Create comfort underfoot with a good-looking, hard-wearing surface.
What better floor for a woodworking shop than one made of wood? If you’re lucky enough to have a basement or dedicated outbuilding with sufficient headroom and a concrete floor that’s dry and reasonably flat, wood flooring can’t be beat as the starting point for a workshop. We chose southern yellow pine for the Woodcraft Magazine workshop floor for a number of reasons. First, it’s affordable and widely available. The 1 × 6 tongue-and-groove boards cost just under $3 per square foot in our neighborhood. Even though southern yellow pine is a softwood, this flooring offers an excellent combination of durability, strength, and resiliency—which probably explains why it’s been used for centuries as flooring in residential and commercial buildings.
As you’ll see on the pages ahead, a premium shop floor isn’t difficult to install if you have the right tools. You’ll need a flooring nailer, which you can rent from a local tool rental outlet for about $25 a day. The nailer comes with a special rubber-faced mallet, and the rental outlet will probably stock the 1⅜" flooring nails you’ll need. Once the floor is down, trade in your nailer for an orbital floor sander ($40/day) and an edge sander ($25/day), to smooth the wood surface in preparation for finishing. While you can do the installation and finishing on your own, recruiting a helper will make the work go much faster.
We installed flooring from Grizzly Forest Products (www.grizzlyforest.com), but you can order flooring from most lumberyards and building supply outlets. The installation process we used is recommended by the Southern Pine Council (www.southernpine.com) and will work over any sound, dry concrete slab floor. Or if you’ve got a shop floor framed with joists and covered with underlayment, the yellow pine can be fastened onto this subflooring.
Stack the flooring in your shop and let it sit for several days to acclimate it to its new home. Use a moisture meter to determine that the flooring has stabilized and is under 14o moisture content.
Prep the floor
1 Begin by vacuuming the concrete floor to remove as much dust as possible. Then test the concrete to determine if enough moisture is coming through the slab to cause problems with the floor after installation. Do this by taping a 24 × 24" square of polyethylene sheeting to the concrete and waiting 24 hours before peeling it up. If the underside of the poly is wet, your slab has too much moisture for a wood floor. A good way to solve this problem is to coat the floor with a commercial-grade moisture barrier, like Bostik’s MVP4 (www.bostik-us.com).
2 To cover the concrete with a vapor barrier, first apply Armstrong S-89 Asphalt Floor Tile Adhesive onto the surface with a 3/16" notched trowel. Apply an even layer about 40" wide, along the longest wall that’s opposite the shop’s entrance. Then adhere a layer of 15-lb. builder’s felt (which comes in 36"-wide rolls) in the mastic (Figure 1). Repeat this application with a second course of builder’s felt, overlapping the previous course by about 4". Cover the entire slab in this way.
3 Next, using ¾" exterior-grade A/C plywood, install a plywood subfloor at a 45° angle to the walls. Keep the “A” side of the plywood facing up. Start the angled installation by cutting several 45°-45°-90° plywood triangles to go along the wall. Maintain the diagonal orientation by installing square-ended panels adjacent to the angled panels. Now drill countersunk pilot holes in the plywood, spacing them every 24". Then use the specially sized masonry bit that comes with the screws to bore at least 1" into the concrete. Now fasten the plywood to the slab with ¼ × 1¾" flathead self-tapping concrete screws. When laying the subfloor, pay attention to critical clearances: allow ¼"-½" clearance between panels and ¾" between panel edges and the walls.
4 Stack the flooring in the shop and let it acclimate as shown in Photo A. It helps to separate the bundles with wood “stickers” made from scrap 1× strips. Don’t install the flooring until it reaches an equilibrium moisture content (EMC) of 14% or less. It typically takes 5-14 days for southern pine flooring to attain EMC. Take readings with a moisture meter (Photo A Inset) every day. When the readings are the same for several days, it’s time to start the installation.
Face-nail the first course of floor boards, spacing them ½" to ¾" from the wall.
Lay down the tongue-and-groove flooring
1 Snap a line to lay out the first course. You want this line to be parallel to the longest wall in the workshop and about 6" from the finished wall surface. That should leave a gap of about ¾" between the edge of the flooring (which has an actual width of 5¼") and the finished wall. Stretch the chalk line tight before lifting it up (near the center) and releasing it to snap your layout line.
