Use of Ungraded Timber in Framing

[SinStrucEng]

Good day everyone,

A friend of mine has requested that I take a job on for him. That's great and I am willing to do so, but he has an idea to create a deck using Eastern White Cedar from his own property for the framing and decking. The issue is that the wood is ungraded (i.e. sawed, planed, and dried on their property). This is acceptable to the township provided they get a stamp/letter from a structural engineer. Has anyone ever encountered this? Any thoughts or recommendations? It's not a big deck and not very high off the ground, but I am still curious about what things I should keep in mind when dealing with this.

 

[phamENG]

You're in Canada, so I'm not sure exactly what you'll need. In places governed by the IBC (or edited versions thereof), we have the following:

Sawn lumber used for load-supporting purposes...shall be identified by the grade mark of a lumber grading or inspection agency that has been approved by an accreditation body that complies with DOC PS 20 or equivalent.

So my stance is no. If you want to build something out of lumber you cut yourself that requires engineering, it needs to be graded. I know it well enough to evaluate existing (historic) structures that predate grading, but those have a history to fall back on. Green lumber with questionable drying practices and no known strength characteristics? Hard pass.

I'm more lenient with logs. Sawn lumber, no thanks.

 

[Enable]

You can use ungraded lumber for farm properties in Ontario, but otherwise our wood code reads substantially the same as the IBC note phamENG referred to.

That said, I'd be game to use it so long as you do some lab tests to get an idea of the relevant material properties and their variability. Then apply some basic sampling statistics to get yourself a credible interval that aligns with our limits states safety index. Way more expensive than buying new I would wager, but if your friend has the cash and wants to do it, I say go for it. Also kinda fun!

 

[BridgeSmith]

How to Get Your Lumber Grade Stamped

Five Steps to Using Your Own Lumber in Permitted Structures

Anyone contemplating producing lumber for construction should follow these steps before sawing.

1. Check with your local city, county, and/or state building code office to find out the exact requirements in your area. Requirements and the level of enforcement vary. Don’t be satisfied until you have seen the rules yourself. Keep a copy for future reference.

2. Purchase the softwood grading rules book that applies to the species of lumber you’ll be using. Thoroughly review the pertinent parts of the book to make sure you understand what the standards apply.

3. Once you have a written plan on how to proceed, contact the appropriate softwood lumber grading agency to discuss your plan with them and to make certain that your lumber will meet all of the requirements, such as thickness, widths, and lengths, moisture content, and required other items. Checking out all of the details before sawing can save time and wasted materials. (If going the self-certification route, make sure your certification is up-to-date)

4. Saw and dry your lumber according to your specific plan.

5. Schedule a visit with the lumber inspector, make sure you have enough time for his visit, and your area is properly laid out for inspection. Make certain any documentation is prepared and available should the inspector ask for it.

If you don't actually need an official grading and stamp for the lumber, you could probably just begin and end with Step 2. It looks like the certification courses are several weeks long, but they're geared towards people without an engineering background. For someone who's a structural engineer, it shouldn't take anywhere near that long to understand how to assess the strength of the lumber.

 

[JStructsteel]

Is this a case of 'when in doubt, make it stout?'

What spans are you looking at?

 

[SinStrucEng]

Thanks guys for the comments so far. Interesting to see that there isn't a consensus so far...

The continuous span of the joists would be 15' or so, but the effective span is 7.5' as there would be a spine beam supporting all of this.

As suggested by BridgeSmith (and touched on by Enable) I have reviewed the NLGA Standard Grading Rules guide (2022 version, latest). The section applicable to joists (page 87 onwards) appears to give most of the information that is required to visually grade the wood once it's been cut to size. I have also reviewed the OBC's permissions pertaining to using ungraded lumber for farm buildings. In the OBC article it says the following:

https://www.ontario.ca/page/using-ungraded-lumber-farm-buildings#section-2[/URL]]The Ontario Forest Industries Association and the Ontario Lumber Manufacturers Agency are capable of applying NLGA grading rules. These organizations have graders who travel to rural properties with portable sawmills and provide on-site inspection for grading and grade stamping the lumber to NLGA Standard Grading Rules. Both dressed and rough-sawn lumber can be graded.

I am thinking it goes like this, then? Chime in if I am misunderstanding something... :

1) Fellow selects and fells his best trees on his property. Cleans, cuts, planes, and prepares the lumber to nominal sizes as per the framing plan.
2) Dries???? the lumber. This part is up to him. He said he will try to find a local mill that can take it on as a special order. It will need to be heat treated and kiln dried.
3) Selects and sets aside the lumber required for framing based on the NLGA grading rules.
4) OFIA or OLMA inspector reviews and grades the selected lumber on site.
5) Framing proceeds.

I understand that this is a long process, and probably more expensive than just buying the lumber, especially for a deck, but he's to clear cut a portion of his land anyways so this would be a hobby-project that is not wasteful, at least. Thoughts? Obviously I would complete the structural design from a very conservative standpoint and require him to show me the inspection report/grading results.

 

[btrueblood]

Why not arrange with a local mill (that is experienced in producing kiln-dried processed lumber to the national specs) to accept timber from his property, and
a) cut it to sizes needed for his project and heat treat and stamp it, or...
b) accept the raw logs in trade for processed lumber

 

[SinStrucEng]

btrueblood, your option a) was my first recommendation to him, but he has a sawmill already and wants to use it. Also he is semi-retired and thus looking for stuff to do.

 

[btrueblood]

Gotcha. Well, if it's a hobby then why not, sounds like you have the steps laid out to make it work.

 

[jerseyshore]

As long as it is properly graded then I would be okay with it. Being a bit conservative doesn't hurt either.

Your outline there makes sense. Just double and triple check the entire process based on the code and procedure because if something happened in the future you don't want to nailed for all of the liability because you missed a step or took a shortcut somewhere.

 

[MotorCity]

If you are governed by IBC, then its pretty clear that the wood needs to be graded based on phamENG's post.

You may be able to ask the AHJ for a waiver by assuming the lowest grade of wood (construction, stud, utility grade??)

Is there anything lower than construction/stud/utility grade? Surely even the most garbage grades of wood have SOME structural capacity.

 

[phamENG]

MotorCity - it's not the wood that's the problem, it's the knots. I've seen otherwise gorgeous sticks of lumber that should have been fine snap like a twig because there was a really unfortunately placed knot, and the framer (who probably cut the logs themselves on site) lined them all up so the knots were in the same place on each joist. Just flipping every other one would have offset them enough that it probably would have held...

 

[TLHS]

From a pragmatic standpoint, I know there has been at least some acceptance in BC of ungraded lumber using an Alternate Solution justification under the code. Effectively, if you were confident that the design values you are using are conservative, you've visually reviewed it for significant issues, and you're happy with it, you could likely justify its use as the design professional.

Whether you're comfortable with that presumably depends on your background, the lumber's appearance, and how aggressive the design is.

 

[SinStrucEng]

Thank you everyone for input on this thread. It was insightful (never thought of looking up the NLGA guide).

To answer those who asked - I am based in Ontario, Canada and thus am governed by the Ontario Building Code.

Overall the design is far from aggressive and it's very average - almost boring. But perhaps that's the best time to try such a project for the first time...

I will share results once possible.