Fixing rotten pole-barn posts

[jwoods]

Hey all,

I've got a 28 by 35 pole barn, around 40 years old here on the farm.

On one side the posts are rotten, -right at ground level.  The barn is still square, plumb, and level (but looks like not for long)

The posts are 4 by 6, not telephone poles.

How should I tackle this problem? I've got a couple ideas but no need to re-invent the wheel since there's so much experience lurking around this place.

Thanks,

Joe

[bandmiller2]

Joe your a reasonably young fella and can use the building for a long time.I'd do one post at a time cut it off at good wood dig out the rotten piece put in a sono tube and pour concrete.They make steel brackets you nail or bolt to the post and set in cement.Frank C.

[Left Coast Chris]

Hi Joe,

You need to take into consideration of the lateral loading (wind) on the structure.  Your lateral load carying capacity was provided by the fixed base of the poles.  In other words they where taking care of the wind load.   As soon as you do what bandmiller suggests you are now pinning the bases of the pole.  No more lateral load resistance.   You will need to add properly designed knee braces at the tops of the poles or put in line footings with shear walls.      One mystery here:  4x6 posts are mighty small for lateral load carying in combination with vertical loading.   Likely the 4x6 posts will be over stressed with the side loading of the knee bracing.   

To get an idea, Im designing a 22 x 36 stand alone canopy that is 13' high.  It will have six posts that have to be 8x8 Douglas Fir with 6x6 knee braces to take the wind loading perscribed by the international building code (Calif adopted it in 07").

Good luck.   Suggest getting some engineering advice to come up with a fix for your location. 

[carykong]

I repaired my porch posts (6x6) by installing temporary jacks and cutting off the rotten end and then pouring a concrete footer and then a concrete post upward to support the butt of the post.  Not much lateral support with my repair but did add 45 degree bracing into the floor joists at the top of the post.

You could ,also, augment the lateral strength of your repair by an additional post installed next to the repaired post and bolting the posts together. This is a common solution for beach houses suffering from beach erosion and are no longer supported by the original posts.

[Qweaver]

I had to do this same job for my 24' x 36' shed.  We bolted a temporary 4x6 about a foot from the rotted post.  Cut off the old post and dug a new hole right beside the old post...pulled the old post out and put a new treated post back in.  I'm glad that we had not concreted the old posts in.  This was all because we took bad advice on what kind of trees would make good posts.  This was a slow, hard process and I'm not sure there is not a better way.  But it was all I could think to do and it worked fine.  We did about 3 a day.   It was an open sided shed and the job would have been much harder to do this way if there had been siding to deal with.
Quinton

[iffy]

You might want to think about the way Morton builds their buildings. They use laminated posts with the bottom portion made out of treated 2 x's and the upper portion made out of untreated 2 x's. You could do one post at a time by putting in a temporary post beside the old one as mentioned before, then digging out the old one. Make up a laminated post out of treated 2 x 6's or 2 x 8's. Use different lengths for the laminated post so that the joints in the next step are staggered. The post just needs to come out of the ground a few feet. Place it in the hole, plumb it, and pour the concrete. When it is set up you can add the top portion of the post by laminating the proper lengths to reach the desired height. You could put some thru bolts in the joint area to strengthen it if desired. Still may want to think about a wind brace at the top.

[ljmathias]

Just for general information, doesn't all this with rotten poles that were not pressure treated set in or right on the ground?  Rot happens...

Lj

[HOOF-ER]

Fixed a pole barn last year with rotten post. Went to the local salvage yard and found some 4" angle iron aprox half inch thick. Dug out the post and bolted these to the post about 3-4' above grond level and poured the base into concrete. Lots of work no more post rotting off  These shoul handle the lateral load ,   oh these were 6x6 post though.

[jwoods]

Thanks guys,

The surprising thing is that these posts are treated, looks like creosote.  I've got some work ahead of me, will try to snap pictures and document along the way.

Joe

[Farmlady]

I noticed that two of the 18 poles in our 40 year old pole barn have rotted off at the ground.  One of the poles is holding a stall door, the other is  center back at the wall between two stalls.  I have talked to several contractor/repair men and all have said high dollar amounts, and complicated repairs.   I helped build the barn and am not a "spring chick" but wondering if my repair idea would work.  
 
Since the poles are NOT supporting anything, could I do this?

1.  Put in a temporary 2x6 support on each side of the rotted pole.  Bolt or screw in place on the rafter above the bad pole and bolt it to a section of another 2x6 "Td" at ground level to keep in place.
2.  Cut off the bad pole about 20 inches above the ground, enough to get a drill and long bit in place so I could drill several holes in the ground part and the bottom of the cut off pole.
3.  Dig out the rotted bottom of the pole until I was well into the concrete  (I remember the poles were set into 3' deep holes)  
4.  Drill holes in the ground part and upper part of the pole so I could slip re-bar up into the top and drop down enough so that the final position will be about a foot into the top and into the ground section.  (Make sense?)  Maybe 3 or 4 re-bar rods (Probably need to wire together.)
5   Frame the poles (Old telephone poles) with treated 2x12s to form a box from ground level to about a foot onto the cut off upper pole.  
6.  Fill  the form with concrete  the front part of the form would have to be added in sections to be able to add the concrete.  
7   After the concrete was all in place I thought I should put threaded rod or bolts through the 2x12s and concrete in both directions and through the top pole.
8. I am thinking that the pole should be cut off at an angle to make it easier to tamp in the concrete.   :-\

I am thinking maybe $50.00 my way.  Compared to their way of digging out the poles and replacing at over $2,000.  : Am I missing something.   I am almost 70 but tough and have all the tools I need and know how to do everything I am talking about.

