Adding on to a pole barn

[Jason McCray]

I have a 31' x 24' pole barn, currently sitting empty, that I'd like to convert to a workshop. I would like it to be larger and want to explore options to do so before filling it with woodworking equipment. The back side of it (the 31' long wall) doesn't have any doors or windows, and there is room on the property to go another 25' or so. Beyond that there are more trees and it starts sloping down in to a ravine - I could go much further, just with more work clearing the land and fighting the slope.

The building is only a few years old (so I'd rather not tear it down). The posts are laminated wood, with OSB on the outside then a wood or composite siding. It has a simple metal gable roof. Ceiling height is 12" along the edges but it is vaulted in the center.

I'm just looking for some ideas to get started as to how it could be expanded.

A simple option might be a lean-to against the back wall. I'm attaching an image of what that might look like - if I follow this example I might start out with a 10' ceiling then slope down to 8', and probably couldn't add more than 10' or 15' while maintaining something aesthetically pleasing.

A second option is another identical building maybe 10' or 20' behind the current one bridged together with the original somehow.

Has anyone here done an addition to a pole barn, or know of any examples I could look at.

The first attachment is just an example of the general shape the building, the second with a lean-to attached. Nothing fancy here, just want to make sure I am describing correctly.

iu.jpgiu-2.jpeg

[Scott Clausen]

If I had 31' x 24' I wouldn't have a need for more room. If you need the room I think I would do the lean to and make it a dust house, Air compressor room and lumber storage.

[Bobby Robbinett]

I would add on the max amount you can get on the back side without going into the ravine. You say about 25ft or so? Do you plan on putting a lot of heavy machines in that part? The easiest way would be to have a slab poured out back that butts up to the current slab. That is also the most expensive. If you don’t have much heavy machinery you could do a wood crawlspace style foundation as opposed to a concrete slab. You could use 2x12’s on cinder blocks and cover it with two layers of Advantec.

I wouldn’t take out the entire back wall as that would require a lot of additional work. I would make an opening large enough to fit your purpose but still leaving some meat behind so that you don’t have a headache structurally speaking.

I would build the addition pole barn style as that would be the most economical. You could have a steel building kit manufacturer make you a kit for the addition that would bolt together end be super easy to install though. Either way if you can afford it, I recommend spraying closed cell spray foam and using a package unit or mini split to heat and cool your new work space

[Jason McCray]

If I had 31' x 24' I wouldn't have a need for more room. If you need the room I think I would do the lean to and make it a dust house, Air compressor room and lumber storage.

That's where I started with this. Just a small lean to for the compressor and dust collector would take a lot of pressure off the workshop.

[Kevin Jenness]

What do you plan to make? What is your budget? If you have the $ and want flexibility for large projects, maximise your space on the lot- extend the existing profile and add a shed along the back as well.

I worked in a 24' x 30' space like yours for many years with more machinery than you are talking about but assembly was a real squeeze and I used to either hoist projects upstairs or send them out to a subcontractor for finishing. I added a 15' x 24' leanto which gives me bench space and a corner for finishing. A slightly larger shed would give a more reasonable finishing area, but my 1100 sq. ft. requires a well lubed shoehorn when building cabinet sets.

[Steve Rozmiarek]

One advantage of a pole barn is the ease of which they can be expanded. A lower pitch shed or extending the length are both viable options. Adding a shed will of course result in a decreasing ceiling height, so there is a structural limit to the size for practical use.

[Jim Becker]

Post frame structures are relatively easy to add on to...easier than many structures because of how they are built. Length is obviously easiest, but out the side is also relatively simple...it can be a lean-too as you show or a perpendicular post frame or stick framed structure. The latter is just a bit more involved to tie in because of the roof structure and angles, etc.

Your current size is actually what I'm shooting for here on our new property.

[John K Jordan]

...I'm just looking for some ideas to get started as to how it could be expanded.
...

I've expanded two pole barns (real barns, used for animals and feed) with lean-to construction. The work was trivial - add poles, beams, rafters, girts and purlins. The most important thing is designing and building the roof to drain properly. I'm currently planning another extension on the primary barn.

The effort, of course is in the planning. You mention one side goes down into a ravine. That doesn't necessarily stop you.

