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Normal movement on roundwod timber frame?  RSS feed

 
J. Tabordiy
Posts: 64
Location: north-west coast of iberian peninsula
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Hi all,

some updates and some questions, 3 months have passed, much of the time we were travelling and not working on the house, we left after installing the plastic over the roof on november (updates till then on this post: http://permies.com/forums/posts/list/40/43534 ) and rested a bit to let the winter pass

we've spent the last month or so building the framing for the light-clay-straw walls and the windows/door of the 1st floor, also apply most of the top floor flooring, and are now starting the framing of the top floor,

now that we installed the flooring on the top floor and the 1st floor is framed, the structure looks sound and don't move with strong winds (also there is no walls so wind passes very easy) but if we apply our body to give rithmetic movement, the frame trembles/moves, is it normal?

i've been at other low-cost clay constructions where the struture moved also and after the walls covered it stops, we built it with much more care (those were post in the ground type of cnstruction), but instead of clay-straw we are going to fill it with light clay,

i would like to hear opinions about that movement, will lthe light-clay filling hold that small movement or the walls will crack if there is to much love on the top floor and we should reinforce with big bracings from the outside (would end up inside the wall)?

it's our first construction and after almost a year on this i feel it completly dferent and would make many small changes, although this was always meant as a learning experince

so we are waiting forward for comments


 
Bryant RedHawk
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Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
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You didn't mention where you were when you introduced the rhythmic movements.
The first floor looks to have enough bracing but I notice there isn't any knee bracing where the first floor meets the second floor, this could be a movement issue.
I also see you have large rectangles formed by your styles and girts, you might try changing that geometry into triangles to see if that stiffens up the framework enough so you wouldn't need to add knee bracing at the first floor/ second floor junction.

Any frame, regardless of construction type, is going to have some movement until it is all buttoned up. This is partly a function of the added weight, weight is stabilizing since it travels down.

If you put the full roof on, that weight will travel down through the posts or at least it is supposed to.

Triangles are stiff in all directions, their shape takes loading from one post to the next and so stiffens the superstructure.
Rectangles are able to wobble on the long sides since there really isn't any loading of that portion of the superstructure, that is one reason geodesic domes are so stiff, every section is diagonally braced.
 
J. Tabordiy
Posts: 64
Location: north-west coast of iberian peninsula
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thanks for your comments, Bryant

You didn't mention where you were when you introduced the rhythmic movements.


up on the top floor and the movement is more noticeable on one direction than the other (to where the roof hangs)

The first floor looks to have enough bracing but I notice there isn't any knee bracing where the first floor meets the second floor, this could be a movement issue.


can you clarify what you mean by knew bracing where the 1st floor meets the topfloor?

I also see you have large rectangles formed by your styles and girts, you might try changing that geometry into triangles to see if that stiffens up the framework enough so you wouldn't need to add knee bracing at the first floor/ second floor junction.
Any frame, regardless of construction type, is going to have some movement until it is all buttoned up. This is partly a function of the added weight, weight is stabilizing since it travels down.

If you put the full roof on, that weight will travel down through the posts or at least it is supposed to.

Triangles are stiff in all directions, their shape takes loading from one post to the next and so stiffens the superstructure.
Rectangles are able to wobble on the long sides since there really isn't any loading of that portion of the superstructure, that is one reason geodesic domes are so stiff, every section is diagonally braced


we will make the rest of the framing of the walls (for the ligth straw) with more diagonals, and with all the weigh will hope it' enough,

we also though on adding a diagonal bracing on both sides of the house that would go from 1st floor posts, to the roof beams, screwed to the post and girt
if you would reinforce it with some screwed in bracing, where would you put them?

