Drying 8 x 8 timber

[D6c]

Putting a new basement under my house this summer and since the old basement had old hand hewn oak supports (from the "old" house), I thought I'd put wood posts back instead of steel posts.
The old basement had 6 posts but since I changed to a steel I-Beam under the floor joists I only need two supports.

I sawed an 8 x 8 black locust to use for one support...I may cut another, or maybe an oak for the second one.
Sealed the ends of the post, but my question is, should I put anything on the sides to slow the drying?
Being that thick I'm expecting it to crack some on the sides as it drys and wondered if there's any way to prevent it.

Leaving it a couple of inches oversize, letting it dry of a year, and then trimming it down would probably be my best bet, but I don't have the time to wait unless I put temporary supports in and change them out later, but I'd rather not be jacking on the house again after I get all the drywall fixed and painted.

[Brad_bb]

No, just let the outside dry enough so there's no mold growth and go ahead and install them.  Make sure they don't have direct contact with steel or concrete, or the steel will rust and the wood might rot locally.  For example on the bottom of timber posts I've installed 1/4" thick lexan plates screwed onto the bottom of post(with epoxy coated screws).  The plates are a half inch less than the post cross section so that you don't see them.  You could use lexan again or coat the beam to prevent direct contact.  Keep an eye on them in the basement to assure no mold growth in the first couple weeks.  When the outside has dried enough, it won't grow mold.  In green wood posts use only hot dipped galvanized or epoxy coated fasteners.

[Don P]

Locust will check far less than oak and has some degree of natural decay resistance which is good in that location, if you get a good one the foundation stones will rot first.

[GeneWengert-WoodDoc]

You can minimize checking by drilling a large hole down the center, full length.  Of course, this affects the strength.  The cracking, if it spirals, does affect strength.  A log cabin maker probably has the equipment to drill a long hole...a 2" diameter hole is 5% strength loss.  Buckling of a smaller size is an issue too.

Fasteners put in green wood that then dries lose quite a bit of strength.

Did you consider a steel post and then use the outside 4/4 lumber from the 8x8 to box it in?  It will look like an 8x8 to most folks.

[mike_belben]

An asphalt shingle or few scraps of tar paper makes a good barrier.  The load will kinda squeeze tar into the end grains and seal them up.

[Don P]

 getting into compression just some random post thoughts. One rule of thumb is that when the depth to height ratio of a column is below 1:12, buckling ceases to be a concern. the failure mode is crushing, the compressive strength parallel to grain is the column's control. So for an 8" thick 8' tall post the allowable compressive load is all you need to check. You don't need to then check whether the column will buckle. So that is a nice handy ratio to keep in mind when you're posting under mongo loads. One inch of column thickness for each foot of height.

Locust is not listed in the NDS. The closest similar species groups in my mind are Beech,Birch, Hickory and White Oak. This is where I try to use some judgement and refer to the Wood Handbook. Those species run around 7-9,000psi in compression in the wood handbook, black locust is 10,000psi. That is the average of small clear samples in a lab. In the NDS the allowable max stresses for those species runs 800-900psi for #1 posts in compression so I'd feel comfortable using those numbers for locust.

Also check the material that is under and over the post transmitting load to it. For a wood beam bearing on the post check the allowable compression perpendicular to grain with respect to the area of the post top. Crushing the side grain of the beam is often the control in all of this. With a steel beam that is not the problem although it may need web stiffening in the post area.

Aside. Look at that tested average max compressive strength of clear locust, 10,000 psi. Its sitting on 3-4,000 psi concrete. Ultimately the locust can hold its own at that end.

An 8x8 post top at 64 square inches supporting 800 pounds per square inch (using that <1:12 H/D ratio) = 51,200lbs... that was just using the rule of thumb.

using the full NDS math it actually comes in at around 46,000 allowable so close but be conservative.

[D6c]

I cut a burr oak for the second support...nicer looking than the black locust....I don't like it I can replace it later.
Think I'll put some linseed oil on them once I get them in place.  I'm going to wait until they get the floor poured to set them to keep them from getting splattered with concrete.

At an average 60# per sq foot loading for the floor I'm only holding up around 10,000 lb.....I don't think the posts will have any problem.

I sealed the ends with anchor seal and I'll put a couple of layers of roofing felt on both top and bottom.  The footing will stick up above the floor a couple of inches so it shouldn't get wet....although from what I saw in the old basement, that's not an issue.

One of the original oak posts (reused from the old house so probably over 100 years old) was about 5' from an open shower mounted on the wall.  The bottom of the post was a couple inches above the floor but it got a little wet every day that shower was used for the last 70 years.  Don't know why but the post wasn't rotted at all.

