How to Build a Lean-to Shed





Introduction: How to Build a Lean-to Shed

I heat my home with wood, mostly. I have a Charmaster forced air wood/oil furnace in the basement of our old farm house in southern Michigan. The fuel oil burner is back up for the wood burner and shares the combustion chamber with the wood. I burned about 20 face cords of wood each winter, which I cut most on my own property.

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Step 1:

For the past several years I simply piled the wood behind an outbuilding which is some distance from the house. This exposed the wood to rain and snow and was sometimes a bothersome chore to carry it, drag it, cart it that distance into the house. So I built a lean-to shed on the side of my garage, closer to the house, and with a roof to protect the wood from rain and snow.

Step 2:

I started by deciding how big I wanted the shed. I wanted the length of the garage and out about 8 feet from the side. Then I decided it should have about a 7 ft. ceiling. With that I need to figure out what the pitch of the roof would be, still fitting about a foot lower than the eaves on the garage and using only 8 ft. 2X4s for the roof joists. After a few calculations I knew the distance from the garage to place the 5 4X4 treated posts with the 2X8X16 joist carrier.

Step 3:

After laying out a string on pegs in the shape of the shed, I dug post holes by hand approximately 3 feet deep. One hole could not go any deeper than a foot due to large rocks and tree roots. Using 2 - 80lb bags of ready mix concrete for footings, I dropped a few shovels full in each hole except for the shallow hole. I set a 4X4 post in each hole after the concrete hardened, filled the holes, squared and leveled the posts, then bolted on the 2X8 joist carrier with 4” X5/16 lag screws. Next I poured a concrete pad in the shallow hole, and set the post with threaded rods inserted into holes on its bottom, over the pad. I held it in place after leveling and squaring, by nailing it to the joist carrier. Once the concrete hardened I bolted that post in place also.

Step 4:

I then bolted 4 16ft. long 2X6 stringers to the side of the garage using 6”X 5/16” lag screws recessed in to the wood. Two were for attaching the roof joists, the other two were for roof joist supports and were attached about 2ft apart. I tried to attach the stringers at the 2X6 posts in my pole barn framed garage and placed large pieces scrap 2X lumber between the garage siding and the garage posts in the inside to give the lag screws something more to bite into.

Step 5:

The 2X4 roof joists were attached at 2 ft. intervals with nails an metal L-brackets at the wall side and hurricane ties and nails on post side. The 2X4 joist supports were attached with nails and metal brackets between the lower stinger on the garage wall and the roof joists. The length of the supports was chosen so that I could get two supports from one 8 foot 2X4, rather than using any architectural calculations. I anticipate a fair amount of snow sliding off of the garage roof onto the shed roof, so I hope it will be strong enough to support the weight.

Step 6:

Next 2X4 nailers for attachment of the roofing panels were nailed onto the top of the roof joists about 2 feet apart. I added some extra scrap 2X4 where I suspect the snow sliding from the garage roof will hit. I then attached a few lengths 3X3 angle edging to the end of roof joists to help protect from the weather. Eleven galvanized steel 3ft X 8ft roofing panels were screwed to the nailers with #10 1-1/2 in. External Hex Flange Hex-Head Wood Screws which had a rubber washer. The gable ends of the roof were also covered with metal roofing material. I used aluminum flashing from a 50 ft. roll between the garage wall and the shed roof.

Step 7:


Almost all material was purchased at my local Home Depot store except for the steel roofing panels, angle flashing and roll valley flashing. I purchased those items through special order at Menards because I saved about $3 per panel on the steel roofing.

Step 8:

To finish it off I built a large gate out of cedar fence boards and pressure treated 2X4s. It was then attached with heavy duty hinges to the last post. I rigged up an short piece of chain with a dog leash clip that clipped on to a screw eye bolt to hold it shut.


Its working out great. It keeps the wood dry and I'm amazed at how much more heat I can get from the wood now.

As to the roofs structural integrity, it recently held up to a snow storm which dumped 14 inches of wet snow.

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    I didn't seal it, haven't had any problems. Thanks for reading.

    Great instructable. This is not so much for you, but for others reading this. Check with city and state ordinances before building anything that permanently attaches to your home. I live in Southern California. I helped a friend add a pergola to the back of his house, but he had to get all kinds of permits, and it had to be WAAAAAAAAY overbuilt (probably due to earthquakes). Had to use yuuuge freaking beams, through and lag bolts, and everything had to be inspected. Building it took a weekend, but the paperwork and inspection took forever.