2 Using 6d finish nails every 16", face-nail the first course of floor boards to anchor them to the subfloor as shown in Photo B and referenced in the fastening detail in Figure 2. Choose the longest, straightest flooring boards to make up this course and align them with the chalk line. Face the floor board tongues toward the center of the room. After securing the boards, anchor the tongue edge of this course to the subfloor by blind-nailing (toenailing) 4d finish nails as shown in Figure 2. Blind-nail every 16", placing nails between the face nail locations. Set the nails with a nail set, driving the nail heads 1/16"-1/8" below the wood surface.
3 Lay out your next several courses of floor boards. Select board lengths so that butt joints in adjacent courses are offset by at least 2'. Snug the next course against the nailed course by tapping the tongue to groove edges together using a 6"-8"-long block of scrap flooring as shown in Photo C.
4 Load the flooring nailer with barbed 1 3/8" flooring nails, and position the flooring nailer to blind-nail through the tongue edge of the board. Drive the nail by hammering on the nailer’s drive head with the rubber mallet that comes with the nailer as shown in Photo D. Repeat the nailing technique to drive nails every 16". Blind-nail successive floor board courses.
5 Face-nail the final course. As you get close to the opposite wall, use wood wedges to force tongue-and-groove joints together. When there’s not enough room to use the flooring nailer, toenail through the tongue using a pneumatic or cordless finish nailer as shown in Photo E. Use a nail set to set these nails below the wood surface.
6 Rip the final course narrower so that there will be ¾" of clearance between the flooring and the finished wall if needed. Then use a pry bar to force the final tongue-and-groove joint tight and secure the last boards in the last course by driving 6d finish nails every 16" as shown in Photo F.
Sand and finish the floor
Note: Before turning on the sanders, be sure to slip on a dust mask and protective eyewear. Have a shop vacuum ready to collect sawdust. If sanding in the basement, tape the basement door shut with duct or packing tape to limit the amount of sawdust penetrating the living spaces upstairs.
Fit the groove of the mating floor board to the tongue of the nailed floor board; tap into place with a piece of scrap flooring and hammer.
Use a flooring nailer and 13/8" flooring nails to blind-nail the floor board to the subfloor.
When you no longer have the space to use the flooring nailer, wedge the flooring board tight to its mating floor board and fasten it down.
Face-nail the final course of floor boards, using a pry bar to pull them tight to the neighboring floor boards. Maintain a 3/4" gap.
Cut in along the walls furthest from the door with the nylon pad, and follow with the larger applicator..
..applying small amounts of finish and then spreading it evenly over the flooring.
1 Sand the floor with an orbital or drum sander. The drum sander works more aggressively and should only be needed if the edges of flooring boards stand proud of adjacent boards after installation. Since our floor didn’t have significant high spots, we got away with using an orbital sander with 100-grit sandpaper. Start sanding in the back corner of the room (farthest away from the door) and move the sander parallel to the flooring courses as shown in Photo G. Keep the sander moving and let the weight of the machine take care of downward pressure.
2 Remove all the sanding dust from the shop. Clean sawdust off shelves, cabinets, and light fixtures, and then wipe down the walls to remove any dust that might contaminate the floor finish. Vacuum the floor thoroughly with a shop vacuum and wipe it off with rags.
3 Prepare the finish for application and gather your applicators (Photo H). We used a water-based polyurethane from General Finishes (High Performance Polyurethane) in a satin sheen. Following the manufacturer’s directions, pour a small amount of crosslinking additive into the finish. This additive (Enduro Crosslinker from General Finishes) makes the finish harder, more durable, and adhere better. Use a clean mixing stick to blend the additive into the finish.
4 Flow on and spread the first coat of finish, applying it in the corner of the room that’s farthest from the door and working out from there as shown in Photos I and J. For more control, we transferred the finish from the can into a clean spouted watering can. Pour a small amount of finish on the floor and then use a squeegee-like applicator to spread finish evenly (ours is made by Padco; www.padco.com). Keep pouring and spreading until the floor is coated completely. Apply four coats in total, letting each coat dry between applications.
5 Install the baseboard shoe molding to the baseboard, driving 6d finish nails every 16". If you haven’t attached the baseboard, then do it first and follow with the shoe. To install baseboard, drive 8d finish nails through the baseboard and into studs at 16" centers.
