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Renovation 4th Edition

Page 95

by Michael Litchfield


  such as plywood, particleboard, and OSB may

  just have surface mold, so probe them with an ice

  pick or pocketknife to see how sound they are. If

  they are spongy, replace them. Engineered wood

  products are particularly susceptible to rot

  because they contain adhesive binders that fungi

  feed on.

  Remediation. Wash surface mold with soap and

  water and let it dry well. There’s no need for

  caustic bleaches to kill mold spores (and irritate

  your lungs) because washing should remove

  mold. After the surface has dried, paint it with a

  stain killer such as B-I-N®. If mold has caused

  the drywall’s paper facing to roughen or delami-

  nate, cut back the drywall at least 1 ft. beyond the

  damaged area and replace it.

  If your inspection revealed mold growing

  inside wall cavities, use sheet plastic to seal off

  the affected area, including the heating registers,

  Whether they’re removing asbestos or mold-contaminated

  then cut back damaged drywall to the nearest

  drywall and framing, pros dress for the job. Here,

  stud center on both sides, and cut out damaged

  protective clothing includes a respirator mask with N95

  framing, if any. If you must replace more than

  filters, gloves, boot covers, and disposable Tyvek coveralls

  one stud, erect temporary shoring to support the

  and hood. Duct tape seals the coveralls at the wrists

  and ankles.

  loads above (see chapter 10). To contain spore-

  laden dust, have a helper hold the hose of the

  commercial-grade HEPA vacuum near the mate-

  rials being cut. Using soapy water, scrub the sur-

  the end of each day. After assessing the mold’s

  face mold from the framing, and allow all materi-

  extent, determine the shortest way out of the

  als to dry well before installing new drywall—

  house for contaminated materials—maybe out a

  framing moisture content should be 15% to 20%

  window—to minimize spreading mold spores to

  or less. (Borrow or buy a moisture meter to

  clean areas. Use sheet plastic to seal doorways

  check.) Wrap moldy debris in 6-mil plastic and

  and heating registers in affected areas, and turn

  have it carted away.

  off HVAC systems until the remedial work is

  complete. Seal damaged materials in plastic

  Choosing Insulation Wisely

  before transporting them from the site. Never

  sand moldy materials because that will spread

  There are dozens of insulating products, which

  spores. Finally, rent a commercial-grade

  I’ll classify into five groups: (1) batts (precut

  vacuum with HEPA filters; if possible, vent

  lengths or continuous rolls), (2) loose fill (blown

  it to the outside.

  into open spaces) (3) dense pack (blown into

  confined spaces), (4) rigid-foam panels, and

  Assessing the extent. If mold is limited to small (5) spray foam.

  areas at the top of a bathroom or exterior wall, it

  may be surface mold caused by condensation or

  BATT InSulATIon

  inadequate ventilation. However, if mold is wide-

  spread around windows or doors, bathroom dry-

  Batts may be made of fiberglass, mineral wool,

  wall is crumbling, or tiles mounted on drywall

  or recycled cotton, but fiberglass batts are by far

  are loose, there’s probably mold growing in the

  the industry leader, accounting for three-quarters

  walls. Start looking at the base of the walls. Turn

  of residential insulation sales. Inexpensive and

  off the electrical power to the area, remove the

  easy to install, batts are favored by DIYers. Faced

  baseboard, and use a utility knife or a hole saw

  with kraft paper or foil, batts may be stapled to

  to cut small holes in the drywall. If there’s no

  the face or edges of studs, joists, or rafters;

  mold, you can easily patch the holes and cover

  unfaced batts are friction-fitted between framing.

  them with the baseboard. More likely, you’ll

  In unfinished attics, unfaced batts are placed

  Energy Conservation and Air Quality

  405

  between floor joists or atop existing batts to

  proof to a degree, and insulate well. Made from

  improve heat retention.

  recycled cotton, batts are treated with a natural

  However, for batt insulation to meet the

  biostat (borate) to inhibit mold and make them

  R-values claimed by manufacturers, batts must

  fire-resistant. Wear a disposable paper mask

  be installed precisely so they fill cavities between

  when installing cotton: Although its lint is more

  framing members without gaps or thin spots.

  benign than airborne glass fibers, avoid breath-

  One problem is that framing in old houses is fre-

  ing it anyway.

  quently irregular, so batts with precut widths

  mineral wool (also called rock wool) is spun

  often don’t fit well. Consequently, if installers

  from natural stone such as basalt or made from

  don’t fill gaps, cut batts a bit short, allow facing

  metal oxides and is the most fire-resistant of any

  flanges to pucker, or don’t take time to fit insula-

  insulation. Rock wool, used to insulate wall cavi-

  tion behind pipes and electrical cables, air move-

  ties early on, is now enjoying a revival among

  ment can dramatically reduce their R-value. This green builders. Relatively dense, it insulates and

  is especially true for batts made of fiberglass

  soundproofs pretty well. Wear a respirator and

  because fiberglass is less dense than most other

  gloves when working with it, for it has health-

  P R O T I P

  insulating materials.

  related concerns similar to those of fiberglass.

