Official Luthiers Forum!

Hi all,

First post here but I first want to thank everyone for the collective wisdom I have gleaned from reading posts the past few years.

I am building a (mini) wood shop this summer. Because of local restrictions, it is 10x12, and will have a 10 foot height max. I already poured the concrete slab last fall, so this is fixed. I have been moving all my tools around in a 9x9 section of our garage, so this is actually an improvement in size for me!

Other important info:
—The shed will be wooden frame construction.
—Floor will be plywood on sleepers on top of concrete.
—The front of the shed will have 2 doors (total 7 foot width) that can swing open and the shed floor and concrete patio outside are flush.
—I spent extra on nice mobile bases for both my table saw (36” cabinet) and bandsaw (Laguna 1412), so mobility in the shop and outside to the patio is part of the plan. These are my only 2 power tools that are not benchtop
—I live on the CA coast—average annual humidity is 70%

I’m hoping you might be able to help with these questions:
—in my review of the forum and info elsewhere about controlling humidity, larger shops often will build a humidity control closet for work during essential glue ups. Well…my shop is the size of some of these closets! Would the recommendation be to control humidity in my entire 10x12 space, build a dry box and take out for essential ops, or something else?
—I am building the shed myself—it will be dedicated to guitar building/woodworking only. What weatherproofing/insulation would be recommended to control moisture transfer before getting into dehumidifiers etc?
—I am hoping to use the rafters as wood storage to maximize use of space. Considerations for making this area part of the climate envelope?
—I would also love/appreciate any other recommendations or photos for a small shop like this. Beyond the mobile tablesaw and bandsaw, I don’t have plans for any other large power tools (I happily get by with my hand tools now).

Thanks in advance! I am so excited to get out of the garage/gluing up on the kitchen table and into a space that is small but dedicated!

It sounds like you are off to a good start.
If you will be working in the shop on a daily basis, then it might make sense to climate control the whole thing. This will not only keep the wood properly conditioned, but will also reduce the tendency of tools to rust from intermittent condensation cycles. Good weather sealing around the doors and thermopane windows might be a good choice depending on what part of the left coast you are on.
Another option may be to do both - have a closet that houses a portable dehumidifier (which is probably all you will need) that you can normally leave the door open to control the whole space, but close to only control the closet for those times when you are working al Fresco and going in and out of the shop.
Insulating between the rafters might be a good idea. A single pitch roof using parallel truss type rafters may allow you to insulate them well but still have enough space to ventilate the eave and ridge. You could build a storage shelf on the high side of the roof.
California covers a wide variety of climate conditions, so depending on where you are indoor climate control recommendations can vary a lot.

Yep I would do the entire thing too and good on you for addressing RH before jumping in.

I see guitars nearly every day that were built without strict humidity control and that's why they come to see me, C R A C K......!

Welcome to the forum Kyle and thanks for using a real name too, much appreciated.

That's about the size of my main workroom. I would insulate the heck out of it beyond code, as well as vapour barrier as much as can be done. I'm fortunate to have two other work areas with many other machines, but here's how I,laid out my room with a tablesaw and a laguna 1412SUV.

An important note is that the benches are all coplanar, so even in the tiny room, you can still whittle down an 4x8 sheet if needed. But, these days if I need something like that I just pay the extra buck at the big box cut shop. I'll also add that since getting the laguna, I only use the tablesaw for two things with a dado, cutting the truss rod channel, and the x brace lap joint. But that's because I have a second tablesaw in another room for making fingerboards. I hope you're allowed to put a roof over your shop apron, bending sides and such can happen in any RH. Tablesaw is mounted on heavy duty slides from Lee Valley...

I'd love to pretend my shop wasn't always messy like that, but that'd make me a liar. Can't wait til the 10x new shop so I can have 10x the problem, lol...

I glossed over your actual question, you can see in the shot with the 5hp Oneida dust collector (your next main priority) that RH is handled quite easily with a simple home use humidifier and a 30 pint dehumidifier, but, mine is a basement shop half underground, so your needs may be different.

You can also see my ceiling is 7' something at the max. With 10' ceilings, I would consider building shelves around the entire perimeter at 7'6", 24" depth, with an extension the same footprint as your main peninsula bench, reinforced so that you can use your bench as a go bar deck, but I digress...

If it were my choice to make, I would insulate like the Dickens and regulate the whole shop, probably with a mini split for temp control and dehumidification, then see what else is needed beyond that to keep conditions at the optimum. I would also buy a good hygrometer, like an Abbeon, because you can’t accurately adjust what you can’t accurately measure. It’s surprising how unreliable most modestly priced hygrometers are. Good luck with the shop!

