| Insulating your Existing Houston Home |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
| |
 |
today. Older homes are likely to use more energy than newer homes, leading to higher heating and air-conditioning bills. Allow
ATEX Inspects to perform an Energy Audit or home maintenance inspection on your new or exist Houston area home to start
saving money from energy drains in your home. We provide thorough Energy Audits in Galveston, Katy, Spring, Richmond,
Jacinto City, Santa Fe, Seabrook and all the greater Houston surrounding area.
Where and How Much Insulation Is Needed In My Texas Home?
Adding more insulation where you already have some, such as in an attic, will save home energy. You can save even greater
amounts of energy if you install insulation into places in your home that have never been insulated. Which building spaces should
be insulated, these might include an uninsulated floor over a garage or crawlspace, or a wall that separates a room from the attic.
A qualified Houston home inspector will include an insulation check as a routine part of an energy audit or full service home
inspection. For information about home energy audits or home inspection services, contact us at ATEX Inspects - 281-216-1171.
State energy offices are another valuable resource for information. An energy audit of your house will identify the amount of
insulation you have and need, and will likely recommend other improvements as well. If you don't have someone inspect your
home, you'll need to find out how much insulation you already have.
This recommendation balances future utility bill savings against the current cost of installing insulation. So the amount of insulation
you need depends on your climate and heating fuel(gas, oil, electricity), and whether or not you have an air conditioner.
How Much Insulation Does my Houston Home Already Have?
Look into your attic. We start with the attic because it is usually easy to add insulation to an attic. Look into your walls. It is difficult
to add insulation to existing walls unless:
You are planning to add new siding to your house, or you plan to finish unfinished space like a bonus room. If so, you need to
know whether the exterior walls are already insulated or not. One method is to use an electrical outlet on the wall, but first be sure
to turn off the power to the outlet. Then remove the cover plate and shine a flashlight into the crack around the outlet box. You
should be able to see whether or not insulation is in the wall. Also, you should check separate outlets on the first and second floor,
and in old and new parts of the house, because wall insulation in one wall doesn't necessarily mean that it's everywhere in the
house. An alternative to checking through electrical outlets is to remove and then replace a small section of the exterior siding.
Look under your floors. Look at the underside of any floor over an unheated space like a garage or crawl spaces. Inspect and
measure the thickness of any insulation you find there. It will most likely be a fiberglass batt, so multiply the thickness in inches by
3.2 to find out the R-value (or the R-value might be visible on a product label). If the insulation is a foam board or sprayed-on foam,
use any visible label information or multiply the thickness in inches by 5 to estimate the R-value.
Look at your ductwork. Don't overlook another area in your home where energy can be saved - the ductwork of the heating and
air- conditioning system. If the ducts of your heating or air-conditioning system run through unheated or uncooled spaces in your
home, such as attic or crawl spaces, then the ducts should be insulated. First check the ductwork for air leaks. Repair leaking
joints first with mechanical fasteners, then seal any remaining leaks with water-soluble mastic and embedded fiber glass mesh.
Never use gray cloth duct tape because it degrades, cracks, and loses its bond with age. If a joint has to be accessible for future
maintenance, use pressure- or heat-sensitive aluminum foil tape. Then wrap the ducts with duct wrap insulation of R-6 with a
vapor retarder facing on the outer side. All joints where sections of insulation meet should have overlapped facings and be tightly
sealed with fiber glass tape; but avoid compressing the insulation, thus reducing its thickness and R-value.
Return air ducts are often located inside the heated portion of the house where they don't need to be insulated, but they should still
be sealed off from air passageways that connect to unheated areas. Drywall- to-ductwork connections should be inspected
because they are often poor (or nonexistent) and lead to unwanted air flows through wall cavities. If the return air ducts are located
in an unconditioned part of the building, they should be insulated.
Look at your pipes. If water pipes run through unheated or uncooled spaces in your home, such as attic or crawl spaces, then the
pipes should be insulated.
