Who knows about pole barns?

[Rob_Red]

Hey everyone, I have a nice pole barn in the back yard of my new house that I would like to fix up.

A little about the barn. It's a typical pole barn with board and baton siding, the wood came from the native lumber sawmill down the road (rough cut pine, not kiln dried, but the barn is at least 35 years old). It has a compacted stone dust floor and I would like to pour a concrete floor. I would like to have the floor thick enough to support parking vehicles and general workshop activity, I have a Bridgeport mill that weighs about 2500 lbs that I would like to possibly put in there .

My questions are:

Should I poor the floor around the posts? Or build a form around the posts? They are rough cut soft wood and are making direct ground contact so I assume some day they will need to be replaced. I was thinking if I build a form around them I could always remove the board and baton on the out side and dig them out if they rot. Am I on track with this thinking?

Is there a good way to make a barn like this actually weather tight? Right now its rodent paradise and some snow and rain blows in through the cracks. Currently I wouldn't store anything that isn't a piece of yard equipment in there. Due to the current environment I would not store rust prone woodworking or metal working hand tools, most fishing and hunting equipment and certainly no soft good that a mouse could destroy.

Our house is from the late 1800's and is built on a crawl space, our last house had a nice dry basment that was used to store and organize all of our stuff so we could really use the extra storage. I am not afraid of carpentry work or spending a couple of dollars to make this a great workshop/ storage space. Any advice from experienced barn owners would be appreciated

 

[Bad LP]

I wouldn't put my Bridgeport there due to the rapid change in temps and humidity resulting in rust. I'd have to have a room built inside the pole barn to prevent that plus protecting my measuring tools from the same fate. FYI the wire in my MIG welder turned all rusty from such weather changes.

As for your floating floor idea I did it on a lean-to that was built off the back of the garage but it was a little different. We poured the 2 post pads in a sono tube and left the elevation high to be above the slab elevation that was poured later. I had placed some rebar in the tubes and mesh in the slab.

 

[Rob_Red]

I wouldn't put my Bridgeport there due to the rapid change in temps and humidity resulting in rust. I'd have to have a room built inside the pole barn to prevent that plus protecting my measuring tools from the same fate. FYI the wire in my MIG welder turned all rusty from such weather changes.

As for your floating floor idea I did it on a lean-to that was built off the back of the garage but it was a little different. We poured the 2 post pads in a sono tube and left the elevation high to be above the slab elevation that was poured later. I had placed some rebar in the tubes and mesh in the slab.

I'm inclined to agree, unless climate controlled delicate/rust prone items are going to be a no go. I also had my MIG wire flash rust!

 

[Bad LP]

I meant to add that planning ahead for post removal is smart. You may need to "box out" and area large enough to work in for their replacement day. This would not be difficult if you think of it as pouring a footing up to the finish slab elevation.

How's the attitude on the local building department?

Yes, I was speaking of a climate controlled room within the pole barn. Alternately a stand alone climate controlled out building might be a whole lot easier and cheaper in the long run.

I'd love a pole barn for my wood and tractor attachments and have been kicking around a 24X24 for just that. No need to care for rodents running around. I absolutely do not want them critters in my detached garage for any reason and I'm proactive on keeping them away. SO far so good.

 

[Grizzerbear]

They now make steel or plastic sleeves that your post can go into that would stick up above your cement that are suppose to protect your posts from ever coming into contact with the dirt or concrete .....thereby making them last forever......or a person's lifetime anyways. I know that doesn't help you now but if you ever do replace what you have you could get some.

 

[gzecc]

Provide a picture of the pole barn interior posts and how many there are.

 

[Rob_Red]

Provide a picture of the pole barn interior posts and how many there are.

The barn is 25x25 and has 4 corner posts and a post in the middle of each wall. So 8 posts.

 

[gzecc]

I would probably use a small backhoe to excavate the posts from inside the building one at a time. Cut posts a couple of inches below bottom plate, install sonotubes (depth for your area), imbed metal post bracket between post and cement. Be prepared to temporarily support wall/ ceiling with appropriate structure.
I would also remove 4" of floor material to bring new concrete floor up to the bottom of the bottom plate.
Its a lot of labor, not much in materials. Concrete floor will be the most $.

