Rough Sawn Maple Paneling?

[Homer Faucett]

My wood shop is what used to be a functioning barn. I guess it still functions, but the barn is now my wood shop! The original 1800's barn was struck by lightning in the 1950's, and the current barn with block walls up to the 8' height replaced it. The owner at the time of construction was a timber man, so the hay loft and interior structure were properly replaced with 12x12 oak beams, with the cribbing and floor made of proper oak 2 x 10's. But I digress . . .

It is colder than the dickens in the winter, and draws moisture like no tomorrow this time of the year. I am currently sealing all the block walls, and will be framing up stud walls against the blocks to allow for proper insulation. I haven't bought the framing lumber yet, but will be going either 2x6 or 2x8 to get the most insulation possible.

I have been reading all the past threads on whether to use plywood, OSB, or sheetrock, but we have had a few silver maples fall on the property this spring, and I've set the logs aside, end sealed, to be sawn up by a custom sawyer with a Woodmizer.

So, here's my plan and questions: I hope to have the lumber rough sawn to about 1 x 4 (actual 1 x 4), ship lap the edges with a rabbet bit on the router, and nail the boards to the studs horizontally using Tremonton cut nails. I plan on nailing the boards up fairly green--stickered for about a month or so before using. I think it should make for a pretty nice, strong, rustic looking workshop wall.

(1) Does anyone have any general thoughts, good or bad, about this plan?
(2) Do you think I could get away with having the boards ripped to 6" wide without too much problem with shrinking? (the logs are 24" to 32" in diameter, and I'll likely save the pith for some other rough project)
(3) I'd like to get away without rabbeting each board, but I don't want to provide hiding spots for vermin, and I don't think I want to mess with doing this Board and Batten style. Any ideas?
(4) Would you leave the walls natural, do a light wash with white milk paint, and/or poly the walls with a light sanding afterwards? I want to maximize the light, but would really like to keep a rustic barn feel.

The next step after insulating will be to think about insulating the concrete floor and pouring a pad with PEX embedded underneath. I think that's next year's project.

Thanks for your thoughts!

[John Jendro]

I'm thinking it isn't a good idea. Depending on how you have the logs cut up they could shrink a lot. Also your going to have a problem as they dry because once their installed you won't have any air circulation on the back side of the boards. Could result in the boards cupping and twisting.

[Henry Ambrose]

I'd do something else with the maple.

I have used rough T111 siding for interior shop and garage walls and would do so again. You can put it up and do nothing and have a nice rustic barn look or put some transparent stain or paint on it. Light stain or paint is nice for better light distribution and fewer shadows.

T111 is exterior material so less worry about moisture and its thick and tough enough to put a nail or screw in to hold something. If you bang something into it its no big deal.

Last and best is the part about how sheet goods go up - fast!

[Thom Porterfield]

+1 to do something else with the maple.

Ship-lap joint paneling is by and large terrible for architectural use when a sealed (or at least controled) environment is desired. For decorative purposes, maybe--if installed on a contiguous substrate.

+1 about using sheet goods to sheath your shop. Uniform surface, rapid installation and WAY fewer joints.

I recommend you install a polyethelene moisture barrier on the interior of your concrete walls. Build stud walls with an inch or so gap between the wood and the poly. Insulate the stud cavities, maintaining the air space. I also recommend that you ventillate that gap (to the exterior) between the inner stud wall and the exterior masonry wall. Wherever wood comes in contact with concrete that is in contact with the earth or weather, you should use treated lumber.

Two-by-four studs are perfectly adequate. If you want greater insulation, install them farther from the masonry wall. (Unless, of course, any of the new wood walls will carry a load from above.) Apply another poly vapor barrier on the interior face of the studs, then sheath the inside face of the studs with plywood or dry wall.

At least, that's how I've done barn remodels here in Oregon. Hope the above is of some use.

ETA: I heat my house with PEX in a 2" concrete slab on wood frame over a crawl space. It is wonderful!

[Homer Faucett]

So, anything from someone who has actually used green dimensional lumber? It used to be done all the time. Why is it now a bad idea?