  Fiberglass batts. Because it is such a big seller,

  Standard fiberglass can itch

  fiberglass makers are constantly reworking the

  looSE-FIll InSulATIon

  like crazy. So even if you wear a

  long-sleeved shirt and a pair of

  stuff. Fiberglass is famously itchy, of course. So

  Usually cellulose or fiberglass, loose-fill insula-

  gloves, wash well at the end of

  in response to eye, skin, and lung irritation

  tion is most often used to retrofit unfinished

  each day with cold water. Exactly

  caused by loose glass fibers, makers now offer

  attics. Loose fill can be blown in quickly, does a

  why cold water reduces itching is

  batts encapsulated in perforated or woven plastic great job of filling irregular and hard-to-reach

  unclear (shrinks pores perhaps),

  wrapping—which you can carry bare-handed and spaces, and outperforms batt insulation. It’s also

  but it works.

  install overhead without fibers raining down on

  something a homeowner can install. Smaller

  you. In some products, the fiberglass has been

  blowers can be rented at most home centers,

  reformulated so that it’s soft, itchless, and form- />
  along with a 2-in.- or 3-in.-diameter hose and the

  aldehyde free. There are also fiberglass batts of

  bales of insulation that one worker feeds into the

  varying density: 31⁄2-in.-thick batts that are rated

  blower hopper, while the other worker sprays the

  at R-11, R-13, and R-15; and 51⁄2-in.-thick batts

  loose-fill insulation. The more inches of loose fill

  rated at R-21. Note: If you compress batts into

  the cavities, you decrease the insulation’s loft and

  thus reduce its R-value slightly.

  cotton batts (often called blue jean insulation)

  are formaldehyde-free and itchless. Because of

  their density, they slow air movement, sound-

  Precut fiberglass batts are by far the

  most commonly installed insulation.

  Always read labeling before opening

  to be sure the batts inside are of the

  correct length, width, thickness, and

  R-value for the task at hand.

  The explosion of new insulating materials includes

  these itch-free, environmentally friendly cotton batts,

  also called blue-jean insulation, which are created

  from mill wastes.

  406 Chapter 14

  Recommended levels of Insulation

  Insulation levels are specified by R-value. R-value is a measure of insulation’s ability to resist heat traveling

  through it. The higher the R-value, the better the thermal performance of the insulation. The table below shows what

  levels of insulation are cost-effective for different climates and locations in the home.

  Uninsulated wood-frame wall:

   drill holes in the sheathing and blow insulation into the empty wall cavity before installing the new siding, and:

   Zones 3 to 4: Add R-5 insulative wall sheathing beneath the new siding.

   Zones 5 to 8: Add R-5 to R-6 insulative wall sheathing beneath the new siding.

  Recommended Levels of Insulation

  Insulated wood-fr

  Insulation lev

  ame wall:

  els are specified by R-value. R-value is a measure of insulation's ability to resist heat traveling through it.

   Zones 4 to 8: Add R-5

  The higher the R-v insulative sheathing befor

  alue the better the ther e installin

  mal perf g th

  or e new siding.

  mance of the insulation. The table below shows what levels of

  insulation are cost-effective for the different climates and locations in the home

  Map courtesy of the department of Energy, www.energystar.gov

  7

  6

  7

  4

  5

  6

  6

  5

  5

  5

  4

  3

  3

  3

  2

  2

  All of Alaska is in Zone 7 except

  the following Boroughs in Zone 8:

  2

  Bethel

  northwest Arctic

  Zone 1 includes:

  dellingham

  Southeast Fairbanks

  Hawaii

  Fairbanks n. Star wade Hampton

  Guam

  1

  nome

  yukon-koyukuk

  puerto Rico

  north Slope

  Virgin Islands

  Zone

  Added Insulation to Attic

  Floor

  ADD INSUlATION TO ATTIC

  Uninsulated Attic

  Existing 3-4 inches of Insulation

  1

  R30 to R49

  R25 to R30

  `

  R13

  Zone

  Uninsulated Attic

  Existing 3–4 Inches of Insulation

  Floor

  2

  R30 to R60

  R25 to R38

  R13 to R19

  1 3

  R30 to R60

  R30 to R49

  R25 to R38

  R25 t o R30

  R19 to R25

  R13

  4

  R38 to R60

  R38

  R25 to R30

  2

  R30 to R60

  R25 to R38

  R13 to R19

  5-8

  R49 to R60

  R38 to R49

  R25 to R30

  3

  R30 to R60

  R25 to R38

  R19 to R25

  4

  R38 to R60

  R38

  R25 to R30

  5 to 8

  R49 to R60

  R38 to R49

  R25 to R30

  Energy Conservation and Air Quality

  407

  you install, the higher the R-value you’ll achieve.

