Am I crazy to set 'moisture content' of framing in specs?

la_koalaJune 21, 2011

As you all could probably tell by now, I am extremely detail oriented, and we are heading into the last part of the planning phase--which means my detail-oriented mind is laser-beam fixated on details and I worry that I'm going to make a mis-step. :-)

This is for a gut kitchen remodel. Some reframing (new windows) and new casing/trim. I'm the homeowner, not an architect or construction pro.

I'm asking because a book I read says "You should accept dimensional framing lumber with no more than a 19 percent moisture content and finish lumber with no more than 10 percent." (To avoid gaps showing later when the wood shrinks.)

Would I be crazy to specify the moisture content for the wood in the specifications document?

Or rather, what impressions do you think good GCs would get about me if I did specify it?

Thanks in advance!

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You should always tell the contractor something in order to avoid surprises.

Specifying 19% MC tells the contractor is that you don't want green lumber and it doesn't have to be kiln-dried.

A lot depends on your climate, the species of the wood, and how soon it will be installed and enclosed.

    Bookmark   June 21, 2011 at 12:59PM
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Renovator8, thanks for that ("you should always tell the contractor.."). Well, actually thanks for *all* that you wrote--and especially that. I do worry that I'm going to drown them with my wordiness.

My difficulty is I don't know what I don't know, and what surprises are bad and thus to be avoided.

For example, why would someone want "kiln-dried"?

The house is located in Massachusetts (sometimes humid days, sometimes dry days, weather for all four seasons).


    Bookmark   June 21, 2011 at 4:07PM
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I'm in Massachusetts too and always specify kiln-dried framing lumber because the least expensive lumber here is Spruce-Pine-Fir and it needs to leave the kiln at 15% MC to have a fighting chance of staying straight long enough to get used.

    Bookmark   June 21, 2011 at 6:26PM
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Wow, thanks Renovator8! Glad I asked, and can thank my lucky stars that you are reading GardenWeb. :-)

Do you think the finish woods (door and window casings, etc) ought to be specified as kiln-dried also? My finishes will all be painted. The last time I did a project with door casings, the guy at the mill recommended poplar. That project turned out great (though I have no idea if his poplar was kiln-dried or not).

    Bookmark   June 21, 2011 at 9:33PM
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The MC of interior millwork should ideally be 12% but no more than 15% which requires kiln-drying.

Poplar is the best for painted trim and the best place to buy it is Anderson McQuaid in Cambridge.

Here is a link that might be useful: Anderson McQuaid

    Bookmark   June 22, 2011 at 5:48AM
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I've bought trim and framing lumber at real lumberyards and at home improvement stores.

The trim that is unusable will be evident in the store or before installation.

I am a hobby woodworker as well and am quite familiar with moisture content, air drying, and kiln drying.

I've literally never worried about MC with factory made trim. I have had issues with shop made trim(some that I made as well) because of MC problems.

MC as a problem with framing lumber is a bit more prevalent, so that is an area where specifying kiln dried is applicable.

And, if any pressure treated lumber is used, it is critical to use dry lumber. PT lumber is not kiln dried, so it has to be air dried. Out of the treatment vessal, PT framing wood can need up to 6 months of air dry time, depending on how it was handled/packaged/shipped.

    Bookmark   June 22, 2011 at 5:02PM
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Most treated lumber products are air dried but "kiln dried after treatment" is a more controlled drying method and tends to reduce warping so look for or specify a KDAT stamp when dimensional stability is important.

    Bookmark   June 22, 2011 at 10:35PM
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Commonly available lumber and millwork may meet the standards you want but without a detailed specification a contractor is free to use other (even used) materials that could lower the quality of the work below your expectations and/or with no cost savings to you.

Since your best interests (quality) can be in conflict with the contractor's best interests (profit), you should always provide detailed specifications in a contract whether they seem necessary or not.

Another benefit of a written specification is that you avoid the necessity of comparing the different proposals from multiple bidders which can make it impossible to award the contract with confidence. Ask the bidders to show any alternate materials & methods proposals as add or subtract line items modifying the base bid price.

    Bookmark   June 23, 2011 at 7:39AM
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la koala, if you need more information specific to Massachusetts, put an email address on "My Page". I recommend using one you don't need to keep.

    Bookmark   June 23, 2011 at 9:09AM
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Just remember the more detailed the requirements the higher the price of the material (fewer vendors, etc.) and the more YOU are going to pay the GC (especially if he has a % markup on material costs).

You can also expect tighter and tighter adherence to the letter of the contract, and more opportunities for change orders (and harder negotiation on them).

Asking for things you have no way to verify is also not very productive.

The purchase of KD lumber is only a general indicator of what its moisture content was immediately after drying.
Since that time it could have absorbed moisture and be significantly higher.
There can also be issues with things like HVAC in a house under construction that lead to moisture content changes and warping AFTER the wood has been used.

Focusing on the desired end result is often more productive than trying to control every step of the construction process.

