Renovation 4th Edition
Page 61
dense. Wrap pipes with preformed foam pipe
insulation. Wrap ducts and larger objects with
sheets of vinyl-faced fiberglass insulation, which
is well suited to the task because vinyl is a
vapor barrier. Use duct tape or insulation tape
to seal seams.
A dehumidifier also can remove excess
Insulated water pipes conserve energy
and reduce condensation in humid
humidity. For best results, install a model that
basements.
can run continuously during periods of peak
humidity; place it in the dampest part of the
basement at least 12 in. away from walls or
obstructions. To prevent mold from growing in
CorreCting Condensation
the unit’s collection reservoir, drain it daily and
If the problem is condensation, insulating base-
scrub it periodically.
ment floors and walls with rigid foam panels can
Finally, look for other sources of moisture. An
be a complete and cost-effective solution to the
unvented clothes dryer pumps gallons of water
problem. See “Curing Basement Condensation”
into living spaces; vent it outdoors. Excessive
on p. 257 for more.
moisture from undervented kitchens and bath-
Installing foam panels to isolate always-cool
rooms on other floors can migrate to the base-
concrete surfaces should solve the problem.
ment; add exhaust fans to vent them properly.
Piecemeal solutions include insulating cold-
Finally, weatherstrip exterior doors and keep
water pipes, air-conditioning ducts, and other
them closed in hot, humid weather.
dampness due to exterior Water
Position and maintain gutters and downspouts
so they direct water away from the house. And, if
possible near affected walls, slope soil away from
zzzzzz pedestal sump pump
the house.
Besides those two factors, water that migrates
through foundation walls or floors is more elu-
Pedestal
sive and expensive to correct. Basically, you have
sump pump
11/2-in. rigid PVC
three remedial options: (1) remove water once it
discharge pipe
gets in; (2) fill interior cracks, seal interior sur-
faces, and install a vapor barrier; and (3) exca-
Permeable liner
vate foundation walls, apply waterproofing, and
or fine screen
improve drainage.
option one: remove water. Sump pumps are
the best means of removing water once it gets
into a basement. If you don’t have a sump pump,
you’ll probably need to break through the base-
ment floor at a low point where water collects,
and dig a sump pit 18 in. to 24 in. across. Line
the pit with a permeable liner that allows water
to seep in while keeping soil out, and put 4 in. of
Ball float
gravel in the bottom.
There are two types of sump pumps. Pedestal
sump pumps stand upright in the pit. They are
Check valve
water-cooled and have ball floats that turn the
4 in. of gravel
pump on and off. Submersible sump pumps, on
Sump pit
the other hand, have sealed, oil-cooled motors, so
they tend to be quieter, more durable, and more
expensive. And because they are submerged, they
allow you to cover the pit so nothing falls in. A
1⁄3-hp pump of either type should suffice.
18 in. to 24 in.
258 Chapter 10
The type of discharge pipe depends on whether popular solvent-based membrane that
the pump is a permanent fixture or a sometime
contains rubberlike additives to make it more
thing. Permanent pumps should have 11⁄2-in.
flexible and durable. Asphalt emulsions are
rigid PVC discharge pipes with a check valve near water based and widely used because, unlike
the bottom to prevent expelled water from
modified asphalt, they don’t have a strong
siphoning back down into the pit. If the water
odor, aren’t flammable, and won’t degrade
problem is seasonal, many people simply attach
rigid foam insulation panels placed along
a 50-ft. garden hose and run it out a basement
foundation walls. Synthetic rubber and
window. In either case, discharge the water at
polymer-based membranes also are water
least 20 ft. from the house, preferably downhill
based; they’re popular because their inherent
and not directly into a neighbor’s property.
elasticity allows them to stay flexible and span
small cracks. Note: Water-based membranes
option two: interior solutions. If basement
dry more slowly than solvent-based ones and
walls are damp, try filling cracks as suggested on
can wash off if rained on before they are cured
p. 237 and applying damp-proofing coatings.
and backfilled.
