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  • OT adding some roof above garage door

    My house used to have a carport- when I bought it a previous owner had walled it in and installed a garage door. There is no overhang on that wall, so I want to install one to help keep rain and sun out when the door is open. The door is 8 ft wide and the garage is 11 ft wide. I'd like to make this overhang as wide as I can get away with considering the inside structure. I'd also like for it to extend about 4 ft out from the wall.

    Last time I thought about doing this it was to extend the 3 ft wide overhang above my side door. I made the mistake of asking the city for permission and they acted as if I wasn't even worth saying hello to. Flat out refused, barely looked at the plan. I'm not going to ask for a permit to do this again.

    I'm able to do all the work to a high standard of construction, and if I build it I know it won't fall down- but that doesn't satisfy an engineer. If for some reason it comes up in relation to selling the house or whatever, it should pass the real estate inspection.

    I have enough left over roofing shingles to cover it to match the rest of the roof, so it won't stand out in that regard. It's the sticking out 4 ft that worries me- I don't want to use support columns, but if I must then I'd want them flush to the building. I'd cut and refit the siding to suit, but I'm not going to add siding. I'll just paint the columns and be done with it.

    Because I have pavement coming right up to the edge of the garage, I'd have to chop some out if I wanted to make a footing. Lot of work, messy to repair afterwards, want to avoid.

    My plan is to extend a pair of 2 x 10s out from the walls in the attic, attaching them to all the studs that I can- 4 ft of rafter outside and 6 ft of rafter on the inside. I'd like to get by with just a front header, probably a double 2 x 6 (would be 10 footers) and then properly spaced 2 x 4s for the roof ply to nail to. These 2 x 4s would have to terminate at the wall above the door. I'm thinking that this way I won't be adding too much weight, and I can rely on the existing wall to support the back edge of the new structure. If I start adding more rafter inside, I'll be forced to reinforce the piece of wall above the garage door- and then it starts getting to be more than I want to put into it.

    Many awnings are supported on cables or steel arms attached to the wall above them. I think if I do anything like that, it will draw attention. All I want is an innocent-looking overhang that has little chance of being failed by an inspector. Any thoughts?
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    IMHO better to ask forgiveness that approval most of the time. May turn out build it & they will come but maybe not but I'll guarantee if you tell them they will come. That's whay I love living on a farm no codes or permits except for the house but I overbuild so no cause for alarm. Some places still have no building code in some states.
    As far as building can you add a diagnol from the new overhang back to the lower front wall of the existing front wall?
    Last edited by flylo; 01-31-2016, 11:40 PM.
    "Let me recommend the best medicine in the
    world: a long journey, at a mild season, through a pleasant
    country, in easy stages."
    ~ James Madison

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    • #3
      Very tough question with the information available. Snow load can be very large and 4 foot is a huge overhang. The roof and overhang pitch will be a major consideration. The shingles will be very heavy, as will be the timbers required. A car port around here isn't normally considered a strong structure, frequently just a roof supported by 4x4 posts. Kinda makes me nervous.

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      • #4
        My concern would be with snow/ice load under worst case conditions. I'm doing a shop at my house outside Portland Ore. and was surprised at the snow load requirements for the roof. No 2x4s for the rafters, takes 2x6s min. with 7 in 12 pitch. I would imagine the snow loading in BC would be the same or (probably) worse. I paid an engineer to review and bless my plans, whether I have them inspected or not.

        Mike

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        • #5
          If the show load worries you consider putting 2 4x4s at the end of the 4' OH in the winter. Our house is tall & has a hip roof with 4'OH & my hanger has 2'OH which makes it nice, no rain running down your neck.
          "Let me recommend the best medicine in the
          world: a long journey, at a mild season, through a pleasant
          country, in easy stages."
          ~ James Madison

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          • #6
            As far as I know, I have to support 40 lbs/sq ft snow load. I will have 40 sq ft.

            Yes, I could use diagonals, and if I did I'd add the support columns as well, for somewhere to end the diagonals. Can I plant the columns on concrete supports, laying them directly on the pavement? I would be fine with that, since all I'd be doing is standing them against the frame structure for the door. Those little tapered concrete blocks with the steel saddles would be fine to keep the bottom of the columns off the ground. That would support the rafters on either side of the door, and perhaps a doubled 2 x 6 beam against the wall too. There's the support for the back edge of the roof.

            It's sag on the front edge that I don't want to see happen, and that's the full 10 ft wide. Perhaps I could consider one extra rafter in the middle, anchored inside with some cross bracing.
            Last edited by darryl; 02-01-2016, 12:00 AM.
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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            • #7
              Having difficulty with the visual, did/does the existing "carport" have an "A" shaped roof? And the 8' door you are wanting to have a cover over is in the wall with a gable end? And if that is the case, are you wanting to just extend the existing roof line out that 4' or do you want the extended roof area to have something like a hip roof line to it?

