How to Build a Post and Beam Barn

There are many articles on the web about building a post and beam barn. However all of them are wrong! They describe building a pole barn not how to build a post and beam barn. This article explores building an authentic, traditional, post and beam barn like grandpa used to do.

The easiest way to build a post and beam barn, is from a kit. A kit will save you time and money. All the hard work has been done for you. The angles have been cut. The holes have been drilled. The plans have been drawn. Then all you need to do is assemble the bents, set them in place and install your girts, purlins, siding and roofing.


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    Before you even get your materials delivered, prepare the site.
    • Clear any brush from your site.
    • Have an excavator come in and level your site. Or rent the equipment and do the site prep yourself.
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    Build your foundation. There are many options when choosing your foundation type. Post and beam barns can be constructed on most conventional foundation systems. The most popular type of foundation is poured concrete piers. However your barn kit can also be constructed on poured wall foundations, concrete wall foundations, and slab on grade foundations. Check your local building codes to see what is required.
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    Before your barn kit arrives be sure that you have adequate space to unload a tractor trailer. Depending on the size of your barn kit more than one Truck may be arriving at your site. Be sure that you have a 5,000 lb capacity or larger forklift on site for unloading the truck. It is a good idea to rent a Tele-handler type forklift with a 35' or more reach.
    • A forklift like this will be a great help not only in unloading but also in raising assembled bents and lifting material to workers on your barn.
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    Carefully unload your lumber making sure not to damage your material with the forks on your machine.
    • Be sure to stack all lumber off the ground, try not to open the banding until you begin building.
    • Do not cover your material with tarps. Doing this will lock moisture inside the cover. Store your wood in a shaded area if possible. Prolonged exposure to sunlight can cause your wood to discolor. The less wood to wood contact during storage the better.
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    Bent Assembly
    • On a level plane lay out all of the timbers for your first bent. Arrange them according to their joint labels. Use bent jacks to support the timbers off the ground if you have them. Otherwise heavy duty saw horses can be used.
    • Bolt the posts and beams together with 1/2" x 7 1/2" Hex head bolts and steel T plates.
    • Determine the exact length of your posts according to your plans and trim them to length.
    • Use a drilling jig to drill two 9/16" holes through the bottom of your posts to accept your U brackets.
      • place the U bracket on the bottom of your post and mark the location of the holes.
      • Drill two starter holes about 1/2" deep.
      • Place 2 bolts in your drilling jig and slide it over the holes until they drop into the holes you drilled, this lines up your jig for drilling. (the jig keeps your bit square to the post)
      • Clamp the jig securely to the post. Remove the bolts and drill the holes through the post.
      • Remove the jig and bolt the U bracket in place.
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    Once you have bolted all the timbers together and have an assembled bent it is time to raise it into place. (Note: bents wider than 20' will need to be erected in smaller segments)
    • Raise your bent and brace it securely. It is very important to adequately secure and brace your bents. Use 2x6 boards nailed or screwed in a criss cross pattern to the posts. Do not remove any bracing until all the bents are raised and secured together with girts and purlins.
    • Place the U brackets in their proper locations on your foundation. Drill into the foundation through the holes in the flange.
    • Drive wedge anchor bolts into the holes and tighten them.
    • As your bents are raised into place it is time to attach your 3x6 purlins and 2x6 girts. Attach purlins with 6" screws or nails, and girts with 4" screws or nails. Refer to your plans for proper spacing. Be sure to leave an overhang on the gable ends.
      • Here is a drawing showing the correct placement of your board and batten siding. Try using 2 1/2" ring shank exterior grade nails. Be sure to use careful cutting procedures to minimize waste.
      • Here is a drawing that illustrate the correct installation of your Loft joists and decking. Be sure to cut carefully. Joists should be placed 16" on center and are supported by the tie beams.
      • Here is a drawing that shows how your roof sheathing should be installed. Be sure once again to cut carefully.
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    Before painting or sealing your barn with any finish allow your barn to season. Avoid painting or sealing until after 6 months or more. It would be best to allow your wood to go unfinished one full winter. This allows your wood to fully season and prevents moister from being trapped inside the wood. The suns ultraviolet rays may discolor the wood during this time period. A simple way to correct this is to power wash the barn a week before applying finish. Do not hold the power washer nozzle to close to the wood, you could damage the wood fibers. Make long sweeping motions across the surface of the wood. This discoloring is only cosmetic and no power washing is needed if color is being applied.


  • The following are terms and definitions used in this guide.
    • Bay - This term refers to the open space between the bents of your barn.
    • Bent - This term refers to one section of framework made up of posts and beams. Bents are spaced 10 or 12 feet (3.0 or 3.7 m) apart. (Refer to your plans for spacing of the bents in your barn.)
    • Bent Jacks - Bent jacks are small saw horse like supports used to hold the timbers off the ground for assembly before the bent is raised.
    • Board and Batten - This is the vertical siding of your barn. They are full dimension rough cut 1"x10" boards, and 1"x3" battens. These will need to be trimmed on site to fit.
    • Collar Tie - This rough cut full dimension 4"x4" or 6"x6" timber runs between rafter beams on either side of your bent. These come with some

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Categories: Sheds and Garages