How to Build a Pole Barn Style Garage

Two car garages can cost upwards of $25000 today for a simple garage with a concrete floor. With nothing fancy and by using vinyl siding on the exterior, you can build a garage yourself for under $5000. In fact you will need some free hands form time to time to aid you in some of the building work bur friends and family should be able to help without you becoming too much of a pain in the butt to them.

If you are starting with a level or almost level site for the garage, that is a big help. Heavy machines needed to level a site can eat up a great deal of cash really fast. Assuming the site is flat layout the rough size of the garage you are going to build with some string lines and stakes. A typical two car is twenty-four feet wide and twenty four or twenty-six feet deep. Roof trusses are spaced every two feet apart so keeping the garage measurements in even two foot increments is important.

Having laid out the garage location, step back and take a good look at the area. Is there enough room between the garage and the road to park a car outside? Is the garage square with the house? Is the garage aligned with the property lines? Is the garage the proper distance from the side property lines? All these questions are very important. Once the garages main poles are set, it will cost you good money to move it if it is wrong.

If you have decided you are happy with the garage location now is the time to lay out the garage accurately to drill or dig the holes for the main posts of the building. Start in one corner and setup a string line on the center of the post locations and drive a stake in at the other end of that wall. Continuing on with all four sides, the string lines should all be in the center of the pole locations and cross at the four corners exactly in the center of the four corner posts. Using a can of upside down paint ($2.99), paint the holes for the four corner posts on the ground. Now add four new stakes at the locations where the four strings cross. These will help hold the tape as you measure and layout the other post hole locations. If you have a helper you can avoid this step and let them hold the tape measure end at the string crossing for you.

Checking your drawings you will see that perhaps the poles are to be six feet apart on center. Starting on the outside of the corner post (not the center), measure along the line exactly six feet. Draw the post hole on the ground. proceed along the string and mark all the post holes. Along the back wall there will be five holes counting the corner holes. Now do both sides. Five holes here also for a twenty-four foot deep garage. The front of the garage is a bit different. Lets assume you are going have two eight foot garage doors. Starting on the corners on the outside of the post, the post hole spaces will be, two feet, eight feet, two feet, eight feet and two feet, totaling twenty-four feet. Garage doors come in exactly eight foot widths so you want your post exactly eight feet apart. if you choose nine foot doors, adjust your column widths to suit. When you install the typical 2×10 wood trim, the openings will downsize enough for the doors to butt against them when they are closed. The finished measurement of the opening would he seven foot-eight inches for eight foot doors.

Now it is time to dig the holes. Keeping our budget in mind and if the ground is actually the type that can be hand dug again you will save a bundle of your muscles can take the work. If the ground is very rocky or clay soil type, hand digging may not be possible. Rental stores have gas driven post hole augers with a twelve inch diameter bits that with the aid of a helper can make short work of the post holes. There are contractors that offer this service with truck mounted augers but again your budget will feel the pain. If it is at all possible, dig the holes yourself. It may take several days but by carefully covering the holes against weather, kids and stray animals and your wallet will love it.

You should have a helper for the pole work but it is not impossible to do it alone. I have set sixteen foot pressure treated posts alone but it is a real chore and a little dangerous. Your drawings will show the various lengths of poles for each hole. Longest poles go on the sides at the ridge center and shortest on the front and rear. if the gables are on the left and right. If the gables are over the garage doors, (front and rear) the longest poles will be center of the front and back wall. I have found if you install a pole slightly longer then the top of the truss, construction is a great deal easier. The first end truss will be supported on the top of the perimeter beams and lean against the poles. No bracing is necessary. Set all the posts in their respective holes. Check your drawings to determine if a concrete footing is required for the posts. If yes, pour a bag of pre-mix concrete in each hole and wet with a hose. Using a hole or shovel, stir up the mix so the water penetrates the concrete mix and level as best as possible in the bottom of the hole. Allow the concrete to dry overnight.

