottom due to decades of neglect.

[Kent A Bathurst]

Me - I would use PT for the posts and joists. As noted, I would be sure to get Ground Contact at minimum - but would prefer Critical Structure, at least for the posts. Those are labels for the level of treating chemical in the wood. n "Above Ground" is for fence pickets, decks, etc. And for joists, to be honest, but for your project, I'd still get AG for the joists.

Yes - if you leave it sitting uncovered outside, it will get ugly. If, instead, you are putting it inside - and doing the framing work to tie it to the other components - you'll be fine.

More readily available. Less expensive. You need to go to a local or small regional lumber yard - the big box guys won't have easy access to those big posts.

Full disclosure - the company I work for is the leading producer of PT lumber in the SE. I don't work on the PT side of the business. I am not prosthelytizing for the industry. It's just that I have a pretty good knowledge of the product and what it's performance capabilities are.

[Jim Andrew]

Are the posts buried in the ground, or are they sitting on a foundation? If the old ones are buried, I would make up some anchors, and replace the portion in the ground with concrete and anchor that holds the post a small gap above the concrete. Have you seen the steel anchors Morton buildings uses? I built some similar anchors using 1/2" by 5" plates, about 3 feet long, so that half of the anchor went into the concrete, and half the anchor goes up to accept the post. I drilled holes so bolts could go through the post, and used a piece of channel iron to hold the post off the base. They look like an H before putting into the concrete. There are also holes below grade in which I put short pieces of rebar, so the anchor is well held by the concrete.

[Justin Edmonds]

They were sitting on cinder blocks turned on their side, done before my time. That was the problem. Cattle hit them and knocked them into one of the block's holes, leading to leaks. I was thinking of putting the new posts in about 2-3' in the ground and hitting them with concrete. I had thought about doing concrete columns going about 2 feet above the ground. I know what you're talking about on the brackets. I've used them once before. Been a while. Usually I use something that's been rigged up.

[Peter Quinn]

I'd use the oak, its probably a bit more expensive than PT, but a lot stronger over span than yellow pine. For wall studs…it matters little if they are not in earth contact, probably untreated is a better call in the stud of your choice, yellow pine may be the local choice, here in New England we use doug fir. Not sure how the pacific northwest got to be closer than South Carolina from here, but almost all the dimensioned lumber is DF. If this is a post and beam barn I'd at least keep all the structural members consistent in species to avoid having to splice in larger timbers of a weaker species. There is a mill a stones throw from me, and a few more within 100 miles that mill beams for barns. I bought a few 18'+ WO timbers for a porch repair, something like #3 common, maybe #2 depending on who's grading, 8X8's, full dimensioned, it was actually much cheaper than buying similar lengths in a 6X6 SYP PT.


Poke around the net and you can fine span charts for different species, WO is vastly stronger than most soft woods, and its a joy to lift too! You may want to check the span charts for the parts you are replacing should you decide to go with an alternative species.

[phil harold]

And we Have a Winner!




Poke around the net and you can fine span charts for different species, WO is vastly stronger than most soft woods, and its a joy to lift too! You may want to check the span charts for the parts you are replacing should you decide to go with an alternative species.