 | 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
|
| |
