I need some advice to evaluate contractor suggestions regarding replacing a flat roof on my 80 year old garage.
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The critical facts include: <!—-><!—->
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>> the Garage is 20 ft deep by 22 ft wide,<!—-> <!—->
>> built-up beam of (4) 2x8s spliced together runs front to back with one support in the middle,<!—-> <!—->
>> current roof deck sits on 2x6s 24 inches on center, joists sit on top of the built up beam (no fasteners to beam which is starting to show signs water damage) and sit on top of a 2×6 attached to the wall framing at each wall, the joists are nailed to the stud in the wall cavity (but not to the 2×6),<!—-> <!—->
>> Roof deck is a mixture of plywood and miscellaneous scrapes that the last owner found laying around,<!—-> <!—->
>> Roofing looks like the low-slope DYI product made by Henry that you can buy at HD;<!—-><!—->
>> The whole damn garage sits under the biggest buckeye tree you have ever seen and gets bombed for extended periods in the fall. <!—-><!—->
>> When the buckeyes stop the snow starts falling and we get lots, <!—-><!—->
>> The city will not let me convert to a pitched roof because of proximity to the property line (could fight but won’t). <!—-><!—->
>> Only planning on being in the house for another couple of years but I can’t tolerate shoddy work.<!—-><!—->
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Any suggestions on the best replacement strategy for the roof? How about the built up beam? I would love to have no supports in the middle of the garage but I’m not certain that’s possible with a built up beam. Should I consider an engineered beam? <!—-> <!—->
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Any thoughts on buckeye-proof roofing materials? It will cost a fortune to cut the buckeye tree down (which I recognize as probably the best approach) and will Raise the ire of my neighbors who have never been hit with a buckeye.
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Getting all kinds of suggestions from financially interested parties and incompetent DYI neighbors – thus I throw it out to the wisdom of the board. <!—-> <!—->
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Thanks.<!—-> <!—->
Replies
I would say flat roof = problems, with or without buckeyes.
No real suggestions, just some random questions that my help you think about the issues:
Are the buckeyes damaging the roofing? Limbs and leaves holding the water? Just looks unsightly?
Is the rest of the building sound? Hard to want to spend much money putting a nice roof on somthing that's about to fall down anyway.
Really no pitch allowed at all? Even a 1/4" per foot slope would make a big difference in drainage and still look pretty dang flat.
Personally, if I were only going to be in the house another couple years, I would work harder at tolerating the existing roof.
A 2.25% pitch over 20" is 5 1/2". Think 2x6. 2% is good drainage.
Rip a 4x6x20' corner to corner. Place on each end wall.
Tell your lumberyard you need a laminated ridge beam 26' long to carry a 20' roof span with your local roof load.
Notch the beam ends around the existing (level) top plates to fit top flush with the ripped 4x6 at mid span of the 20' depth. Set 26' of 4x6 over the front headers.
Have your local welder make two columns like this fine architectural drawing shows:
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The column has to be over the bottom plate. The upper shelf must extend past the top plate. Set 'em under the beam. Use keeper flanges. Your AHJ can tell you what size steel posts you need.
Set 2x6 16OC on top of everything. 5/8" ply. I&W Shield. Roofing. If I could afford it, I'ld use two layers of I&W because it's so flat.
Only raises the rear 5 1/2". The front, 11".
My carriage house is similar, except that it is a walnut tree rather than a buckeye.
Anyway, if you want to hide the slope, (and if this is easy) add in a parapet wall. I mean slope like 1/8" to 1/4" per foot. Then put on a rubber roof, like EPDM.
Seal-O-Flex
Seal-O-Flex
Seal-O-Flex
God, I sound like a broken record.
Forrest