Bonnet roof anyone?

[Scoutman]

Wondering if anyone has put a bonnet roof on their log home.

From the web: Hip roofs are the second most common in North America. Harder to construct than a gable but sturdier in high wind areas. This type of roof slopes down on all four sides. Bonnet style is the same as a hip roof with the addition of a lower pitched eave along the outer perimeter.

[StressMan79]

I know of one member who did a slighter pitch over a deck. I would think that eating into all four sides would be hard on upper story space. I don't think it is worth it, IMO. I'd just beef up the gable.

Actually, I am not doing a Gable. I'm doing a single pane shed style roof. This only works for smaller homes (I'm doing a 24x24). There are methods to my madness (passive solar, space considerations, etc.)

Become a member and come out to my place and see what it is all about! (scout, I know you are signed up. I said that for anyone else.)

[tgb3]

Hey stressman,
I have been reading things on here for several years now and have been watching your progress in Curlew. I have been looking at propery in that area and will be going on a trip that way this summer I hope. I will have a great many questions after the class on the members side. :)
Tom

[Scoutman]

Thanks Stressman. I'm thinking a high pitched roof (on a 32x32 home) to give me more room on the 2nd floor and a wide shed dormer on the back of the house. This would give me a single larger room on the 2nd floor and both sides could be used as closet space on one side and bathroom on the other side. The "bonnet" would cover a wraparound porch.

[StressMan79]

scout,

oh, I thought you were talking about

http://www.allianceconstructionco.net/resources/bonnet_roof_angle.gif

The bonnet would be fine to incorporate with a gable, although it may look a bit funny. Usually the gable end is clear all the way down. I have visited 3 with a partial bonnet.

the pitched roof will give you more room, but more unused volume also. take it to extremes, say you have a 30x30 with a 24/12 roof. then if you have a 15 ft run, your roof will go up another 30 ft. You don't need that much headroom. usually members do from 4/12 to 12/12. most do a 6/12. I am only going 4/12, but there are lots of things to maximize airflow and comfort level.

[StressMan79]

TGB, Thanks for the words of encouragement. If you are in the area, I have a lead on the best logger to get, the best Realtor to get, considerations on going off grid, etc. Plus, member's are free to stop by any time and bring firearms for hunting. Maybe we'll see eachother this summer. stressman79@hotmail.com

[rocklock]

bonnet roof
I am unsure why anyone would want a bonnet roof. Most of us want natural light, hence if we want to use a second (or third) story, then at a minimum you would need to add dormers, or sky lights.
We would also need to alter the ridge pole and some other stuff to make this work. There would be problems because we tend to want to put the supporting members on a log wall. These RPSL's tend to be in different places not on a wall, and require different types of support.
In other words, this is not s simple design. It is complex and not something that should be built on your first log home... And besides it make the livable space in the home smaller... Why bother?

[loghousenut]

Every time I have altered from the teachings of Skip Ellsworth it has cost me money. Sometimes it has been worth the money... Sometimes not. The basic LHBA roof structure is simple, cheap, and will never leak (well it could leak but if it does it is your roofers fault). The gable ends offer a good place to put a bunch of cheap windows that let in light and it looks cool.

At the risk of repeating myself... Every single time I have wavered from the LHBA way it has cost me money.

[Scoutman]

Just wondering if anyone had done it. Great points by all. Some rough measurements. And correct me if I'm wrong anywhere. 32X house, roof 16' at peak, roughly 18/12 pitch, 6' of headroom about 6' into the room.

I'll continue to calculate and build a model with a bonnet. Stressman, yes the pic is correct. But the bonnet will be at least 8' wide.

[rocklock]

OK, here it goes... I've got lots of honey doe's but then again it just elemental math...
32 foot square - good choice... I like it. Probably only 8 foot of walls.

12:18 roof not so much for the following reasons. 1/2 of 32 = 16 so the height of the ridge pole will be 24 feet above the top of the logs... So the total height of the building will approach 34 feet. That is 8+24+ roof which can be two feet or about 34 feet. Remember, the logs will be the cheapest thing and your minimizing the cheapest thing. Humm...

Rafter length - will be about 28.8 plus about 1 for overlap plus the overhang will be 3 or 4 or about ... probably about 33 feet. Probably need to be 12 by 4's and they will be special cut or you will need to go with I joists... Roofing cost will approach about 40 thousand... for a metal roof like mine. Then the cost of dormers and skylights. But there is a problem with the rafters being only 5 feet off the ground. This whole thing will be dark, unless you have a ton of dormers and skylights. I have three skylights that provide lots of light even on a cloudy day...

Then there is the problem of a shortened ridge pole, and the girders to lock them in place... and a steel bracket that will enable a log or something to make the bonnet. All which will need to be engineered.

The good news is that you will have a three story building with only 8 feet of log walls. There is a student built log home with a barn roof that is MUCH more practical.
http://www.loghomebuilders.org/image-galleries/student-log-homes/mark-lisa-sherrodd
or a double ridge pole design
http://www.loghomebuilders.org/image-galleries/studentloghomes/roy-africa

I would really like to know how you are going to support that shortened ridge pole... My quick estimate is it will be only 14 feet long...
good luck

[Scoutman]

Thanks Dave. I posed the question so that the people with the experience and know-how can tell me where I'm screwed-up. The 2nd floor will be seldom used. For company only and that will be rare. The 1st floor won't be open to the RP. Guess I'll have to do that model to show what I'm thinking. Of course NOTHING is set in stone. My desire is that no logs will be directly exposed to the sun and weather. Come to think of it, I could lower the roof substantially. No 2nd floor. And have the rare guests stay in a smaller log guest home.