  loose-fill cellulose is mostly recycled newspa-

  Depths of 12 in. to 18 in. are fairly common.

  pers, ground up and treated with borate to make

  Note: Prepping the space is important, so see

  it fire- and mold-resistant. Denser than fiber-

  the earlier section on air-sealing an attic. You’ll

  glass, it is less air-permeable and averages

  want to cover any large hole such as chases, keep R-values of 3.2 per in.; to attain an R-49 rating,

  loose-fill insulation 2 in. away from the chimney,

  you’d need to blow in about 15 in. of loose-fill

  and install some kind of baffle to prevent loose

  cellulose. Its lower cost, higher R-value, and

  fill from blocking soffit vents.

  lower tendency to irritate skin give cellulose a

  slight edge over fiberglass. Cellulose’s major

  loose-fill fiberglass has fluffy, spun-glass fibers downside is that it absorbs water and dries slow-

  and an R-value of 2 to 2.7 per in.; to attain an

  ly. Were there a major leak, that retained water

  R-49 rating on an attic floor, you’d need to blow

  could soak the drywall ceiling below.

  in a thickness of approximately 19 in. Not as

  Spray polyurethane foam is rarely used to insu-

  dense as cellulose, it is more air-permeable.

  late attic floors because it’s prohibitively expen-

  Researchers report that in temperatures below

  sive. But it is occasionally used as a thin flash

  0°F, convection currents passing through loose-

  coat to air-seal an attic after it’s been prepped.

  fill fiberglass can reduce its effectiveness by 30%. The foam is then covered with loose-fill fiberglass

  In the event of a minor roof leak, fiberglass will

  or cellulose until the desired R-value is achieved.

  probably dry quickly; being inorganic, it is also

  mold-resistant. Loose-fill fiberglass is slightly

  dEnSE-pACk InSulATIon

  more expensive than cellulose.

  Dense-pack insulation uses the same bales of cel-

  lulose or fiberglass as loose-fill installations,

  except that the materials are blown into confined

  spaces at higher pressures—say, 3 lb./cu. ft.—by

  Insulation Values more powerful blowers. Dense-pack insulation

  TYPE OF

  R-VAlUE

  should be installed only by trained specialists. It

  INSUlATION

  PER INCH

  is not a job for DIYers.

  In renovations where interior surfaces have

  Batts and blankets

  been gutted (or in new construction), the insula-

  Fiberglass

  

  3.2

  tion is confined by a polymer mesh netting

&nbs
p; stretched taut across studs or rafters, then glued

  Cotton

  

  3.5

  or stapled to framing edges so it stays put. The

  Mineral wool

  

  3.2

  installer slits small holes in the netting, inserts

  the nozzle of the blower hose, and fills each bay.

  loose fill

  It takes skill. If too much insulation is blown in,

  the netting may bulge so much that drywall can’t

  Fiberglass

  

  2.2–2.7

  be installed over it.

  Cel ulose

  

  3.2

  More often, renovators use dense-pack insula-

  tion when they want to increase the R-value of

  Dense pack (3 lb./cu. ft.)

  walls while leaving interior finish surfaces intact.

  They gain access to wall cavities by removing

  Fiberglass

  

  2.5–3.5

  small sections of siding, drilling holes through

  Cel ulose

  

  3.8

  exterior sheathing, and blowing in insulation

  (usually cellulose) until each cavity is filled. Here

  Rigid-foam panels

  again, it takes skill. A seasoned installer can tell

  by the whine of the blower when the correct den-

  Expanded polystyrene (EpS)

  

  4.0

  sity is achieved. How long it takes to fill a stud

  Extruded polystyrene (XpS)

  

  5.0

  bay is also telling. If a bay fills too quickly, fire-

  stops may be blocking part of a bay; if a bay takes

  polyisocyanurate

  

  6.5

  forever to fill, it may be open at the bottom and

  insulation is billowing into the crawlspace. As

  Spray-on (contractor applied)

  with any installation, it’s important to survey and

  Closed-cel polyurethane

  

  6.5

  prep the structure to avoid such problems. An

  open-cel polyurethane

  

  3.6

  energy auditor’s thermal image of cold spots can

  also help an installer insulate around obstruc-

  Magnesium oxide

  

  3.8

  tions in a wall.

  408 Chapter 14

  At low densities (1.5 lb./cu. ft.), cellulose traps

  Note: Installing rigid-foam insulation over

  air and is an effective insulator (R-3.5/in.). When

 

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