Pole barn on plate?

[geog272]

I am working with a builder to design a 26X26 two story pole barn. I live in Northern New England. The gravel pad is done. I have only ever seen other people's pole barns done with the poles set into the ground, in a concrete footer, below the frost line, which I think means something like 4ft deep here.

This builder suggested that rather than setting posts in the ground, we do a "plate" consisting of pressure treated 2X8s that sit on the gravel pad, then the barn on top of that.

I am wondering if anyone has ever heard of or used this method, and if so will it hold up and be structurally sound?

Thanks in advance!

 

[DT86]

I have never heard of this, but that doesn't mean much. How do you secure the plate to the ground? What about the posts to the plate?

 

[Murfster3]

What is going to anchor the plates, it seems like to me with the frost you will have problems.

 

[Carl_NH]

No never heard of this method on gravel - as others state frost, anchoring etc will be issues. You need some footing/sonotube/post in the ground to attach the 2x8.

Also, 26x26 is not a 4' common dimension - like 24x28 or 24x32 so you have standard 4' O/C for materials.

Then 2 story, assume you will have 10 or 12/12 pitch, and have you decided on support for second floor, like posts or a steel beam, or using floor joists/trusses? There is a company in Biddeford that makes these floor trusses so you don't have posts or steel.

 

[Woody65]

I am working with a builder to design a 26X26 two story pole barn. I live in Northern New England. The gravel pad is done. I have only ever seen other people's pole barns done with the poles set into the ground, in a concrete footer, below the frost line, which I think means something like 4ft deep here.

This builder suggested that rather than setting posts in the ground, we do a "plate" consisting of pressure treated 2X8s that sit on the gravel pad, then the barn on top of that.

I am wondering if anyone has ever heard of or used this method, and if so will it hold up and be structurally sound?

Thanks in advance!

I am surprised a builder in the northeast would recommend this type of building. I have never seen it done or attempted it myself except for a small garden shed ( 8'x8'). There are two reasons to sink the posts. 1. To prevent settling/heaving in the winter/summer thaws and freeze. The other is to give the structure shear strength ( side to side stability). They can be bolted down to concrete pillars that are below the frost line. But not a 2x8 that is just sitting on top of gravel. A good noreaster and the poles would pull loose from the "plate" and topple the structure. Sill plates are used in stick framing and are bolted down to a concrete foundation every 4 feet or what the architect/engineer requires. Did he not explain his method fully?

 

[bandaidmd]

this is a great alternative to wooden posts in the ground.
https://www.permacolumn.com/

 

[Mike476]

Just built a 26X42 barn. Compacted dirt, laid concrete block, starter course of shingles on top of that and then 6X6 pressure treated as my sill, framed up from that. Just had over 100km/hr winds and driving rain last week, no anchors and building stood it no issues at all. A lot of wieght in a stick framed building.

As has been said in other threads, most older barns were built in a similar fashion, sometimes on rock walls.

 

[Woody65]

Just built a 26X42 barn. Compacted dirt, laid concrete block, starter course of shingles on top of that and then 6X6 pressure treated as my sill, framed up from that. Just had over 100km/hr winds and driving rain last week, no anchors and building stood it no issues at all. A lot of wieght in a stick framed building.

As has been said in other threads, most older barns were built in a similar fashion, sometimes on rock walls.

<img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=348174"/> <img src="http://www.tractorbynet.com/forums/attachment.php?attachmentid=348175"/>

The OP stated it is going to be a pole barn. Not a stick built structure. Like comparing apples and oranges.

 

[dave1949]

Yes, it used to be the way barns and sheds were built. Those buildings didn't blow away. My son has a friend whose family owns a log cabin camp in Maine that sits on rock piers. It's ancient. They do have to shim a pier here and there every couple years to keep it level. Obviously, you won't get the exact stability of a below the frost foundation.

I know of a goat barn over in St. Albans, ME that was built much the same as Mike476's barn. It hasn't moved. It makes a big difference on what the building is used for and how exposed it is. With animals and hay/straw bedding/manure build up, I doubt the ground freezes below the sills. People used to bank snow against their foundations and walls too for frost protection and to cut the wind whistling through the cracks.

Most small utility sheds bought ready assembled and delivered by sliding off a truck sit on 4x4's. They don't blow away and stay reasonably level if placed on a compacted gravel base with drainage, with no heat.

I don't know what the best advice is. For that size building I would choose standard stick framing, not poles.

 

[DutchHenryBrown]

:welcome: Good luck with your project sounds as if you might have a few question for your builder.

 

[geog272]

I see so many of those prefab sheds like you are talking about dave1949, and as you say they don't blow away. I guess I am more concerned about the 2X8s rotting and about frost heaving the building so that it is unlevel. It will be a livestock barn, but I would still expect the ground underneath the sills to freeze solid.

