Treating lumber--what do you think about.....

[azmtnman]

    I am in design stages for building a pole building for a house. I want to use my own lumber (6x6 posts). I looked online a found a recipe for home-treating lumber with borax and boric acid. Anyone ever use this?
   My main frame posts will be "dry" as it will have a 8' covered porch on all four sides and concrete floor. Would they even need to be treated? (I'm guessing yes--for bug prevention) My climate is fairly dry but we have a rainy season.

[Kbeitz]

My recipe is 50/50 diesel fuel and roofing tar. Works great for me. This building was built 35 years ago with soft pine. No rot anywhere on it yet.

[Deere80]

I do the same thing as Kbeitz but use 25% diesel 75% roofing tar and heat it up in a metal bucket to mix it together then paint it on the post.  here is a hunting shack I built with 8x8 posts.

 

[Georgia088]

Interesting.  This "tar/diesel" paint you apply works well enough to set the posts in the ground? Or, are you only using for above ground applications?

[nybhh]

I'm very interested in this too.  

I'm milling lumber for a bridge across our creek out of EWP that I'd like to last a while.  I'm pouring a concrete pad on each side of the creek for the 10"x10" timbers to sit on to keep them off the ground and decking the bridge in 2x8s.  Was also thinking about using Rustoleum Creocoat but could see using the tar/diesel mixture on the timbers and the creocoat on the decking.  Does anyone know how this creocoat holds up compared to a regular oil or water based stain?  

Sorry to hijack  :-[

[Deere80]

I use it for under ground, the posts are cedar.  You could use it for above ground but you rub against it you will be full of tar.  I did the same thing on a 48'x40' pole barn.

 

[Kbeitz]

My gazebo sets 1/2 in water. With the 50/50 mix after a couple weeks nothing rubs off nothing. It's the same mix I used in my solar kiln.

[azmtnman]

Was also thinking about using Rustoleum Creocoat but could see using the tar/diesel mixture on the timbers and the creocoat on the decking.  Does anyone know how this creocoat holds up compared to a regular oil or water based stain?  

Sorry to hijack  :-[

I'd be interested to know about the Rustoleum product too.

[YellowHammer]

Kbeitz, nice place on the water.  

[azmtnman]

I use it for under ground, the posts are cedar.  You could use it for above ground but you rub against it you will be full of tar.  I did the same thing on a 48'x40' pole barn.

Nice building!
I see you are in ND. Are those trusses on 8' centers? What's the snow load on those?

[loganworks2]

If you are going with a cement floor in the house you could pour a monolithic grade beam slab. Then you do not need to have any wood in contact with earth. 

[azmtnman]

If you are going with a cement floor in the house you could pour a monolithic grade beam slab. Then you do not need to have any wood in contact with earth.

Had to Google that!
We call that a "foundation" here.
I'm going with post frame, or pole building, for quick, inexpensive and versatile construction.
I was hoping someone would weigh in on whether or not my idea of the posts being 8' inside the roof would keep posts moisture free.

[starmac]

I would sure think they would stay pretty dry, especially in your area.

[reswire]

There is a site called Poles Inc., that sells copper napathate for $200 for four gallons of concentrate.  If you mix it at 2% (strongest sold in stores now is 1%), with diesel fuel, you can get 20 gallons total.  My dad used it 25 years ago on untreated 2x4's, and they are still solid.  He laid them down for a walkway in the swampiest part of his land.  I'm impressed every time I look at them.  I've used this for fence posts on my farm, and 5 years later, no problems  (I coated poplar 4x4's).  I've been told that it works best on green lumber: the green wood will allow the mix to penetrate where dried wood will not.

[Don P]

But I wouldn't bet the farmhouse on these methods.
The footings under the columns and the columns themselves are your foundation.
Borates do leach into a "sink" like the earth if and when the wood gets above about 25% mc.