(This approach won’t work if the walls are peri-
Peel-and-stick membranes are typically
odically wet.) After scrubbing the basement
sheet or roll materials of rubberized asphalt
walls, parge (trowel on) a cementitious coating
fused to polyethylene. They adhere best on
such as Thoroseal® Foundation Coating or Sto®
preprimed walls. To install these membranes,
Watertight Coat or a polymer-modified system
peel off the release sheet and press the sticky
such as Surewall®. These coatings can withstand
side of the material to foundations. Roll the
higher hydrostatic pressures than elastomeric
seams to make them adhere better. Peel-and-
paints or gels. Epoxy-based coatings also adhere
stick costs more and takes longer to install
well but are so expensive that they’re usually
than sprayed-on membranes, but they’re
reserved for problem areas such as wall-to-
thicker (60 mil, on average) and more durable.
floor joints.
Although not widely used on houses, these
Impervious plastic vapor barriers were long
materials seem justified on sites with chronic
advocated to block the flow of moisture through
water problems. They’re often called
foundation walls. But, as explained in “Curing
Bituthene®, after a popular W.R. Grace
Basement Condensation” on p. 257, a better solu-
Construction product.
tion may be to install semipermeable, moisture-
tolerant insulation panels against condensing
Air-gap membranes aren’t true
surfaces and thus allow a slight amount of mois-
membranes because they don’t conform to the
ture to pass back and forth. Building scientists
surface of the foundation. Rather, they are
are monitoring this solution, but so far it seems a rigid plastic (polyethylene) sheets held out
reasonable one in basements where dampness is
from the foundation by an array of tiny
the result of condensation. This solution was, in
<
br /> dimples, which creates an air–drainage gap.
part, a response to the now discredited but long-
Water that gets behind the sheets condenses
used method of installing a wood frame wall next on the dimples and drips free, down to
to a foundation, insulating between studs, and
foundation drains. (For this system to work,
then covering that wall with plastic and drywall.
you must coat the foundation walls first.) Air-
A recipe for mold if ever there was one.
gap sheets are attached with molding strips,
clips, and nails; caulk the sheet seams.
option three: exterior solutions. To water-
Until technology transformed
proof exterior foundation walls, first excavate
waterproofing compounds, cementitious
them. At that time, you should also upgrade the
coatings rivaled unmodified asphalt as the
perimeter drains, as shown in “Foundation
most common stuff smeared onto
Drainage” on p. 235. Then, after backfilling the
foundations. These days, acrylic additives
excavation, slope the soil away from the house.
make cement-based coatings a bit more
That is, no waterproofing material will succeed if flexible, but they will still crack if the
water stands against the foundation. Before
foundation flexes. Bentonite, a volcanic clay
applying waterproofing membranes, scrub the
sheathed in cardboard panels, swells 10 times
foundation walls clean and rinse them well.
to 15 times its original volume when wet,
Liquid membranes are usually sprayed
keeping water away from foundation walls.
on to a uniform thickness specified by the
Use construction adhesive or nails to attach
manufacturer, typically 40 mil. That takes
the panels. These panels are costly and not
training, so hire a manufacturer-certified
widely available, and they can be ruined if
installer. Liquid membranes are either solvent
rained on before the foundation is backfilled.
based or water based. Modified asphalt is one
Foundations and Concrete
259
11 Electrical Wiring
This chapter is designed to give you a quick Understanding Electricity
overview of the electrical system in your home.
Electricity (flowing electrons called current)
Solid connections are the key to
Respecting the power of electricity is essential to
moves through a wire like water in a pipe. The
reliable wiring—especially connecting working safely. Always follow instructions care-
flow of water is measured in gallons per minute;
wires to screw terminals on recept
fully, use appropriate safety equipment, and
the electrical flow of electrons is measured in
acles, switches, and light fixtures.
when in doubt consult a licensed electrician.
So here’s a great tip. Some wire
amperes or amps. Water pressure is measured in
Before beginning work, check with local building
strippers have a small hole near the
pounds per square inch, and the force behind the
authorities to make sure regulations allow you to
handle. Insert a stripped wire end,
electrons in a wire is measured in volts. The larg-
flip your wrist 180°, and—voilà!—
do your own work and that you are conforming
er the pipe, the more water that can flow through
a perfect loop.
to code requirements.
it; likewise, larger wires allow a greater flow of
electricity. A small diameter pipe will limit the
flow of water, compared to a larger pipe; similar-
ly, wiring that is too small will resist the flow of
current. If that resistance (measured in ohms)
is too great, the wires will overheat and may
cause a fire.
