Upcoming log building codes pro's/con's

[Dana]

In an unrelated post, DonP mentioned new log building codes. I thought this might be an interesting subject for a new post. DonP, and other's care to fill me in?

[sawdust]

I know a couple years ago logassociation.org created some. I had a copy, i think they can be downloaded from their site.


sawdust

edit found em!
http://www.logassociation.org/resources/standards.php

[Dana]

I'm wondering if this will become part of the International Residential Building Code?

[Don P]

That's where they started sawdust, they've progressed into something a whole lot bigger in the hands of the code folks. This will become a part of the IRC when its adopted, its still in development. the public comment period ended over a year ago, there have been some changes and errata fixes since then and it will go through review for awhile. I'm looking for it in the '09 code cycle.
This link will take you to the drafts;
http://www.iccsafe.org/cs/standards/is-log/draft060105.html

Hey found the kerfing section;
302.2.4.9 Kerfing. Where kerfing is provided,
the depth of the kerf shall be no deeper than
HL/2. The sum of the depths of the kerf and
cope shall not exceed HL/2.
So don't go over 1/2 the finish depth.

One perspective;
Building codes as now adopted allow one of two ways to build. You can either hire an engineer to design the structure or you can use what they call the prescriptive method. The building codes have within them rules that prescribe things like how far a joist can span, how to build a stud wall and brace it against normal winds, etc. Its known as cookbook building by some and works for simple structures. It doesn't take much to cross the line. It does work for simple homes. It will evolve to where you cannot build without an engineer.

Once you step outside of those prescriptions spelled out in the codes tables and provisions an engineer is required to design the structure, or the parts of it that are outside of the prescriptive allowances. That leaves all log and timber structures on the "engineering required" side of things. The log home community is attempting to write a set of prescriptive codes that if followed will allow you to build some simple structures without an engineer.

If you look in your codebook now there is precedence. I have chapters, charts and tables on steel studs, ICF's etc, that allow me to use them in typical situations without calling in an engineer every time my hand touches one.

A common roof truss is one situation where an engineer must stamp a drawing for every one. An LVL beam is an engineered product that for common situations there are approved tables but I often use them in situations where they go outside of these and must be checked for the particular application, for instance a beam supporting a post in midspan that supports a structural ridge.

The TF community is working on something along these lines from what I understand.

We can't go back so these are attempts at moving forward within the framework. Like most laws we protect some and exclude others. I chafe under laws where common sense and personal integrity would work better but it is the world we have created. We have come to a point where we gladly trade freedom for a sense of security. I'd tap my heels together but it won't get us back home  :-\.

We have a fair number of folks who post and state that they have no codes. There is a difference between law and enforcement. Generally these folks have no "sheriff", they usually do have law, so I post to the law whenever possible. If things go south they will be expected to have built to code. Generally insurance will not pay if something that was built below code fails, don't want to find yourself there. This map shows adoption by state, there are also I think 27 foreign countries, TW for instance. Needless to say if many folks here are unaware of adoption, I can about guarantee the average Afghani doesn't have a clue that his government has adopted the IRC.
http://www.iccsafe.org/government/adoption.html

4.5" of rain since yesterday... I think our drought just broke in spades  :D

[TW]

Does this affect us who live outside USA somehow, and in case it does, how?

There were surprisingly few directions given for engineers.
One difficult excample is buckling caused by vertical compression on a short wall. For excamplew between two windows. As far as I have seen such a wall does not get crushed, it buckles instead. The stiffness is difficult to predict and therefore the common buckling formulas  are of little use.

[Don P]

I don't know how our codes affect others. The code people (iccsafe.org) claim a pretty impressive list of countries have adopted their codes. Like I said, I wonder if it affects the average person. It does concern me when laws just kind of slip in unawares for possible enforcement later. For me grading was that way, on the books since I was a kid, enforced about 5 years ago.

Within the US different states adopt different year versions of the codes. We are on the 2003 version now, will switch to the '06 version in March. We make very few ammendments to the provided version in my state. Some states add sections or reject sections. Pennsylvania recently adopted the '06 version but rejected the foundation changes in that version... which are crazy. You're jurisdiction may adopt any, all, or none. I don't know how that works, I've just seen your country on the ICC's list.

If log construction is in the '09 version we will likely adopt it a year or two later in my state. That actually frees up the current situation where an engineer is technically required every time now. Most of the log homes I've built were drawn by designers and not checked by engineers. That has been changing, I need a stamp here now. Maine for example exempts log construction from some of the provisions in the code I believe.

Inspectors have typically not known what they were looking at in log construction so tried to not notice the logs and checked everything else. A set of standards might not be a bad thing from that point of view.

I agree on the buckling of short walls, I'm sure they'd be happy to write more rules if you point it out  ;). If you go to the comments on the draft, I know alot of the writers there from E-mails that were going around at the time. There are a number of areas that aren't what makes everyone happy, some of those comments are mine. I'm sure within one or 2 cycles after first adoption the log codes will be modified and ammended as more people look at unadressed areas. For instance a coastal inspector here would probably want an engineers blessing on wall bracing for high wind if there are no prescribed ways of doing it in the draft. That may trigger a prescriptive section on short walls for typical situations. That's one example, but that's how I've seen code development work.

