I've been looking at some cabins being built in my neck of the woods and I have a question regarding the need for a ridge beam, or not. These camps are being built with steep roof pitches ( 10/12 or 12/12 ), in an 85# snow load area. They have cathedral ceilings, but no RIDGE BEAM, just a 1.5 inch ridge board. Does the steep roof pitch eliminate the need for a RIDGE BEAM???
You mean to say there is no trace of any collar ties, no joists across the tops of the first story walls ? ???
Mtn. D's on to it. Ridge beams let you have a full vaulted ceiling with no wall spreading. The ridge beam needs point load support, IE post under each end and maybe center of span depending on the span/ beam sizes / etc.
The joist and or collar ties prevent outward forces from spreading the walls.
So it depends on a few different things in the exact design of the building.
raku, sorry to intrude on your thread. I have a similar question for the pros as well, only slightly different circumstances.
Mountaindon and Peg, how necessary are collar ties on a gambrel roof? I have a single tie I would like to get rid of entirely. 6 foot side walls, loft on one side. 16' width, collar tie about halfway between end of loft and end of shed. (overall length is 24')
The collar tie is placed about 4" above the topplate and not up closer to the top. zero snow load in this case. I believe it was installed in preparation for moving it (as in flatbed on a highway) and I would like any thoughts on removing it.
(http://www.loopy.org/pictures/galleries/Dixon%20Ranch/June%202008/_thumbs/640x480-DSCF1899.JPG)
A picture of it, the 2x8 in the foreground (http://www.loopy.org/pictures/galleries/Dixon%20Ranch/June%202008/_thumbs/640x480-DSCF1899.JPG)
Quote from: muldoon on October 16, 2008, 08:53:48 PM
raku, sorry to intrude on your thread. I have a similar question for the pros as well, only slightly different circumstances.
Mountaindon and Peg, how necessary are collar ties on a gambrel roof? I have a single tie I would like to get rid of entirely. 6 foot side walls, loft on one side. 16' width, collar tie about halfway between end of loft and end of shed. (overall length is 24')
The collar tie is placed about 4" above the topplate and not up closer to the top. zero snow load in this case. I believe it was installed in preparation for moving it (as in flatbed on a highway) and I would like any thoughts on removing it.
A picture of it, the 2x8 in the foreground (http://www.loopy.org/pictures/galleries/Dixon%20Ranch/June%202008/_thumbs/640x480-DSCF1899.JPG)
IMO you could remove that lone "collar tie" the loft will add the stiffness you need , the buildings not that wide AND there appears to be gussets on each rafter joint on both sides. If those are well nailed it will be fine without the lone collar tie.
That being said in a high roof / snow load area , a Gambrel roof is still subjected to the outward forces that a gable roof is subjected to. I think Gambrels where designed with a hay loft in mind, added storage, still under simple roof . The loft provided the "collar tie " resistance to outward spread of the side walls.
In fact just the weight of the roofing materials over time would cause the spreading without the ties on a larger building.
I see at lot of the "Tuff Shed" type of gambrel roofed sheds around here. Most do not have any cross ties, except maybe at the back end where they have a small loft area for storage. None have fallen over that I've seen. They use metal truss type plates at each joint. That roof of yours looks sturdy, especially for no snow.
FWIW, on a gambrel roof there is more outward force where the upper and lower slopes meet, than where the lower more steeply sloped roof section meets the side wall.
So I believe in this case the strongest gambrel roof would have ties at or nearer to that upper joint. Of course the loft would be next to useless. Always a compromise. :D
rakuz... It would be nice to see a photo or two showing all the structural components.
I'm trying to get a photo of the interior from the realtor. These are new construction camps and I'm thinking of buying one, thus my reason for asking you guys. Basically, they are 20 x 24 chalet style camps with a loft section at one end that probably takes up 10 or 15 ft. So, that still leaves another 10 or 15 ft of open exposed ceiling w/out any collar ties or ridge beam. I know there is no ridge beam because there are windows at the midpoint as well as sliding glass doors, ain't no posting there!
Look at the above pic submitted by muldoon, they're very similar, except no gambrel roof, just gable with an 85# snow load.
Quote from: rakuz66 on October 17, 2008, 08:13:36 AM
I know there is no ridge beam because there are windows at the midpoint as well as sliding glass doors, ain't no posting there!
They could have posted up the sides of the window then headered across the window top , with a "center" post off the top of the header. Not a direct path BUT still taking the ridge beam ( IF there is one) to bearing.
As PEG pointed out the absence of a post directly under the ridge does not mean there is no ridge beam. It simply means the downward force must be supported by some other means. Hopefully the buildings the are selling were designed by an architect or engineer who properly calculated the loads. And hopefully the construction crew followed the plans. d*
When you look up at the finished open end cathedral ceiling all you see is what appears to be a 2x, a ridge board? Is that correct? Perhaps that is just the interior cosmetic finish? Is the roof insulated? How much? The beam could be hidden up there. Unless you can see a shot of the building under construction it might not be obvious how it's put together. ???
I asked for the plans.