Old House, New Floor: Installing A Hardwood Floor

By Bruce W. Maki, Editor

You Get What You Pay For...

That saying is applicable to most products used in residential construction and remodeling, and it's doubly true about flooring. Installing, sanding and finishing hardwood flooring takes a lot of work, but when it's done, all that effort is easy to forget.

A comparable product is pre-finished hardwood strip flooring. Essentially pre-finished hardwood flooring is the same as the material used in this project, but there are small bevels milled around the perimeter of each board. These bevels prevent you from noticing the small inaccuracies in machining that cause some boards to lay slightly higher than others. The procedure for installing a pre-finished hardwood floor would be about the same as the methods used in this article.

Before: The room with just the sub-floor.

After we picked up the white oak flooring, we stored the bundles of wood in a utility trailer in the garage. We chose white oak instead of red oak. Red oak is more common, is slightly cheaper, but is softer and has a more open grain pattern. White oak has a lighter appearance when finished with a natural coating and no stain.

Storage:

Hardwood flooring manufacturers advise that the wood be allowed to acclimate in the same environment as the room it will be used in. During damp weather, the wood should be kept indoors for at least three days. Since our flooring had been milled at least a year earlier, and had been kept in a dry storage area, it was already good and dry. Being summer in Michigan (not a terribly humid place) storing the wood in the garage was just as good as storing it in the house. 

The first step in installing a hardwood floor is laying out an accurate reference line. See hardwood flooring preparations for more information on that step and other preliminary work.

Direction Matters:

The normal method for installing hardwood strip flooring is to lay the boards perpendicular to the floor joists. The boards can be installed parallel to the joists, so I'm told, but an extra layer of sub-floor plywood must be added.

We drew a line, parallel to the reference line made earlier, to indicate the end point of all the boards.

Normally we would just run the boards through the doorway and continue into the adjacent room. But the remodeling process of this old house has to occur one room at a time. So we decided to install transitional pieces by installing some perpendicular boards in the doorway. Later, when the dining room is remodeled, we can resume runs of flooring parallel to the flooring in this bedroom.

We drew a line near the wall to indicate the edge of the first board. It is important to leave about a 1/2" gap around the entire perimeter to allow for expansion.

We carefully selected several of the straightest boards for the first pieces.

The very first piece of flooring had to be notched to go under the door jamb.

A Note On Doors:

In the past we have removed the doors and jambs while remodeling rooms. But in this case we decided to try leaving the door in. We did not need to raise the door because it was already high enough to clear the thicker floor. We did cut off the lower part of the jambs (see flooring preparations). Working around the door was a slight inconvenience. Sanding around the door was a chore. But having a door in place meant we could keep dust under control, and more importantly, keep our 4 dogs out of the work area.

This 3/8" diameter drill bit was necessary to drill holes in the face of planks that could not be reached with the rented floor stapler. That tool in the background is a 3/8" diameter plug cutter, which will be used to make tapered plugs that will cover the screws.

First we drilled clearance holes for the deck screws... ... and then we drilled the large 3/8" hole, but only half way through the board. Later these holes will be filled with wood plugs.

The Result: The holes for the face-screws have a deep counter-bore so the heads will be recessed quite far.

Installing The First Row:

The location of the first board was carefully determined so it would be perfectly parallel to the reference line made earlier.

The first board was fastened with 3" deck screws. We located the holes to occur over the floor joists. Note the joist and stud markings on the wall.

The second piece was not so simple. We cut a board to fit in the remaining space...

... and then we used a straight piece of flooring as a guide to ensure that the second piece was perfectly aligned with the first piece.

We used a pry bar to push the second piece towards the first piece, closing the end gap. We secured the second piece with deck screws.

The alignment plank was removed. If these first two boards were not perfectly in line, the entire flooring job would be flawed and full of gaps.

Note how the end of the first row aligns with the line we drew at the beginning. This is critical for the doorway transition we will be doing.

After the first row was installed, the fun began... using the pneumatic stapler to fasten the flooring.

This is the Bostitch Mark III FS floor stapler. We rented it from Nations Rent (which has locations inside select Lowe's stores)  Nations Rent can be reached at 1-800-No-Sweat.

This tool takes 2 inch long 1/2" wide 15 gauge staples. These are more like 2-legged nails. Beware: There are also 16 gauge staples of the exact same size that may jam the stapler. The stapler holds a couple of sticks of staples.