Air Sealing
Air sealing is important, not only because drafts are uncomfortable, but also because air leaks carry both moisture and energy,
usually in the direction you don't want. For example, air leaks can carry hot humid outdoor air into your house in the summer, or
can carry warm moist air from a bathroom into the attic in the winter.
Most homeowners are aware that air leaks into and out of their houses through small openings around doors and window frames
and through fireplaces and chimneys. Air also enters the living space from other unheated parts of the house, such as attics,
basements, or crawl spaces. The air travels through:
around windows and doors. Since many of these leakage paths are driven by the tendency for warm air to rise and cool air to fall,
the attic is often the best place to stop them. It's important to stop these leaks before adding attic insulation because the insulation
may hide them and make them less accessible. Usually, the attic insulation itself will not stop these leaks and you won't save as
much as you expect because of the air flowing through or around the insulation.
We talk about moisture control in an insulation fact sheet because wet insulation doesn't work well. Also, insulation is an important
part of your building envelope system, and all parts of that system must work together to keep moisture from causing damage to
the structure or being health hazards to the occupants. For example, mold and mildew grow in moist areas, causing allergic
reactions and damaging buildings.
When Is Moisture a Problem in your Houston Home?
When moist air touches a cold surface, some of the moisture may leave the air and condense, or become liquid. If moisture
condenses inside a wall, or in your attic, you will not be able to see the water, but it can cause a number of problems. Adding
insulation can either cause or cure a moisture problem. When you insulate a wall, you change the temperature inside the wall.
That can mean that a surface inside the wall, such as the sheathing behind your siding, will be much colder in the winter than it
was before you insulated. This cold surface could become a place where water vapor traveling through the wall condenses and
leads to trouble. The same thing can happen within your attic or under your house. On the other hand, the new temperature profile
could prevent condensation and help keep your walls or attic drier than they would have been.
Four Things You Can Do to Avoid Moisture Problems:
1. Control liquid water. Rain coming through a wall, especially a basement or crawlspace wall, may be less apparent than a roof
leak, especially if it is a relatively small leak and the water remains inside the wall cavity. Stop all rain-water paths into your home
by:
watering systems for your lawn or flower beds do not spray water on the side of your house or saturate the ground near the house.
It is also a good idea to check the caulking around your tub or shower to make sure that water is not leaking into your walls or
floors. You can place thick plastic sheets on the floor of your crawlspace to keep any moisture in the ground from getting into the
crawlspace air, and then into your house.
2. Ventilate. You need to ventilate your home because you and your family generate moisture when you cook, shower, do laundry,
and even when you breathe. More than 99% of the water used to water plants eventually enters the air. If you use an unvented
natural gas, propane, or kerosene space heater, all the products of combustion, including water vapor, are exhausted directly into
your living space. This water vapor can add 5 to 15 gallons of water per day to the air inside your home. If your clothes dryer is not
vented to the outside, or if the outdoor vent is closed off or clogged, all that moisture will enter your living space. Just by breathing
and perspiring, a typical family adds about 3 gallons of water per day to their indoor air. You especially need to vent your kitchen
and bathrooms. Be sure that these vents go directly outside, and not to your attic, where the moisture can cause problems.
Remember that a vent does not work unless you turn it on; so if you have a vent you are not using because it is too noisy, replace
it with a quieter model. If your attic is ventilated, it is important that you never cover or block attic vents with insulation. Take care to
prevent loose-fill insulation from clogging attic vents by using baffles or rafter vents. When you think about venting to remove
moisture, you should also think about where the replacement air will come from, and how it will get into your house. When natural
ventilation has been sharply reduced with extra air-sealing efforts, it may be necessary to provide fresh air ventilation to avoid build-
up of stale air and indoor air pollutants. Special air-to-air heat exchanger's, or heat- recovery ventilators, are available for this
purpose.
