Monday 3 October 2011

fibbonacci

the fibbonacci sequence - is a numerical sequence where each number is the sum of the previous two numbers, starting with 0, then 1

see also the golden ratio - http://en.wikipedia.org/wiki/Golden_ratio

both things constantly occur in nature, in a self replicating way, from soft spirals of shells to the perfect arterial design of trees.



sometimes things have a way of working out that you could not have planned for, as such, sometimes very much for the better, and sometimes not. building this phase of the frame has been an entertaining experience. in that, i have had to learn quickly. sometimes it has meant adjusting things, and sometimes even re-doing things.



the very size and shape of the building was not entirely determined by the book i was following, nor by the space in which i had to build, but owed some to the size and shape of the trees that were on our land that i felled for construction. they in large part determined what i have so far been able to build. in it was their natural selection that evolved the parameters of the site into the fibbonacci sequence almost to the thousandth point.



generally, in construction, sequences are very key. not only in the way in which things have to go together, but also in the way in which you do things.





in essence, much of building, outside of the art and craft of it, boils down to your ability to prioritise sequences and repeat procedures.





as you progress along your way as a builder, you are often in a position to refine and redevelop those sequences, and sometimes even throw them away.





it depends, as they say here, on many things, particularly on what you are doing and the way in which you choose to do it. if, for example, you have a number of the same activity to achieve, you may choose to do it all at once if it is feasible.





it isn't always, as there are many things which can prevent that, for instance, i have something like 60 odd braces (in number, and description, in that, they are not uniform) to cut and install, and a number, as yet undecided, of collar ties, which approximate the shape of the braces, their method of construction and installation.





if you were very methodical in your approach you might consider cutting them all in one go. it would achieve one objective, having them done, but it would leave no further room to change the way in which you were doing it in response to the rest of the construction.



and here's the thing. timber framing needs to evolve.



it needs to evolve as a response to what you are doing and how you are doing it, in addition to the materials you are using; the shapes, the forms, the inherent strengths and weaknesses, the relation to other parts, and conflicts of position, and location.



i had been loosely following a design by jack sobon, in his excellent book 'timber framed house', i've used his design for the sizing of timbers and choice of joints, but have changed the dimensions.



in so doing, i've changed the house. you could call it serendipity, you could call it luck, you could call it fortuitous, but somehow, somewhere along the way it has developed itself thru my hands into a design that is the golden section, the very fibbonacci sequence itself. that is why the building looks so harmonious, because even on an architectural level, mathematically, it is.



it takes a lot to break away, to follow you heart, to listen to what you are doing, and be responsive to it. but then, if you can, sometimes magic happens.









in the vast majority of professional construction all you are dealing with are very uniform materials, of given sizes and dimensions, with specific requirements for placing and fixing. framing in non-dimensional timber (nominal sizes, and timber not sawn square on all faces) is a whole other book. invariably, you end up with a combination of systems of layout and cutting, square rule (where everything relates to everything else from one squared face to another), and the scribe rule (where no meeting of two faces is equal, and one or both of them has to be adjusted to conform to the shape of the other, to make them fit together).



here, in portugal, even the weather plays a role in your ability to sequence things. to cut all of one thing in one go, assumes that between the time of setting out and cutting, and installation there is nothing acting on any piece which has adjusted its shape or size. in an environment where 42 degree heat is frequent, it can have a massive impact on the fitment of timber to timber. the previous perfect faces of mortices and tenons, of braces and housings, of scarfs, and socket joints, can all distort in a very short time, sometimes irrevocably; and you have two choices, either adjust one or both of them, if possible, or live with it.

in the process of changing Sobon's design to fit both my site and the building's requirements, i changed the way in which i needed to construct the house on my own, without a crane, and without a team of 57 other people, in point of fact, without anyone. for instance, it meant halving the height of the main posts, and having twice as many of them (stacked one on top of the other) which in turn meant increasing the number of braces (there are twice as many as in his design) which has added a huge amount to the construction time, as they are all scribed into their housings.



it has also meant a return to what he refers to as not only a more modular way of construction, but also a more three dimensional way of building. rather than prefabricating the entire building, or even large cross sections, i choose to reduce the amount of pre-construction to a minimum, by raising the structure as i went along, and prefabricating only the minimum amount of components that would enable that.



essentially, that meant finding the bracing material for one area, then cutting it. getting one of the girding beams on site (the beams that run from the back to the front) and a pair of posts to support it. setting out, then making all the cuts, cleaning them and only checking the pre-assembly of the braces. i couldn't pre-check the fit of the thru mortices, as i couldn't manage into position the posts into the beam on my own, too big, too heavy, too awkward, and that's just the posts. so i measured carefully, checked and re-checked countless times, and hoped i was right. but, when you are measuring off of sides whose edges aren't square, there is always room for error. so far, i haven't been out by more than a few pairings with a slick chisel or plane.





even in the relatively short time, one summer, between felling and milling, and the start of assembly, the big timbers have dried a lot, and have lost quite an amount of weight. when they arrived at the road side, i could hardly even manage to bar up one end of an 18ft (6m) 8x10 (200x250mm) now i can lift one end, thou not that far. so it meant, initially, even getting the girding beams on site was a mission, let alone working them.



i think its really important to be able to respond to the building as you erect it, especially when using non-linear material. shapes within the non-linearity of certain materials inform your choices of where to segue in other parts. sometimes forms present themselves in places where you hadn't expected to see them, that add a new dimension to the to structure. and although i am a staunch supporter of form following function, sometimes though, the form needs to be allowed to influence the function. what i am looking for is a balance of form and function, where one doesn't just dictate the other but improves and transforms it. the key, as a friend used to say, is in the word.

often with building, when something looks right its because it is, and if it looks wrong, equally, its because it is.

in sobon's book, for ease of construction he suggests cutting the braces out of straight and squared stock. easy for setting out, but not very interesting.



its only when you begin to put the frame together that you can see other things, such as the intrinsic beauty of the brace, and how more natural curves not only soften the design but are every bit as strong if not stronger, particularly when they operate primarily in compression. not only are they in keeping with the traditional construction of frames, they serve, like diminishing rafters, an other purpose; using smaller section stock to cut your brace from, and keeping the curves, you reduce the amount of trees you have to fell, and utilise parts that would often end up as firewood.





curved braces add a lot, they have a greater elegance of shape which contribute to an overall flow of the frame. they help the frame breathe, like they are still a part of the living tree. invariably, you can't buy curved braces, you have to cut them yourself. and that means seeing them in the tree, seeing the wood for the trees.