Are wood foundations durable?
Click Image to enlarge.
SHEATHING FASTENED WITH 8d STAINLESS STEEL NAILS; FRAMING
WITH DOUBLE-DIPPED 16d NAILS
Q
I’m considering installing a wood basement
under my new addition instead of the poured concrete type under my house,
mostly because I can do it myself. Do wood foundations really stand up over
time without rotting, and are they strong enough to hold back the
earth?
Eli Coats, Holland,
MI
A When you’re
considering an unfamiliar type of construction such as a wood foundation, it’s
best to get an opinion from someone who’s built a few dozen and had to
guarantee their performance—me! I’m positively gleeful over the 20 trouble-free
years we’ve had with ours at home and have yet to hear a single complaint from
any of the dozens of customers I’ve built them for. The clients I still hear
from love the advantages wood foundations have to offer. You can build them
yourself, they’re dry and warm, and they’re easy to finish (inside and out).
And because they’re simple wood frame construction, they’re easy to alter even
after the basement’s in. In fact, I added six windows and doors in my walkout
basement three years after the house was finished.
You won’t find too many unhappy wood foundation owners
as long as the installation is done
properly. Successful wood foundations depend on using the proper
wood, good drainage and waterproofing. Most people considering a wood
foundation are concerned about rot and strength. “Foundation-grade” wood used
in foundations is treated by steam-impregnating it with a chemical called CCA
(chromated copper arsenate) at a concentration of at least .6 lbs. of chemical
per cubic foot of wood so that the chemical penetrates deep into the core of
the wood. The copper part of the compound is toxic to fungus, mold and
bacteria, while the arsenate is toxic to pests like carpenter ants and
termites.
Long-term durability isn’t an issue with a sound wood
foundation. That’s been well documented by U.S.Dept. of Agriculture’s Forest
Service testing. Proper construction techniques are everything. When wood
foundations fail, it’s always a case of poor construction techniques. The key
elements are properly sized sheathing and framing, secure floor tie-ins and
proper drainage.
Strength is a matter of engineering
Strength is simply a matter of following the guidelines
laid out in the wood foundation manual (see “For More Information,” below).
Framing member widths and spacing as well as sheathing thickness depend mostly
on backfill height. The deeper into the ground, the stronger the wall needs to
be. In our example, 2x8s are spaced every 16 in. with 5/8-in. sheathing, with
the wall resting on 2x10s, which in turn rest on an 8-in. thick gravel footing.
The concrete floor resists ground pressure at the bottom, while the top is
anchored to the floor system above with joist hangers and clips. This design is
acceptable for most normal-height backfill scenarios. Any and all water will
filter through the gravel backfill, footings and under-slab fill where it’s
collected by a perforated sump basket for pumping away from the house, or
drained to daylight if your home’s on a hill.
Hire a wood foundation
built and the cost is roughly equivalent to concrete block and a little cheaper
than poured walls. If you build it yourself, you’ll get it for half the price
of a conventionally built masonry basement. But keep in mind that finishing is
much easier and cheaper because you’re finishing a stud wall.
For More
Information
If you plan to install a wood foundation, get help with
the design and construction first by ordering a booklet from The Southern Pine
Council called “Permanent Wood Foundations.” Contact the council at
www.southernpine.com or call (504) 443-4464.
What type of glue should I use for exterior work?
Q
What’s the best type of glue to use for
outdoor projects? Specifically, I’m repairing my deck rail post that has a
piece broken off it. Can I get away with yellow woodworking glue or do I need
something else?
Bill Wegman, Eugene,
OR
A An exterior-grade yellow
woodworking glue may work fine, especially if it’s protected by a coat of
paint, but it’s not my first choice. I would use a polyurethane-based glue;
it’s fully waterproof and bonds wood and other materials well. It’s not
gap-filling, so be sure to get a good fit and clamp
it.
Click Image to enlarge.
Gaps in wood plank floors
Q
My red oak hardwood floor (3-in. plank) was
installed three years ago, and some areas are showing shrinkage gaps. This is a
random problem, and I wonder if there is a filler I could use in these
seams.
Bruce Bergman, Ridgeway,
CO
A Sorry to
say, Bruce, but there’s not much you can do at this point. Plank flooring
expands and contracts with humidity changes and may show some gaps. In fact, on
old plank floors, gaps are considered part of the “look.” To minimize them, try
keeping your home’s relative humidity close to 50 percent. During dry seasons
or heating periods, the humidity often drops and you’ll need to use
humidifiers. During periods of high humidity, you may have to dehumidify
(although air conditioning often takes care of it).
I don’t recommend that you use a filler; it may look
worse than the shrinkage gaps. A non-hardening color putty will fill the
cracks, but it will dry and pop out within a year and need redoing. A putty
that sets hard can create larger gaps or even buckle the floorboards by not
leaving any expansion space. Conversely, it will crack if the floor
shrinks.
