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Frans
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# Posted: 24 Nov 2015 08:07
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I live on a small cattle farm near a small town, Smithfield, in central South Africa. The Caledon river runs through the farm and there are also two smaller creeks running through the farm. I have always wanted to build a small hunting/fishing cabin on the river bank.
In my area there are no shops or suppliers where you can buy timber, but I believe I might have everything that is needed on the farm. I have an Aspen tree grove and a small saw mill, so I can cut my own timber. I don't know how good it is, but that is what I have. I also have a lot of common reed along the river and I was wondering if I could use it for thatching the roof and maybe some walls. I also have a good supply of sand stone. Our area has a low rainfall, (about 16 inches/ year) and no snow.
I have no experience with wood construction.
Any comments or advice will be appreciated.
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old243
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# Posted: 24 Nov 2015 09:28
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frans, what materials are commonly used in your area. In our area aspen would not normally be used for structural , if it was going to be in a damp location, or in contact with the ground.Since you have your own mill , I would think it would be fine above grade, for structural , siding sheeting etc. As long as it was kept dry.I am assuming the aspen would be similar to our poplar. You can oversize any timbers and use preservative if you are in doubt. What kind of a mill have you got? I have a bandmill, and mostly use it as something to do, As I can't do much heavy slugging. Have fun with your project. I am sure you will get others , chiming in as well. old243
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Don_P
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# Posted: 24 Nov 2015 20:12
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Your reeds would work in a wattle and daub wall. I don't think they'd be good for roof thatch. This is a series of 3 videos of a young man doing wattle and daub infill on a timber framed structure.
https://www.youtube.com/watch?v=Y-LtatHVlfA
Do you know the latin name for your aspen?
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Borrego
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# Posted: 24 Nov 2015 21:10
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Welcome Frans - you will find a wealth of good info from the people on this forum, I still use it all the time to bounce my ideas off of the guys...
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Julie2Oregon
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# Posted: 24 Nov 2015 22:12
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 Welcome, Frans!
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Don_P
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# Posted: 24 Nov 2015 23:32
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Google earth is such a fun way to spy on the neighbors...
Neat terrain, is that the Caledon south of Smithfield near Bospoort?
I see some center pivots and what looks like irrigated row crops, what do you grow locally?
Does the ground ever freeze?
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Frans
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# Posted: 27 Nov 2015 00:58
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Thank you for all the replies and welcome.
Quoting: old243 frans, what materials are commonly used in your area. I am assuming the aspen would be similar to our poplar. You can oversize any timbers and use preservative if you are in doubt. What kind of a mill have you got?
The old houses and barns were built with raw or baked bricks, soil and plastered with lime. Roofs are corrugated iron with Douglas fir timber, ceilings and floors. You also find many stone buildings, but never wooden cabins. I have an old barn with stone and soil walls which was built around 1925. They used only raw poplar squared roughly with an ax for the roof timber and it is still as strong as the day it was built.
Our poplar is the European white poplar (Populus alba) and is actually an invader plant for which we now need a permit to keep.
My mill is an Oscar 228 which my father imported about ten years ago to cut and sell the poplar trees. Unfortunately he became tired and passed away at age 83, three years ago without ever using the mill.
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Frans
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# Posted: 27 Nov 2015 01:04
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Quoting: Don_P Your reeds would work in a wattle and daub wall. I don't think they'd be good for roof thatch.
Thanks Don, this is a good idea. The early settlers (voortrekkers) used this method for their first houses and it was called a "hartbeeshuisie" in my language. (I really don't know what the hartebeest had to do with it.)
Maybe I must use corrugated iron roofing with a layer of reeds below it as ceiling and isolation.
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Frans
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# Posted: 27 Nov 2015 01:23
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Quoting: Don_P Google earth is such a fun way to spy on the neighbors... Neat terrain, is that the Caledon south of Smithfield near Bospoort? I see some center pivots and what looks like irrigated row crops, what do you grow locally? Does the ground ever freeze?
yes, Bospoort is my neighbor. My farm is Traacha on the northern side of the Caledon.
The guys with the pivots mostly grow corn and alfalfa. I am also planning a pivot next to the river.
