Timber Framers Guild

Chicken or the egg?

Posted By: Free State

Chicken or the egg? - 02/12/09 05:08 PM

I am working with a client who wishes to utilize reclaimed timber. We have designed the project using standard sections of new Doug Fir. I am being asked to provide a list of materials, but feel uncomfortable sizing timbers with defects (bolt holes, pipe holes) without seeing them first. I am feel that each timber will have to be inspected, and depending on the size, quantity and location of the defect will determine the increase in size required. This will greatly affect and complicate the design and standardizing timber sizes.
I would like to know if anyone has developed a rule of thumb starting point to deal with this dilemma. Also if a defect is plugged how does this affect the integrity of the timber?
Posted By: Gabel

Re: Chicken or the egg? - 02/12/09 05:38 PM

Is the client supplying the wood?

We have had success in the past with the client supplying reclaimed timbers. The way I approached it was to stipulate in the contract that the timber was to be a certain species and a minimum grade. I sized the timbers with that species/grade in mind. I also say that we can reject any timber based on twist, bow, crown, or other defects. It helps to be specific, eg -- "Timbers are to have no more than 3/4" of crown in 16 feet" or "timbers are to have no more than 1/4" of twist" etc.

You have to retain control over the quality of the timber. This adds the potential for additional cost if you are waiting 2 weeks for the client to bring you another 8x10-20 because the last 3 were rejected. Make sure you cover that in the contract -- maybe you add a mobilization/demobilization fee each time you have to stop and wait for materials.

If you are supplying the materials, you either approve the timbers proior to buying them or stipulate that they have to be a certain grade. Realize you will have to buy extras.

The above was for fixed price contracts...

I would really consider doing the job on a time and materials basis. That takes a lot of the burden of estimating the impossible off of you and you can focus on doing a good job efficiently. Make sure you set a reasonable budget and keep to it. If something comes up that will negatively influence the budget (hidden defects in timber, etc), immediately inform the client of the circumstances and how much time and money it will add to the project. As long as you communicate thoroughly and start out with a reasonable budget, it is the best way to do these types of jobs.

Our experience is that while a lot of reclaimed timber is high quality wood (tight grain, dense, etc) you won't find very many timbers that will grade better than #2 because the bolt holes, etc are graded as loose knots and the checks are usually enough to knock it down to #2 alone.

Any hole or defect weakens the timber, whether it is plugged or not. As for how much, you'll need an engineer and possibly a timber grader to answer that.

We've found that it isn't cheap to build with reclaimed timbers because of these issues as well as increased labor (especially if using original surface or hewn timbers). The results can be absolutely great, though.
Posted By: TIMBEAL

Re: Chicken or the egg? - 02/12/09 06:03 PM

Gable, that is interesting that a loose knot would grade the same as a hole. I would think a drilled hole would drop the grade lower than a knot. This whole grading thing has me wondering. With knots the grain is still running around the branch and it gets smaller as it works into the timber. We take a #2 or better timber and cut mortices and peg holes into it completly severing the fiber.

It sounds tricky designing without seeing these timbers.

Tim
Posted By: kfhines

Re: Chicken or the egg? - 02/13/09 11:55 AM

Originally Posted By: djswan
Looks like a cart before the horse design. They need a timberframer.


Now there's a bumper sticker!

kfhines
Posted By: bmike

Re: Chicken or the egg? - 02/14/09 12:49 AM

You should be able to find an engineer or timber grader who can do this work for you. There are guidelines similar to the knot size and grading rules for the various defects found in reclaimed. I've worked on many projects which required graded material and a sealed timber list (reclaimed typically doesn't come with a grade stamp) - including several projects in earthquake country - shallow trusses, high snow load - but narrow pieces of beautiful reclaimed fir.



How are you procuring timber?

In my years working with New Energy Works and Pioneer Millworks we did (and still do) this all the time. Often we would design the frame for optimal sizing, then seek out what reclaimed materials are available - and speciify what grade they need to meet - often redesigning a bit along the way (ie - if we found a stash of 3x10s that could be used as common rafters instead of the 4x8's specified).

A competent reclaimed supplier / mill should be able to visually grade to a #1 or BTR in Reclaimed Fir, Heart Pine, and probably mixed softwoods. Note - I'm assuming re-sawn industrial salvage reclaimed - but it can be done with 'as found' industrial salvage as well.

If you are talking about agricultural salvage - that is a very different problem - sawn or not - as mortise location and repetition from barn timbers (typically hewn) and damage from weather, rot, and insect make it far more challenging.


Its a chicken / egg problem no matter how you look at it - we're just lucky that currently we can all pick whatever timber we want 'off the shelf' of the fresh sawn forest. There are creative ways to work with what the forest (industrial buildings or local mountainsides) gives us... and in a world of declining resources - at some point we probably won't be able to order up whatever we want, whenever we want...

-Mike
Posted By: bmike

Re: Chicken or the egg? - 02/14/09 08:26 PM

Originally Posted By: djswan
Originally Posted By: bmike



Its a chicken / egg problem no matter how you look at it - we're just lucky that currently we can all pick whatever timber we want 'off the shelf' of the fresh sawn forest.

-Mike


mad


Not sure how I'm supposed to take that...
Posted By: Free State

Re: Chicken or the egg? - 02/16/09 04:45 PM

The Client will be supplying the Materials.

I think stipulating the quality and grade value would be the best starting point.

When I was in Washington I meet a Forest Service employee who was in charge of the grading specifics. In our conversation concerning the values of White Oak, he mentioned mechaniclly grading materials. Does anyone know of a company that provides this service?
Posted By: daiku

Re: Chicken or the egg? - 02/16/09 06:02 PM

Originally Posted By: bmike
Originally Posted By: djswan

mad

Not sure how I'm supposed to take that...



Mike, I do believe you've left him speechless - no small feat, that.
Posted By: bmike

Re: Chicken or the egg? - 02/16/09 08:33 PM

Is the client buying out the materials? What species? Or do they have a pile of 'reclaimed' wood they want you to turn into a frame?

If they are buying out the materials be sure the client sources them from a reputable reclaimed source (there are a few around) - and be clear that the materials need to meet a grade or you are free to reject the pieces. This will mean the client orders extra, or they buy from a reclaimed supplier that can provide visually graded materials.

Posted By: Free State

Re: Chicken or the egg? - 02/17/09 07:17 PM

The Client is purchasing the materials.

I have already designed the frame utilizing KD FOHC #1 or better Douglas Fir. In our first conversations the client is looking at Long Leaf yellow pine. The only mecanical values for this material is in a 1902 book "Encyclopedia of Timber Framing and Carpentry and in Steve Chappell's first book. Neither help with the defects of being reclaimed.
Thanks for the help.
Posted By: Gabel

Re: Chicken or the egg? - 02/17/09 10:42 PM

Free state,

Long Leaf (along with loblolly, shortleaf, slash, and virginia pine) is a species that falls under the lumber category "Southern Pine" or occasionally "Southern Yellow Pine (SYP)". Current design values are available here ...
http://www.spib.org/timbers.shtml?/publications.

There is another category "mixed southern pine" that has lower design values because it allows a few of the poorer species to be included.

If I remember correctly, you only need 6 rings per inch to meet the "dense" requirements. Any first growth timber should meet that. (I've seen over 30 rings per inch in it).
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