Help Designing/Building Techniques a Lean-To

[Model A Fan]

On my property, I have about a 1.5 car garage (detached) and on the left hand side, there is a patch between the fence (neighbors) and my garage that I would like to put a lean-to structure over so I can park a car/boat/project/UFO/whatever under to free up space in my garage, driveway or whatever.

I am looking for some building techniques that would show how to properly join the boards together to get a rigid structure.

For the footers, would you recommend going with a 4x4 inset in concrete, 4x4 on a pier block or something else?

I am leaning toward a free standing structure instead of attaching a side to my garage via a 2x6 toe board (or whatever its called). I would like to have the roof at a slighter angle than the garage roof pitch, that way I have more clearance and it will still drain. The lean-to roof would start under the actual garage roof so there is overlap and no leaking between the two roofs. The only reason I would attach one side to the garage would be to have MAXIMUM square foot in the lean-to by eliminating the 4x4s along the garage.

I am planning on an open side design because I don't want to mess with siding, but I may put up some siding just to match the garage. I was also reading that going with a metal roof instead of plywood/shingle would be good because I can get away with fewer crossbeams and it is less weight. Who knows, so I guess we'll see.

Any ideas and pictures of existing structures would be nice. I have included a plan for mine, I just need to refine it and start building.

Purple is existing garage (needs a different color, I hate purple) and red is proposed lean-to structure).

 

[Cyberbear]

After seeing your simple proposed shed roof addition, this what I'd do if it were mine:
1. Attach a horizontal ledger 2 x 6 lag bolted into the existing wall as support for the sloping roof rafters, and using rafter hangers to attach your rafters.
2. Build either a stud wall or open beam construction to carry the outer rafter ends.
3. Cover the rafters with appropriate sheathing and roofing materials. Keep in mind the flatter the pitch the more prone it is to leaks. Stay away from metal unless you are very familiar with the types and proper installation needed. A very flat roof may need to be hot mopped, or use a 90# rolled roofing well sealed against seam leakage. Flat roofs don't weather well unless done properly.
A free standing structure is not as strong as attaching to the existing one, and requires more space, and materials, according to you sketch/plan. Of course, wind and snow loads may be a consideration, as well.

 

[Model A Fan]

The proposed area of cover is 12' 2"x24' long.

Thank you for the reply. What I am proposing to do is leave it open on all sides to reduce the chance wind will affect it. The only reason I would enclose it would be to protect something I don't want exposed to harsh wind. If I enclose the sides, what kind of permits would I need? Since I am close to the property line, I didn't want to run into that kind of issue.

I was thinking of the corrugated metal roof, but since it does rain here a bit, maybe it would be better to go with the shingles and wood structure? I was going to do at least three 4x4 posts along the side, perhaps four in total. Does that seem like enough? Would cement encased 4x4s be better or use the pier blocks?

 

[SteveCh]

As far as what is permissible, that will depend 100% on where you live and what county or city bldg. dept. hassles you might find. Plus, some municipalities have minimum set-back rules for building near the property line. In my case, it's 35 feet. Yours may be far less than that, if you even have them.

What you are proposing is actually more of a "carport" and not a lean to if it isn't attached to the garage wall. Not that it matters. But free-standing it needs bracing at each 4 x 4 at the top. I did mine this way, and it's held up through a 115 mph wind storm and a big 4' snowfall we had.

The roofing shouldn't matter. Galvanized tin and other metal or shingles...whatever you want or whatever your bldg. dept. will approve. The flatter the roof, the less I would like shingles. With metal panels, you can skip the decking.

You can sink the 4 x's in concrete if you want, or you can bolt post holders, galvanized steel, available at any bldg. supply, into the concrete. If you have a moist ground situation or high water table, I would recommend not sinking the posts in concrete, as even pressure-treated ones can eventually rot from moisture down in the concrete. For my carport, I did sink the 4 x's in concrete, and I live in a very dry climate with average maybe 10% humidity. I've been doing this for decades and never had a problem. If you do this, don't set the post directly on the ground and then pour concrete around it, moisture will wick up through the wood grain from the ground. Either place a bed of broken rock down first, then the post atop that, or you can place a stone in the hole, the post atop the stone, then pour around it. Some people pour a footing several inches deep, then when firm, place the post atop the footing, then pour more concrete. I find it simpler and faster to just place some rock in first, saves a step of pouring concrete and waiting.

 

[Model A Fan]

So it looks like after calling my city planning board, I have to have a 5' set-back if I have an open structure, but if I have a wall between my property and the neighbor's, I can build RIGHT UP TO THE LINE as long as there is the 5/8" gypsum board "to protect against fire" as a 1hr fire wall. Retarded rules. I guess I'll be putting up a wall to go along the side of the neighbor's! I would have thought it would be frowned upon.

So I guess I'll have a 24'ish wall running the length of the carport now.