 

[GManBart]

this is a great alternative to wooden posts in the ground.
https://www.permacolumn.com/

I'm using their sturdi wall brackets....you can see them here (rear 12ft lean to going up):

 

[PeterK]

This is my barn in process of building in 1997. It's a kit from shelter-kit in N.H. Design is a modern post & beam using 6x6 pt posts set on a concrete slab. Slab is on prepared base 6" with 1/2 rebar and 2'x2' cubes poured at every post location. I am close to you if you want to see it. (K-055)

 

[CDN Farm Boy]

A pole barn on a plate won't work from a structural standpoint. The point loads of a pole barn need much more than a 2x8 plate to distribute the load.

If you want a pole barn, you need to sink them in the ground below frost or an engineer-approved monolithic slab to take the stresses of the point loads.
If you want to build on-grade you need to go stick framed.

Since you already have the gravel pad, I'd go with a either a monolithic slab or a floating footing with a short (12" - 24") knee wall. Either way, get concrete in contact with the ground/manure.

More importantly, I'd be looking for a different builder/designer. That's WAY too big of a building for what he's suggesting.

Opinion based on being a Licensed Carpenter, 20 yrs experience and Heritage Carpentry Diploma working in the Ottawa Ontario area.

 

[Mike476]

The OP stated it is going to be a pole barn. Not a stick built structure. Like comparing apples and oranges.

Actually he said he was working with a builder to design a pole barn, but rather than poles the builder suggested he consider a 2X8 PT plate directly on a gravel base.

I still suggest that should you choose to do that, rather than place your 2X8 PT sill on gravel I would recommend laying block as per my original suggestion if a footing or slab is not in the cards.

 

[dave1949]

I see so many of those prefab sheds like you are talking about dave1949, and as you say they don't blow away. I guess I am more concerned about the 2X8s rotting and about frost heaving the building so that it is unlevel. It will be a livestock barn, but I would still expect the ground underneath the sills to freeze solid.

I just noticed you said two stories. Poles would be probably be better for two stories than stick framing, plus that height will catch a lot more wind. Do you plan on putting hay on the second floor?

For livestock, you don't really want a concrete floor is my understanding. A confinement operation where the floor gets hosed into a manure collection trough is a lot different than animals on bedding.

Old barns and the remains of old barns that I have seen didn't put wood on the ground. They had stacked rock piers to carry sill beams, or a stacked rock continuous foundation wall with sill beams running on top of that. Of course, they didn't have the option of laying down treated sills either. That is where your builder deviates from the old method.

I think you will be happier using more modern methods for a two story building.

 

[Rustyiron]

Welcome to tbn! What is your use for this bldg going to be? Do you ever plan for a slab or heating? I completely agree with another poster(s) that a 2x8 will not be anywhere close to the size timber you'll need to distribute the weight of a pole buildings posts at the typical 8' spacing. I'm thinking more of an 8x8! I have found that if you plan on finishing the interior of a post frame (pole) bldg. it is generally better to just frame conventionaly on some sort of foundation. This is even a bigger factor if you plan on insulating & heating it. I am a big fan of those prema column mentioned previously. I would seriously question your "guy" & what he knows about pole buildings.

 

[geog272]

Do you plan on putting hay on the second floor?

Yes, I do.

For livestock, you don't really want a concrete floor is my understanding.

That and potential cost savings were the reason behind avoiding a slab and going with a pole building.

 

[Woody65]

Actually he said he was working with a builder to design a pole barn, but rather than poles the builder suggested he consider a 2X8 PT plate directly on a gravel base.

I still suggest that should you choose to do that, rather than place your 2X8 PT sill on gravel I would recommend laying block as per my original suggestion if a footing or slab is not in the cards.

I understand what you are referring to, but I understood the OP statement as instead of putting the posts in the ground they lay a 2x8 pt board on top of gravel and the posts on the 2x8 plate. This would provide a poor connection between the post and sill plate. All the downforce of the structure would be on the 1.5 inch plate that has no foundation or proper footing underneath it. In your case, because it is stick built, the weight is evenly distributed throughout the block and 6x6 footing. In addition, this is to be a two story structure, not a single story shed.

The method you utilized is much stouter with concrete block and a 6x6 sill plate.

I have been building residential structures for 30 yrs and have more than a few pole barns and stick built structures under my belt. Unless something was missed by the OP in his discussions with the builder, I would find someone else to design and construct the building.

 

[QRTRHRS]

The builder I used to haul for built plenty of barns that had the posts on a plate but not on gravel. They would pour a foundation with strategically placed anchor bolts. The posts would be bolted to large galvanized angles bolted to the plate and post.

This company also had a Perma Column franchise/plant. If you take the time to look up Perma Columns, there are steel brackets on two sides of the post that the posts gets bolted to with just a couple of bolts. The steel is welded to rebar that runs through the concrete. This was back around 05' so they may have changed. As I understood it at the time, engineering tests showed these structures to be as strong against wind loads as the standard post in the ground setup.

I have seen precast concrete sections set directly on tamped gravel but these were for foundations. The exterior backfill and interior basement slab stablized the walls. Don't Maine builders also use grade beams on gravel for some applications?