Think of alternating current (AC) electrical
systems as a loop that runs from the generation
point (or power source) through a load (some-
thing that uses electrical power, a lightbulb, for
instance) and back to the generation point. In
your home, the main loop, which is the service to
your home, is split into smaller loops called cir-
cuits. Typically, a hot wire (usually black or red)
carries current from the service panel to one of
the various loads, and a neutral wire (typically
white or light gray) carries current back to the
service panel.
Working safely
To work safely with electricity, you must respect
its power. If you understand its nature and heed
the safety warnings in this book—especially shut-
ting off the power and testing with a voltage tes-
ter to make sure power is off—you can work with
it safely.
260
Use a voltage tester to be sure power
is off before working on an outlet. If
the tester light glows, there is still
voltage present at the outlet.
S a f e t y a l e r t
To work safely on existing
circuits, always turn off electri-
cal power at the service panel,
and use a voltage tester (see the
photos on p. 268) at the outlet
to verify the power is off.
Throughout this chapter (and
book), you’ll see this symbol as
a reminder:
Turn off the power to the circuit at the main service panel
Wear proper safety equipment when doing electrical
before removing receptacle, switch, or fixture covers.
work, such as gloves to protect hands from the sharp
edges of wires, cables, and boxes.
The cardinal rule of home-improvement proj-
ects, which goes double for electrical work, is
Key Terms
this: Know your limitations.
Unless you have previous experience doing
Watts. a measure of power consumed. In
electrical work and feel confident about your
residential systems, watts are virtually the same
skills, you should leave certain projects to a pro.
as volt-amps.
Working inside a service panel or even removing
Voltage. the pressure of the electrons in a
its cover can be especially dangerous. In most
system. Voltage is measured in volts.
panels, there is an area around the main breaker
that remains hot even after the breaker is set to
amperes (amps). the measure of the volume of
the off position. Also, some older panels don’t
electrons flowing through a system (current).
have a main breaker, and it takes experience to
Current. the flow of electrons in a system.
understand the layout of a panel.
Current is measured in amperes (amps). there
S a f e t y a l e r t
Never attempt to remove the cover of, or work
are two types of current: DC (direct current) and
in, the main service panel or a subpanel. Call a
aC (alternating current). aC power is supplied
Test the tester first and last.
licensed electrician rather than risk harm.
by
utility companies to homes.
no matter what kind of tester
The safety alerts and safe working practices
you’re using, test it first on a cir-
poWer (Volt-amps or Va). the potential in the
explained in this chapter will go far to protect
cuit that you know is hot to make
you, but the best protection is knowledge. I
system to create motion (motors), heat (heaters),
sure the tester is working proper-
strongly recommend that readers visit the OSHA/
light (fixtures or lamps), etc. Volt-amps = avail-
ly, and do the same after you’ve
NIOSH website on electrical safety: www.cdc.
able volts x available amps (Va).
done the testing. Most testers
gov/niosh/docs/2009-113.
ohms. the measure of resistance to the flow of
run on batteries, and those bat-
Always wear appropriate safety gear, includ-
teries could die after your pre-
electrons (current) in a wire. the higher the
ing rubber-soled shoes, heavy gloves, safety glass-
test check and before the voltage
resistance, the lower the flow of electrons.
es, and a respirator or dust mask when sawing or
test. The post-test check will
neC. national electrical Code.
drilling overhead. Remember that 120 volts can
catch that. and don’t think it
can’t happen—it does happen.
kill or cause serious shock, so learn and use safe
work practices—your life depends on it.
electrical Wiring
261
Electricity in Your Home
Play It safe
Power from the utility service is commonly
delivered through three large wires, or conduc-
only a licensed electrician should work in a service panel—or even remove the
tors, which may enter the house overhead or
cover. even with the main fuse or breaker turned off, some of the parts inside a
underground. Overhead service wires are called
panel are always hot (carrying voltage) and could electrocute you. Don’t mess with
a service drop. The drop runs to a weatherhead
electric meters, either. Call the utility company to install meters or upgrade their
atop a length of rigid conduit. When fed under-
service drop wires.
ground, service conductors are installed in bur-
ied conduit or run as underground service-
entrance (USE) cable. Whether it arrives over-
head or underground, three-wire service delivers
120 volts to ground and 240 volts (v) between
the energized conductors.