When I moved into my current home, I had nowhere to set up shop. Coming from 2-1/2 bays of a 3-1/2 car garage, I was potentially – as they say – SOL (Dung Out of Luck). Fortunately, finances came through enough to lure a contractor into constructing a 24′ x 36′ building in the new back yard. But I could only afford bare studs and rafters, leaving the interior walls and ceiling up to me to deal with as my shriveled wallet slowly re-hydrates. I saved up enough to tackle the walls and spent several weeks researching and watching videos, learning how to properly do the job. And now I’m ready to share what I’ve learned. If you don’t mind a little manual labor, crack open a box of sweat rags and roll down your sleeves. Let’s insulate and start sheathing garage walls, all without drywall!
From Studs To Studly – Insulate And Sheath Those Ugly Things
Before going any further, take the time to research your local building codes. My research and experience was focused on my specific situation, but the rules and requirements of insulation and other details vary with respect to region and jurisdiction. Especially in basements, which should not be insulated with fiberglass, due to risk of mold.
At minimum, this will give you a good jumping off point. At most, I’ll recruit you to come help do the ceiling when the time comes; you are on my short list, after all. Oh no… you’ve already started reading; there’s no backing out of it now!
My first mistake was not doing the walls BEFORE filling the building with crap. Unless you enjoy moving everything you own multiple times, either take care of the walls before moving everything in or be sure to leave a 4-5 foot margin in which to work. Some things are learned the hard way. Truth be known, I’ve yet to do the front wall for this very reason. I must first move an 18” depth of sheet goods and the forest of lineal stock that’s leaned against the naked studs.
Insulation – A Cozy Blanket For Your Garage or Shop
Your local building codes should be considered final authority on any construction protocol. I used rolls of paper faced R-13 insulation. You’ll probably want higher rated insulation for any walls shared with climate controlled spaces, such as your house. Note that basements have different insulation requirements than above ground walls and are not covered in this discussion.
Home Depot and Owens Corning’s nifty insulation calculator is a great resource to estimate how much insulation you’ll need. I figured I needed 19 rolls, but Home Depot’s price break was at 20. Buying that extra roll saved me a lot of money.
Whether you use batts or rolls, be sure to purchase insulation in the width that matches your stud spacing (16” in my case). Don’t use loose insulation to fill a wall. It will eventually settle, leaving open air space at the top and compressed insulation at the bottom, both of which dramatically reduce efficiency. Some alternatives to fiberglass include recycled denim insulation and products like Roxul, both of which have some useful sound-dampening characteristics and environmentally friendly traits.
It’s recommended to wear long sleeves and pants when working with fiberglass insulation. Naturally, I opted for a T-shirt and shorts. Sure, I itched a tiny bit but it wasn’t the end of the world. I did my best to avoid rubbing against the fiberglass, but some fibers will end up airborne. Therefor, gloves, goggles and a dust mask are a must. Fiberglass in the sinuses and lungs can be an unpleasant and hazardous experience, to say the least.
Insulation Laceration – Cutting To Length
Roll insulation is easy to cut. Measure the length and use a framing square or other straight edge to squeeze the insulation flat against a scrap piece of plywood and cut it with a razor knife. Alternatively, the oversized scissors I used worked like a champ.
Your insulation should be cut the same length as the height of the opening. You don’t want gaps or bunching at the top or bottom. I chose paper backed rolls for both price and convenience. The Kraft paper backing has a vapor barrier coating between it and the fiberglass and should be installed with the paper side facing the interior of the garage. The paper also has tabs to prevent sagging.
Insulation Manipulation – Negotiating In-wall Obstacles
It’s a well known fact that the number of obstacles in a given wall is directly proportional to the severity of your wanting to just get the job done and over with. I think it’s a law or something. There may be wiring, outlet and switch boxes, water pipes and gas lines, and you’re going to have to work around them safely while losing as little “R-value” as possible.
“R-value” is the insulation’s resistance to heat transfer. Insulation works best when it’s fluffy and fills the entire space. So, rather than crush it up against in-wall utilities, peel it apart and feed half behind and half in front (or whatever proportion matches the situation).