Not quite the question but I love Ed's notion of having all the surfaces at the same height. Using some existing benches in my inherited shop I constantly run into objects that stop what I'm trying to do.

On the same issue though, actual height is worth thinking through. If you are a bit taller than average as I am then benches need to be a bit higher to avoid back issues.

Dave

Seal your concrete slab. Lay a vapor barrier under the floor sleepers and insulate under the ply flooring. Lots of moisture can percolate through the slab, DAMHIKT.

I went through the same process a few years ago. Mine is 10x 20.

Here are some of the things I did right:

Lots of outlets a little over 4 ft above the floor
Vapor barriers everywhere, including floor
R19 on walls and ceiling
Rigid insulation under floor
Got a smaller, jobsite tablesaw on a folding stand
Good mobile bases
Small window AC

Things I wish I'd done differently:
Not gotten the bigger bandsaw that was too cheap to pass up
more planning on big tool and workbench layout would have changed window placement
more outlets in the ceiling for lighting

I'm in eastern Washington where winter temps get down to single digits, and with such a small insulated space, an oil-filled heater is more than sufficient. A small room humidifier with a separate contoller takes care of humidity.



Not in the picture to my left is a thickness sander, folded TS, disc sander, drillpress. Behind me are the dust collector and bandsaw. On my right are cabinets above and wood storage below. Swing down buffer is on the ceiling directly above.

_________________
formerly known around here as burbank
_________________

http://www.patfosterguitars.com

With adequate vapour barrier you’ll be fine. I have a 9x9 “dry room” within my workshop and have no problem keeping it at 40% rh year round using a medium size home dehumidifier - this is in a damp subtropical climate practically surrounded by rainforest. Outside RH today is 94%, it’s been like this for a month now. So you should be able to manage the humidity level without going to huge lengths.

It's expensive but spray foam insulation is absolutly fantastic. I only put it in the sub floor and in the roof with regular pink bats in the walls. I can put one of those portable heaters in my shop and heat the whole place up and when it pours rain I hardly get RH fluctuations.

I don't use a simple heater, just saying... What I would also recommend is a minisplit.

You will need to control the sub floor some how being on concrete but that is a nice small space too so even just a household dehumidifier and humidifier would work.

Wow, thanks everyone for the replies and pictures! It’s great to see how well people are using smaller spaces. I love the idea of shelving+go bar deck over the bench—definitely going to implement that!

A few more questions if folks would be so kind:

Is there a consensus on best insulation for humidity control? Pat I see you used R19 for walls and rigid under floors. Temperature in my area is between 50-70 degrees for majority of the year, so my focus for insulation is humidity control.

Carl, you mentioned sealing your concrete slab. I know the big box stores sell the epoxy paint for garage floors, but is there a better product that is more focused on moisture control that folks have had success with?

Is there a consensus on best house wrap for humidity control? I know tyvek seems to be the industry standard but I am willing to pay a bit more to control humidity especially since it is such a small shop

If I am going to attempt controlling humidity in the whole 10x12 (and include the rafters as part of the envelope) do I want to eliminate/minimize the number of gables/soffit vents? There seems to be no consensus from my research, so I would appreciate those with experience maintaining/blocking these. I guess I can always install them and then block them later

Thank you again so much!

Drylok. It's sold by HD and Lowes.
The insulation in the walls depends on whether you've got 4X or 6X wall studs, R13 or R19. Tyvek on the outside of the walls is not the humidity control. A poly sheet on the inside under the sheetrock is the vapor barrier and also under the sleepers under the flooring and inside the insulation between the roof rafters.
Good thought about your venting. Might be good to have dampers on gable vents. With the size of the structure, probably would only need those.
Where on the Cali coast are you? Can make a difference in your approach.

Thanks re: Drylock!

Ed, I love that soundboard/lumber storing rack--I'm guessing you have no issues warping with a well maintained shop after stacking the lumber for a bit to acclimate?

I'm in Santa Cruz CA, so fog is the name of the game. Temperature isn't really an issue in the same way it is for many of you around the country (our "low" this winter has been 30ish), but obviously humidity is important being coastal and building with thin pieces of wood

With that in mind, is there a preference between the rigid foam board vs spray vs insulation batts for the walls/ceiling?

Spray is the best. Takes care of the vapor barrier issue too, but is not a DIY process. Batts would be OK for the walls. Rigid foam for the roof and under the flooring. I've also done a 20x20 floor over slab with sleepers around the edges, rigid foam through the center and 3/4" t&g ply glued together and to the foam, just nailed on the edges. Ten years later it's still as firm a surface as it was new.