 

[Rob_Red]

I have no doubt what you described is the best way to do it, but it would be a ton of work (my soil is very rocky). Would leaving the posts as they are and pouring a floating floor be a disaster? I would think the risk would be if a post rots out I would have to get creative with fixing it.

Right now the posts are rock solid. Is there a version of this where I poor the floor and replace the footings with sonotube if/when they rot?

 

[gzecc]

I have no doubt what you described is the best way to do it, but it would be a ton of work (my soil is very rocky). Would leaving the posts as they are and pouring a floating floor be a disaster? I would think the risk would be if a post rots out I would have to get creative with fixing it.

Right now the posts are rock solid. Is there a version of this where I poor the floor and replace the footings with sonotube if/when they rot?

Is there a possibility they will not rot?

 

[Highbeam]

I have a finished pole barn. It’s like a house. Pour concrete right against the posts. If untreated you can wrap with tar paper before the pour.

You won’t be replacing that post without cutting the concrete. No big deal, rent a saw, cut out enough floor to do your work IF it’s ever needed.

 

[PA Mountain Man]

It's interesting that 25 year old posts are still solid. Can't tell species from pic. If it was me, I would do the this. Remove and level crushed stone to get 6" under the bottom plate and 4" across the floor. Add roughsawn 12" 2x4 to the sides of each post on top of the purlin to transfer post load to purlin. Place concrete floor level with bottom plate and work in under with a vibrator.
This will create a shallow footer under the wall to transfer loads from post to plate and footer if the posts ever fail.
To address the walls place unfaced batt insulation in the wall cavity, staple black plastic floor to ceiling and cover with rough sawn 1x6. Similar with the ceiling, but you probably will need to add nailers for the roughsawn.
Rodent control is easier if there is nothing in the building for them to eat. We use cats in the barn. There are effective poisons also.
I've fond roughsawn is now 2/3 the price of lumber and plywood.
I put plastic under all slabs to conserve concrete and get a better cure. 10x10 6 gauge wire mesh in a 4" slab on a tight crushed stone base will support anything you can get in the building. Sawcut using a wet saw to divide the slab in to 4 equal squares to control cracking.

 

[GENECOP]

It's interesting that 25 year old posts are still solid. Can't tell species from pic. If it was me, I would do the this. Remove and level crushed stone to get 6" under the bottom plate and 4" across the floor. Add roughsawn 12" 2x4 to the sides of each post on top of the purlin to transfer post load to purlin. Place concrete floor level with bottom plate and work in under with a vibrator.
This will create a shallow footer under the wall to transfer loads from post to plate and footer if the posts ever fail.
To address the walls place unfaced batt insulation in the wall cavity, staple black plastic floor to ceiling and cover with rough sawn 1x6. Similar with the ceiling, but you probably will need to add nailers for the roughsawn.
Rodent control is easier if there is nothing in the building for them to eat. We use cats in the barn. There are effective poisons also.
I've fond roughsawn is now 2/3 the price of lumber and plywood.
I put plastic under all slabs to conserve concrete and get a better cure. 10x10 6 gauge wire mesh in a 4" slab on a tight crushed stone base will support anything you can get in the building. Sawcut using a wet saw to divide the slab in to 4 equal squares to control cracking.

That bottom plate appears to be toe nailed only into the posts, transferring the load to that will give limited support if settling occurs. If he bolts a new plate across the interior and bolts the bottom plate and the structural posts together, he might accomplish something..

 

[SpaceBus]

It's interesting that 25 year old posts are still solid. Can't tell species from pic. If it was me, I would do the this. Remove and level crushed stone to get 6" under the bottom plate and 4" across the floor. Add roughsawn 12" 2x4 to the sides of each post on top of the purlin to transfer post load to purlin. Place concrete floor level with bottom plate and work in under with a vibrator.
This will create a shallow footer under the wall to transfer loads from post to plate and footer if the posts ever fail.
To address the walls place unfaced batt insulation in the wall cavity, staple black plastic floor to ceiling and cover with rough sawn 1x6. Similar with the ceiling, but you probably will need to add nailers for the roughsawn.
Rodent control is easier if there is nothing in the building for them to eat. We use cats in the barn. There are effective poisons also.
I've fond roughsawn is now 2/3 the price of lumber and plywood.
I put plastic under all slabs to conserve concrete and get a better cure. 10x10 6 gauge wire mesh in a 4" slab on a tight crushed stone base will support anything you can get in the building. Sawcut using a wet saw to divide the slab in to 4 equal squares to control cracking.