Further, I don't understand the recommendation to vent between the concrete wall and the outside. That sounds like a terrible idea, and just a good way to let in cold air and encourage condensation on the back side of the wood.

I guess I should add that the second way I am dealing with what appears to be some seeping is that I am tiling around the perimeter of the barn.

FYI, I have cut and used silver maple from other trees on the property, and I have not observed enough shrinkage that it would cause a problem with shiplapped joints. Or cupping, for that matter. That's why I was not going to use the pith, and was going to stick with narrower boards.

[Tim Offutt]

Hello,
You should consider spray foam insulation. Frame the interior with 2 x 4 walls as described in the previous post, spaced 1 - 2 inches from the block wall. As the gentleman said, make sure you use pressure treated lumber ANYWHERE wood touches concrete. Spray the foam directly onto the block and out onto each vertical stud. This ties the stud to the block wall for a very solid structure.

Most closed cell foams are somewhere in the R5 - R7 per inch of thickness. Three inches of closed cell foam will yield in the neighborhood of R15 to R20. If you want more R value install R-13 fiberglass in the stud cavity. Or if you really want to max out frame with 2 x 6 and use R-19 fiberglass with the R20 foam. My primary home is done this way. But keep in mind there is a point of diminishing return.

Spray foam will behave much better than fiberglass, passing very little if any moisture or air. You would be amazed at the convective air movement within a stud cavity. Air will move vertically as well as horizontal. Fiberglass that has air movement through it has little insulating value. Another very important benefit is the spray foam will create a thermal break from the cold or hot cement block wall.

I have two homes and a total of 8000 square feet in two shop buildings insulated with spray foam. Other than SIPs (Structural Insulated Panels) I wouldn't build any other way.

Concerning your horizontal siding, have you considered tongue and groove instead of shiplap? It wouldn't be much more work to set up the T&G cutters on a shaper or router table. The T&G would allow for shrinkage and also tie each piece to the one below and above. This would help prevent warp or twist.

Soft maple dries pretty quick, especially this time of year. But if you do not let it dry down to 15% or less I would leave a board off the bottom and the top to allow airflow behind the wall paneling. This will help equalize the drying process and help prevent mold growth. After the paneling dries down to an acceptable level you can install the remaining boards.

You are correct in your thoughts on venting the wall. It can allow drying but it also will allow moisture laden air into the wall cavity. The problem is you can't control when air comes in. Dry or wet, it will come into the wall if it is vented. During the humid summers we have in Indiana (right now is a great example) this wet air will come into the wall and if the dewpoint is right it will condense on the framing or block and you will have a mess. I have seen many crawlspaces in Indiana that have rotted floor joists due to venting. Now they seal the crawlspace, cover the earth and insulate the block walls so the crawl is a conditioned space. Works much better.

FYI, I can provide the name of a DEPENDABLE spray foam contractor if you are interested. I have no relationship with them other than they have done a building for me and have worked for a couple friends. These guys are located in Wabash, IN.

Regards,
Tim

[Homer Faucett]

Thanks, Tim, that's some good advice! It was certainly my plan to get the MC of the wood down below 18% before hanging, but I still consider this green. I would expect that I could get it down near 15% in July if I tent the stickered stack with a dark tarp in the shade and run a fan down the pile.

Your advice to keep the bottom and top piece off the wall was also part of my plan for the first month after I put up the wall, along with a fan blowing along the bottom, just to be extra safe.

My plan was to use 3/4" foam sheathing along the block wall after sealing, with taped seams, and use Tapcons to attach some 2x4 blocking at intervals to allow the framed wall to be "tied" to the block wall while never being in contact with the blocks itself. I agree that our humid Indiana weather would allow sweating to occur if those blocks were not covered.

I also plan to tie in to the overhead hayloft joists, and I'll be putting foam insulation and plastic sheathing under the base plate to prevent wicking and rotting from the slab, to provide a true thermal break, and to make the plastic sheathing continuous when I finally do pour the floor. I had considered also placing PT blocking under the baseplate to raise the baseplate above where I plan to have the finished slab level, and I think that sounds like a good plan.