We almost bought staples at Home Depot, where they cost $45 for 7,200, (which is .625 cents each). But we found a local contractor-oriented tool and fastener supply house called Fasteners Inc. that sells 5,000 staples for $27, (which is .54 cents each). We only used about 1,000 staples to install 140 square feet of flooring.

Fasteners Inc. (1-800-327-0980) serves Michigan and parts of Illinois.

For the second row of boards, we laid out one desirable piece and then measure the remaining distance to get a target length for the other piece. We were trying to avoid placing the ends of boards too close together. A common recommendation is to keep the end joints at least 6 inches apart on adjacent rows of boards. We tried to keep the ends at least 2 feet away from each other.

The second row was started. The near end had to be carefully aligned with the end of the first row, for reasons that will soon become apparent.

The flooring we used was end-matched, which means the ends are milled with tongues and grooves. This keeps the ends of the boards from warping. End-matched flooring is common, and costs a little more than square-end flooring.

It's tempting to just fit the boards together along their long sides, and then move the board downstream to close the end gap... but that doesn't work well. When positioning a board, we tried to get the ends to connect first (right photo)...

...and then the long edge of the new board was pushed (or tapped) into place so it interlocked with the last row.

But often the end gap opened up as the board was driven tight.

In which case we used a large pry bar (bearing against a block, not against the wall directly) to move the board lengthwise. We often used a hammer to tap on the pry bar... the impact made the board move easier.

A Doorway Transition: Perpendicular Boards

We cut a piece of flooring to the a length that would fit under the door jambs... ... then we used a large speed square to accurately position the perpendicular board. We marked the location.

Accuracy is critical here, or all the boards that butt against this perpendicular threshold strip will show a gap, and it will be highly visible, being right in the doorway.

We took a scrap of flooring and tapped it into the groove of the "threshold piece".

We put the combined boards back in place (and re-checked for squareness) and drove some 2" deck screws into the scrap piece. We had pre-drilled the holes before we tapped the boards together. This scrap is only a backer, to hold the threshold piece in place while staples are driven. If we didn't do this, the threshold piece would surely move when the stapler was struck with its hammer.

The threshold piece was stapled... ... and the scrap was removed.

We are pleased to report that the trick worked... the threshold piece remained at a perfect right angle to the main run of flooring.

Prepare For Take-Off...

Remarkably, the Bostitch flooring stapler fits in rather tight spaces. On the second row (of 3" wide boards) we were already far enough from the wall that the stapler fit with no problem.

At this point we were ready to proceed at full speed, so we hitched up the trailer and moved the materials near the front porch, which kept the walking distance as short as possible.  We also set up the miter saw on the porch.

We liked the idea of keeping materials in the trailer. If it started to rain, we could back the trailer into the garage in a heartbeat. This little utility trailer is very handy as a mobile workbench.

Again, efforts were made to greatly stagger the joints between boards. 6" is minimum, but more is better.

Problems Arise

Wood has it's flaws, and the worst flaw with wood flooring is the tendency to bow sideways, causing a gap in the middle of the span. We tried several methods for closing the gaps, such as standing on a 2x6 and using a huge pry bar to push on the floor board. Sometimes this worked.

Sometimes prying like this only pushed the pusher backwards. In those cases we nailed the 2x6 down with duplex nails (the kind with double heads, that can't be driven in all the way) and then pried.

Bananarama: Some boards seem to be made from "banana wood" and are quite tricky to flatten and interlock with the previous boards. Sometimes it took two people to hold these boards down and drive them snug. But once they were fastened in place they stayed put.

In spite of a few problems, the floor progressed quite rapidly. When we got within 6 inches of the edge of the red rosin paper, we cut another strip and stapled it to the sub-floor, overlapping the previous piece by a few inches.

I'm not exactly sure what red rosin paper is supposed to accomplish. It may provide a tiny amount of cushioning, and it may let the flooring slide slightly over the sub-floor as changes in humidity and temperature cause the wood to expand and contract. All the sources I've read say to use red rosin paper or 15 pound felt (tar paper). We bought red rosin paper in the flooring department at Home Depot.