Set all your pressure treated poles into their respective hoes based on length.. Remember there are two very long poles at the ridge, four of the same length for the next set of four holes (two each side of the ridge center) and so on with all the poles on the front and back the same length. Set a corner post first. The post outside faces must be exactly in line with the two crossing string lines. Take your time with this part. The four corner posts must be exactly in line with the strings and square to the building. Bracing each post with some 2 x 4’s and stakes, plumb the posts with a good four foot level. Not a two foot shortie. With all four post in their holes, braced and plumb, now with a helper measure across the garage form corner to corner to see if the measurements are the same. Exactly the same. The length will vary depending on the garage size you are building but these two measurements will and must be exactly the same.

If it is twenty eight feet four and one quarter inch one way, it must be exactly that size the other way as well. If it is not, you must move the poles until the measurements exactly match. Once they match, double check the lengths of your walls to see that you have not stretched or shrunken them by squaring the poles. This takes a bit of practice and effort but if you take your time and get the building sides perfect and the cross measurements perfect, you will see a square building is a lot easier to build that one that is not square.. Now go ahead and set, brace and plumb all your other poles. Make sure the separation distances are correct as well. Brace the poles well. You will be climbing on them and do not want them to topple or move out of alignment while you work. The band or rim boards come next.

Typically the sides that the trusses bear upon are 2 pieces of non-PT 2 x 12 lumber nailed and then through bolted to the posts. The opposite or gable ends are smaller sized lumber typically 2 x 8’s and do not need to be through bolted. This work is also a heck of a lot easier with a helper but not impossible to do alone if you can lift the 2 x 12’s. The front and rear boards on a twenty-four foot garage would be two 2 x 12 by 12 foot each and three 2 x 12 eight foot each or any combo that adds to twenty-four feet and lands on the center line of a post. An eight footer and a sixteen footer will work as well. These bands go on the inside and outside of the posts to support the trusses..Make sure all the posts are plumb as you proceed around the garage. One additional word about the band joists These 2 x 12 band joists must be perfectly level and especially on the truss bearing sides. The top of the 2 x 12 is the height that the bottom of the truss will be above the garage floor.Typically this is eight feet however it can be nine, ten or whatever you wish it to be. You must adjust your pole lengths to accommodate this added interior wall height.

Trusses are the cheapest and easiest way to frame a roof. A typical 4/12 slope trusses for a twenty-four foot garage is about $35 or so. Watch for sales at big box stores or local truss companies that are clearing out their lots. A twenty-four foot garage needs 13 trusses. You will have twelve two foot spaces plus one to start with. That comes to twenty-four feet overall. Another trick is to order two trusses as gable end trusses. These will come “flat” framed and when installed on each end of the garage will continue the wall line to the roof from the 2 x 4 girts leaving one straight face for the exterior plywood. Placing the first truss on top of the perimeter 2 x 12 band joist, line up the flat bottom portion of the truss (or birds mouth) with the outside edge of the 2 x 12. If you purchased trusses with an overhang or soffit, that portion of the truss will hang over the 2 x 12’s on both sides of the garage.

Holding the truss firmly against the poles, atop the perimeter 2 x 12, nail the truss to the poles. The poles should stick up slightly past the truss s’s at this point but will be trim cut later. Truss installation is a heck of a lot easier with a helper. Two men can take all the trusses and hang them upside down on one end of the garage and stack them. With one man on top of the garage, the other man can slide the truss over to him and using a pusher pole made of scrap 2 x 4, flip the truss upright into the waiting hands of his partner. I highly recommend the use of metal truss spacers. They are sized so when nailed to the first truss, and after sliding the second truss into the end of the spacer, the end result will be two foot space between truss centers. A quick nail in the top of the spacer and the truss will stay in place.