Do you plan on checking each piece of lumber for a grading stamp?
If so it needs to be done after delivery but before ANY cutting has occurred (the grade stamp may be on the off-cut).

    Bookmark   June 23, 2011 at 9:39AM
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In the unlikely event of KD SPF lumber being stored at a MA lumberyard outside without protection, the only thing you can do is to specify the desired MC on arrival at the site and describe how lumber must be stored on site and then enforce it. After the framing is complete is not the time to deal with substandard lumber.

You should definitely look at the grade stamp on the majority of the framing, as early as possible, especially studs supporting more than one floor/roof and large headers and beams.

The grade stamp on cut down framing pieces is of little or no consequence but it is good for them to be of the same species and MC so they will shrink in a similar manner as the overall structure but inspection is not necessary.

Whatever you provide for the contractor, someone should inspect the work on a regular basis. I've been doing this for far too long to trust any builder to not make mistakes and the sooner they are discovered the easier and cheaper it is to correct them. Some of the best builders I've ever worked with have made many mistakes, the most serious of which were usually discovered during the structural engineer's final inspection.

    Bookmark   June 23, 2011 at 1:33PM
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"In the unlikely event of KD SPF lumber being stored at a MA lumberyard outside without protection, the only thing you can do is to specify the desired MC on arrival at the site..."

Without a moisture meter to verify the level you are still wasting your time.

    Bookmark   June 24, 2011 at 1:31PM
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Simply specify that framing lumber is to be KD. That's it.

Specify that all drywall will be fastened with screws, no nails. That'll eliminate any nail popping that the KD should take care of in the first place.

With a typical construction schedule, it may be weeks (addition) or months (a house) before the shell of the addition/house is completely weatherized. during that time wet wood can lose moisture and dry wood can take on moisture. So no worries, just specify KD lumber for your framing.

Tell your GC of your concerns, and they are these: When framing, I save the straightest sticks (studs) for framing the corners and for the king studs for window and door framing. I also use the best for kitchen and bath walls, where cabinets will be hung of walls tiled.

Slightly crowned studs can be used elsewhere. Ones a little worse can be cut up for cripples. The worst, if there are any true nasties, get sent back to the lumberyard.

If your framing needs (quantity-wise) are not great, then have your GC go to the yard and had-pick the best studs out of the lift. Yards around here know I won't accept crappy wood, so they won't knowingly send it my way. If any does make it on the truck they know it'll be coming back to them.

If your GC has any relationship at the yard they'll let him hand-pick, even if they have a "no hand-pick" rule in place.

Interior trim, no worries. It's all low-MC to begin with, and it's stored under cover or even indoors. Proper joinery can prevent or minimize any movement concerns.

    Bookmark   June 24, 2011 at 2:13PM
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Hi all, I'm the original poster. Finally got a Friday-work deadline completed and the weekend chores done, and could come back to this.

Wow! Thanks for all of the great info, and thanks so much for posting! And especially for the details--I cannot tell you how much I (a novice) appreciate the time you've taken to share your experienced knowledge here.

handymac, thanks for sharing your experience from the hobby woodworking side of things. And for that additional point about pressure-treated wood (at least, I assume that's what you meant by "PT"). It reminded me to double-check our spec document and see if we had any involved in this project. :-)

Renovator8, thanks again for all of your input, tips of what to look for, and wise words about this. And for the tip about Anderson McQuaid in Cambridge! I had no idea they existed--just a few months ago I was doing Google searches trying to find a Boston-area place with a wide range of mouldings to choose from, and missed that one. It's nice to see a place that's taken the time to put images of the mouldings on their web site.

brickeyee, you wrote Focusing on the desired end result is often more productive than trying to control every step of the construction process.
Yes, I can see the truth in that--and if this were a project in my own area of expertise and experience (software programming), I'd know more how to approach it. I mean, in my own past work experiences, I know I could describe the desired end result to a team of software programmers and say "I don't want to prescribe how you implement this, because I expect you (the team) will come up with the best solution, now that you understand what end result is desired." Even so, my ability to do that with the software team depends on what I know of the experience level of the actual members of the team, and how well I've described the desired end result (and even *why* that's the desired end result--how our customers will use it).

My challenge for this construction project is that:

  • Construction is not my area of experience/expertise (so I don't always know the right way to describe the end result I want, other than the sparsest ("I want straight walls and windows and doorways"). I don't know what I don't know.

  • I know it's a lot easier/faster in software programming to re-do something when it turns out to not match the desired end result, than it is in a hard building. :-) As Renovator8 put it "Some of the best builders I've ever worked with have made many mistakes," -- we're only human and make mistakes for all kinds of reasons.

  • In my work experience, me and the programmers are all on the same team (= the same company), so we share the same incentive to get the desired end result done in the most solid, no-bugs, "won't break later" way. (Because if they implement it and it breaks down the road, a customer will find it and call it in and they'll have to fix it anyway.)

So, while I know that I don't want to specify...

    Bookmark   June 26, 2011 at 6:25PM
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