What Carl D said: concrete is transparent to humidity.

My shop is in a barn that was originally set up for dairy cows. The concrete floor was not level, and had gutters every few feet for manure removal. I had a skim coat poured to make it level, and used a cartridge nailer to put down pressure treat 1x4 flat on a 2'x4' grid. I put foam sheet in the spaces, laid a heavy vapor barrier over that, and put down the plywood for the floor. Being related to Captain Overkill I used two layers of ply with the joints overlapped. Nice flat floor...

The walls and ceiling were already plywood, so I just put up a heavy vaper barrier and sheet rocked over it.

I have a wood stove for the colder spells in my New England winters. It draws a lot of air, which tends to dry out the shop, so when it's cold, as it has been lately (-24 a couple of mornings last week) I have trouble getting the R.H. above 35%. The rest of the time, when I use my mini-split, I have no problem keeping it at around 40% with a large room humidifier and a smaller table top one. My shop is about 900 square feet, iirc. It looked like a dirigible hanger when I moved in, but 'things expend to fill the available space'...

With a decent vapor barrier, and good insulation (I love spray foam!) you should have no problem controlling the humidity with a small table top humidifier. You may want to look into some sort of air-to-air heat exchanger, though. A well sealed room like that can get stuffy. I have that problem sometimes when I have a half dozen students in. You should be able to heat it with a cup of tea and a racy novel...

Carl D wrote, as I was typing:
"Spray is the best. Takes care of the vapor barrier issue too, but is not a DIY process."

We used spray foam on two walls when we re-did my kitchen a few years ago. The front wall was a mess; it had been re-configured a few times and the last time they had just stuffed in bits of fiberglass and didn't seal the vapor barrier. I could feel drafts through the outlet boxes. We got a large area foam kit from Home Despot and sprayed both walls with a ~2" layer to seal things up. Then we put in R-11 or so fiberglass and a plastic vapor barrier under the sheet rock: remember, the vapor barrier has to be on the warm side of a heated space to avoid condensation in the walls. My home heat bill dropped noticeably and I no longer get the drafts.

I stole the rack idea from my time at Larrivee. Theirs was freestanding above each go bar shelf, probably 15' long times 4.

I look ahead in my build schedule, and try to have the material in the RH room several months before it's needed. That includes neck blanks and fingerboards and bridge blanks.

As for warping, the wood will do what it does. You can still use warped wood as long as it's not too far out of line...if it flattens with moderate finger pressure I feel ok about it.

Rafters are very useful for storage and other things. I have nails all over the place to hang tools on and also my clamp storage space is on the rafters. Tried to take a few pics to illustrate. I would definitely include that in your RH controlled environment.

My workshop is about the same, 10x13. I built a room inside our 100 year old garage. Dry lock on concrete, did raised floor, well insulated, and a Mr Cool unit for air (does heat too, but I am in Florida, and cooling and humidity are the items I need to control). I use a dehumidifier as well… bottom line my shop stays around 40% Humidity, with very little variance. My goal was to have as much bench space as possible, and get my power tools in designed logically. Mostly did ok, although, I have 2 bandsaws, only 1 made it in (other 1950 Craftsman 12”, if anybody local to st Pete and interested lol). I utilize ever6 inch of the space I have, and very happy so far.

Glenn

Thanks for all the replies everyone! The photos are great too!

Sounds like spray foam is something to look into—is what you guys used the open or closed cell variety? (I see there are mixed opinions online re: humidity control between the two)

Closed.

Thanks! Since I introduced myself and am no longer lurking, I figured I’ll bury my photos from my first build, currently in progress here

Following Cumpiano’s classical plans/book

Sitka spruce from Alaska specialty woods with African mahogany back, sides, and neck from Hibdon. Next steps: routing the binding ledge for ziricote binding to match the head plate and back strip, then fingerboard and neck carving!


Proud of getting this far on the project and loving every second—looking forward to finishing it and finally hearing it! (and going on to the future builds)

Bummed about the inner border of the rosette—I used the popsicle stick method and I tore out the grain in the right side. Already have plans to follow Chris Paulick’s router jig. Again, I can’t thank everyone enough for the collective knowledge I’ve gained from here

You would do well to install a split unit. It's out of the way and it will control temp and humidity. I live in FL where it is 90% through the 8-9 months of summer. My climate controlled space is 11' x 17' and I rarely have to kick on the floor unit dehumidifier to supplement the split unit. Down here everything is block though and I am on the shade side of the house. You'll definitely want to insulate that space as well. If you don't go that route make sure to store your wood somewhere that is humidity controlled.