I would start by making a detailed topo map of the available area including the ravine. Quick to do with a rotating laser level. Depending on the characteristics of the ravine it may be possible to get closer to it than you imagine. It's impossible for me to evaluate without seeing and studying the land, the composition of the ground, and whether the ravine has flowing water and increasing erosion. It's possible in some cases to put in proper support and build out over a slope. The old adage that "fill always settles" is not necessarily true, except where the fill is not compacted properly.

For example, when I cleared the site for my post and beam 24x62 shop building (basically a 1-story pole barn) the far back corner was 4' below grade due to the slope of the land. I did three things: I filled and extensively compacted with 4" lifts, I dug down with the backhoe too undisturbed ground and embedded several very large rocks (4-5') and positioned them like pillars to support the concrete slab (I could have built concrete supports but the rocks were quicker and cheaper), dug footers to undisturbed sub soil, built a strong grade beam in that corner full of rebar, added rebar on that end of the building on 12" centers, and poured a 6" concrete slab on that end of the building.

The right end in the first two pictures is the part that dropped off, the left end of the last photo. Can't see it from the pictures but 20' from the end of the building the ground is maybe 8-10' lower.

concrete_rebar.jpg shop_bay_doors_IMG_3047.jpg shop_llamas_IMG_20150422_08_re.jpg

You might get an architect and/or structural engineer and maybe even a geologist to advise. (fortunately I have a geologist friend) The most important thing (IMO) is to keep the water away from the building so it can't erode the foundation. Depending on the slope, a properly built retaining wall might not be out of the question. I my case I built out the ground to a gentle slope at least 10' from the building before sloping it down the hill. So far (7 years) there is no sign of settling, erosion, and no cracks in the concrete.

One big advantage I had was I did all the design, grading, footers, forms, rebar, and construction myself so I didn't have to rely on the work of some contractor who's primary goal was to cut corners to put more money in his pocket.

JKJ

[Lisa Starr]

I'd consider adding on to the gable end, whichever dimension that is without removing the siding. The addition could have a lower ceiling height, eliminating the need to match in the roof lines. Then you could add a door between the old and new sections. One portion would be lumber storage, air compressor, paint booth???,dust collector. The other section could be tools and bench. I think the separation would be very beneficial.

[Jason McCray]

I'd consider adding on to the gable end, whichever dimension that is without removing the siding. The addition could have a lower ceiling height, eliminating the need to match in the roof lines. Then you could add a door between the old and new sections. One portion would be lumber storage, air compressor, paint booth???,dust collector. The other section could be tools and bench. I think the separation would be very beneficial.

Unfortunately neither gable end has room to expand. One side is the driveway, and the other immediately starts a steep descent in to a ravine. It does seem like whatever I do isn't going to result in one large space but separate rooms, which I think has advantages too.

[Jim Becker]

Separate rooms can truly be an enhancement to the shop environment so you can segregate certain functions...finishing, for example, for better environmental control.. as well as storage, metalworking, office functions, etc., to help keep the major part of the shop more focused on work flow.

[John K Jordan]

Separate rooms can truly be an enhancement to the shop environment so you can segregate certain functions...finishing, for example, for better environmental control.. as well as storage, metalworking, office functions, etc., to help keep the major part of the shop more focused on work flow.

I very much agree - I built separate rooms in my shop: small office, small weld shop, large maint/machining/storage room, tiny air comp/dc room, and the main shop room. But even in the main shop I built two walls to define a woodturning area although it’s not a closed-off room with a door. (extra walls also provide more coveted wall space)

With separate rooms and areas there’s one thing I recommend: at the main entrance(s) wire a switch that powers a light circuit with fairly low wattage lights strung all the way through the shop, through each room; I call them the passage lights. My shop is 62’ long but I can flip one switch at either entrance door and have enough light to access tools and supplies anywhere without turning on any of the sets of bright working lights in each zone.

When wiring a building with separate rooms don’t forget emergency lights that come on automatically off the power goes out!

JKJ

[Greg Hines, MD]

My pole barn shop needed interior walls to be able to put up the French cleat tool wall that seems mandatory in shops, and I could not do it on the exterior walls as much as I wanted to. This creates another room where I can have it relatively clean, compared to the rest of the shop. I still plan to built a small lean-to outside one end for a dust collector and big compressor, but that is still in the future.

Doc

[Kevin Jenness]

Since you can't add to the gable ends, how about extending the front roof plane up far enough so you can get a reasonable roof pitch on the back extending out horizontally the full 25' available? That would essentially double your floor area, making room for all the machinery you are considering.