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Thread: I need a carpenter's (pro or hobbyist) advice

  1. #1
    Join Date
    Feb 2018
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    Mantorville, MN
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    51

    Default I need a carpenter's (pro or hobbyist) advice

    My sugar shack is located in my sugarbush, 3/4 mile from the farm or roads. I built a versatube metal carport and closed it in added windows and a cupola. Here's my issue. When cooking, the metal roof provides enough rain inside the shack to put out a california wild fire. I'm thinking off replacing the roof this winter before the sap run. I will use plywood, a water shield and then a metal roof.
    My question, if I make rafters and attach to the metal roof rafters, is the spacing good enough or should I add more rafters in between the metal rafters. My building is 12x20 feet. and there are 5 metal rafters approximately 55 inches apart. too wide? rafter in between? Purlins?
    Thanks in advance,
    Tom

  2. #2
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    May 2002
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    Cabot Vermont
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    455

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    why not add hoods to the pans to control the steam instead of building a new roof.
    Blaisdell's Maple Farm

  3. #3
    Join Date
    Apr 2019
    Location
    Nashville, MI
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    I agree with Brian.. Adding a hood to remove the steam will be much less expensive than re-doing the roof. With the span you have you would have to add rafters. Besides this time of year is not the best for completing a project like that. If you don't do things like this is there a local amish metal fabricator near you?
    2004 - 2012 2x3 flat pan 25 to 60 taps
    2012 2x3 new divided pan w/draw off 55 taps
    2018 - didn't boil surgery - bought new evaporator
    2019 new SML 2x4 raised flue high output evap. 65 taps
    made 17 gal syrup
    2020 - only put out 53 taps - made 16.25 gal syrup
    2021 - going for 50 bags and 50 on tubing

  4. #4
    Join Date
    Feb 2018
    Location
    Mantorville, MN
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    Guys, good advice. I have given thought to a hood and will look into it. The problem will unfortunately still exist. As the cold metal warms, condensation begins and water starts to drip. The humidity accentuates the problem. Even today, I was in the shack and started my 2 burner sunflower heater and within minutes I had water dripping. The daytime is usually less severe, if sunny, the roof warms and water does not condense. But I tend to cook all night and you know the saying, when it rains it pours.
    I'm thinking roof and hood might be best.
    Thanks

  5. #5
    Join Date
    Mar 2017
    Location
    Granville, PA
    Posts
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    Your plan to replace the roof will prevent the rain inside your sugar shack. The problem will move to between the plywood and the tin. The water shield will help but because the plywood on one side will regularly be a different temperature than the tin on the other side keeping your roof screws tight will be a nightmare and eventually your plywood will start to rot because roof screws will be missing and steam will saturate the underneath.
    A different approach would be to install 2" closed cell foam insulation on the underside of the tin. That would lessen the temperature difference and therefore reduce the condensation. Plus it should last a longer time with less cost and less work. But make sure to have an air space between the insulation and the tin and also ventilate the inside cathedral ceiling peak.
    I think that the advice stated earlier to look into a hood will help also but after you get the temperature/ventilation controlled.
    And yes, that is too much distance for wood rafters to support purlins unless you would use 4x4 as your purlins.
    Last edited by minehart gap; 01-04-2021 at 05:58 AM.
    Matt,
    Minehart Gap Maple

  6. #6
    Join Date
    Jan 2017
    Location
    Williston, VT
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    Unless you're a carpenter and a structural engineer, then you shouldn't modify a prefabricated metal building, especially the roof framing. Even the modifications you've made with the cupala may have compromised the structure.

    From a structural perspective, the only correct and safe plan would be to rebuild the entire building frame - roof and walls from the ground up. At the very least, I would expect you'll need to add rafters but the extra roof weight will require more robust walls.
    Ken & Sherry
    Williston, VT

    2017 - 13 gallons on 65 taps (12 buckets, rest 3/16), 2x4 flat bottom, modified cargo box sugarhouse
    2018 - 90 gallons on 418 taps (gravity lines), Leader 30"x10' Vortex Arch & Max Raised Flue with Rev Syrup Pan, New Sugarhouse
    2019 - Burned through alot more money: heated kitchen, 2x2,000 and 375 gal ss sap tanks, CDL1200 RO, Bauch Vac Pump, More taps, etc., etc., etc.
    https://www.facebook.com/pumpkinhillmaple/

  7. #7
    Join Date
    Mar 2008
    Location
    Lake County Ohio
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    I wholeheartedly agree with Ken.