Insulating Around Electrical Boxes
It would be insulting to the insulation (and your wallet) to just cram it behind electrical boxes. Tempting as it may be, crushed insulation is highly inefficient. Work around such obstacles by cutting out for the box, leaving about half of the thickness to fill in behind it.
You’ll have to remove outlet and switch plates – and maybe a breaker box cover – in the process of this job. Use caution. Better yet, kill the main power so it doesn’t kill you.
Be aware that flipping off the main breaker may not protect you from live bus bars in the breaker box. If you don’t know what you’re doing, consult a qualified electrician. This is no time for carelessness.
An Insulation Installation Situation – Insulating And Sheathing Garage Walls
Windows, doors and builder errors will undoubtedly create areas where you’ll need a wider or narrower strip of insulation. For wider pieces, you can cut a strip to fill the gap then use special insulation tape to join the pieces. Just make sure you have paper tabs at the studs.
For narrower strips, cut the insulation lengthwise, but leave an extra inch of width. Then peel and trim fiberglass away from the backing to create a paper tab on the cut edge.
Finally, use a staple gun to attach the paper tabs to the studs. With metal studs, spray adhesive can be used instead. The insulation will fluff up when unrolled. But, once in place, gently rub and pat the paper facing to fluff it even more.
Wall Sheathing – Insulate And Sheath Your Garage Walls
Nothing beats a wooden wall in a garage or workshop. Plywood and OSB (Oriented Strand Board) are both excellent choices, with OSB being less expensive. You can bump things into a wooden wall without fear of punching holes. And things can be hung with screws pretty much anywhere without having to locate studs (though studs are nice for heavy objects, such as cabinetry). The drawback is that the finish isn’t going to be as smooth or pretty as drywall; a minor price to pay, considering the benefits.
I used 7/16” OSB, a wall sheathing I’ve been very happy with in the past. Some people falsely conflate OSB with particle board. But OSB is widely used to sheath roofs and to skin the exteriors of houses. It can handle a surprising amount of rain before swelling and breaking down. That said, it’s not intended to be exposed to the elements for any long period of time. My point is only that it’s a lot more durable than it looks. Particle board, on the other hand, will disintegrate and contort if you look at it funny; or feed it after midnight. Compare the two photos above.
Stud Finder – Points To Self
Before placing each panel of sheathing, be sure to measure where the studs are. Don’t take for granted that the builder spaced them all perfectly. Odds are, they didn’t.
To be sure you can find the center of the studs – especially if you find one that’s out of position – mark its location on the panel or hang a plumb bob so you know where to drive your nails. This is your last look inside the wall, so consider marking the center of each stud at the top and bottom of the wall that’s still visible once you have the sheathing in place.
The sheathing should be nailed at every stud. But be very careful to avoid wiring, gas lines and water pipes! In other words, know where the utilities run through the studs and avoid them like the plague. One ill-placed nail can open a huge can of worms.
Stud Gets Nailed – Recommends Eye Protection
I used 2-1/2” long, 8d ring shank nails. Once they’re in they aren’t coming loose without a fight! OSB is usually used for exterior wall sheathing. In that application, it’s recommended to locate nails 6” apart around the perimeter of each sheet and 12” apart on the intermediate studs; and to leave an 1/8” expansion gap between sheets.
Given that these are interior walls, I used 12” spacing around the edges (including top and bottom) and minimal gap between sheets. To determine your “nailing schedule”, don’t listen to me: check your local building codes.
Also, it’s a good idea to wear goggles or a face shield while nailing. It’s possible for one to come flying back at you as you try to get it started, especially with OSB.
Placing And Raising The First Full Sheet
The sides of each sheet should land in the middle of a stud. But, often times – at corners, windows and other irregularities in a wall – some studs are going to have different spacing than the standard 16” or 24”. I started at a corner and figured out where the first full sheet can be placed. I also took window placement into consideration when deciding where to start.
In general, try to place any narrower sections at the ends of a wall, rather than in the middle. But every wall is different so you’ll have to play it by ear.
