Ever wanted to know how hard it is to lay hardwood flooring over concrete?
I recently did in my Tulsa home and it turned out great. You can save thousands doing it yourself! I will say this is a job that requires patience. This installation is over concrete so it will require a little more work to install the sub-floor.
We went with #1 grad red oak to match what was already there. If you take a close pic of your wood and email it to the wood floor store, they can usually tell you what kind of wood it is just by the grain pattern.
First we removed the carpet, floor molding, and tack strips.
Tip: Label your trim so you can easily nail it back on.
Connecting New Hardwood to Existing
Since we had hardwood in the entry already, we will have to connect the new wood to the old. To do this we needed to remove the end trim piece on current wood floor. We scored it with a utility knife down the line where it connected to break up the old polyurethane so it would be easier to pry off.
Sawing Trim to the New Height
Next, we cut the trim to the height that the wood floor would butt up to. This didn’t necessarily have to be done at this point, but since we were in mess mode, I figured we would just do it. Just take a piece of the plywood and put under the oak plank to give you the right height.
Wood Floor Underlayment
There are different options for what moisture barrier to lay over the concrete before putting plywood on. There is a 6 or 8 mil plastic at your local hardware store will work. The reason for installing this is on a concrete slab is the moisture underground may eventually absorb into the subfloor and possibly the hardwood. You don’t want this because moisture warps wood. So, a little extra protection never hurts.
Fastening Plywood to Concrete Floor
Next we laid the 5/8 in plywood onto the plastic. Don’t use pressure treated plywood. Use the regular dry plywood and not the ones with greenish tint. After we cut it and laid it out, we predrilled about 16 holes into every sheet.
Tip: Put duck tape on the top of concrete drill bit to know how far to drill. Then after you have your hole, use a counter sink drill bit to widen the hole so the blue Tapcon screw can be flush with the surface.
Here is the Tapcon products we used. We went with 1 3/4″ length but 1 1/4″ would of probably been fine as well.
There will be parts of floor that you will need to improvise. I think I just double taped this little piece of plywood to the plastic underlayment. Ha! It ain’t going anywhere.
Sometimes if the side by side plywood heights are way off, just sand down one edge to be closer to the height of plywood next to it. A belt sander does a fast job on this.
Yes you can buy $500 worth of name brand equipment, but we just got a basic $120 floor gun from Harbor Freight. It did the job. It did get some floor staples stuck inside along the way, but we managed to fix it. I used 2” but I was told by the floor company that he 1 ½” would of worked better and cause less puncturing of the plastic vapor barrier.
Now that Prepping is Done, on to the Fun!
We started by connecting the first strip to the already installed floor.
Since there was a long strip that had to be cut to go against the wall, I had to use a jigsaw. A table saw would of worked better, but didn’t have one available. Please invest in a better jigsaw than the one you see! I’ve been using this thing forever. It’s been past down to me from generations past but gets the job done!
After sawing glue and nail the narrow wood planks that butt up to the wall. The reason you do this is because the floor nailer can’t reach that close to the wall. If the plank is cut to less than an inch you can probably get away with just gluing it and minimum nailing. This will hold them in place so you can continue your rows. Do the same thing when you get to the other end of wall where the floor nailer can’t reach. You can also use a finishing or trim nail gun if you don’t want to hand nail.
Once I got that the first 2 rows connected to the existing hardwood floor the rest was a breeze!
There was the occasional floor staple that didn’t go in. These are a pain. Just pull out the best you can.
This is how it should look.
Now starting on the other side in room 2. You can see the old floor next to the fresh wood. Neat contrast. I did have to belt sand where it connected to get the height the same because the new wood floor was a bit higher.
When I got to the end of this room there was a thin piece I needed to cut. I glued it on to the last row.
Now Time to Use the Floor Sander!
Rented drum sander from Home Depot.
I used 80 grit on first pass with the drum sander. 60 grit on second pass with drum sander. Last pass was with a square floor buffer that used a 100 grit sanding screen. On the floor edger I only used 60 grit.
Online tutorials said to go at a slight angle with the drum sander. I did that most of the time. One thing I should have done better was to make sure I got all the polyurethane off. There were some patches that looked bare but still had a thin layer of poly. I found this out when I was staining, and the stain wouldn’t penetrate well on those spots. The only bad thing about sanding at 1am, you don’t have great lighting to see if you missed any spots. You even want to sand the new wood too.
Rented a floor edger sander from Home Depot for along walls. You will need to use a small hand sander for the hard to reach edges.
Tips on Sanding with a Floor Edger
I was in a bit of a rush with the floor edger and had to go back and resand some areas because of swirl marks. Watch video to see how I resolved it and how not minimize this problem when using the edger.
Spread Wood Filler on Hardwood Flooring
Trowel wood filler on the hardwood surface. This will fill in cracks and knots in wood. After the wood filler dried, my son finished off with a floor buffer from Home Depot with 100 grit paper. Just take it slow and overlap. The last sanding left some fine dust. So I vacuumed and wiped everything down with a slightly damp cloth.
Here is buffer I used: https://www.homedepot.com/tool-truck-rental/Square-Buff-Floor-Sander/07014A/index.html
This video gives a quick rundown of the sanders I used.
Now here is where you need to watch Youtube videos on water popping. It is the art of wetting your floor just enough to open the pores in the wood to allow the stain to absorb deeper for a richer finish. You don’t have to do this, but it can bring out more deep color from the stain. I did this and it turned out great. But it may have also made the stain a shade darker because it absorbed so well. The key is to get the water on evenly and not to overlap the water absorption because those lines will be darker as the stain will absorb more in those areas. I used a wet rag, but am thinking a sprayer may have been better. Like I mentioned, you don’t have to do this. I thought about leaving it out of this blog post but I felt it may be something my readers would at least like to look into.
Tip: Tape off areas you don’t want to get stain on.
Staining Hardwood Floors
Here we go..stain away! I decided to put tape down in case I needed to take and break and come back the next day to stain the other areas.
Time to Poly!
I then put a coat of satin oil-based polyurethane on with the “Candy Stripe” Wooster paint roller. These work great on wood floors. Get the one with low nap. Here is link. https://www.amazon.com/Wooster-Brush-R209-9-Stripe-Roller/dp/B000BQSF7S
Let it dry for 24 hours at least. Then lightly scuff with 100 grit sand paper. I wish I would of rented the floor buffer, but I just decided to use 100 grit sand paper with a hand sander. Remember this is just a light fast sand. Just enough to scuff the first coat of poly.
Wiped dust with terry cloths.
Then roll on a second coat of poly and let dry for several days before heavy floor traffic. Turned out beautiful in my opinion!
Hardwood Flooring Before and After!
The stain color was antique brown. I was quoted up to $10,000 for the project by local installer. It cost me $2500 to do myself. That included the flooring, plywood and everything needed to do the job.