The real cure for cracks in a wood plank floor is to
minimize them in the first place. Here are the two main ways excessive cracks
develop.
Excessive moisture
-
The wood flooring has too much moisture content when
installed and then shrinks as it “dries out.” The solution is to buy dry wood
and to acclimate the flooring to the room you want to lay it in. All work that
introduces moisture (concrete floors, drywall taping and texturing, painting)
must be complete and dry. Then store the wood on location for at least two
weeks. A normal humidity level must be maintained during this period (by
heating or air conditioning).
Compression set
2.The wood is
too dry to start with and the flooring absorbs excessive moisture after
installation. As the wood expands, the pressure will crush fibers at the edge
of the boards along tight joints. This is called compression set. When the wood
dries out again, it will shrink; the crushed fibers won’t completely rebound
and a gap will form. Again, the solution is to acclimate the wood to the space,
making sure the humidity is kept close to its normal
level.
In all cases, put a coat of finish on new floors as soon
as possible, as this will slow down moisture movement into and out of the wood
floor planks.
Locating antique hardware
Q
Where can I find hardware such as antique desk
lid supports, door hinges and dresser mirror
hinges?
Dick Ames, Freeport,
IL
A Here are a
couple of different approaches. Search antiques stores, architectural antiques
stores and building reuse (salvage) outfits for the real deal. If you find
something suitable but in bad cosmetic shape, you may be able to have it
cleaned up and restored. Most large cities have businesses that specialize in
metal plating. Look in the Yellow Pages. Replating also adds the option of
changing the finish, say, from polished brass to chrome. This also works for
light fixtures, locksets and plumbing fixtures.
Click Image to enlarge.
The other
approach is to shop for reproductions of antiques. Check with local home
centers and hardware and woodworking stores and see what they stock or what
they can order from their suppliers.
Finally, call or go to
the Internet for mail-order sources. Here are some catalogs to
try:
-
Van Dyke’s Restorers, (800) 558-1234.
www.vandykes.com
-
Hershbergers Hardware Ltd., (800)
734-8044.
-
Constantine’s Woodworkers Catalog, (954) 561-1716.
www.constantines.com
-
Rockler Woodworking and Hardware, (800) 279-4441.
www.rockler.com.
What about the letter ‘d’?
Q
You guys are always specifying
“d” sizes for nails such as 16d,
8d,
etc. What in the world does “d”
mean? How about giving us the
nail lengths along with the “d”
designation?
Gary Hakkenen, Lake Elmo,
MN
A The “d”
stands for penny, so 8d refers to an 8-penny nail, 16d to a 16-penny nail and
so on. It’s a way to indicate nail length, as you can see in the table
below.
Now for the obvious question: Where does the sizing
system come from and why does “d” stand for penny? The “d” goes way back to the
time when the Romans occupied what is now England. The “d” is associated with a
Roman coin called the denarius, which was also the name for an English
penny.
So what’s that got to do with nails? It was associated
with nails when they were hand-forged, one at a time. Some say a hundred 3-1/2
inch nails would have cost 16 pennies and thus became known as 16-penny nails.
Others say that the number and the “d” indicate that one 16d (3-1/2 inch)
hand-forged nail cost 16 pennies.
Who knows which version
is true or why the “d” designation persists even in the building codes today,
but fortunately, retail boxes of nails are marked with the penny size as well
as the length in inches. As you can see in the photo, length is only one factor
of many in choosing a nail.
Nails for Light Construction
| Size
|
Length
(in inches)
|
| 4d
|
1-1/2
|
| 6d
|
2
|
| 8d
|
2-1/2
|
| 10d
|
3
|
| 12d
|
3-1/4
|
| 16d
|
3-1/2
|
| 20d
|
4
|
| 30d
|
4-1/2
|
Click Image to enlarge.
Web sites that work: On-line painting information
Paint Quality Institute, paintquality.com
Aimed at the do-it-yourselfer, this Web site covers a
broad range of painting topics from how to deal with a chalky surface to
techniques for avoiding mildew growth. There are plenty of photos to make the
instructions clear, and you can E-mail the institute with questions not
answered by the Web site.
National Paint and Coatings Association,
www.paint.org
Visit this Web site for how-to information if your
biggest concerns about paint and painting involve lead issues and
environmentally friendly practices. Avoid all the trade-related stuff and go
straight to the Consumer Info section where you can download how-to brochures
on this and other important painting topics like preventing moisture
damage.
Sherwin-Williams, www.sherwinwilliams.com/diy/
This Web site contains plenty of detailed information and
tools to make it worth a visit. Click on the site map icon to access a
well-ordered index. From the index, try these topics: The
paint
calculator helps you figure out how much paint to buy. The
rating chart
matches a type of paint to a specific application. And the
project planner
is an interactive question-and-answer tool that helps you choose paints,
brushes and colors.
Art Direction • GREGG
WEIGAND
Photography • BILL
ZUEHLKE