 
Niko Economides
Posts: 26
Location: Marquette county Michigan's upper peninsula
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This looks like beautiful work for your first build, you are a real artist. I have several of this type of structure I built on my homestead used for out buildings. We get lots and lots of heavy snow load and I don't want to clime up and shovel of my roofs so I try to build strong and this means lots of braces. And not to short. As a general rule I like to brace every post on the outer walls and all structural interior posts. Looking at your picture it looks like your second story posts are separate from the first if this is true I would agree with B Redhawk I would brace them. Have the braces go from each corner post down to the first floor beam and joist logs, a mirror image of what's below. Filing the walls in will defiantly stiffen the place up, my woodshed probably wold fall over if I did not keep lots of wood neatly stacked between posts.
 
Glenn Herbert
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Your idea of diagonal braces going from the edges of the roof to the corner at the top of the first floor would give a good amount of stiffening. I wouldn't just screw in any added braces, but make a notch at least a few cm deep perpendicular to the brace so it will be naturally strong in compression. It will not have so much strength in tension even with screws, but braces on each side will work together.

Does the upper floor move more than the roof? (do the lower posts sway more, or the upper posts?) Those roof braces will not help the lower posts. The lower post braces look good, but you may just need them on more posts, or braces at the floor as well as at the ceiling.
 
J. Tabordiy
Posts: 64
Location: north-west coast of iberian peninsula
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thanks for your input, it's our (me and my partner) first build... probably/hopefully not the last, as i think we learn a lot and could improve a lot if starting over ...

can't understand why the pic on the first post is on it's side now...

was playing with sketchup again (running it on wine on an old linux computer) to confirm if this is what you were referring to, adding braces to connect the top floor posts to the girts,
we were thinking on other diagonal reinforcement, , but this now makes more sense
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Bryant RedHawk
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Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
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Yes, that is the bracing I was trying to describe to you.
 
J. Tabordiy
Posts: 64
Location: north-west coast of iberian peninsula
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sorry for the delay on updates, we started postponing and always lazy to organize a couple of pictures to upload....

many changes on the meanwhile, thanks for your suggestions,

so 2 month ago we took some time to do the diagonals suggested on the top floor, and then we also did then on the first one

will post on this thread a couple of pictures of that

then we started 2 or 3 weeks ago, the straw light clay (SLC) to fill the walls

we never saw this tecnic before live, so we were not so confident on it, but now i understand we did a lot of work that actually wasn't needed (we will try to start another post about it with some links for videos and websites about SLC), i'm even doubting these last diagonals we did were really necessary, as we then read/saw some videos about it and SLC has a good lateral forces resistance, just not vertical, and the house is very solid now (since the diagonals, but the SLC i think would make the same effect, i may be wrong though) we also had many horizontal woods on the SLC framing that we made before and were really not practical so we took them off, as we can simply put horizontal pieces of wood louse inside the wall when we fill the walls with the SLC mix.
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J. Tabordiy
Posts: 64
Location: north-west coast of iberian peninsula
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some pics of the diagonals on this post and then i will post more pics on the post we started before about the house

all those small pieces of wood (were taken out when we started the SLC filling we spent a week dong it for fun)
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Bryant RedHawk
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Posts: 3004
Location: Vilonia, Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
243
chicken dog forest garden hugelkultur hunting toxin-ectomy
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That looks sweet!

I like making my frames stand on their own, that way the walls are not Loaded which makes it easier to infill.

I have a friend who built his cob house just like his old one in Ireland, the walls are really thick but the only wood is for window and door frames.
He had a bunch of friends help with the build, something I don't have access to, so I am designing our house to be built by two people.
It will take us about a year to get it in the dry and livable if all goes according to plan (never does for me).
 
Richard Cobbs
Posts: 16
Location: Yalaguina, Nicaragua
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I've been thinking about roundwood building for awhile and trying to come up with an easier means to join the timbers and braces.  A technique that seems quite interesting is the split-ring connector.  Unfortunately, the split-ring and the installation tool are very expensive.  I am considering making my own split-rings out of schedule 40 PVC pipe, cut to around 2” lengths and then angle-cut at 15 degrees to make the split.  A properly sized (I.D and O.D.) hole saw could cut in 1 1/8” in both of the mating surfaces, and the joint could be tightened with a SPAX type screw.
I would be interested to hear opinions on this type of connection.
Thanks,
RWC
 
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