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jes
Joined: 01 Apr 2005
Posts: 1
Location: Alabama
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 Posted: Fri Apr 01, 2005 7:26 pm Post subject: Roof collapse on "Prow Front" A frame |
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We are considering buying a 20-30yr old A frame as a 2nd home. As a retired mechanical engineer, I am concerned over what looks to me like beginning failure of the main roof beam support post at glass end of living room. Prow Front is similar to a Lyndall Cedar layout with no interior cross beams tying lower end of roof rafters together and with a single post at center of the glass end supporting the ridgepole beam. Face of this "Prow" has both sides at an angle to each other, with both as 2 planes intersecting along the central support post. Above sliding glass doors each side of central post I visualize 2 separate beams from each outside wall joining the central support post (I visualize them notched into the post, though not sure due to presence of inside and outside walls).
The central support post, from this joint down to floor, slopes inward to tune of around 3 or 4 inches at the referenced joint. It looks like the post above this joint also slopes inward at joint though harder to tell due to ridgepole 12 to 15 ft above the joint vs joint only 7ft from floor. Opposing walls both appear vertical so the sliding glass door units appear cockeyed with outer end vertical but inner end (by central post) slopped inward along with lower section of central post.
As noted, opposing walls look vertical but I think I can see some exposed rafter tails sticking out maybe 1 inch or so further (more overhang) at wall end towards the glass prow end. Rafters laminated of (3) 2x8 boards are on 4ft centers with a sloped ceiling of exposed 6inch T&G boards.
I interpret all of this to mean the referenced joint in the single central post at prow end is failing at the joint with beams over sliding glass doors on each side of it, the ridgepole beam (looks like 6x12) is dropping and the rafters at this end are following the ridgepole yielding the longer overhang (the whole roof is collapsing and clollapsing the glass end wall as well).
I can visualize jacking the ridgepole up but have nothing inside the house to support this kind of load (on steep slope with finished lower level). This lower level has cement block walls in area under the central post but inaccessable to use for jacking base. If post was collapsing outward I have a very substantial rock fireplace wall at center of the house from which we could tie a heavy come-along and cable to pull the joint back vertical -- but joint is collapsing the wrong way (inward). I might be able to arrange this fireplace wall to serve as a base from which to jack the joint back outward to vertical. Angles involved would make jacking the joint this way to be far more efficient with more result for less effort than jacking the ridgepole vertically. Once vertical with roof again lifted back up, I would install heavy steel plates on both outside & inside with bolts, etc to reinforce the joint & hold post vertical (I would remove both outside & inside walls to install the plates).
My question is does this make sence, any other ideas, is it worth the work, how much might it cost to have this done professionally, or should I find another house to buy, etc, etc??
Thanks for any thoughts -- jes |
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