No, the ground does not freeze here. Our winters (April to September) are dry and night temperatures get down to average -4° to-6° Celsius. Very cold spells can get down to -12° to -16°, but not very often. Winter day temperatures are quite nice (if the wind does not blow) with temperatures around 15° to 20° Celsius. We don't really get snow. The last time I have seen deep snow here was in 1965 when I was three. Once in about ten years we will get light snow that will melt away before ten the same day.
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Don_P
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# Posted: 27 Nov 2015 19:02 - Edited by: Don_P
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For us in that climate the bottom of the foundation would only need to be 12" below grade.
This is a link to the wood database for raw numbers to compare.
http://www.wood-database.com/wood-identification/by-scientific-name/
Compare populous alba to p. grandidentata , bigtooth aspen and to p. tremuloides, quaking aspen. These are two closely related species that we do have span tables for. Mainly interested in specific gravity, MOR and Elasticity comparisons.
Our span tables that would contain those two are here;
http://awc.org/codes-standards/calculators-software/spancalc
Notice it simply lists aspen, so it is taking the lowest design value from whichever of those two is weaker in that particular strength category. Your trees seem to land in the same range, so this should work. If you understand our dimensioning system, eg a 2x4 is actually 1.5"x3.5". If the dimensions are something other than the ones in that calc, I have some more calcs that allow custom dimensions.
Aspen is not decay resistant at all. I have a small dip trough that I use just behind the sawmill to dip boards in a borate solution. This stops decay and wood eating insects but has very low mammalian toxicity. I use the same wettable powdered boron (D.O.T) that field crop growers use to boost that micronutrient, I mix at a rate of 1lb/gal of water and soak the green boards for at least 3 minutes.
And I'm curious... are they growing GMO, roundup ready corn, or other GM crops there?
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Frans
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# Posted: 30 Nov 2015 02:35
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Don_P, thanks for the useful information. I am not really familiar with the dimensioning system and all the terminology, but I will figure it out.
Thanks for the tip to dip the boards in a borate solution. I will do that. Fortunately it seems that we don't really have insects that eat the poplar wood. Water and weather are the main enemies. We also use the poplar for fence posts and droppers (hangers) in wire fences. They are not as good as the harder woods, like the Australian wattles, but that is what we have and I have seen them lasting for 15-20 years untreated. We now just dip the ends in old oil to try keep the water out.
Quoting: Don_P And I'm curious... are they growing GMO, roundup ready corn, or other GM crops there?
Yes, they are growing the genetically manipulated stuff. Monsanto is the main supplier here.
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Frans
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# Posted: 30 Nov 2015 03:15
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Quoting: old243 frans, what materials are commonly used in your area.
The only timber we can buy here is pine (Pinus radiata). In my town we can only get 1½x6, 1½x4 and1½x 1½ (brandering).
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Don_P
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# Posted: 30 Nov 2015 09:46
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Sorry to hear the evil empire is there as well.
The radiata pine is a California tree, kind of funny, I'm in pine country and pretty often I see imported radiata in doors.
Page 16 of this pdf has the chart of finished lumber dimensions that we use. So these are the dimensions the awc span calc, or any US span tables, would be using. http://www.alsc.org/greenbook%20collection/ps20.pdf
No harm in being larger, just don't undersize.
To carry that thought off into the weeds...
Nails and hardware can get interesting if you work with plump lumber so think that through. Basically you need to get at least 10 nail diameters into the main member when nailing to develop full nail strength.
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Frans
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# Posted: 1 Dec 2015 01:04
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Thanks Don_P, very useful information.
Another interesting fact: Douglas fir is known here as Oregon pine. Nobody knows what Douglas fir is.
What do you mean by this? Please explain, because I am really dumb when it comes to wood.
Quoting: Don_P Basically you need to get at least 10 nail diameters into the main member when nailing to develop full nail strength.
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Don_P
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# Posted: 1 Dec 2015 08:15 - Edited by: Don_P
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I didn't know that about Dougfir, cool stuff
If you decide to use "full dimension" lumber, for instance 2" thick rather than 1.5" thick, watch your nail sizes.