[Brad_bb]

For green timber you really want a finish (if you have to have one) that doesn't seal so that moisture can still come out.  Heritage Natural Finishes "Original Finish" is what most timber framers use on green timbers.  It lets the timber breathe.
Heritage Natural Finishes

[logman 219]

steel beam!!! just buy STEEL column and bolt it in!!!

[GeneWengert-WoodDoc]

A few notes.

A post has slope of grain restrictions, such as 1 in 6, which is about 10 degrees....pretty small.  Further, it is rather high quality with few large knots.  As a rough rule, a No.2 post is similar to the No.2 Dimension Lumber grade.  Compression or tension wood, shake and pith, which are all weak, are also limited in the detailed grading rules.  Such details are not on the Internet sites which give general grading information.

Check out https://courses.cit.cornell.edu/arch264/calculators/example7.1/index.html
Note that the calculations are for upper grade posts.

The flooring number of 60 pounds per square foot is for the load of the contents on the floor and does not include the load from the building which is huge, floor framing, flooring itself, etc.

The load calculations are for dry post.  The nominal 8x8 size is 7.5 x 7.5" or maybe 7.25 x 7.25".

Fastening the post to the floor, top and bottom, is critical.

Check the site http://www.twincreeksloghomes.com/images/Pdf/wwpa-design-load-tables-columns-posts.pdf
Again, be aware of the grade requirements for a No.2 post, which has around 30,000 pounds total load.

[Don P]

I can't recall seeing a pith restriction in post grades other than foundation grade treated. Citation?
http://www.nelma.org/wp-content/uploads/2013/08/Section_6.pdf

Residential floor design load is 40 psf LL + 10psf DL. Sleeping rooms can use 30psf. A girder supporting a floor can be at less than 60 psf but yes it could be supporting something else.

[Brad_bb]

Gene, is that the NELMA description of a post?

In Timberframing, most posts are boxed heart.  Helps them be more stable drying.  Also, since posts are in compression in a frame, they can typically have more defects- knots etc. compared to horizontal beams.  

[Don P]

Those are your grading rules Brad.

Go back to about 1927 Congress charged NIST with developing uniform nationwide grading rules for structural softwood lumber DOC-PS-20. As time has gone on that includes all structural wood, hardwood, softwood, lumber and heavy timber. Timberframes too.

The building code says
"
R502.1Identification.
Load-bearing dimension lumber for joists, beams and girders shall be identified by a grade mark of a lumber grading or inspection agency that has been approved by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted."
This appears in every chapter that talks about wood and references the members discussed in that chapter.

NeLma, SPIB, WWPA are rules writing agencies, they publish those grading rules under the oversight of the ALSC, the American Lumber Standards Committee. Those as well as other non rules writing accredited grading agencies oversee the grading of structural wood in this country. The NeLma link I posted above is the grading rules for posts. On their website you will find the grading manuals for other sizes and uses. You will find more regional manuals and other good info on the other rule writing agencies websites as well.

The US and Canada both use the NGR, National Grade Rule for the basic grading manual.

There are states with exceptions to audited grading, however, you are supposed to be grading to exactly the same standard.

I went back in my email to the last ALSC BOR meeting from a couple of weeks ago. Just to round out kind of how the bureaucracy works, this is the overseeing board, The ALSC, meeting with its member grading agencies discussing a new domestic species classification, testing of various types of lumber, a rule change, etc. The workings at that level, see attached

[GeneWengert-WoodDoc]

Brad points out another key factor...the posts must be straight.  A bowed post is prone to buckle. 

 Also, be aware that internet grading rules for posts are for softwoods; sometimes hardwood lumber  has been included in lumber rules...I am not aware of any rules for No.1 or No.2 hardwood posts, but maybe someone knows of them.  Knots, shake and tensionwood would all reduce compression strength, along with even slight slope of grain, such as over 1 in 6 or 10 degrees.

I do believe a building inspector might have difficulty approving the two posts you have; maybe that is not of concern.  Note that compression failure of a post will initially shorten the post.  Eventually, you could have catistrophic failure if the post buckles or shears.

[Don P]

Read the NeLma grading rules. Pg 6-3 species... from aspen to oak. Those are the rules that matter.

As mentioned buckling isn't of much concern at this thickness to height ratio. As a column gets taller and more slender the allowable load is decreased proportionally to prevent a buckling failure.
You can see the column stability factor decrease in the calculators as the post becomes more slender. Play with the height of the post and thickness and watch what happens to the Cp. This is factored in as the calculator determines allowable load. Keep your column stability factor high as much as possible in design.

I've had smaller but similar solid sawn locust and white oak posts pass inspection in basements supporting girders with no issue. This isn't typically a catastrophic failure point. As mentioned this post, as is typical, is being loaded at about 20% of capacity... this probably isn't the bear in the room.

