OP
LD1
Epic Contributor
If you had to do it over again, would you go the trench route? or rent a machine with 18" auger?
Posts Footings: What do you prefer?
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If you had to do it over again, would you go the trench route? or rent a machine with 18" auger?
OP
LD1
Epic Contributor
So if I understand you, you dont like gravel OR a tile running next to the posts?
My concerns were the exact same actually. But kept reading everywhere online that said gravel allows for better drainage. But in my mind, it would seem to create a little french drain around the post. Thats why I tought about the addition of a tile.
As to the posts, as per tables and my soild type, I am guessing 3000-4000PSF bearing capacity. At max truss loading plus dead load, each post should see ~6000lbs. Thus a 2 sq ft or a little better pad. Certainly not just a post set in the ground, at least not in my area.
EddieWalker
Epic Contributor
Undisturbed soil is going to be the best at shedding water and have the highest load bearing ability. Once you dig that soil, everything changes. Getting it compacted to being as solid as it was before you started digging is impossible. When I worked construction in CA, we had to get it to 98 percent to pass inspection before anybody could build on it. That meant getting the moisture level perfect and vibrating it in lifts with heavy equipment.
You will never get the soil in a ditch or even around the post close to what the soil was before you started digging no matter what you use or how long you work at it. Not a criticism, it's just a part of building and something that has to be dealt with. With just dirt in the hole, compacted as good as you can get it, you will still get more moisture in that hole then the surrounding soil.
Adding rock to that hole now allows it to hold even more water. Rock mixed with soil means lower compaction and more voids for moisture. You are in fact creating a place to hold water. More rock, the more moisture you will have in there. This means less strength on the post, greater opportunity for rot and an attraction for termites.
Overbuilding is one thing, over engineering is another thing. I feel your trench idea is over engineering a simple method of building that has been proven to be very effective just the way it is.
Eddie
You will never get the soil in a ditch or even around the post close to what the soil was before you started digging no matter what you use or how long you work at it. Not a criticism, it's just a part of building and something that has to be dealt with. With just dirt in the hole, compacted as good as you can get it, you will still get more moisture in that hole then the surrounding soil.
Adding rock to that hole now allows it to hold even more water. Rock mixed with soil means lower compaction and more voids for moisture. You are in fact creating a place to hold water. More rock, the more moisture you will have in there. This means less strength on the post, greater opportunity for rot and an attraction for termites.
Overbuilding is one thing, over engineering is another thing. I feel your trench idea is over engineering a simple method of building that has been proven to be very effective just the way it is.
Eddie
OP
LD1
Epic Contributor
I certainly wasnt trying to over engineer it. Just trying to save time and money.
I need a trench along the north side anyway for tile as it slopes toward the building. I could have that 72' trench dug in an hour with equipment I already own. So was mainly wondering the feasibility of setting posts in there with the tile and be done.
I dont own a PHD bigger than 9". With our average soild bearing capacity of 3000psf, that leaves each colum only able to support ~1300lbs if I poured a 9" round pad in the bottom. With my building span and 8' center posts and snow load, I need to support ~6000lbs per post.
Thus would leave me spending $200+ and half a day with travel just to rent a PHD and SS. On top of still having to dig a trench, lay a tile, and back fill. I was just trying to kill 2 birds with one stone and be done.
But looks like I will be renting a PHD
I need a trench along the north side anyway for tile as it slopes toward the building. I could have that 72' trench dug in an hour with equipment I already own. So was mainly wondering the feasibility of setting posts in there with the tile and be done.
I dont own a PHD bigger than 9". With our average soild bearing capacity of 3000psf, that leaves each colum only able to support ~1300lbs if I poured a 9" round pad in the bottom. With my building span and 8' center posts and snow load, I need to support ~6000lbs per post.
Thus would leave me spending $200+ and half a day with travel just to rent a PHD and SS. On top of still having to dig a trench, lay a tile, and back fill. I was just trying to kill 2 birds with one stone and be done.
But looks like I will be renting a PHD
2manyrocks
Super Member
- Joined
- Jul 28, 2007
- Messages
- 8,677
I agree with Eddie that loosening the soil with a trench and then trying to make post construction work is going to create more work and the loose soil will be a problem. However, it shows foresight on your part to be thinking about controlling water run off on the site before you start construction. If it is primarily a surface water run off issue you have to deal with, sometimes the most effective means is to re-grade and cut a berm/ditch to divert water flow from your building site.
A picture of the site could be helpful to the discussion.
A picture of the site could be helpful to the discussion.
nybirdman
Super Member
We had access to a backhoe and the trench made it easier to work the forms ect.Back filled with the tractors we had on site.We wouldn't have done it any different if a large post hole digger was available.
As stated per code we had to have a reinforced pad with fixed dimensions an a very large post hole digger would have been required.
As stated per code we had to have a reinforced pad with fixed dimensions an a very large post hole digger would have been required.
farmer2009
Elite Member
I am not advocating this as I don't have any experience with it. But one thing I have seen builders in my area do is on the new PT post wherever they contact concrete they put atleast a 1/4" of roofing tar on the post. They say it will seal the water away from the wood. You have to remember concrete is also porous. Not saying it's a supplement for proper drainage or nothing like that.
On my Pole building we put in large 36" holes double concrete pucks, then backfilled with crushed limestone..its hard packed. Its not gravel that is loose it
I have started redoing my old wood fence posts this way they set tight and hopefully will last longer than the locust post in clay dirt
I have started redoing my old wood fence posts this way they set tight and hopefully will last longer than the locust post in clay dirt
OP
LD1
Epic Contributor
You you did a pole bard like I am describing by digging a footer? Any tips on how to pull it off successfully or how you did it? the whole back filling and compacting without damaging or shifting the poles thing?
Oldgreybear
Bronze Member
Our 40 yr old pole barn was installed using the following tools
Strong arm post hold digger
GroundWork® Post Hole Digger with Wood Handle - Tractor Supply Co.
Drive shaft from a Model A for a tamping bar
A shovel
and a saw.
it is 40 years old built using used utility poles for the uprights. They were dug down a 4 feet and tamped solid. The barn is 40x64 feet. with a full length loafing shed. The only posts to be replaced in that time have been on the loafing shed. This is really the best way in blackland to build a hay barn.
Strong arm post hold digger
GroundWork® Post Hole Digger with Wood Handle - Tractor Supply Co.
Drive shaft from a Model A for a tamping bar
A shovel
and a saw.
it is 40 years old built using used utility poles for the uprights. They were dug down a 4 feet and tamped solid. The barn is 40x64 feet. with a full length loafing shed. The only posts to be replaced in that time have been on the loafing shed. This is really the best way in blackland to build a hay barn.
