 | Old House, New Floor: Preparations For Hardwood Flooring |
| In This Article: We cut off the bottom of
the door jamb, lay red rosin paper, and layout the reference line. | Related Articles: | | Skill Level: 2-3 (Basic to Moderate) | Time Taken: 2 Hours |
There
are several preliminary steps that must be taken before a hardwood floor can be installed, such as making accurate base lines
to guide the first rows of wood. Also, if the door jambs are not removed, the jambs may need to be cut off.  | The bedroom being remodeled had just received a coat of veneer plaster, two coats of primer and one coat
of paint. We will apply a second coat of paint after the hardwood floor is finished. The floor installation and sanding
process tends to mark the walls. |
 | At the beginning of this project we had ripped up the carpet and old painted softwood flooring. Then
we fastened a layer of 7/16" OSB (Oriented Strand Board) on top of the old sub-floor, to provide a secure and gap-free
surface. |  |
The original sub-floor is made of wide 1-by planks, most of which are 11 to 15 inches wide, but
some are as wide as 19 inches. That's like a 1x20. You don't find that kind of lumber any more. One problem
with the old sub-floor is the wide gaps between planks. Some of these gaps are big enough to lose a dog through them! But
seriously, the gaps, as big as 3/8" in places, allow movement of air, water, bugs, rodents, and, in the worst case, easier
spread of fire. Drawbacks of OSB:Since installing the OSB I have read about some drawbacks to particle board sheathing
materials. If OSB gets wet repeatedly it will swell much more than plywood, and after a few wettings it becomes more absorbent,
which is a troubling feature. Also, OSB impedes the flow of water vapor, sometimes resulting in fungus formation
on the underside of the sheet. With a full basement below, fungal growth should not be a problem, but OSB installed on a floor
over a crawl space could let fungus build up as water vapor rises up from damp soil and cannot escape. If we had to
do it over again, we would have used 1/2" plywood, which costs about twice as much as 7/16" OSB. |
| Unlike
other rooms we remodeled, we left the door and jambs in place on this room. |  |
But when it came time to prepare for the hardwood floor, we realized that we needed to install
some strips of flooring directly under the door jambs. Otherwise, when we remodel the adjoining room (the
dining room) we would have to remove the door, causing a newly finished room to have no protection from the dust and dirt
of the work in the next project area.  | So we peeled back the carpeting (that brown surface is the original floor) and lopped off a chunk. |  |
 | We pried up the small pieces of carpet tack strip. |
| Then we used a
circular saw (my oldest saw, with a "trash" blade that has met many nails) to cut through the old flooring in the
doorway. |  |
 | The old softwood flooring was removed with a flat pry bar. |
 | The original sub-floor was exposed. See what I mean about wide gaps? We installed a strip of 7/16"
OSB to extend the extra sub-floor we installed at the beginning of this project. |  |
Some Mistakes Needed Correcting: | When we installed the OSB supplemental sub-floor, we foolishly failed to follow the instructions (printed
on every sheet of OSB) and did not leave the required 1/8" gap all around the panel. As the summer weather
progressed, we noticed that the OSB was curling up around the edges, wherever the panels were butted close together. |
Why Does This Matter?This is an often-ignored rule with contractors and carpenters. A few months
ago I looked at a house that had just been re-roofed with new OSB and shingles, and there were slight ridges at 4-foot and
8-foot intervals. You could see the outline of each sheet of OSB. The lady had spent $9,000 getting her roof replaced, and
was not happy. Manufacturers put these warnings and instructions on their products for a reason, not just for fun. Their
engineers have determined that warnings must be made, or they will face liability problems. When people don't follow these
instructions they are "playing engineer" and taking things into their own hands. |
| To correct
this problem, I simply cut along the edge of the OSB panels with a circular saw, with the depth set to cut only the thickness
of the OSB. |  |
 | It took about two minutes, and the proper gaps were created. |
| I spent
another minute smoothing out the curled edges with a belt sander. |  |
Cutting The Door Jambs: | This handy tool is a Japanese pull saw. The blade is very thin, very flexible, and quite
sharp. It cuts on the pull stroke. |
| This product carries the "Shark Saw"
brand. We bought it at Sears for around $20. The neat part is that the handle is removable so it fits in one of our tool
boxes. |  |
 | We laid the pull saw on top of a scrap of flooring and carefully cut the jambs. |
| We placed
a piece of flooring under the jambs to test the fit. The thin blade left a tiny gap that will surely not be noticed. |  |
A Small Opportunity: | Before the evidence got concealed, we took a few minutes to mark the joist locations and stud locations
on the lower part of the wall. These marks will be covered by the 7 inch tall baseboard. |
 | We caulked the gap at the bottom of the wall. This should prevent some cold air infiltration, and possibly
reduce the number of bugs that crawl in. This is an opportunity that is passed up by virtually every contractor whose
work I have seen. It just doesn't add any visible value, but costs (a little) money. If people become aware of this, maybe
they will demand it. |
| Smoothing the caulk is quick and simple and gives the best
result. For 26 feet of exterior wall it took half a tube of caulk and a whopping ten minutes of work. |  |
 | We rolled out the red carpet. Actually this is red rosin paper, which is used
as an underlayment for wood flooring. |
 | This innocent-looking tool is called a hammer-tacker. It's a staple gun that
drives a staple on impact. You swing it like a hammer... |  |
| ... only it doesn't really work that way. A hammer head hits the board and leaves
room for your hand. In order to keep from bashing your knuckles, you'll instinctively hold the hammer-tacker
like this, but at this angle it doesn't drive staples worth a darn. |  |
 | When it works well, which is rarely, it still leaves the staples sticking up a bit. This staple could
interfere with the flooring. So all the staples had to be tapped down with a hammer. Plus it tends to puncture the material
being stapled. |
Laying Out The Reference Lines:| We decided that
the door jambs represented the best base line for the layout of the flooring. The wall nearest the first row, which is the
most logical choice for a base line, had a bad warp to it, so it was ruled out. We set a straightedge across the jamb (with
blocks to space it away from the plaster) and made a mark. |  |
 | Then we used the biggest square we could find... a drywall T-square... and set it against the straightedge.
We made a line. |
| These are the first two layout lines, which have been digitally enhanced
to make them more visible. |  |
 | From this geometry we made a longer reference line with an ordinary chalk line. |
| The
end result looked something like this. At this point we were ready to proceed with the hardwood floor installation. |  |
Tools Used: - Circular Saw
- Cordless
Drill/Driver
- Chalk Line
- Pry Bars
- Pull Saw
- Basic Carpentry Tools
| Materials Used: - OSB, 7/16"
- Red Rosin Paper
- Staples
- Caulk
|
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