Prescriptive allowances are often based on our cumulative experience more than engineering. That foundation change thats coming up for us is an example. The present system doesn't work on paper as well as it seems to have worked in real life over generations. One of the changes is that we will now need to place anchor bolts 9" apart instead of the present 4' apart on full basements with high backfill. I've never seen a failure related to this but somebody's math says its a big problem  :. The log community was trying to get more prescriptive methods adopted to preclude having to engineer everything. Its a fine line to walk in several ways if you think about the whole situation.

Myself, I think its your God given birthright to crawl under the rock shelter of your choosing if its raining out ... but I'm a neanderthal  :D

[Thehardway]

Amen to your last comment Don.  Let a man shelter his family as he sees fit in a house built with his own hands and money. A town not far from me just outlawed the use of copper pipe for potable water in homes.  They claim it is leeching into the water and causing health issues.

The codes are primarily written to protect insurance companies, banks, and inexperienced contractors as well as to line the pockets of material suppliers that have enough lobby money and a niche product.  Now we are chasing our tails so to speak because everyone is overengineering the stuff that gets inspected and cutting corners on the stuff that doesn't.  Have you seen all these shrink/swell disclaimers? 

I see houses going up every day that are built on a pile of fill dirt that passed "compaction tests".   If you put the right kind of beer in your cooler you can leave your tamper at home.  Not even Nostradamus could tell you what that soil will do 30 - 40 years from now.  I looked at a building this week that is 25yrs. old and has started to fail structurally due to the soil and foundation it was built on as well as poor engineering of the design itself.

I see all kinds of problems with the way "roofers" flash valleys and chimneys.  Structural rot will be inevitable 10-15 years from now with the multiple gable and valley designs that the architects and designers are so keen on these days.  I can't recall the last time I saw a BCO on a roof :D   yet every good builder knows that the longevity and soundness of a structure relies primarily on a leak proof roof.

I understand the logic of having a prescriptive building code for log building to get away from having everything engineered but also have a pretty good idea where that road will eventually lead.  A cabin used to be one thing a guy could build for himself with a lot of sweat and little money without asking anyone for anything.  Now the only people who have housing free of government regulations are the homeless in their cardboard boxes.  I'm starting to get into polotics so I'll shut up.

Thanks for the great links to what the future holds.

[TW]

To me the log building code seems overly detailed in many cases, but lacking important details as soon as any engineering calculations are needed. Of cause this may come from my lack of engineering experience, but it feels a bit strange to have nothing to go by.

In my oppinion the ideal code is one that allows ordinary moderately sized one family houses and farm buildings to be built by eye, but gives firm and clear guidance for an engineer when one gets in doubt and starts calculating.

As said, I am no professional yet.

[Don P]

The prescriptive code adresses areas where they are comfortable allowing me to build by following the described methods and tables. As soon as it gets beyond that you're into where engineering is required. Then you look to the code referenced documents for engineering guidance. In this case most of that is in the NDS and some in ASTM reports. The book says engineering required (it used to say simply engineering calculations required) but that is now commonly interpreted as, a professional engineer practicing in the area of his expertise. The plus side is that the engineer should be well versed in the requirements of his field. So when in doubt our inspector has the option of asking for engineering on anything I cannot "defend" by pointing to clear guidance from the book. Mine does use his ability to make judgement calls. On simple stuff where I've obviously given it thought and it looks good in his judgement, he's not asked for proof. We talk about these before I do the work. In some instances he has asked for a stamped detail. When he uses his judgement he is putting himself and the jurisdiction at risk though, so I understand why he has to be that way sometimes.

This might give a little insight as to how it can begin;
http://www.iccsafe.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=10;t=001862

I'm curious now TW, how does permitting and inspections work there?

[TW]

Wooden farm buildings and small industry buildings and one family houses are allowed to be built by eye, except sometimes some specific parts. When a building is built by eye at least one of the worker has to be an experienced carpenter, at least in theory it is so. The old B10 wood design code is more or less a brief manual with which any construction engineer can design simple wooden structures. The new Eurocode is more complicated and clearly not aimed to others than specialized engineers, but still it will be both allowed and possible for anybody with a structural engineering education to design simpler structures. I have some months engineering studies left but in practise I have already done some simple calculations for others and they were accepted by the building inspector.

Construction wood can be used either ungraded with low strenght values given in the code, or graded. In practise graded wood is mostly used for large trusses and important beams, and for large buildings.
Wooden buildings of larger size and steel or concrete buildings of any size worth talking about have to follow stricter rules. There the engineer in charge needs to be a second class engineer  with at least one year experience of the material. For extremely large or complicated buildings and highway bridges and such the engineer in charge has to be a first class engineer with many years experience of the material and type of design.

I am a bit worried about this specialisation trend. It might end up like the safety rules for wooden scaffoldings. It became so complicated to design a legally correct scaffolding that people started to work from flimsy ladders, or standing on the back of back hoe buckets instead of building scaffoldings.

[Stephen1]

TW very interesting, funny how you are able to build by eye, I like that a lot especially for small buildings. The year I went to move and assemble my cabin, Ontario came in with the BCIN. Basically everything built has to be designed, and or built by a insured engineer, and or builders. Even if you want to build a deck, the designing, and drawings have to come from a firm that is BCIN, Home Depot has to be BCIN to design a deck for you. if you were to design your own deck it would have to stamped by an engineer. This has taken away a lot of responsibility  from our building inspector. They have really tried to shut down the small person like myself, form building and or designing. I know that the lumber yards like the new process, since the  engineers have to stamp everything the tend to increase the size of lumber to "make sure it is safe".