[Don P]

I'll bring this up to the thread from a related PM, more links and stuff;
"Do you think an inspector in Iowa would be familiar with NeLMA rules for hardwood posts?  I would expect he/she would want to see some certificate, letter, etc.

I do.not understand the NeLMA post grades as they are apparently taken from the WWPA.  How can they be used for hardwoods without accounting for tensionwood, growth rate, and other hardwood characteristics?  I do not have the WWPA rules, but I am surprised if they do not include something about compression wood.  Is the info in paragraph 26.1 to 26.3 what the NeLMA grader uses, or does the grader have a more complete set of rules?  I do recall that SPIB had a more complex rule book for graders years ago when I was at VT and took a class from SPIB"


No an inspector in Iowa probably won't know one stamp from another, all he needs is some audited third party stamp, they come in on all my engineered goods now from the side of SIPs to glulams, to plywood. All he looks for is a good stamp. Names of grading agencies are in the Supplement, facsimiles of their stamps are on the ALSC website.

Go to the NDS supplement, free download at awc.org. it has the commercial species allowable design values softwood and hardwood. Section 2.1 List of sawn species combinations and which rules writing agency is responsible for those species rules. Another agency would then grade to the rules writing agency's rules. The NeLma rulebook is cross referencing similar sections of the WWPA rulebook here.

The model grade rule is the NGR for dimensional lumber, check the definitions and interpretations sections for some of the concerns, slope of grain, splits, knots, etc;
http://secure.itswebs.com/nawla/Level_II_Jeopardy/story_content/external_files/National_Grading_Rules.pdf

Compression wood... reaction wood is something that I have complained about quite a bit, notice how lightly they treat it in the grade rules.

The auditing check graders do quite a bit of field training and I'm sure there is more training literature but you are seeing the text.

[Don P]

These are related to some of what has been talked about

This is a tech note from the engineering wing of the TF Guild on checking in timbers. It offers more in the way of explaining how an engineer looks at checking.
https://www.tfguild.org/timber-frame-engineering-council/technical-bulletins/view/253/download

This is a paper from the USFPL on grading hardwood dimension;
https://www.fpl.fs.fed.us/documnts/pdf2006/fpl_2006_green005_Page.pdf

This is the index page for the NeLma grading Manual, section 1 lists species under those rules;
http://www.nelma.org/library/2013-standard-grading-rules-for-northeastern-lumber/

Those are the minimum structural dictates. The job specs can always exceed those minimums. Gene just ordered straight, check free, #1 FOHC in eastern hardwood, sweet! Bill accordingly and that is fine.

Where I was going with white oak and locust is they also take care of any possible requirements for needing to use treated wood or a naturally decay resistant species. If there is a locust in the pile the first thing I'm looking for is a post.

[Brad_bb]

All I can give you is my experience from Timber Framing.  Posts are usually way oversized  for the load they carry, especially hardwood.  If you want to be sure of your loading situation, have it engineered.  A proper engineer will analyze the loads and tell you if your hardwood posts are sufficient.  

In Timberframing, we visually grade timbers and have some of our own specifications.  NELMA is a good reference, but in timberframing, you typically box the heart in hardwood or you end up with banannas.  Oak is very commonly used in timber framing and I can tell you, if you saw a beam Free Of Heart, there's a very good chance it will bow, and more than is acceptable.  

Dc6 never said this was being inspected or had to meet NELMA grading. Nor do we know it has to, to work safely.  Only an engineering analysis will tell us that.

[Don P]

All just informational, there have been and continue to be quite a few misconceptions surrounding this subject, let's try to clear some of that bunk out of our heads so we can move forward with real knowledge.

 Grading was put into place and done so with uniformity in order to maintain rules and to provide reliable, consistent design values across the country. This springs out of a time when two mills might be producing #2 lumber but the wood from one mill was inferior to that of another. The engineer's paperwork is worthless if the material is not on grade. We needed a uniform simple grading system.

 The links I posted above are the rules that would be referenced in construction documents whether engineer or inspector, there is not a separate set of timber framers grade rules. Read and learn them, they are your rules. When you consult the NDS, The guild engineering publications, any engineering with regards to wood construction, or the builder down the street, they are all using these grades and their respective design values in their work. This is basic, understand this. All wood engineering is based upon understanding the "grade" we are talking about. So we need to be talking about the one, the only, reference document in these negotiations. We must be on the same page, this is that document.  Grading is done under the oversight of the ALSC. go to their website, these are the rules writing agencies and their respective grading manuals;
http://alsc.org/untreated_graderuleorg_mod.htm
 All the accredited grading agencies are listed here, Non rules writing as well as rules writing agencies;
http://alsc.org/contacts_untreatedlist_mod.htm

When the guild was teaching grading this past year the instructor was from SPIB, one of those agencies. Log builders also work under this same grading system.