Our house was insulated in this fashion and built on a slab above grade in the 70's. We bought and moved into the house in late 2018, come summer 2019 I had to replace the sill plates and most of the studs. The plastic and insulation was also sandwiched under the sill plates and that probably didn't help. Now we have an external house wrap under our siding and no plastic inside. I would not suggest the plastic to anyone as it just hides your problems and causes issues.

To the OP:

If you want the space to be finished remove the battens from the exterior siding and put some Tyvek, Typar, or Zip System sheathing wrap around the entire exterior and apply another finish siding on top of that. Maybe even rough sawn board and batten. Your roof will likely require the same treatment, but I would use EDPM rubber or similar product for a base layer on top of the roof deck/sheathing. I think @Highbeam is spot on about the poles. The poles shouldn't rot or have issues if the poles are on the inside of the building and you have French drains or gutters around the barn.

I dropped some rough cut Fir 4x4's into our gravely clay soil for an elevated chicken coop and they stay dry. My roof overhangs a bit on the sides and eventually I'll put some gutters on the structure.

 

[SpaceBus]

Excavating the crushed stone/gravel floor for a slab sounds not very fun.

 

[PA Mountain Man]

Our house was insulated in this fashion and built on a slab above grade in the 70's. We bought and moved into the house in late 2018, come summer 2019 I had to replace the sill plates and most of the studs. The plastic and insulation was also sandwiched under the sill plates and that probably didn't help. Now we have an external house wrap under our siding and no plastic inside. I would not suggest the plastic to anyone as it just hides your problems and causes issues.

To the OP:

If you want the space to be finished remove the battens from the exterior siding and put some Tyvek, Typar, or Zip System sheathing wrap around the entire exterior and apply another finish siding on top of that. Maybe even rough sawn board and batten. Your roof will likely require the same treatment, but I would use EDPM rubber or similar product for a base layer on top of the roof deck/sheathing. I think @Highbeam is spot on about the poles. The poles shouldn't rot or have issues if the poles are on the inside of the building and you have French drains or gutters around the barn.

I dropped some rough cut Fir 4x4's into our gravely clay soil for an elevated chicken coop and they stay dry. My roof overhangs a bit on the sides and eventually I'll put some gutters on the structure.

What vapor barrier do you have on the inside of your insulation?

 

[SpaceBus]

What vapor barrier do you have on the inside of your insulation?

None, the vapor barrier is on the outside of the structure and we do not have any water coming into the house. On half of the first floor the walls are just studs with insulation. On the walls I didn't have to rebuild the whole structure there is still plastic hiding behind the drywall. That all being said I can see if there is any water coming into the house and so far so good.

 

[PA Mountain Man]

None, the vapor barrier is on the outside of the structure and we do not have any water coming into the house. On half of the first floor the walls are just studs with insulation. On the walls I didn't have to rebuild the whole structure there is still plastic hiding behind the drywall. That all being said I can see if there is any water coming into the house and so far so good.

I hear what you are saying. In 36 years of designing and constructing commercial and residential occupied buildings I've never seen a detail or code standard that did not require a vapor barrier on the interior climate controlled side of a wall or ceiling. Kraft paper on fiberglass insulation provides the minimum permeability rating to meet code. There were some drywall products that met the standard.
I have fixed a lot of damage in walls and ceilings due to poorly installed, missing/no vapor barrier.
The vapor barrier prevents moisture from migrating thru the wall to make contact with temperatures that cause condensation.
I'm glad your situation is working but I don't think the plastic on the inside of the walls caused the rot of the framing. But I could be wrong.
Thought I was once, but I was mistaken!
I have retrofitted several pole barns using the technique described above and they work great. I believe the best thing you can do on an exterior wall is keep rain from entering and provide as much ventilation from the exterior as possible.
Board and batten do this very well.

 

[Bad LP]

RE: Vapor barrier

In my research a while back when researching spray foams and other insulating methods for my own home I learned that an exterior vapor barrier was the accepted practice down south. Up here in the north the vapor barrier goes on the inside to prevent the moisture forming on the inside of the enclosed walls/ceiling.

Keeping any weather off the sheathing under any sidewall by the use of a breathable house wrap is a no brainer but a plastic sheeting barrier is not recommended.