Your probably right about the T&G, but it just sounds like a lot more work than running a rabbeting bit in a handheld router over some long boards. I may have to think long and hard about that, as you make some good points.

I would love to know who you recommend for spray foam, and if you could give me a rough estimate in what it cost you (please feel free to send that to me in a PM). I need to have my 1870's house crawlspace done as you indicated, and a friend of mine just had his old house foundation done similarly. Luckily, the underside of my old house is all white oak, so we haven't seen much decay . . . yet. Venting just doesn't do it with a dirt crawl.

Thanks Again!

[Henry Ambrose]

So, anything from someone who has actually used green dimensional lumber? It used to be done all the time. Why is it now a bad idea?

snipped....

You did ask if anyone had any ideas to share.

(1) Does anyone have any general thoughts, good or bad, about this plan?

I offered what I think is a better idea. I'd use the maple for something else as I perceive it to have higher value and requiring lots more labor than buying and nailing up plywood sheet goods.

I'll go further now and say that your general plans seem to call for more labor and expense than you'd need to make a nice shop and you're in reverse order. Doing the floor first makes better sense. And I'd paint the -outside- of the block really thoroughly - that will cut down on moisture transmission greatly and at low cost and labor. Then I'd build interior walls on a pressure treated plate on the new floor with about a foot of space between them and the block and I'd vent that space to the interior or loft/attic.

Think about how a brick veneer, stick framed house is built and go from there. Its a proven method that works.

[Homer Faucett]

Thanks, Henry. I did ask for comments, but did not realize that I was not allowed to comment back. I'm sure that I'm getting a visceral reaction from woodworkers who just don't like to see hardwood used for anything but "serious" woodworking projects, and I can understand that. However, I was hoping to get some more thoughtful comments about what I need to take into consideration from the voice of experience.

Yes, I agree that wood shrinks, and I've dried lumber before. In particular, I've dried similar trees off this property. However, according to what I've read, and my experience, you only get about 10% shrinkage (about .4" on a 4" wide board) from green to kiln dried to 5% MC. See http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2535/NREM-5009web.pdf . That goes back to my original statement about using 4" wide boards that would be stickered and stacked for a month prior to putting them up, which would result in far less shrinking than the .4" that might otherwise be expected from true green to kiln dried. Even a 1/2" rabbet on each side would be more than double the shrinkage expected in the worst case scenario there.

I appreciate your recommendation that I use something that has a lower perceived value--T-111--instead of the maple, and would result in less work. However, we're woodworkers here, and if we just wanted to do something that was less work we wouldn't be here. This will be my shop for probably the next 50 years, and I want the interior to pay some homage to where the building came from, and put my touch on the history. The barn across the fence from mine was built primarily with maple--beams and all, and my house originally had some tongue and groove interior paneling.

Second, T-111 in this neck of the woods runs about $30 a sheet, or close to $1.00 per square foot. I can get my logs sawed for about $.25-$.50 per board foot, depending on how good I am at helping the sawyer. I bought 50 lbs of new cut nails for $20. Using the maple instead of T-111 for a 40 x 30 portion of my barn would save me about $1,100-2,200 by those rough calculations.

Third, I'm not a big fan of T-111 or its looks. We paneled my dad's basement with the stuff to give it a "lodge" feel 20 years ago, and I just don't like the looks of it--to each his own. Further, on its performance as exterior siding on houses around here, I don't think it should get any better exterior rating than pine, as the stuff wicks moisture from the bottom and ultimately delaminates and falls apart.

I really don't get your criticism that I'm adding more labor and expense than necessary. As I noted above, maple is cheaper than T-111. Adding a foam panel to the block wall after sealing eliminates moist air from condensing on the interior of the cool block wall. That's common practice for concrete basement walls, and research has shown this to be the most effective approach to insulating a block wall even when those walls are below grade. While we could get into a debate on the theories of insulating best practices, I’m taking my plan from the research here: http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf, as it has proven true for block walls that are even below grade, and does not result in an effective loss of 200 square feet like your proposed plan to build a barn inside a barn with 12" air gap between them. At the end of the day, this is not a brick façade, and shouldn't be treated like one.