The ground man using a ladder can nail the truss to the perimeter 2 x 12 band joist securing the truss from any further movement. A third man in the crew helping with nailing makes this job even easier. Thirteen trusses should be erected in about two hours start to finish. With all the spacers nailed in place, a least two two by fours are required along the bottom chords of the truss as a permanent truss spacer as well. A typical W truss has two equal bays that the 2 x 4 may be run straight down the center on top of the chord and the ends nailed to the top of perimeter 2 x 12. While you have the extra manpower, pass some sheets of plywood up on the roof. Use 5/8″ plywood if possible. 1/2″ plywood meets code with metal support clips but is nowhere near as permanent a roof as 5/8 plywood.

At this point I install the 2 x 4 “girts” or perimeter horizontal boards that the side wall plywood will be nailed to. On the bottom of the posts at the finished floor height another 2 x 10 or 2 x 12 is installed around the entire perimeter with the exception of the spaces between the garage door openings. A temporary board is nailed across the opening to hold back the concrete when it is poured and then removed later for car traffic. Install the side plywood on both gable ends and the walls. This helps stiffen the structure as well. Install a one by two along both gable ends flush with the top of a scrap piece of plywood laying on top of the truss. It will stick up past the truss top 5/8 inches. Install your fascia boards on the truss bearing sides remembering the roof plywood when installed must be flush with the fascia so as not to create a bump in the shingles. Now install your roof sheathing (plywood). If you have access to an air nailer it will greatly speed this work. Make the roof plywood flush with the inside edge of the perimeter one x two you nailed on earlier.

Start with a full sheet of plywood. If you did your truss spacing properly, the eight foot sheet of plywood will fall directly in the center of a truss for nailing. Tack all four corners and perhaps the middle and move to the next sheet and so on. Start your second row with a ½ sheet of plywood to avoid having any vertical joints line up on the trusses in two consecutive rows. Then go to full sheets and so on. The third row starts with a full sheet again. Leave at least a 2″ air space along the top of the roof at the highest point or ridge. On both ends of the ridge on a twenty-four foot garage make the plywood go all the way to the top for about two feet. This will leave a twenty foot slot. When the roof shingles are completed and the vent cap is installed, this slot will let the summers hot air escape out the roof. With all the plywood in place now proceed to nail it all as per your drawings specs but eight inch spacing on the edges of the sheet and 6 inch centers on the field of the sheets should be fine. No less the eight penny common nails are used for this purpose.

There will be some minor plywood infill work at sofft ends or “pork chops”, around door openings and the like. Now is the time to nail the all plywood in place permanently. Install your 2 x 10 jambs at the over head door openings and do not forget to let them project past the plywood sheathing to allow a 3/4″ vinyl siding J channel trim to rest against them on all three sides. Racially your framing is finished.

Install your two layers of ice and water shield on the roof and the balance of the felt paper. Many companies today say you do not need the felt but it is cheap insurance when a broken shingle appears and unless you can install thirteen or so square or shingles by yourself in one day, it will help keep the inside of the garage dry as well.

At this point many carpenters will install the garage floor to provide them with a nice dry flat surface to work on while doing the siding. Not a bad idea. See my article on pouring sidewalks and slabs if your going to try and your the concrete yourself. A typical 24 x 24 foot garage will use approximately 7.5 yards of 3000 pound concrete (24 x24 x.33 divided d by 27= 7.04 cubic yards, Round up to 7.5 cubic yards at least.) I would get eight yards to take into account a thicker depression at each garage door and around the perimeter edges. Eight yards at $85 per yard is $680.00. Be prepared to pour for when the truck gets there to offload within one hour. Ant time after that you will charged extra waiting time and increase your bottom line costs. Have enough manpower handy to wheel and place the concrete as quickly as possible.

By buying my siding and trims at a going out of business sale I spent another $1200. The wood garage doors were $350 each. You can add windows and walk doors at any time to a pole barn style building with little extra effort so they not required in the basic garage to start. With my garage complete I spent a total of $4100 cash money and a lot of my own man hours. Beats $25000 all to pieces. See my article on vinyl siding for help with this part of the work.