How do I open ceiling with rafter ties in the way?

Discussion in 'Framing and Foundation' started by sab, Feb 10, 2013.

  1. Feb 10, 2013 #1

    sab

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    Description: Swiss chalet built as a summer home (Maine). Second floor ceiling has strapping nailed to the joists (rafter ties), with cardboard white tiles stapled to the strapping. The 1959 installed tiles is falling down plus I'm installing Andersen's on a gable ends and had to open the ceiling to reframe.

    Q: The ceiling joints are 2"x 4" x 30'(?) and 20"-24" on center. What are my choices to open up the ceiling and install sky lights? Can the licensed contractor install LVL's like every 4' or something if I remove the ties? How can I open up the ceiling?
     
  2. Feb 10, 2013 #2

    BridgeMan

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    Your post doesn't make sense. "Ceiling joints" are 2" x 4", 30' long? First I thought you meant "joists," but realized a 2 x 4 cannot span 30' without sagging terribly, just trying to support its own weight. How about a better description of what you actually have? And a few pictures and a sketch would help a lot, too.
     
  3. Feb 10, 2013 #3

    sab

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    No one is standing on the joists they are covering the catherial ceilling of the chalet (there is no third floor). Yes they're 25 or 30' long because they where milled that way and they measure a real 2" x 4" (or 2.25 x 4.25). The house was problaly ordered from the mill and built in 2 or 3 days like dozens of others. Like a ocean beach cottage used for the summer months and converted to year round this is a lake cottage. That ocean beach cottage that cost 5K to build may be worth 500K today or more. BTW - Your right I had to sister the 2x8(?) on the 1st and 2nd floor because they were 24" on center and the floor was too bouncey.
     
    Last edited: Feb 10, 2013
  4. Feb 11, 2013 #4

    nealtw

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    Your rafters sound like they are well under designed and removing the collar ties would weaken the structure. I would get permits for the work and they may require an engineer, anything else is just guess work.
     
  5. Feb 11, 2013 #5

    sab

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    Agree, As an engineer, I just wanted to understand what my options are and what the structural engineer is going to propose, if anything. I want to install a new roof, and if I install a new roof then I should install skylights, and if I install skylights then I need to open up the ceilling. That doesn't include the fixing furnace chimney thats tied into the fireplace chimney that pass through part of the roof. Looking forward to that condo in FL!
     
  6. Feb 11, 2013 #6

    nealtw

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    For the structure alone you would at least double up the rafter on each side of the window and hang a double above and below and then hang the cut rafters off that but the ties, maybe you get away with doubling those but I don't know.
    But like Bridgeman mentioned the rafters a questionable.
     
  7. Feb 11, 2013 #7

    Fireguy5674

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    Ok, let me rephrase your description and make sure I understand what you have. The 2.25 x 4.25 x 30' members are rafter ties to stabilize your roof from bowing in or out at the center of your rafter span. Attached to the bottom of these are some 3/4" (?) "straps" running perpendicular to your rafter ties to which your ceiling tiles are stapled. I am assuming probably roughly 12" x 12" tile size. Now you want to remove the tile, the strapping and every other rafter tie to open up the area and create a cathedral ceiling effect?

    If I understand your intentions correctly, taking down the tiles and most of the strapping should not be a problem. I would not remove all the strapping because I would be concerned about a 30' long rafter tie wanting to bow sideways from the compression of roof load. A 2x4 or 2x6 could be added on top of the rafter ties to keep them from bowing. I would break the 30' span into at least thirds and run two rows the complete length of the roof similar to stabilizing the bottom chord of a truss.

    I am like others here who are amazed that the rafter ties have not sagged. Are there any verticle supports going to the rafters anywhere along this 30' length? Also, what is the pitch of your roof and what is size and span of your roof rafters? These will make a difference in what you can do. If you decide to try to elimnate every other rafter tie, you will definitely need structural expertise. From an appearance standpoint instead of LVL's you might think about double 2 x ?'s (whatever the load requires) with spacer's which you can slide over both sides of the existing rafters and bolt through. In other words, two 2 x 8'2 (?) with a 2.25" spacers which you can fit over the rafters at the ends and bolt through. This approach might also eliminate the need for horizontal stabilization. Hope that is a little clearer than mud.

    One more headache. Be careful when removing ceiling tile. I will be willing to bet that they contain asbestos. :( The are the right age for it.
     
    Last edited: Feb 11, 2013
  8. Feb 11, 2013 #8

    BridgeMan

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    And with all the rafter ties gone, then the only problem will be how to bring the exterior walls back into alignment, because they will be bowing outward. I saw it happen on a place in the mountains of NM some years ago, where significant snow loads on the roof were an issue--the guy yanked all of the rafter ties, and then was surprised when both outside walls deflected outwards several inches, each. What a mess. He finally "corrected" the problem by installing 1"-dia. steel tie rods every 6' or so--looked ugly as sin, but they kept the walls from completely letting go.
     
  9. Feb 11, 2013 #9

    nealtw

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    I would like to see a photo of the inside, what about insulation?
     
  10. Feb 11, 2013 #10

    sab

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    FireGuy5674 - your correct in your description. I'll see what the engineer says. I was thinking tie-rods would be the best solution. LVL most likely only provide compressive strength not tensile. The roof is 45 degrees (12/12 pitch). The roof overhangs the sidewall 2.5 feet. The second foor rooms are impacted by the slope of the roof. Thanks boys. I thought maybe there was a best practice to install tie rods or something. I can't be the only chalet owner you wants to do this.
     
  11. Feb 11, 2013 #11

    Fireguy5674

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    Sounds like BridgeMan is on the right track. Most of your rafter tie load may be tensile. If that is the case and you prefer the look of the tie rods, they will probably work well. Let us know what the engineer has to say.

    Is the current insulation laying on the top of the ceiling tile? If so, are you planning to insulate between the rafters and drywall the bottom of the rafters? Just additonal dead load to think about which may contribute to a compression load on your rafter ties. With 30' rafter ties, a 12/12 roof pitch and assuming an 8' ceiling height that makes it about 23' to the roof peak from the floor? That is going to be quite spectacular when you get done. I don't think I would want to try to heat it though. :D
     
  12. Feb 11, 2013 #12

    sab

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    I need to measure those rafter ties maybe there 18' (almost 3 beds long). I would like to use spray foam between the rafters (incr R value) and cover the rafters with wallboard/blueboard. The rafters are not pretty and I have to insulate like you said. At 53, I write checks now. The place isn't occupied year round so if I turn the heat on it would only be a few days (ice fishing season). However, that brings up the next issue is heat. There only a crawl space and a horzontal forced air sysem that doesn't work. The oil tank is there too (horzontal). The house mover said he wants to "move the house into the backyard so he can blast the ledge under the house" for the foundation ($50K). The house is sitting on posts/columns and there ledge that the glaciers dug up when they made the north-to-south pointing lakes in the area. The house is sitting on a Gigantic rock
     
  13. Feb 12, 2013 #13

    nealtw

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    2x4 won't give you enough depth for insulation, you may want to add to them. If the roof extends past the floor, the floor would be the tie in the lower third. If you beef up the rafters perhaps you could raise the upper ties. Do you have a ridge beam supported all the way to the ground?
     
    Last edited: Feb 12, 2013

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