Nail laminated columns are another way, using treated below the splices and untreated above.
http://products.midwestpermacolumn.com/Asset/Nail-Laminated-Column-Design-ANSI-ASAE-EP559.pdf

Dr Bonhoff is pretty much the guru of that way of making post frame columns, many papers online by him.
http://www.constructionmagnet.com/frame-building-news/what-every-post-frame-builder-should-know-about-laminated-columns

Permacolumn makes a concrete post bottom and wet set anchors as well

This is the powerpoint Dr Manbeck uses in an introduction to post frame buildings, some good info;
http://www.woodworks.org/wp-content/uploads/C-WSF-2012-Manbeck-PF-TX-VA.pdf

[Gary Davis]

I have a deck used borate salts on it then coated it with coper naphthenate  (the borate will leach out if in contact with water)   the copper goes on an ugly green but after a month turns a golden brown ,I my built my deck in 03 still looks almost like new

[nybhh]

There is a site called Poles Inc., that sells copper napathate for $200 for four gallons of concentrate.  If you mix it at 2% (strongest sold in stores now is 1%), with diesel fuel, you can get 20 gallons total.

This is a great resource.  I just looked up the technical data on the creocoat (here) and it uses the same copper naphthenate plus some other chemical which I assume is what makes it black. That is $40 per gallon vs about $12.50 (including disel) for yours.  Mixing in a little roof tar might give it a more pleasant color than the green.  I have a gallon of this that I always used on the cut ends of PT lumber.  I just looked it up and it is 10% copper naphthenate (by volume) at $28 per gallon so that isn't too bad either but it is an awful green color as well. Looks like the concentrate that poles inc sells is 68% by volume. This is really great info everyone!  Thanks for sharing.

[azmtnman]

Great info, guys! 
I'm learning a lot!

[Larry]

Having worked as an outside plant design engineer for a telephone company I learned a lot about treating poles. Bell Labs spent years testing every combination of pressure treatment known. I learned its not an exact science with a lot of variables, some we don't understand. I've seen in service 100 year old poles just as sound as the day they were planted. Also seen poles a couple blocks away with rotted butts after 30 years. Same species and treatment. The design life of poles is 50 years meaning they are expected to last that long before failure.

A couple of things I learned. Pressure treating normally only penetrates a couple of inches. All poles crack leaving untreated heartwood exposed. Rot normally starts in the center of a pole. Most of the strength of a pole is in the outside shell.

For outbuilding construction, I'm sold on nail laminated posts. Since the treated part in the ground is 1-1/2" thick, complete penetration of the treatment is assured. Don provided a couple of links to well designed laminated posts.

[starmac]

Question for the op, are you running your poles through the concrete slab into the dirt under it?  I would think even though your poles are back 8 feet from the overhang, they will still wick moisture from the ground.

[azmtnman]

Question for the op, are you running your poles through the concrete slab into the dirt under it?  I would think even though your poles are back 8 feet from the overhang, they will still wick moisture from the ground.

Yes. I was hoping the 8' covered perimeter would limit moisture contact. There isn't much moisture to wick from the dirt I wouldn't think. We get 3-4' of snow (winter average) and some short downpours in the summer.
Soil is well drained and humidity is low most of the year. I wonder if those posts would ever see moisture after the floor is poured and the roof is on??

[starmac]

I guess I don't understand why you want the post under the concrete, I would prefer no ground contact with them myself. I guess it is possible they last forever, but what a wreck if they don't.

[nybhh]

I agree.  If you are pouring a slab, set some lag bolts into the wet concrete at your post spacing and come back with these.  That is a 4x4 but they make a  6x6 also.  Makes it a breeze to replace post if you ever need to.  We did this on our deck and one of the PT post warped real bad when drying out so we came back and replaced it later, was a breeze.

[Kbeitz]

Not treated and touching the ground... Will get termites ...

[azmtnman]

I agree.  If you are pouring a slab, set some lag bolts into the wet concrete at your post spacing and come back with these.  That is a 4x4 but they make a  6x6 also.  Makes it a breeze to replace post if you ever need to.  We did this on our deck and one of the PT post warped real bad when drying out so we came back and replaced it later, was a breeze.

You'd have to pour a foundation under those. 
In a post frame/pole building, the underground part of the post is your foundation.