The Sequence Of Setting A Board In Place:

There is a sequence that got repeated for each plank. It started with placing the tongue end of the board into the grooved end of the previous piece

The side was tapped near the interlocking end, to draw it towards the previous row. Then the side was tapped at the far end

Tapping a board is always done by hitting a small scrap of flooring (we called them Smacker Blocks and labeled them with a big "S"). Never hammer directly on the flooring.

A pry bar was used to move the plank downstream... ... hammering on the pry bar helped a lot. Sometimes the other person had to watch the end gap because the "prying eyes" couldn't see it.

Often the end gap closed tightly but the side gap remained... ... so a final tapping was needed.

The Sequence Of Stapling:

When a board was ready to be stapled, the base was gently tapped to make sure it rested firmly against the wood. Then the operator stepped on the base.

The base plate on the Bostitch stapler is not meant to be hammered upon. It may be tempting to use the base plate as a short cut to tapping a board in place, but such a practice could damage the stapler or leave a dent in the wood.

The smacker block was given one last whack, to ensure the boards were tight.

And the mallet was used to drive the staple.  It takes a pretty firm hammer blow to activate the stapler, and consequently the board is drawn tight as the staple is driven.

Staples: Where and How Many:

The resources we read said to drive the fasteners into the floor joists, and to space the fasteners apart by 16 inches. Since the staples only cost a nickel, and we had plenty of them, we decided to staple over the floor joists and also in between, which meant a spacing of 8 inches.

However, after only a few rows of flooring, the stapler jammed. It turned out that one staple had hit a screw that held the sub-floor to the joists, causing that staple to fold over and jam. So at the suggestion of the folks at Nations Rent, we tried to aim a little off the center of the floor joists.

On the previous floor we installed, which had the same 3/4" thick white oak stapled to 7/8" thick tongue-and-groove fir sub-floor, the staples just barely poked through the back of the sub-floor. So they didn't even really penetrate the joists very far, maybe 1/16". The floor in this article had 7/16" OSB laid over the original 7/8" thick wide plank sub-floor. There is no way any of these staples will reach the joists.

Some Tips:

We tried a device from my collection of auto repair tools... a automotive pull hammer. This tool is used to remove dents from fenders, among other things. There are several end fittings. The best was this curved hook.

The pull hammer worked in places where the gap between the board and the wall was about 3/4" or more. But much of the time the gap was too small to get the hook in place, so we resorted to the usual pry bar method.

When we approached the corner of the closet, we couldn't fit the stapler between the flooring and the 12 inch wide wall, so we stapled the boards on either side of the wall.  It was important to avoid end joints in front of this wall, because we wouldn't be able to staple the boards near the ends

We always tried to put a staple within 2 or 3 inches of the end of each board.

The last board before the closet wall had to be notched. It is important to leave a 1/2" gap between the floor and the wall, to allow for expansion.

Whoops! Somehow we stapled a board that had already been cut, leaving no groove on the end. That board had to be removed. It isn't that hard to remove these boards, we discovered. It was possible to salvage this piece and use it elsewhere.

This raises the question: Could old hardwood flooring be pulled up and salvaged? I believe it could be, without a lot of effort. Of course there would be a lot of work to drive out the nails. It would be a business decision... how much time does it take, and what is your time worth?

By evening we had almost half the floor done. We started around 2:00 pm. We didn't exactly work fast.

Towards the end, we reached a point where the mallet could no longer be swung to hit the stapler.

Then we used a pneumatic 2" finish nailer to install a few more rows. It's also possible to hand-nail the boards through the tongue, but pre-drilling the holes would be a good idea. Ring-shank siding nails work well.

The last two rows had to be installed with screws through the face.

We used an elaborate setup of blocks and shims to force the board tightly against its neighbor.

The board was secured with 3" deck screws.

The final strip had to be ripped on a table saw. A circular saw with a ripping guide could also be used.

Completion.

We left a decent gap between the last board and the wall. Some sources say to leave at least a 3/4" gap, but since this floor was installed in summertime, it is not likely to expand much more, so we left a 1/2" gap.

The power source we used was this small 1.5 HP 3 gallon air compressor made by DeVilBiss. Similar products are sold at Sears with the Craftsman label.

Additional Reading:

• Building Walls, Floors and Stairs, Fine Homebuilding's Builder's Library, Taunton Press.

Copyright © 2001, 2005  HammerZone.com

Written July 23, 2001
Revised January 11, 2005