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Greenie
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# Posted: 3 Aug 2012 04:29pm
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I am just starting a cabin project. The cabin will be a very basic 10'x14' on cement sona tube footing with a gable roof. I don't have any designs and am pretty comfortbale with most of it except the roof. The cabin will be for light use but I want to make sure it is safe. How do I amke sure I am building a secure roof and where can I get some guidelines?
This year I am just cutting and peeling the trees and will begin construction next summer.
Thanks
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fpw
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# Posted: 4 Aug 2012 02:40pm - Edited by: fpw
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Greenie,
You have to understand the design loads in your area, this will determine what materials you would need (you can look them up on the internet). Then, you make sure your materials are adequate for the load.
Once you understand the loads, you can use a calculator like the following to determine if the tree you will use for ridge between the gable is large enough;
http://www.forestryforum.com/members/donp/beamindex.htm
I like this calculator as it has one set up for round logs.
For a 10 x 14 structure figuring the loads is very straightforward once you understand the design loads for your area (it might look confusing but it is not as bad as it seems).
Some photos are below that show some basic design. One design is king post with ridge, the second is truss with ridge. These are timber frame project that I drew up using sketchup; however, both roof designs can be done with logs. I also included a couple photos that show my cabin. I used King post with ridge and because the ridge had to span 22 feet, I put a vertical post in the center of the cabin. The ridge is aspen and I think it was about 14" on the butt end and 10" on the top.
Truss Design
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King Post Design
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Rigging in a Vertical Post
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Stump Ranch (King Post Design)
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Greenie
Member
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# Posted: 5 Aug 2012 09:39pm
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Very helpful! Thank You! Beautiful cabin also. I am definitely going the King Post design as well. Your cabin is almost exactly what I am looking to build down to the footings but mine will be in smaller proportion. I am taking trees approx 12" on the butt end for the walls. I have been thinking all along I would tie my floor into the sill logs or second log up and just frame the floor with standard lumber and used rough wide pine floor boards but it llooks like you essentially built the floor and then built the cabin right on top. Is that right. I like the lloks of it. Any toughts in hindsight? Any other details you can share on your design would be apprecited. It looks like you used a saddle notch with a channel cut in under each log. Looks tight. Nice work!
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Malamute
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# Posted: 6 Aug 2012 01:02am
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You can do log gables also. The cabins I've done have had log gables, they are simple to do, and look good. The log gables also support purlins if you want them.
I prefer the floor to be inside the walls. In a regular concrete foundation, I have a floor ledge formed in the concrete, on piers, you could notch the tubes for a floor ledge, or bolt the rim to the logs as you mentioned.
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Greenie
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# Posted: 6 Aug 2012 07:49am
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Malamute,
Do you know where I can get a detailed drwaing of the log gables? I have seen these and like the style but, while I am no engineer, I still don't understand what is supporting everything on the gable ends especially where the smaller logs are not notched into another log near the top.
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Malamute
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# Posted: 6 Aug 2012 09:11am - Edited by: Malamute
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There are plenty of cabin books.
The load is straight down into the walls. Once it's all tied together with the roof, it isnt going aywhere. When building, I use paired lengths of 2x6 with 5/8" holes in them as clamps, drilled through a log joint and held with pieces of 1/2" all-thread and washers and nuts to hold each additional row in place, sticking up about 3 or 4" to give a holder for the next row going up. I drill down through the ridge into the window and door openings, or down the wall as far as I can, using a log joint to bolt the gables together with all-thread. I also "X" 24" pieces of 1/2" smooth steel rod through them and the purlins, offset slightly to clear the all-thread. I drill through the walls as far as my 6' bit extension will go and all-thread through each wall a foot in from each corner.
Log gables seem sort of loosy-goosey when building, but when done with the roof in place and chinked, are very solid.
After getting the flats on the cap logs and ridge log, and purlin if you use one, I nail or screw lengths of 2x4 to the walls inside and out as guides for the chainsaw to get a clean line for the roof and ceiling. I've used a chain saw or an electric planer to get the flats on, after snapping lines for guides. They can be done in place, or on the ground.
When setting purlins or ridge, notch the wall for them, not the purlin or ridge. They are the structural member that needs the srtength. They are back under the roof, so don't get much rain on them, and are simple to seal with caulk/log jam.
I like the tradidional look, so after the log work is done, I lay the ceiling with 1x8 boards, or 1x6 T&G from ridge to eaves (I break them at the cap log anf finsih the soffit separately), then put down felt, lay 1x4's across the ceiling boards and screw to the ceiling boards to get them all evened up, then the rafters, insulation, sheathing, then roofing. Yes, it sounds backwards, but makes a very nice ceiling.
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fpw
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# Posted: 6 Aug 2012 10:01am - Edited by: fpw
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Greenie,
Yes I used hand-scribed techniques on my cabin (saddle notches and lateral grooves cut on the botttom side so the logs fit perfect).
I built the floor structure and set the building right on the structure. I opted this way because I buildt the walls offsite and a hauled them in one at time with an ATV. If I was building in place, I would notch log joists into the 3/4 sill log and then run a cut (making the width the correct dimension for the planned flooring) along the logs at flooring level to tuck the flooring into the log.
There are two books that I found very useful, they cover all aspects of cabin building (including foundations and gables as Malmute used). If I was building a lower roof with no loft, I would use log gable ends for sure.
The Owner-Built Log House by B. Allen Mackie
Building with Logs by B. Allen Mackie
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Greenie
Member
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# Posted: 15 Aug 2012 11:41am
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After more thought I really feel I need some real plans signed off on by an engineer. I am no engineer and with 4 kids don't want to be winging the structural design. Anyone have any ideas or leads on where I could get plans. At this point my best idea is to go to a local architect we have used for construction projects on our house and start there but he certainly isn't a cabin expert.