 

[Highbeam]

My pole barn is metal outside, then wrapped with tyvek. Then an air gap. Then I have faced insulation with the paper on the warm side, and then osb sheeting with all seems caulked. I even put baseboards in. I stick framed walls between each post.

On the ceiling going up I have white metal, 6 mil plastic, then r50 cellulose to a ventilated attic space.

 

[PA Mountain Man]

That bottom plate appears to be toe nailed only into the posts, transferring the load to that will give limited support if settling occurs. If he bolts a new plate across the interior and bolts the bottom plate and the structural posts together, he might accomplish something..

Yes plates could work also, but if you screw 2x4's to the side of the post on top of the plate you get enough load transfer for this small building.

 

[Rob_Red]

Thanks for the replies guys, you all gave me lots of food for thought. This project will begin once the weather starts to turn, I will keep everyone updated with pictures.

 

[SpaceBus]

I hear what you are saying. In 36 years of designing and constructing commercial and residential occupied buildings I've never seen a detail or code standard that did not require a vapor barrier on the interior climate controlled side of a wall or ceiling. Kraft paper on fiberglass insulation provides the minimum permeability rating to meet code. There were some drywall products that met the standard.
I have fixed a lot of damage in walls and ceilings due to poorly installed, missing/no vapor barrier.
The vapor barrier prevents moisture from migrating thru the wall to make contact with temperatures that cause condensation.
I'm glad your situation is working but I don't think the plastic on the inside of the walls caused the rot of the framing. But I could be wrong.
Thought I was once, but I was mistaken!
I have retrofitted several pole barns using the technique described above and they work great. I believe the best thing you can do on an exterior wall is keep rain from entering and provide as much ventilation from the exterior as possible.
Board and batten do this very well.

We do have board and batten siding hung on strapping. The plan is to install radiant barrier foam product with tape on the inside of the house and then using lime plaster over lath for the finish wall. While not a pole barn, it is a framed house on a slab. Perhaps the poly didn't cause the sill plates to rot, but it did hide the damage. Our home inspector went to the house twice after we checked the house twice and nobody caught that the south 2/3 of the first floor was rotten. I wish we could have put the rigid foam on the outside of the house, but the roof didn't give us enough room for that.

 

[Highbeam]

We do have board and batten siding hung on strapping. The plan is to install radiant barrier foam product with tape on the inside of the house and then using lime plaster over lath for the finish wall. While not a pole barn, it is a framed house on a slab. Perhaps the poly didn't cause the sill plates to rot, but it did hide the damage. Our home inspector went to the house twice after we checked the house twice and nobody caught that the south 2/3 of the first floor was rotten. I wish we could have put the rigid foam on the outside of the house, but the roof didn't give us enough room for that.

When you put a layer of rigid foam on the outside of the house under the siding, does that not create a vapor barrier on the cold side in addition to the vapor barrier on the warm side to trap vapors in the middle? Selfishly asking because I want to reside my home and foam is really easy for more R value than the R5 fiberglass currently in the wall!

I should say that when I stick framed walls between my pole barn posts on top of the concrete I applied that pink foam seal stuff to the bottom plate. That pole barn is built much better than my home.

2" foam under the slab and around the edges as well.

 

[SpaceBus]

When you put a layer of rigid foam on the outside of the house under the siding, does that not create a vapor barrier on the cold side in addition to the vapor barrier on the warm side to trap vapors in the middle? Selfishly asking because I want to reside my home and foam is really easy for more R value than the R5 fiberglass currently in the wall!

I should say that when I stick framed walls between my pole barn posts on top of the concrete I applied that pink foam seal stuff to the bottom plate. That pole barn is built much better than my home.

2" foam under the slab and around the edges as well.

There are so many different opinions about this and I really don't know. The house wrap is supposed to release moisture, but like you said, many folks run the foam on the outside of the wrap creating a vapor barrier. I've seen several builders up here not use a vapor barrier inside the home and instead rely on exterior barriers. When we put foam on our studs we might not even use tape just to allow any trapped moisture a means to escape. Perhaps not the most energy friendly install method, but should be good for house longevity. Lime plaster deals with moisture very well and can "heal" cracks by absorbing water.


I did remove the foam on the outside edge of our slab due to vermin damage/infestation, and the floor has been noticeably cooler. Eventually I will insulate the slab with mineral wool or XPS.