    Here are just two questions that will give you an idea. This is from Costa Mesa, Ca:

    Q: Do I need a building permit?

    There are very few exemptions to the requirements for building permits. As a general rule, building permits are required for the construction of structures, additions, alterations, retaining walls, and most miscellaneous structures. It is suggested you check with the Building Division prior to constructing masonry walls and all types of fencing as there may be requirements for permits. Re-roofing also requires a building permit. Swimming pool enclosures require plan review, permits and inspection.

    Electrical, plumbing and mechanical permits are required for new construction, alterations to existing systems, most repairs to existing systems, etc.

    Prior to commencement of work, it is recommended you call the Building Division and check for permit requirements. You can reach the Building Division at (714) 754-5273.

    Q: How do I obtain building permits?

    The scope of work determines how permits are obtained. In most instances, permits for attached patio covers, block walls/fences up to six feet in height, in-ground pools, retaining walls up to four feet in height, storage sheds, etc., may be issued at the counter. A minimum of two site plans are required. The site plan must indicate the property layout and show the location of the proposed work. Standard plans are available for block wall and patio construction.

    Permits for minor residential repair work, such as water heater change outs, electrical service upgrade, furnace change outs, etc. are generally issued at the counter.

    Permits for larger projects usually require plan check.

    The Building Division counter staff is available to assist you in obtaining your construction-related permits. The Building Division counter is open Monday through Friday (except holidays), 8 a.m. to 5 p.m.

    Note: It is suggested you arrive at the Building Division counter no later than 4 p.m. if possible. This will allow adequate processing time for obtaining over the counter permits and/or plan check submittal.

    jimmar57, this was an easy to follow instructable. From the picture of the roof frame, I could not see if you used nails or bolts on the horizontal 2x6 that goes from post to post in front which supports the roof joist. I am asking because after a few snow seasons, with all the snow weighing down on the roof edge, the nails could pull out of the 2x6 and 4x4 post and your roof could give way. Using bolts, washers, and nuts or placing an additional 6 inch piece of 2x4 below the 2x6 at each post as a ledger board would help support the weight better. Just a suggestion so you get many years out of your roof.

    2 replies

    Thanks for reading and thanks for the advise. I use long lag screws (3/8" x 5") and washers. Bolts running all the way through probably would have been better but I figured the hefty lag screws would be sufficient. I also used metal hurricane ties between the roof joists and the horizontal 2X6. I thought about adding some Y-bracing from the posts the horizontal beam but the ledger board sounds like a good idea.

    The 3/8" x 5" lag screws and washers will last a long time especially if they are galvanized. I just could not see them in the picture. The ledger board at this point is not need because of the lag screws. The hurricane straps will prevent the roof joist from flying up if the wind comes up from the bottom. If your post are cemented into the ground you should be good to go if not the wind can lift the roof and post out of the ground especially if the soil around the post is sandy soil.

    Nice shelter, but one thing worries me. I'm not sure the sheet of OSB is enough separation between the house and the rick. Pests are attracted to woodpiles; and could easily damage the siding--and more! Been there, ugly things happen in wood piles.

    3 replies

    Thanks for the concern, you are probably correct. The siding is vinyl but I imagine pest could still do some damage. I'll have to wait and see and make a change in the summer if I see a problem.

    I think I'd leave a gap between the wood and the garage. My cheap thought would be old skids to allow for afew inches of air gap and the ability to spray some insect spray between the wood pile and the garage.

    I'm going to be doing something similar on the side of my garage, but enclosing it. I'm looking for a storage shed for lawn mowers and stuff like that. My hope is to run a 2x6 inside the vertical posts on the 3 open sides and trench down about 4 inches so that the 2x6 sticks up about 2 inches. Then back fill the area with gravel to allow for drainage of any water that gets in.

    thanks for reading and commenting. the particle board is attached to 2×4s between it and the garage siding. so there is about a 2 inch gap. time will tell if that is enough.

    I'm bookmarking this for later reference.. I need to build a lean-to onto the side of my 50' x 50' shop. I want to use steel posts. I have 2 pole barns with square penta treated posts that are 30 years old. Some, but not all of the posts have rotted off at ground level. I fixed 2 by digging 2 ft hole beside the post, inserting steel strap into hole, filling hole with concrete and fastening strap to post with lag screws.

    The rural electric company's fix on their poles is to dig around the poles and wrap with plastic sheeting. IDK if it works or not.

    Very nice job looks like you've done this before. ;-)

    That looks plenty strong with the angle braces on the rafters. I'd say it should easily handle 2" of snow.