Further, by pouring my floor later, I get the benefit of the finished insulated space this winter heated with electric heaters, and I get to let my new drainage system take effect for one year to reduce any damage from settling under the existing pad. I also use 200 square feet less concrete, and actually provide a full thermal break for the top pad, so that my radiant floor doesn't get the heat sucked out into the block wall. From where I stand, my plan looks less expensive, less labor intensive, and more effective than the plan you are proposing.

It was not my intent to delineate and justify my entire project plans and actions; only to get some input on considerations for using maple boards for my wall and how to finish them off. However, I appreciate your feedback, as it has helped convince me that I've thought this thing through properly.

[Greg Cole]

Absolutely, spray foam for insulation. Heck of an R value (depending on what foam and how thick). Ask Mike Holmes about it, or if ya have seen Holmes on Homes.....
If you want to ship lap your shop walls with maple, go at it.

[Thom Porterfield]

Condensation occurs when moisture-laden air arrives at a temperature that is below the "dew point"--ie: that temperature where gaseous water vapor becomes liquid--think dew on the lawn.

My recommendation to ventilate between a warm interior wood-framed wall and a cold exterior masonry wall is not to admit moisture to the system, but to let it out. Warm air can carry considerably more moisture than cold air can. When you insulate a wall, you don't stop heat transfer. You just slow it down. Between the warm interior surface and the cold exterior surface, there will be a place where the dew point exists. If the interior air contains moisture (and it does: your exhaled breath, evaporating glue, finishes, etc.), then unless you prevent moisture from entering the insulation that moisture will condense in the wall.

The recommended method of dealing with this is two-fold. You can do everything you can to prevent moisture from existing in the wall cavity. You can ventilate the COLD side of the cavity so that excess humidity can escape.

If your interior surface is unbroken (like painted dry wall), you have a reasonably effective vapor barrier. But that is an impracticality; you'll have utilities, electric outlets, doors, etc., that penetrate that barrier. If you allow warm interior air to enter the wall cavity, you will, and I can't emphasize this strongly enough, experience moisture problems there. If you insist on a "leaky" wall covering, such as your ship-lap, then I strongly recommend you install a bona fide vapor barrier, such as a film of polyethylene (4-mil Visqueen works) on the warm side of the insulation. Of course then, you will have made a "baggie" of your space and will need to ventilate the interior as well. This is easy: route your dust collection to the exterior and it's done.

As for moisture entering the wall cavity from the exterior, your plan to tile the wall is good, but not bomb-proof. The concrete block walls will be cold and damp in winter, and because you're covering the interior surface with stuff, cold and damp on THAT surface always.

Foam insulation is indeed good from an R-value standpoint. It is also waterproof, for the most part. But the wood studs between the foam aren't. I suppose you could spray foam onto the concrete block walls, but that still traps moisture in the concrete. Gluing rigid foam insulation onto the concrete has almost exactly the same results.

Approximate R-values: extruded polystyrene foam = R-5 per inch; fiberglass batts, blankets, or blow-in = R3 per inch; nominal 8" concrete masonry = R1.11; a 1-inch air space = R1.

But all that insulation is bunk if it's wet. Ventilate it. You won't regret the effort.

(Reference: 35 years of building design and construction in high humidity climates.)

[Henry Ambrose]

Your maple won't shrink that much. I'd be real surprised (amazed) at .4" over a 4" width. (maybe from just cut to dead dry - even then I wonder?) It will dry plenty in a couple of months. I'm almost done with a slab table from silver maple I cut in February and its quite dry. I think half lapped will work fine for you. A little ventilation in your wall system won't hurt.

I guess different folks have different ideas about how buildings work. Keeping moisture out and giving that which does get in a way to exit in good time is my main thrust. Having seen the result of "sealing it up but good" and then scraping the crappy moldy foam and rotted wood off concrete block set me on that path. Others think differently and likely have some reason or proof for their beliefs.

An unpainted block wall is very pervious. From a moisture control standpoint it --is-- a facade or perhaps only a screen. That it is structural has nothing to do with moisture resistance. I'd seal the outside as well as possible.