Qionset hut questions

old · Nov 26, 2012

Well the post down below got me thinking about one I saw years ago where some one took 1X6 or 1X8 boards and then layered/bent them to make a Quonset hut. So here is the question is how do you get the boards to bend that way with out snapping??? By the way this was done with what looked like oak ruff sawed boards from way back when as in maybe the 40s or 50s if not longer ago

Anonymous-0 · Nov 26, 2012

I have a huge round roof barn on my farm that was built by my great-grandfather. Lumber (native oak) was cut and while green (more flexible) nailed together in a curved jig to form the "laminated" curved rafter.

RalphWD45 · Nov 27, 2012

OLD! I surely don't know how those 2x8's were bent, but after you said roughcut oak, it was probably with boiled oak. In the 1970's I used to build and sell catfish baskets which were all white oak except the throat fingers, which were sasafras. Iwould take rough sawed white oak 2x12's from the local sawmill,and rip them on a table saw to 1/4"x2" slats. Put the slats in an oldpiece of 6" pipe, welded on one end to a 12"x12" of 1/4" steel plate. this stood verticaly, around 6' tall, and was filled with water and wood slats. I put my torch to the pipe down low, and boiled the slats. While still hot and wet, I would take one slat at a time out and bend it around a 12" dia. brake drim and nail it togeather where the ends lapped over. this yielded me a 12" diameter round hoop of which I needed 6 hoops for each fish basket. Naturally I used straight grain white oak, and didn't have knots in my slats.

big fred · Nov 27, 2012

1x isn't all that thick, I would guess they either steamed them or soaked them in an ammonia solution. Ammonia will break down the lignin in the wood, enabling it to bend pretty severely without breaking, at least that's the way it works with sitka spruce. For the relatively gentle bend in a quonset roof, I'd guess they just steamed them.

RalphWD45 · Nov 27, 2012

Andy! I'LL BUY THAT! green and wet seems to work with oak.

Bob Huntress · Nov 27, 2012

The two methods that I most use or see used include a steam box, which unless you do a lot isn't worth putting togather and cutting a series of cuts that go part way through the board with varying spacing depending on the arc of the curve. If you have time to wait, you can also secure the top of the board to a wall or something, secure the bottom a bit away from the wall to form a right triangle and apply weight to the center. A curve will begin forming where you apply the weight. It doesn't have to be a perfect match at the curve. Most wood has some flexiability, if you get the curve anywhere close to where you want it. That is the crudest method, but it maintains the full width of the board. Another method that I see in boat building is using very thin strips which are easy to bend, and laminating them in their curved position.

MarkB_MI · Nov 27, 2012

How do you think they make boats? Try bending one inch thick Honduras mahogany without steaming it.

60 acre hillside · Nov 27, 2012

Neighbors told me of a barn in my area with such a roof design. The loft floor was completed and blocks were laid onthe floor and nailed in an arc. The green 5/8 x4 boaeds were bent around the blocks and nailed together in successive layers. They were tied in the arc until time of erection.

JOB · Nov 27, 2012

Back in 23 my grandfather built his round roofed barn with the method you mentioned of laying the boards flat and bending them into an arc and layering them. That barn today is held together with cables and falling down.
The round roofed barns and Quonset huts that are not falling down are built out of 1x8's or so. the curvature of the roof in cut out of the 1x8 that is maybe 6 feet long. The boards are laid on the floor. the next layers are over lapped maybe 1/3 the length of the board and stacked 3 high and nailed together. That is what I have seen, I will check out u-tube and see how they are done there.

John B. · Nov 27, 2012

My dad and his dad put up a Quonset back in the 1950's. The rafters are laminated out of 1 x 2's and formed in an arc.
Each rafter consists 8-1x2's glued together. They're spaced every 2ft apart but can be spaced up to 3ft apart.
I would think these are very strong! It's still standing today!
I bet these rafters would make a room look neat if you used them on the wall instead of old barn wood!

dino in iowa · Nov 27, 2012

The Barns I have seen have concrete fondations and walls, the
roof formed from 1by4's three thick, must have been 100 ft.
bent into roof shape. It does not seem like each piece was bent
that much, to form the roof, still in all I really liked, the process.
the barns, all had hay rails, very strong,

JOB · Nov 27, 2012

Look at that roof a little closer. I would bet those 1x4's are cut out of a wider board. Those 1x4's are a series of short 1x4's that make up each section of the three. Three 1x4's seems sort of under built, any barn I have seen all had at least three 1x6's nailed together. I was on a farm once and all his out buildings had a round roof of some sort and the smaller buildings had narrower roof boards, not thinner, all were built three boards thick. Things are built differently in different parts of the country, so who knows.

Anonymous-0 · Nov 27, 2012

wellRich , my 1st guess is water , and i have heard tell granpa used steam ...100 yrs ago granpa ( MOMS Dad )was a fine school trustee ,farmer carpenter , sawyer ,steam thresher and a moonshiner (formedicinal Purposes) , LOL , he keptlogs fresh in a lake ... and helped build a few round roof barns ,,most the time with green poplar ,, but they did experiment with steam with good ressults ...he was a 3rd generation german immigrant in Dubois Co , and knew his stuff ,,. btw ,. there is the legendof the circular staircase in santa fe n m ...it is said that the wood was cooked before it was formed into a circle

fixerupper · Nov 27, 2012

Oak will bend farther than soft wood before snapping. When I built the trolley I put a 12" bend in in the middle of dry 8' pieces of 3/4" thick oak 2" wide flatways (12" bend over 8' span). Worked fine without any snapping. Then I tried doing the same bend edgeways on the same lumber. It released a lot of energy when it snapped. Jim

Russ from MN · Nov 27, 2012

In 59 my Dad built a Quonset roof using 1/6's. The correct radius was sawed into them and the pieces inverted, then they were stacked 3 high and nailed, lots of nails. This building had a ridge pole, so there was no flat spot in the center. The rafters set on a 2' high poured concrete stub wall. This gave enough wall clearance so the combine could be parked right next to the wall.
In about 1970 I helped build some trusses that were green sawed 1x4's laid flat around a jig. there was a spreader across the bottom and some trussing so they would hold their shape. They were used for temporary cover for a winter construction job. (concrete)

'

fixerupper · Nov 27, 2012

On a farm dad bought there was a fairly new, 1948, round roof barn that had rounded laminated trusses. My understanding is they were made in Minnesota somewhere. I always thought those trusses belonged in a church instead of a barn haymow. My dad, always the penny pincher said the landlord paid way too much money for that barn when it was built and I imagine those trusses were a little expensive. Jim

Qionset hut questions

old

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Anonymous-0

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RalphWD45

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big fred

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RalphWD45

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Bob Huntress

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MarkB_MI

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60 acre hillside

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JOB

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John B.

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dino in iowa

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JOB

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Anonymous-0

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fixerupper

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Russ from MN

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