When sheathing garage walls – especially on a concrete floor – use a temporary spacer (such as strips of plywood) to raise them off the floor about 3/8” – 1/2” while fastening them to the wall or measuring for cutouts. This prevents any ground moisture from wicking up and creating problems. For the same reason, the 2×4’s at the bottom of the studs are also not contacting the concrete. Instead, there is a foam barrier between the two.
Between The Sheets – and Your Garage Walls
Once the first sheet is in place, work outward from there. Get the vertical edges of that first sheet as plumb as you can. If it’s crooked, the rest will follow. Narrower pieces can be cut on saw horses with a track saw or a straightedge and circular saw or jig saw.
Don’t forget to measure the offset between the edge of the tool’s base plate (or “shoe”) and the inside edge of the blade, then compensate when locating your cutting guide.
Cut it Out! Cutouts For Electrical Boxes
If you’re as unfortunate as I, you may have to cut access holes in more OSB sheets than not. But it’s really not that hard to do. Some careful measurements will ensure everything lines up just right. Stand the sheet on your floor spacer(s) so that it’s at the proper height and lean it against the wall, as upright as you can without it falling on your head. Then lay out the required height and distance from the edge.
Cutting Out The Cutouts – Insulate And Sheath Your Garage Walls
To cut the openings in your sheathing, first drill holes at the four corners. Then use a jig saw to cut the opening.
If you’ve crossed your fingers hard enough and measured carefully, the cutout should be in the perfect spot. If not, well, you can always use that sheet to surround a window or to get any narrow strips you may need. That’s what I did! Luckily, I only messed up once.
Let There Be Light – Sheathing Garage Walls Around The Windows
Rather than a patchwork of four separate panels, get cleaner results and two fewer seams by cutting the window surround out of two sheets.
The sheets are each notched to wrap around the window. Of course, your particular window and/or wall arrangement might now allow for this solution. In a pinch, you can always add an extra stud to attach to if none are appropriately located.
Corner Moulding – Insulate And Sheath Your Garage Walls
Once the shop walls were sheathed, I pin nailed moulding to dress up the corners. You can buy wooden moulding, but this paintable extruded plastic was easier on the wallet and has no chance of splitting or cracking.
An Extra Special Electrical Panel Access Panel
I’m not necessarily suggesting you do this, but this is in my workshop. And there are two things a woodworking shop never has enough of: clamps and wall outlets. I figure I may some day need to add more electrical lines. To avoid the possibility of having to later destroy the wall, I decided to make a removable access panel above the breaker box so it’ll be easier to add more lines if/when the time comes.
Unlike the rest of the sheathing, which is nailed in place, the access panel is screwed to the studs for easy removal. With screws, you’ll need to pre-drill and counter-sink the OSB. Use good wood screws; not drywall screws, which are prone to snapping when torqued.
Painting The Newly Sheathed Walls
And now, the moment we’ve all been waiting for! Actually, I hate painting walls. I seriously do not enjoy it at all. But I got a huge feeling of satisfaction when that first coat went on. Even more so after the second.
Personally, I find the look of bare OSB kind of sexy. But painting helps to protect it and brightens up the room quite a bit. We’ve made it this far; we might as well grab a paint roller and rightly finish the job.
OSB is thirsty and has tons of crevasses to fill. No matter what paint you use, it’s going to require two medium to heavy coats.
Welcome To The Wonderful World Of Sheathing Garage Walls
Granted, this isn’t the most fun project one can take on, but doing it yourself can save a lot of money and give you bragging rights too. Not to mention, you’ll finally have walls! It’s hard to appreciate just how nice walls are until you go eight months without. And now that I have walls, I can finally start setting up my new shop. It’s about stinkin’ time!
I’m not going to lie; this was an exhausting job that leached gallons of sweat from my now glass-fiber-filled pores. Failure to enlist help – and the maniacal laughter of a million Florida suns – may have contributed to my self-inflicted desiccation and backache. So did having to first rearrange everything in the building to even get to the walls. But at least I can say it did it all by myself. You know, me trying to be a hero and all. Let us know your tips and tricks for insulating and sheathing garage walls in the comments below!