Timber Framers Guild

gambrel roof without perlin

Posted By: Woodchizzler

gambrel roof without perlin - 09/07/17 02:40 AM

hello everyone, I am hoping for some information/ opinions about a house I was in a little while ago that was built in the late 1600's. it is a cape with a gambrel roof but it did not have purlin posts and beam supporting the intersection of the two roof pitches, I haven't seen a gambrel done that way. Also the top roof pitch was probably only a 3-4pitch, which I would think a house of that era would have had a much steeper top pitch even being a gambrel. As you would expect the top plate in the front of the house is bulging out and 2nd floor joists separating, but the owner is sure that it is from the failing foundation and not the roof. The low corner on first floor seemed convincing as the culprit, until I saw the roof framing. To add to this, there is a monster beam (17"wide chestnut!) in the center of the house to catch 2nd floor joists that only span 9-10' . Is it possible that this house was originally a gable roof that was later converted to a gambrel? I really don't know when gambrel roofs came about in new england. Did they start out with out purlins? I would think that load transfer would have been obvious to the timber framers of those days. I wish I had a camera with me that day and could have taken pics to show but I didn't know that day I was going to end up in that house, just a chance encounter.
Posted By: Woodchizzler

Re: gambrel roof without perlin - 09/07/17 01:25 PM

I forgot to mention that the 17" beam runs the same direction as the ridge, not perpendicular.
Posted By: Jim Rogers

Re: gambrel roof without perlin - 09/07/17 01:33 PM

You might consider contacting the group in the guild known as
TTRAG. Traditional Timberframe Research Advisory Group at this webpage http://www.tfguild.org/traditional-timber-framing someone in that group may know more about this type of roof system.
Good luck with your research.

Jim Rogers
Posted By: Woodchizzler

Re: gambrel roof without perlin - 09/08/17 01:59 AM

ok, I will do that
Posted By: Roger Nair

Re: gambrel roof without perlin - 09/08/17 02:21 AM

Regardless of whatever cause of the original separation of the joist and plate, there is an ongoing problem that could lead to a much more serious movements brought on by roof load. An engineer with restoration experience should be called in for an evaluation and a repair program. I take your description as a serious problem and stabilizing before winter might be prudent.
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