# Structural engineering with wood: determining post size, span, etc, for a timber frame house [closed]

This may be off-topic here, not sure.

My college background is math and physics, but I'm hoping to switch gears and build my own home and live off the land. So, I've been studying and reading up on timber framing, building smaller projects and working out a detailed house design in SketchUp.

Much of the minor carpentry, the joinery, the tools, etc., are becoming comfortable. The big grey area left is the major carpentry -- mostly structural engineering stuff: ensuring the house will be stable, handle wind and snow loads, uses the right woods...

I'm looking for resources. One of my classes studied the Euler beam equation for a bit, and I would like to do something on a comparable technical level: I want to go through detailed calculations and know, from first principles, how big the posts need to be for a given room's framing, what the maximum safe spans are, how much stress and strain the wood will be receiving, which woods have what strengths... I've seen some example calculations in various timber framing forums online, but a lot of it seems ad hoc and not very systematic.

What books and materials do professional building engineers study from?

In short, I want to put myself through an engineering program for building a timber frame house. Since I already have degrees in comparable subjects, I don't want to have to staff this out to an engineer (although, having one check the final design isn't a bad idea.)

Thanks :)

• I'm not going to put this in as an Answer for a couple of reasons but mainly because the title I'll recommend is not something that professional building engineers would use :-) but you wouldn't go far wrong starting with A Timber Framer's Workshop: Joinery, Design & Construction of Traditional Timber Frames by Steve Chappell. There will obviously be a discussion of loads and so forth but do be aware of the potential for over-thinking this side of things, remembering that people with no formal education built houses and huge barns in the 19th c. and earlier that still stand. [contd] Feb 22 '16 at 9:54
• [contd] Also, if you'd like to read some older texts (late 19th c. and early 20th) in digital form there are a few I could recommend. All are free to download and while quite comprehensive obviously the practices and jointing methods will be traditional and perhaps not in keeping with how you want to build, e.g. using modern joist hangers, bolts etc. Feb 22 '16 at 10:00
• OK here are a few: Exercises in Wood-Working, Ivin Sickels, A Manual of Carpentry and Joinery, J.W. Riley, Elementary Principles of Carpentry, Thomas Tredgold. And I think William Fairham's Woodwork Joints would also be well worth reading. These are all available to download for free from Archive.org. [contd] Feb 23 '16 at 17:45
• [contd] At the complete opposite end of the spectrum is Scot Simpson's Complete Book of Framing from 2012 which you may like to go through as a basis of comparison on modern methods. There's a full PDF of this available somewhere online (sorry can't remember where I got it) although I'm not sure how given the recent date, but it doesn't appear to be a scanned illegal copy. Feb 23 '16 at 17:46
• try these. Looks close to the books i used in college awc.org/codes-standards/publications/nds-2012
– user1868
Feb 23 '16 at 23:21

While there are plenty of reference books available on how to do it, remember that every structure is unique. Your natural inclination will be to do something special and this is where you could omit something important. There is much more than simple span calculations. There are lateral loads transferring throughout the structure brought on by wind loads or other conditions resulting from the specific design. Your building must resist all the twists, uplifts, point loads, and movement forces it is subjected to. As an architect I have designed many buildings and know a great deal about structural design, but I never complete a design without at least sitting down with a structural engineer and reviewing the entire plan, so I definitely recommend you do so for your design.

I assume that your building will utilize 'western framing' techniques, the gold standard for residential construction for the last 70 years or so. There are bound to be many books that discuss this, but I learned by doing it. I spent several summers as a young man working on a home construction crew. There are lots of subtle rules and most good framing contractors know them instinctively. If you have the opportunity to actually apprentice under a skilled older carpenter for a while you will learn many of the subtle steps and details that have been mastered in the trades over decades. It is not rocket science, but it is also not always obvious in a book why something is done a certain way.

I looked on Amazon and there are plenty of titles under the category of Western Framing. I have not read them so cannot recommend their thoroughness. Look for ones with an author who has plenty of experience in the field.

One more thing. I know from personal experience that framing a home is not a one man operation. You will need a crew of at least 2-3 men. Consider making one of them an experienced carpenter, one who can lead the project. By the time you have finished your home, you will know a great deal more than you would from reading about it.

• There's a timber framing workshop in nearby Nashville that I'm signed up to take this fall, which hopefully will give some more hands-on practice and personal direction. Until then, I've been building various things (e.g. a very small barn) out of timber framing books, but most of those have very superficial, if any, discussion of structural engineering. (The math is light or non-existent, etc.) As an architect, how much structural engineering do you feel you need to know before you sit down with an engineer? Oh, and this won't be a solo venture, I plan to have help from friends and neighbors. Feb 22 '16 at 15:13
• If you're considering timber framing in lieu of western framing, you have added a level of complexity to the project. Since loads are more concentrated, the connections are more important. In western framing the walls act as a diaphragm that distribute lateral forces. In addition western framing distributes the loads more broadly, reducing the load on any single framing member. With timber framing the loads are concentrated and steel plate connectors (not just joist hangers) may be needed.
– Ashlar
Feb 22 '16 at 17:26
• Consult with a structural engineer early and as often as necessary. He/she will be able to give you good ideas early in the design, let you know when your doing something unusual (pronounced 'expensive'), and size everything up as the design develops.
– Ashlar
Feb 22 '16 at 17:28
• Having tried this myself, I can say that 'friends and neighbors' may not be enough. Building a house is an enormous task, requiring very hard work, and assistance for a long time. Their enthusiasm and support will probably wain. In addition supervising unskilled help requires significant knowledge and a lot of time managing and monitoring their work. For example it is easy to miss a minor dimensional error until later when the window won't fit in the opening.
– Ashlar
Feb 22 '16 at 17:35
• I studied Architecture for five years and have practiced as an architect and Construction Manager for 40 years. I learned as much in the field from construction crews as I did from my consultants. I don't mean to condescend, but this is only a forum for woodworking, The list of things I check for when designing a structure is well beyond the scope of an answer here.
– Ashlar
Feb 22 '16 at 19:14

Designing a house is a complicated problem. Normally builders learn by experience and start from established designs. There are a lot of problems that cannot be solved just by using a simple equation. Only long experience is sufficient to know. If you make a new design, the likelihood will be that, unless the design is very simple, some error will be made which you will not realize.

• Look, structural engineering is a thing, and I'm looking for references to learn it. I'm a smart guy with a science background; you guys can either keep telling me how hard it is, or you can point me to materials to get started, but I'm going to learn this either way. If I have to pick random books off of Amazon, so be it, but I would prefer a little more guidance from people who actually know the subject. Feb 22 '16 at 18:25
• Yeah, well I have worked for multiple architectural firms including Arrowstreet and what I will tell you is that designing a house is not something you can just read a book or two about and be able to do successfully. Feb 22 '16 at 18:29
• Of course not, but becoming educated is part of the process. At the very least, I would like to be able to have meaningful conversations with consulting engineers, and make my design with, at worst, a rough knowledge of the principles involved. This isn't unreasonable. Feb 22 '16 at 18:32
• @AndrewG What type of house do you want to build? Feb 22 '16 at 18:35
• "Timber frame" is not a type of house. Feb 22 '16 at 18:51