[Handy Andy]

  Morton buildings repairs rotted off posts the way Frank C. said.  My neighbors have had some repaired, looked like about 5" flat metal bolted on both sides with bolts through the post, and post dug out and replaced with concrete. 

[PC-Urban-Sawyer]

FarmLady,

I think your repair will last a long time...

And if you can do this yourself I think your a REAL lady...

Herb

[beenthere]

Farmlady
Tough as nails and I say go and getRdun.

But we would like pics, for sure.

Some before pics would be good, in case someone can come up with a better idea that would help.

Welcome to the forum.

[Woodwalker]

We use a lot of these http://www.osmoseutilities.com/content/pages/c-truss-and-c2-truss
Place them against the butt of the pole and push in with the boom, leave 5' or so out of the ground and band to the old pole. It's a lot faster than setting a stub pole beside the old one.
Galvanized angle iron or better yet, channel iron would work just as well. Dig them in if you don't have or can't get anything with down pressure to push them in, then through bolt together.

[wannasaw]

Another opinion...which I know are all based on economics, mostly...Support header, cut out rotten area, put in same or oversized new base in with or without concrete, install splice plates overlapping each 16" or so and it's stronger than the original due to the contrasting grain on the splice plates. It's true 2 boards make a stronger header than 1 board of eq. size. Here you will have 4 contrasting grains for the eq. of the cant. Weight is dead.

[Brad_bb]

I had an extension of my morton building 15'long by the 40' width of the building that was for cows to come in with one closed stall.   We don't have cows anymore so I decided to close it all in and insulate it.  I had 2 posts what were rotted off at ground level. 




1.  I cut the concrete enough with a rented wet saw to get access to dig with a hand post hole digger.  I also rented a concrete hole saw so that I could cut the corners with a radius and prevent cracks from this area, plus the saw could not get into the corners.
There was concrete on the bottom of the post that had to be broken off the post in order to free the old portion.  The lower portion was solid because it was always wet.  Rot only seems to occur in the presence of both moisture and air. 
2. I went to the rental place and they sell these long iron chisel bars probably 5 feet long, with a chisel point on one end , and a mushroom on the other so you can hit it with a sledge hammer.  My cousin and I did this together.  We took turns holding the bar while the other hit it with the sledge.  Trust!
3. I then took a long timber screw and drove it into the rotted post, attached a chain, and used a T post remover(lever) and worked at removing the post.  It pulled out a couple times, but finally got it into some solid wood and slowly got the post out.  More chiseling was intermittently needed.
4. We then worked to remove all the concrete pieces from the hole.  This was not easy as you had to do more breaking up with the chisel and sledge, and lay on your stomach to reach down in the hole and try to wiggle pieces free.

The repair.
Since the posts are 3 laminated 2X6 (nailed together), I cut above ground each 2X6 in a different location and then made up a post extension of treated 2X6 SYP.  This way the all the boards over lap as they did originally for the most strength.  I fastened them with nails and timber screws.  IMPORTANT:  Before I installed the repair section, I slipped a "Post Protector" sleeve on, which is a plastic sleeve that prevents the wood from contacting the earth.  It also allows the post to breath above ground.  From that point, we mixed up some concrete and dumped it in the hole to cover the lower portion of the post protector to help provide rigidity against soil, and then back filled with the old dirt.  I then drilled the old slab with holes for redhead anchors installed horizontally to help anchor the old slap to the new concrete poured to replace the cut area.  I floated it  and it worked great.  I later actually epoxied the floor so you can't even see it anymore.  Sorry I don't have an "during" photo, but here is a finished photo which shows the post protector.  You would not want to use one on an outside repair as the sleeve would hold water, only for an inside repair that rain water wouldn't get to.  Any new pole barn should use these, they'll double, triple or more the life of the posts from the original 20 year life.

[jwoods]

Thanks everybody, I love this forum for new ideas.

Woodwalker, I think I may try an adaptation to those c-truss units, just need to find some galvanized channel or angle-iron.  My posts are 4*6.

I think if I dig on either side of the pole and leave it intact, pour a 6-inch thick pad and set the iron (with welded foot attached) on top of the cured concrete I can repair without trying to remove the old post.  I can then through-bolt the iron above-ground to the old post.

Joe

[Woodwalker]

That's probably the least labor intensive method Joe, and it'll be there for a long time.

[Holmes]

A shop vacuum can make digging out the holes and posts a lot easier. Take the filter out of the vacuum and suck up all the loose dirt and rocks you can . As the hole gets deeper put an extension on the vacuum. You will be suprised how large a rock [ 4 to 5"] can get held onto the vacuum pipe and be pulled out of the hole. Make sure you point the exhaust away from yourself.  Holmes