My ideas were:
1. building a high concrete pier and running at least 3 piece of rebar up through the post a foot or so, but its still sitting on concrete. Maybe putting tar shingles between the concrete and wood? Steel plates between them?
2. Then I saw the 2nd and 3rd pictures below and thought about using knife plates or brackets. I want to do a couple supports that have angles like the 2nd picture, so a bracket of some sort seems necessary, but I know they are incredibly pricey and hard to find. Know where I can find them? And I don't feel like just rebar is strong enough to brace such large posts (12-20" in diameter)
3. My other concern is I have plenty of yellow pines on my property and was going to use those as the beams, but would they be too soft to use as posts, even if I coated them with boat varnish or (god forbid) treat them with nasty stuff? And I didn't know if mixing harder wood for posts and softer wood for beams would work. I might be able to find some Black Locusts, and I know that would solve my problems, but it would be easier to use other wood like Oak, and I would like to eventually be able to show others in my area that we can use local wood. black locust is getting rather rare here.
Any ideas would be very helpful. I plan on getting Ben Law's book "Roundwood Timber Framing," but from what I have read he doesn't address anchoring in a vey detailed way or concerns of moisture seeping into the posts much.. and I didnt see any info on outside porch supports at all.
I would really like these structures to last a while so anyone with experience working with large wood who has any advice at all would be helpful.
we built our timber frame structure out of round wood (peeled redwood) and have them sitting on concrete footings, bolted in with "L" brackets. I also put tar paper on the bottom, and we varnished them. of the 15, only 3 are inside the house. well, there's a 4th that hold up the loft, made from a Madrone tree. you can see the sort of work we did on our blog. Here's a relevant page: http://journeyinthewoods.blogspot.com/2008/10/still-pegging-brackets.html
I've been building a roundwood henge framed home over the past couple summers. I did use a Behr's product for the stain and have not regretted it at all. All the wall caps are spiked into the uprights with massive nails then spiked to the following wall cap. The uprights are 'pegged' onto rebar set into the concrete footing below. The eves are 4' in hopes keeping moisture well away. I plan to bolster the joint with some kind of steel plate I fasteners. Here's some pix...
In some areas code will require that you also have a tie down strap.. so do keep that in mind if there is an aesthetics conflict
5/8 rebar is really all you need it is there to locate the bottom of the post .. remember you have a huge point load and with that much weight its not going to move unless you plan on running a bulldozer into the foundation
Wood should never touch ground and best practice would not let untreated wood touch ANY masonry. Treated wood will last longer if it does not touch masonry and can dry out after getting wet.
I couldnt find a link for the Simpson product we used on these log posts http://www.springtimehomes.com/files/img_2105w969918129.jpg
Rebar or Threaded rod is fine if done right. Be sure to use some type of metal (1/4" thick at least) or plastic to get the bottom of the post off the masonry. Epoxy can be used for the wood connection to eliminate the holes you get with the strap style hold downs.
The bigger the overhangs the better.
Do they have tricks for getting such a tight fit?
The timber framing of Asian is much more advanced, in many ways, than you find in the West. Center line layoff, templates and advanced scribing techniques have been practiced for thousands of years, well in advance of what was being done in Europe.
I suppose the "if done correctly" would involve the proper management of moisture and water.
You nailed it! It's all about the water. You can have it, but you have to deal with it in harmony with the material you build with. That is why so many of our historical structures have started to fail. We add things like concrete, foundations and "chinking," and the rot sets in. We have spent the last 70 years trying to reinvent the wheels of "good building practice," and have made more of a mess than a better wheel.
Of course wood can touch masonry if the masonry if is not exposed to much water or moisture. I have to wonder about the longevity of some of those applications though..
If done by a "Diaku" 大工 (master design/builder) or their equivalent, a naturally built structures on stone can have virtually endless life spans. If you just built one, using the old methods, and did nothing, (minus some major war, fire, seismic or climate event,) the structure would stand several centuries in livable condition, before becoming unsafe and melting back into the earth.
I'm building in Nicaragua and plan on using round wood. I built a tenoner out of pipe and a 4" Harbor Freight grinder with a 4" wood blade. I can make round tenons from 3/4" to 6" with my $60.00 machine. I intend to bury my posts 2' in the ground and will wrap the bottom three feet in two layers of fiberglass and resin. Has anybody done this? Any comments?
Gary Crays wrote:I have decided to make several "roundwood" post and beam structures, or at least using raw log posts as supports, but I can't figure out how to anchor them to the ground. I live in the mountains of TN and it is very moist here, so I am worried about moisture from concrete or stone seeping up into the logs via concrete piers and I plan on doing a few for porch posts outside. Any suggestions on anchoring?
I think that any anchor you decide on will work for you. Just keep the wood off the dirt and don't allow water to get to it and the wood should last more than a lifetime. If it makes you feel better, use some boiled linseed oil on it. Be careful to read the MSDS on BLO....some of it is not truly BLO and contains icky chemical dryers.
2 cents from a permies forum newbie.