For quite some time now I've been dreaming of having a dedicated space to be my woodworking shop. Now that I have a garage I can finally make it happen! I've been wanting to customize it from the ground up, literally. The first major change will be adding a plywood floor to go over top of the existing concrete.
A wood floored shop may not be for everyone. If you plan on doing any automotive work, welding/forging, or anything else that involves hazardous liquids in large quantities and possibly the risk of fire, you may want to stick with the concrete, get some rubber floor mats or maybe get a self leveling epoxy.
In my case, since I plan on doing mostly woodworking (and a good bit of it by hand), the benefits of having a wood floor are definitely worth it. For one thing, I plan on working out of my shop all year round so having an extra layer of insulation will help reduce heating costs during the winter time. Standing up all day on concrete can be damaging to your joints and back. Installing a wood floor can be very forgiving on your feet. Also, sawdust loves to cling to all of the tiny imperfections of concrete and can be a pain to clean, but after a few coats of finish it's very easy to sweep. Not to mention wood helps dampen some of the loud noise from power tools/machines. If nothing else, I think it looks better!
Step 1: Materials and tools
- 3/4" tongue and groove plywood (you might see this as 23/32" underlayment, or subflooring)*
- 2x4 pressure treated lumber (fyi: when you buy these, the longer the piece the cheaper it will be)
- 2" drywall screws
- 2.5" drive pins (these are nails for powder actuated fasteners)
- powder cartridges (i would stick with .25 caliber or higher)
- 6 mil polyethylene sheets
- 2-3 tubes of construction adhesive (if your space is well over 300 sq ft, you may need more)
- 1.5" rigid foam insulation (16" or 24" pieces will work)
- wood finish (I had some floor grade polyurethane left over, but regular wood finish or paint will work)
- caulk gun
- hand saw or chop saw
- cricular saw
- utility knife
- drill/screw gun
- heavy duty stapler
- powder actuated fastener or velocity gun (sometimes called by the brand names "ramset" or "hilti", you can rent this from most home centers)
- brush or applicator for your finish
*In hindsight, after using the tongue and groove plywood, I would save some money and just use regular 3/4" plywood. I was disappointed with the way it came out. It was really difficult to install, and left unsightly gaps. If you do go with the t&g, I recommend installing it with the groove side facing your next piece so that you install the tongue into the groove and not the other way around.
Step 2: Map it out and add it up
If you've read any of my other 'ibles, you know I'm a big fan of drawing my plans out on paper before I commit to anything. This one's no different!
Get detailed measurements of your perimeter, and if you have an idea of where some features will go or already are you can reinforce those areas accordingly. At this stage you can easily map out where your studs will go and how you want to arrange the plywood. This can save you a lot of wasted materials and time.
You also want to take stock of how many 2x4's, sheets of plywood, and insulation you'll need. Add about 10-15% and use that as a rough estimate for pricing out your materials.
The more you figure out at this step, the easier your install will go!
Step 3: Make some room
If your garage space is anything like mine, it's a often a cluttered mess of tools, odds and ends, and leftover house furnishings that had no other place to go. Today, that's all gonna change!
Empty your space out as best you can, and make sure the area you want to be floored is clean and clear of debris. If for some reason you can't clear out the entire space, another option is to move as many things as possible over to one side of your garage, build the floor up, and then move everything to the now finished side and add the second half of the floor. Obviously, this is a more time consuming and labor intensive process but it works none the less.
Step 4: Lay down your base
After everything has been cleared out of the way you can follow your plan and start gluing and nailing the 2x4 sleepers. Start working your way around the perimeter by first laying down a thick bead of construction adhesive, press your 2x4 into it (IMPORTANT: make sure you lay the 2x4 flat and not on edge so the 3.5" side is parallel to the floor), and follow it up with a nail from the powder actuated fastener (1 nail every 18-24" is fine).
After completing the perimeter, continue this process across the floor. I chose to lay the sleepers along the longest side of my space, it was just more economical that way. For your first sleeper, butt up a piece of insulation into the corner and mark where the next 2x4 will go. Do this the whole way across the floor, laying the insulation down as you work. This way you don't need to measure and you can don't run the risk of putting them too close of too far away.
You can also add some blocking in between the sleepers to reinforce areas that will have heavy machinery or equipment on them.
When your sleepers are all nailed in place, it's a good idea to look over the nails and make sure to sink any that seem to be sticking out a lot with a hammer.
Something to keep in mind during this step: if you wanted to lay down some tubing for a heated floor or run electrical wire for outlets or lights now is the time to do it. Feel free to get as creative as you want!
Step 5: Vapor barrier
Once you have the sleepers and the insulation in place, you want to lay the polyethylene sheets on top. This will act as a vapor/moisture barrier and keep any spills you may have from growing mold in or around the 2x4's and insulation.
If you have any seams you want to overlap at least 6" and tape the sheets using housewrap tape or anything else that's water resistant.
Step 6: Install your floor
Now, you can start putting the plywood down on top of everything. It's important that your edges or seams don't line up so I would recommend laying a full row and, unless your space is an exact multiple of 8, starting the next row with your cut off piece. If you took the time to draw this step out, it should be relatively easy with minimal waste!
When you lay the sheets down make sure you stay about 1/4"-1/2" away from the edge of the wall to allow for any seasonal expansion (this is especially true if you live in an area with extreme weather changes from season-season). A small gap (roughly 1/8") between each sheet may be necessary as well to keep the individual sheets from buckling when they expand.
You also want to make sure that edges of your pieces fall along the middle of the sleepers. If you go all the way to the edge, the next piece won't have anywhere to fasten to. The tongue and groove system should help to keep your seams straight.
As you lay each piece down, start adding the screws about every 16". Where two sheets meet, make sure to offset the screws; if they line up you risk splitting the sleeper underneath. You can also use nails for this step, but screws make it easier to remove/replace individual sheets in case of damage or future replacement.
Step 7: Finish it up!
After all your hard work, all that's left is adding a finish of your choice. I had some polyurethane left over from finishing the floors in our house, so I went ahead and applied that. You can use any type of floor finish you want: paint, epoxy sealer, varnish, etc.
And that's it folks! Now you have a solid, long lasting wood floor that will not only protect your tools and joints, but will help keep your space warm for winter!