 As pointed out earlier, the grade rules say nothing about boxing or not boxing the heart, that was a misstatement that can be cleared up by referring to the grading rules themselves. Know the rules 

In specifying a grade when ordering a timber you are using these grading rules. When the engineer has marked up a set of plans it is these grades he is referring to when specifying timbers. This was indeed the purpose of setting up uniform grading rules. This assures we are all grading and specifying to the same set of strength standards.  You can certainly add other stipulations to the specifications when ordering timbers.

Load-bearing dimension lumber for joists, beams and girders shall be identified by a grade mark of a lumber grading or inspection agency that has been approved by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted

[Ljohnsaw]

Thanks, Don.  Interesting but I'm not sure I understand all their buzz words.  I'll have to go through the glossary.    But, do you have a link to western regulations?  I'm assuming they will be close but I need the references to the wood I have out here.

[Don P]

If it's a buzzword I can clarify shoot.

this is a link to the publications page at the West Coast Lumber Inspection Bureau (WCLIB);
http://www.wclib.org/publications/rules-17/

WWPA would like to sell you a hard copy of their grade rules;
https://wwpastore.org/products/western-lumber-grading-rules-2017

I guess that mainly just leaves SPIB for southern pine
https://www.spib.org/about-us/pocket-guides

[Ljohnsaw]

Don,

So more clarification than anything.  I was looking at Section 6 of the link you posted above - 25. Beams and Stringers.  It has a little table about thickness and widths.  If I'm reading that right, my 10x16 beams would still be called that and the calcs would apply to the nominal size of 9.5x15, correct?

I tried to cut a little oversize for drying shrinkage but ended up cutting some at or 1/8" under my target.

It is somewhat shocking that for a No. 2 grade (as specified in my plans), I could have 8-1/8" knot ANYWHERE on the big face of my 16" beams.  I'm cutting my beams with 2 and 3" knots and I think those look bad!  They give the sizes of knots "on edge" and "centered" for No. 1 - how do you adjust when it is in between?

What is "profile" beams and stringers?  Kind of sounds like a beam that has wane on one edge to me.  They mention "rustic effect".

[Ljohnsaw]

Bummer, Adobe says the wclib PDF's are damaged and cannot be repaired. :'(

[GeneWengert-WoodDoc]

When I was an extension specialist in Wisconsin, the State authorized anyone who attended a class on grading to then grade dimension lumber for local use, and authorized the building inspector to approve such lumber.  The grader is not inspected frequently for conformity to the rules, but if the building inspectors think the rules were not adhered to, they do have the last word (but how many inspectors can accurately grade lumber?).  I am not sure how this fits into the ALSC procedures.

The document explaining this system in Wisconsin is at
https://dnr.wi.gov/topic/ForestBusinesses/documents/LmbrGrdngHndbk.pdf

I wonder why other states have not adopted this approach.  

Don P- -Does the "guild" you mention, or it's members, have the authority to grade timbers or lumber?

[Don P]

Exceptions to accredited grading. I agree, more states should adopt it for single family residential. That is a state exception to the model building code. For those exceptions they are waiving ALSC oversight and handling that, or not, from the state level. As you can see it needs to have training so we are all talking about apples to apples. A number 2 is not a pretty piece of wood. I'd venture to say most woodworkers will reject a number 2 before grade will. But I've seen and used myself wood that is below grade. In the end that is what grading is all about though, making sure your material is at least as strong as what the engineer assumed in his calculations. As long as we are all on the same page about those minimums the plans work as intended, anything better than that minimum is gravy.

From memory a profile beam is convex in section... ehh yeah, whatever, I use the KISS method here. draw the largest rectangular section you can inside the log or beam end or section in question.. In other words for a live edge step in a little until you are at least within wane restrictions. You can linearly interpolate between edge and wide face restrictions with respect to how far you are between those points on the timber.

In most of the calcs that specify a beam dimension they are working from a nominal size.
In the NDS read the footnotes under table 4D, the design values for heavy timber use the green surfaced dimension from table 1A... 5x5 and larger surfaced green is 1/2" under in each dimension. In my calcs enter what you actually have.

The Timber Framers Guild does not to my knowledge have any grading accreditation.  The first article here is a good one on grading timbers from their engineering wing. I see Jim Rogers supplied some of the timbers:
https://www.tfguild.org/timber-frame-engineering-council/timber-grading

The log homes council does have authority to grade log home logs so there is precedence if the guild wanted to pursue that. The log home industry also went through the process of creating "standards". The methods of construction described in that document exempt those portions of a project from needing engineering. Something the guild should also do, as well as the post frame industry.