3. Stop Air Leaks. It is very important to seal up all air-leakage paths between your living spaces and other parts of your building
structure. Measurements have shown that air leaking into walls and attics carries significant amounts of moisture. Remember that if
any air is leaking through electrical outlets or around plumbing connections into your wall cavities, moisture is carried along the
same path. The same holds true for air moving through any leaks between your home and the attic, crawlspace, or garage. Even
very small leaks in duct work can carry large amounts of moisture, because the airflow in your ducts is much greater than other
airflows in your home. This is especially a problem if your ducts travel through a crawlspace or attic, so be sure to seal these ducts
properly (and keep them sealed!). Return ducts are even more likely to be leaky, because they often involve joints between drywall
and ductwork that may be poorly sealed, or even not sealed at all.
4. Plan a moisture escape path. Typical attic ventilation arrangements are one example of a planned escape path for moisture that
has traveled from your home's interior into the attic space. Cold air almost always contains less water than hot air, so diffusion
usually carries moisture from a warm place to a cold place. You can let moisture escape from a wall cavity to the dry outdoors
during the winter, or to the dry indoors during the summer, by avoiding the use of vinyl wall coverings or low-perm paint. You can
also use a dehumidifier to reduce moisture levels in your home, but it will increase your energy use and you must be sure to keep it
clean to avoid mold growth. If you use a humidifier for comfort during the winter months, be sure that there are no closed-off rooms
where the humidity level is too high.
Insulation Installation in your Home, the Retrofit Challenges
Whether you install the insulation yourself or have it done by a contractor, it is a good idea to educate yourself about proper
installation methods because an improper installation can reduce your energy savings.
Also, if your house is very old, you may want to have an electrician check to see if:
around the wires because that could cause the wires to overheat. THIS IS FOR FIRE SAFETY. The National Electric Code forbids
the installation of loose, rolled, or foam-in-place insulation around knob and tube wiring.
Adding thermal insulation to the ceiling or walls of a mobile home is complex and usually requires installation by specialists.
If adding insulation over existing insulation, do NOT use a vapor barrier between the two layers!
Attics
On unfinished attic floors, work from the perimeter toward the attic door. Be careful about where you step in the attic. Walk only on
the joists so that you won't fall through the drywall ceiling. You may need to place walking boards across the tops of the joists to
make the job easier. Remember that it is important to seal up air leaks between your living space and the attic before adding
insulation in your attic.
Installing batts and rolls in attics is fairly easy, but doing it right is very important. Use unfaced batts, especially if re insulating over
existing insulation. If there is not any insulation in your attic, fit the insulation between the joists. If the existing insulation is near or
above the top of the joists, it is a good idea to place the new batts perpendicular to the old ones because that will help to cover the
tops of the joists themselves and reduce thermal bridging through the frame. Also, be sure to insulate the trap or access door.
Although the area of the door is small, an uninsulated attic door will reduce energy savings substantially.
In some Houston houses, it is easier to get complete coverage of the attic floor with blown-in loose-fill insulation. It is best to hire
an insulation contractor for this job. Loose-fill insulation must be prevented from shifting into vents or from contacting heat-
producing equipment (such as recessed lighting fixtures). Block off those areas with baffles or retainers to hold the loose-fill
insulation in place.
When you stack new insulation on top of existing attic insulation, the existing insulation is compressed a small amount. This will
slightly decrease the R-value of the existing insulation. This effect is most important if the new insulation is more dense than the
old insulation. You can compensate for this stacking effect and achieve the desired total R-value by adding about one extra inch of
insulation if the old insulation is fiber glass, or about 1/2 inch if the old insulation is rock wool or cellulose.
Reflective Systems are installed in a manner similar to placing batts and blankets. Proper installation is very important if the
insulation is to be effective. Study and follow the manufacturer's instructions. Often, reflective insulation materials have flanges that
are to be stapled to joists. Since reflective foil will conduct electricity, avoid making contact with any bare electrical wiring.