              Or are we talking flat roof?
              In which case, it sounds like, you are, more or less, building a deck that may have a snow load but however many feet up in the air, right?

              Bit confused since you talk about matching shingles, and to me based on my location, that is slope roof, not flat. And, maybe I am missing something, but if the garage is 11' wide and you are making this 10' wide plus 4x 1.5" (2x 2x10 each side) that is only 10'6", are you not then 6" short of getting those 2x10 over the wall? Or is there overhang that accounts for the difference?
              If I were thinking of doing this, I would be going directly over the walls and likely directly over the posts each side of the door should have (even though there is only a foot and a half difference) and see where that left me as to what else to do, I mean we are talking about cantilever of 40% here.
              Last edited by RussZHC; 02-01-2016, 12:25 AM.

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              • #8
                So......

                You want to keep rain and sun out "when the door is open".

                I got an idea for you.... Don't put a "roof" on, put up a frame and do a canvas or whatever awning!

                You won't need it in winter, as I assume the door won't be open that much at -15C, so you can fold it up, or whatever and take off the cover for winter. The snow load then becomes a non-issue. The structural considerations are virtually nil, other than it just blowing away.

                It will work just as well for rain and sun, will be cheaper, easier to put up, and could even be decorative.
                1601

                Keep eye on ball.
                Hashim Khan

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                • #9
                  Deleted- improper links
                  Last edited by darryl; 02-01-2016, 01:17 AM.
                  I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                  • #10
                    darryl:
                    that link shows a main photo of a garage with the doors on a non-gable side and other photos of doors in the gable end, no expert but to me those are both very different design issues.
                    What I think you are describing is a roof design like Adam Booth did to cover in the concrete pad next to his garage/shop but his would have the main door, if he decided to put one in, on the gable end, so all that support structure that is wall for him is open for you since you need to drive the car in that side.
                    His roof went about 2/3 back towards the existing garage roof peak and then came off at a different angle, more or less changing the truss shape after the fact at nearly every truss. This does not sound like what you want to do.

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                    • #11
                      Maybe this works- if so here's a couple pics to show pretty much what I have. This isn't my house, but the door is pretty much the same, on a flat wall just like this. I can't tell how high this door is, but mine is the standard small car garage door. Notice there's no roof overhang at all on the end of this building- same on my house.



                      Here's what it could be afterwards. Mine will end on both sides pretty much like this one. There's no blending in with other roof sections- just a stand-alone addition like this one. Mine would be shingled to match my roof, and is going to need a gutter and downpipe of course, but that's just a detail. I do have an existing drain pipe to funnel it into.



                      I don't have any habitable room above like this appears to have- just an awkward attic space, but which I can get into easily enough.

                      I have an alterior motive for thinking about this now- I need somewhere to mount my solar panels

                      Russ, I don't know what link you followed, but the first ones I posted went somewhere else entirely, so I deleted that all. This page is it now.
                      Last edited by darryl; 02-01-2016, 01:12 AM.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                      Comment


                      • #12
                        Had somthing like that to do, I made a box section frame to go inside the garage, 60mm square tube, bolted to floor and walls then stuck a pair of cantilever arms through the front of the garage bolted on, the arms supported the timber work under the roof, worked well, owner was happy with solution and no columns required
                        Mark

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                        • #13
                          So basiclly it's an awning I don't think you's even need a permit & Boslab has the right idea. I'd consider steel ot fiberglass sheets for the roof keeping it light.
                          "Let me recommend the best medicine in the
                          world: a long journey, at a mild season, through a pleasant
                          country, in easy stages."
                          ~ James Madison

                          Comment


                          • #14
                            I'm thinking it should be pretty much straightforward like that. I don't want to contravene a law regarding the length of an overhang though-
                            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                            • #15
                              I think I'd be inclined to attach two 2 x 6 ledger plates to the front of the structure--put a backup 2x6 on the inside and bolt right through the wall. Place one just above the door and the other about two feet above. Make up a half dozen or so mini-trusses and use metal joist hangers to attach them to the plates. Close it in with plywood sheathing, use appropriate soffit material on the bottom side, run some flashing across the top (seal it well to the face of the building) and shingle the top. If you're still concerned with the strength make your upper inside backing plate wider, run a 2x4 through the inside of the trusses and put in a few more through-bolts--that sucker ain't goin' no where.

                              As you're well aware, snow events here in the Valley are becoming more and more scarce--doesn't mean you shouldn't design for a 40 or 50 lb. load, though. But in the absolute worst case scenario--like the big snowfall we had in 2007--you might have to reach up there with a rake or something to pull the snow off. Not a big job if you've only got 40 sq. ft. to deal with...
                              Keith
                              __________________________
                              Just one project too many--that's what finally got him...

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