I'm on the first cup and pulling from memory.. a 16 penny sinker nail, which is our regular hand driven framing nail is .149" dia x 3.25" long. If that nail is driven through a 2" stick of framing only 1.25" is penetrating into the main member it is attaching to. It should be penetrating at least 1.49" into the main member to develop nail strength, so this would be the wrong nail to use for full dimension work. A 20 penny common is .192 x 4"... that's why those hefty buggers are in old rough cut work.
Incidentally, fasteners that are driven into green lumber that then dries lose a very large percentage of their strength... except hardened ring shanked nails, what we call an Ardox or pole barn nail.
If you are using any joist hangers or metal connection hardware it is generally sold to fit dressed lumber rather than full dimension lumber so another thing to think about as you plan.
Neither of those is a deal breaker just part of planning.
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Frans
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# Posted: 3 Dec 2015 02:10
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Thanks Don_P.
I just bought a very old house. It must be one of the first houses in town built around 1850. Raw bricks, Douglas fir floors and ceilings.
It has a strong borehole with old power head pump and I think it's a Wolsley engine.
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Don_P
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# Posted: 3 Dec 2015 07:22
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Cool, so how is it built? It looks like the exterior is stucco over the brick? I don't know a Wolsley engine, it resembles one of our old Maytag washing machine motors, kick start on one side with a large flywheel, magneto on the other.
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Frans
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# Posted: 4 Dec 2015 02:26
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The walls look like raw or semi baked bricks built with soil and plastered outside with lime. I don't think they had cement here in those times. Inside walls plastered with soil and painted with lime.
I am still using a lot of whitewash lime to paint buildings on the farm. I mix it with a latex bonding agent and then it lasts for a few years.
The Wolsley engine is a British paraffin engine. There were many of them on farms. The Gately power head pump I don't know. I know a National and a Rapid power head pump, but not this one.
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Don_P
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# Posted: 4 Dec 2015 07:28
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I googled Wolsley engines, an interesting company and history. The Gately didn't come up in a search.
So there must be old lime kilns in the area. Portland cement didn't find its' way into common use here in the mountains until around the time of the second world war. Prior to that it was lime mortars and plasters. I know of two old kilns for burning lime in the area. Its' product was quicklime, a very hot product.
My Dad still remembers the tail end of those days. The burnt lime, very caustic, was brought to the jobsite where a pit was dug and the lime was mixed with water and allowed to slake for as long as possible during the course of construction, the longer the better. The old timers here call it "slack lime" but it is really slaked lime. After it is applied, and here the low fired bricks were laid as infill between the posts and beams of a timber framed house, this is known as noggin(g), the plaster was applied to that brick backing. After the plaster has dried it continues to cure, absorbing carbon dioxide from the air to again begin forming calcium carbonate, limestone. Lime renders also pull moisture from surrounding wood and tend to preserve the wood where Portland keeps wood damp and does nothing to help preserve it. The death of an old log cabin here is often the replacement of lime based chinking with Portland based as rot sets in.
We had a carbide plant here years ago that made calcium carbide. When mixed with water it forms acetylene gas, a miners lamp. A number of rural houses had gas light produced from a carbide generator in the back yard. When you clean out one of the generator pots, the mess left is whitewash.
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Frans
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# Posted: 7 Dec 2015 02:04 - Edited by: Frans
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I went to take more pictures at the old house.
The engine is actually a Vetsak WD9. It is a Wolsley assembled under licence in South Africa and named Vetsak.
Thanks for the very interesting facts about lime and whitewash. I don't know about any lime kilns in the area or any quarries where they mined it. They must have brought the lime from somewhere else.
Now that I bought this old house I think it will take some time before I start on a cabin. I will have to start restoration of the old house first. My idea with the place is to fix it and divide it into two guest houses to rent out as self catering accommodation to visitors to town.
Do you think it will be OK if I start a new thread on the forum to cover the restoration of the old house. I know it is not a wooden cabin, but there is so much woodwork to do, of which I know very little. What do you think?
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Don_P
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# Posted: 7 Dec 2015 06:45
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I think that would be a fine idea, it's always fun to see and learn how things are done elsewhere.
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