Radiant barriers may be installed in attics in several configurations. The radiant barrier is most often attached near the roof, to the
bottom surface of the attic truss chords or to the rafter framing. Do not lay a radiant barrier on top of your insulation or on the attic
floor because it will soon be covered with dust and will not work.
If your attic has NO insulation, you may decide to insulate the underside of the roof instead of the attic floor. (This option is more
often used in new houses and is described in Design Option: ATTIC VENTILATION OR A CATHEDRALIZED ATTIC). If you
choose the cathedralized attic approach, all attic vents must be sealed. Spray-foam is then often used to insulate the underside of
the roof sheathing. If batts are used for this purpose, they must be secured in a manner similar to that described below for
insulating under floors. It is best to hire an insulation contractor with experience in this type of installation for this job.
Walls
Installing insulation in the cavity of exterior walls is difficult. However, when new siding is to be installed, it is a good idea to
consider adding thermal insulation under the new siding. The Retrofit Best Practices Guide provides useful information about
adding insulation when you remodel the outside of your house. It usually requires the services of a contractor who has special
equipment for blowing loose-fill insulation into the cavity through small holes cut through the sidewall, which later are closed.
It is sometimes feasible to install rigid insulation on the outdoor side of masonry sidewalls such as concrete block or poured
concrete. However, if that is not an option, you can use rigid insulation boards or batts to insulate the interior of masonry walls. To
install boards, wood furring strips should be fastened to the wall first. These strips provide a nailing base for attaching interior
finishes over the insulation. Fire safety codes require that a gypsum board finish, at least 1/2 inch thick, be placed over plastic
foam insulation. The gypsum board must be attached to the wood furring strips or underlying masonry using nails or screws.
The first-floor band joist may be accessible from the basement or crawlspace.
Floors and Crawl Spaces
If you have a floor over a crawlspace, you can either:
Insulate the underside of the floor and ventilate the crawlspace, or Leave the floor uninsulated and insulate the walls of an
unventilated crawlspace. When batts or rolls are used on the underside of a floor above an unheated crawlspace or basement, fit
the insulation between the beams or joists and push it up against the floor overhead as securely as possible without excessive
compaction of the insulation. The insulation can be held in place, either by tacking chicken wire (poultry netting) to the edges of
the joist, or with snap-in wire holders. Batts and rolls must be cut and fit around cross-bracing between floor joists or any other
obstructions. Strips of insulation may be cut off and stuffed into tight spaces by hand. Don't forget to place insulation against the
perimeter that rests on the sill plate. If you insulate above an unheated crawlspace or basement, you will also need to insulate any
ducts or pipes running through this space. Otherwise, pipes could freeze and burst during cold weather.
Reflective Systems are installed in a manner similar to placing batts. Proper installation is very important if the insulation is to be
effective. Study and follow the manufacturer's instructions. Often, reflective insulation materials have flanges that are to be stapled
to floor joists. Since reflective foil will conduct electricity, one must avoid making contact with any bare electrical wiring.
Spray-foam can be used to insulate the underside of a floor. The spray foam can do a good job of filling in the space around wires
and other obstructions and in filling any oddly-shaped areas. It is best to hire an insulation contractor with experience in this type of
installation.
When a fiberglass blanket is used to insulate the walls of an unventilated crawlspace, it is sometimes necessary to attach wood
furring strips to the walls by nailing or bonding. The insulation can then be stapled or tacked into place. Alternatively, the insulation
can be fastened to the sill plate and draped down the wall. You should continue the insulation over the floor of the crawl space for
about two feet on top of the required ground vapor retarder. Because the insulation will be exposed, be sure to use either an
unfaced product or one with the appropriate flame spread rating. When rigid foam insulation boards are used to insulate the walls
of an unventilated crawlspace, they can be bonded to the wall using recommended adhesives. Because the insulation will be
exposed, be sure to check the local fire codes and the flame-spread rating of the insulation product. If you live in an area prone to
termite damage, check with a pest control professional to see if you need to provide for termite inspections
If you are concerned are need assistance with any of the above issues - now is the time to contact Robert at ATEX Inspects, your
professional Houston Home Inspector at 281-216-1171.