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Malamute
Member
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# Posted: 15 Aug 2012 11:44am - Edited by: Malamute
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You may want to contact a cabin builder for a set of plans that are basically what you want. Many will sell a set of plans with specs that will pass code.
If your guy isn't up to speed on cabins, it may well cost more for him to figure it out than to go straight to a cabin builder and get exactly what you need straight off. If one is close enough to walk in the door, you could probably walk out the door with a set of plans, or get a set in the mail right away if none are in the immediate area..
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fpw
Member
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# Posted: 15 Aug 2012 01:32pm - Edited by: fpw
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What type of cabin construction do you plan?
Hand Scribed?
D-Log?
Timber Frame?
!/2 Dove-tail?
In most cabins the loads are pretty straightforward. Make sure your piers and beams are large enough. Then, make sure your ridge will support the desired loads. Wall loads are transfered directly to the planet so there is not much concern (just make sure the top of your piers are large enough diameter as walls are heavy). However, it is very critical that you place the logs properly (volume centered) as you work your way up to keep everything line. You get out of whack and a log can work its way out. You do this by marking the log ends and lining them up.
Dont' have plans but can help give you some ideas for building if you explain technique, foot print, etc.
If you are building where you need to meet code or get an engineer signoff, you will likely have to educate them. You can go to http://www.logassociation.org/resources/publications.php
to get a look at log building standards.
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Greenie
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# Posted: 15 Aug 2012 02:10pm
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I am doing a very simple 10'x14' with gable roof (not including front porch which isn't locked down yet but thinking 7' deep running width of house). I have no construction background so everything I learned I gathered from a few books I have and from reading online (this forum has been fantastic) but I would describe the cabin as handscribed with saddle notches and log gables. I plan to use sonatubes as footings with log piers between sonatubes and sill logs. Not planning any insulation, plumbing, electric, etc. I hope this helps. Log gables are still squirelly to me. I can understand how the roof holds it together once it is on bu don't get how you keep it together during construction. Malamute
provided a nice description of his process above but still missing a few details (i.e. what are "flats" and "cap logs" in this scenario "After getting the flats on the cap logs and ridge log, and purlin if you use one")
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fpw
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# Posted: 15 Aug 2012 07:55pm - Edited by: fpw
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Greenie,
You can email me at fredrickpwankeratgmaildotcom no spaces. I certainly understand where you are starting from.
exsalior brings up an excellent point. Do you plan to chink or not?
Loghomebuilders are in favor or staking logs (no notches) and chinking. This is considerably faster than hand scribing which requires the following:
1. Put log on building.
2. Scribe rough notch.
3. Remove log.
4. Cut rough notch.
5 Put log on building.
6. Scribe final notch.
7. Scribe lateral groove.
8. Remove log.
9. Cut notch.
10. Cut lateral groove.
11. Put log on building.
12. Test fit.
13. Install insulation an em seal.
14. Roll log into final position.
Staking and chinking works (as described by loghomebuilders.com work). Or you could saddle notch and chink which is the same result but takes a few minutes per notch to cut.
It depends on what you want. I look at my cabin, hand-scribed, perfect fit. Just like the Swedes and Fins did 100 years ago. Can't ask for anything more.
Keep in mind anyone can do this. In 2001, I had never even touched a chainsaw, I had dream. A few classes, some desire, and a number of years later I can build 1/2 dovetail. hand-scribed, stake and chink, and just about any other variation.
If you have a desire you can learn. No problem.
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Greenie
Member
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# Posted: 16 Aug 2012 06:45pm
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Definitely saddle notch and chink no groove. Thanks for the words of encouragement. I'm pretty confident I'll get her done. How sound and tight is another question. This is basically a midlife crisis project for me and it is the first cabin but hopefully not last. I am aqctually thinking of this one as practice run and if the complete dream comes true would put on a bigger addition later.
Did you take the loghomebuilders class?
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fpw
Member
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# Posted: 16 Aug 2012 08:34pm
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Saddle notch and chink will go quick. It doesn't take long to learn to cut notches. Your first ones will be ugly.
A small practice building is a good idea. By the time your are done, you will know what to do the next time..
In 2001 I decided to quit thinking about cabin building and actually build one. I purchased equipment and took a class in Ely, MN (www.schooloflogbuilding.com) with my son. The class gave me the confidence that I could do this type of thing.
It took me a few more years to finally decide to move forward. In the meantime I did some small projects (deck, swing, sauna, etc.). I didn't start the cabin work till 2007.
Since then I've moved forward on many different projects including dove-tail, timber frame, etc. I've taken a number of other classes including rigging and timber frame.
The investment in class for a number of days is very worthwhile. You will save way more than that in time and materials having a better idea of what your are doing.
Probably the best thing I did was take a GOL (game of logging) class on tree felling. After I had already dropped a hundred trees. I learned that I was actually quite lucky and really didn't know what I was doing I was very good cutting notches and grooves, this does not translate to tree felling skills.
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OwenChristensen
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# Posted: 17 Aug 2012 07:31am
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Here's a fuuny thing. At that class you probably were building with logs from my cabin. I sell them to Ron. That makes me happy.
Owen
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fpw
Member
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# Posted: 17 Aug 2012 09:12am
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These your logs? This was probably around 2003 or 2004 when I went back to Ely and helped Ron cut and put the roof structure on a cabin so I could understand how to do so.
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OwenChristensen
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# Posted: 18 Aug 2012 03:02am
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It could be, I have sold him logs for several cabins. I have a tree farm down in Aitkin Co. My dad and I planted the trees in 1963, 220,000 of them. That's where my cabin is. I have never built with logs myself.
Owen
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