    That car port is only designed for a 22 lb/sq ft snow load! Adding anything to the roof will just increase the dead load - on the walls - and decrease the live/snow load capacity. You may be able to insulate with some lightweight foam board but adding anything like plywood or wood rafters is a recipe for collapse.

    As it is, a 22 psf snow load is Not Suitable for any part of MN where 35 psf is the norm for the southern half and 42 is used in the northern half.
    John Allin

    14x18 Hemlock Timber Frame Sugar House 2009
    Leader 2x6 w/Patriot Raised Flue Pan 2009
    Leader Steam Hood 2014 - Clear Filter Press 2015
    Leader Revolution Pan and SS Pre-Heater 2016
    CDL Hobby RO & Air Tech L25 Hi Vac Pump 2019
    06' Gator HPX to collect wood & sap
    14' Ski-Doo Tundra for winter work in the woods
    Great Family 3 grown kids+spouses and 7 grand kids who like the woods
    7th Gen Born in Canada - Raised in Chardon Ohio - Maple Capital of the World..<grin>.

  8. #8
    Join Date
    Feb 2018
    Location
    Mantorville, MN
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    Thank you all for the responses.
    Weight has been a big concern as I have been thinking of doing this. When I enclosed the building I added 2x4's to the walls. They are not 16 on center but I could add more if needed to support a new roof.
    My thoughts was to run a 2x10 down the length of the roof and then have 2x8 rafters running from the peak and sitting on the walls. I would join the 2x8's to the metal rafters but most of the weight would be supported by the wall. I was hoping by adding a little additional pitch I would reduce the load on the metal rafters. As I am a dreamer and not a carpenter or a structural engineer I was only hoping this would work.
    I do like the idea of the closed cell insulation. How would I go about adding it securely? I am starting to look for someone who can fabricate a hood for me.
    Thanks again. I really appreciate the input.

  9. #9
    Join Date
    May 2010
    Location
    Savoy, MA
    Posts
    354

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    If you add enough 2x4's to support the rafters you should be fine. And if you make the roof steep enough (10/12 or 12/12) you will have almost no snow load.
    16x24 Timber Frame Sugar House
    Mason 2x4 Evaporator
    90 trees on buckets

  10. #10
    Join Date
    Mar 2008
    Location
    Lake County Ohio
    Posts
    1,307

    Default

    Quote Originally Posted by tpathoulas View Post
    Thank you all for the responses.
    Weight has been a big concern as I have been thinking of doing this. When I enclosed the building I added 2x4's to the walls. They are not 16 on center but I could add more if needed to support a new roof.
    My thoughts was to run a 2x10 down the length of the roof and then have 2x8 rafters running from the peak and sitting on the walls. I would join the 2x8's to the metal rafters but most of the weight would be supported by the wall. I was hoping by adding a little additional pitch I would reduce the load on the metal rafters. ....
    As long as you're not using any of the carport tubes to support rafters or a ridge beam, you should be fine. Lots of those kits are "engineering marvels" designed with minimal materials to make them affordable. Change or make one modification and it can be lights out. If that roof gets loaded to 35 psf, you've got over 8,000 lbs over your head.
    John Allin

    14x18 Hemlock Timber Frame Sugar House 2009
    Leader 2x6 w/Patriot Raised Flue Pan 2009
    Leader Steam Hood 2014 - Clear Filter Press 2015
    Leader Revolution Pan and SS Pre-Heater 2016
    CDL Hobby RO & Air Tech L25 Hi Vac Pump 2019
    06' Gator HPX to collect wood & sap
    14' Ski-Doo Tundra for winter work in the woods
    Great Family 3 grown kids+spouses and 7 grand kids who like the woods
    7th Gen Born in Canada - Raised in Chardon Ohio - Maple Capital of the World..<grin>.

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