New Home Construction Phased Inspections:
Residential Home (Buyers) Inspections:
Four (4) Point Insurance Inspection:
Commercial Property Inspections Services:
ATEX Inspects to perform an Energy Audit or home maintenance inspection on your new or exist Houston area home to start
saving money from energy drains in your home. We provide thorough Energy Audits in Galveston, Katy, Spring, Richmond,
Jacinto City, Santa Fe, Seabrook and all the greater Houston surrounding area.
Where and How Much Insulation Is Needed In My Texas Home?
Adding more insulation where you already have some, such as in an attic, will save home energy. You can save even greater
amounts of energy if you install insulation into places in your home that have never been insulated. Which building spaces should
be insulated, these might include an uninsulated floor over a garage or crawlspace, or a wall that separates a room from the attic.
A qualified Houston home inspector will include an insulation check as a routine part of an energy audit or full service home
inspection. For information about home energy audits or home inspection services, contact us at ATEX Inspects - 281-216-1171.
State energy offices are another valuable resource for information. An energy audit of your house will identify the amount of
insulation you have and need, and will likely recommend other improvements as well. If you don't have someone inspect your
home, you'll need to find out how much insulation you already have.
This recommendation balances future utility bill savings against the current cost of installing insulation. So the amount of insulation
you need depends on your climate and heating fuel(gas, oil, electricity), and whether or not you have an air conditioner.
How Much Insulation Does my Houston Home Already Have?
Look into your attic. We start with the attic because it is usually easy to add insulation to an attic. Look into your walls. It is difficult
to add insulation to existing walls unless:
You are planning to add new siding to your house, or you plan to finish unfinished space like a bonus room. If so, you need to
know whether the exterior walls are already insulated or not. One method is to use an electrical outlet on the wall, but first be sure
to turn off the power to the outlet. Then remove the cover plate and shine a flashlight into the crack around the outlet box. You
should be able to see whether or not insulation is in the wall. Also, you should check separate outlets on the first and second floor,
and in old and new parts of the house, because wall insulation in one wall doesn't necessarily mean that it's everywhere in the
house. An alternative to checking through electrical outlets is to remove and then replace a small section of the exterior siding.
Look under your floors. Look at the underside of any floor over an unheated space like a garage or crawl spaces. Inspect and
measure the thickness of any insulation you find there. It will most likely be a fiberglass batt, so multiply the thickness in inches by
3.2 to find out the R-value (or the R-value might be visible on a product label). If the insulation is a foam board or sprayed-on foam,
use any visible label information or multiply the thickness in inches by 5 to estimate the R-value.
Look at your ductwork. Don't overlook another area in your home where energy can be saved - the ductwork of the heating and
air- conditioning system. If the ducts of your heating or air-conditioning system run through unheated or uncooled spaces in your
home, such as attic or crawl spaces, then the ducts should be insulated. First check the ductwork for air leaks. Repair leaking
joints first with mechanical fasteners, then seal any remaining leaks with water-soluble mastic and embedded fiber glass mesh.
Never use gray cloth duct tape because it degrades, cracks, and loses its bond with age. If a joint has to be accessible for future
maintenance, use pressure- or heat-sensitive aluminum foil tape. Then wrap the ducts with duct wrap insulation of R-6 with a
vapor retarder facing on the outer side. All joints where sections of insulation meet should have overlapped facings and be tightly
sealed with fiber glass tape; but avoid compressing the insulation, thus reducing its thickness and R-value.
Return air ducts are often located inside the heated portion of the house where they don't need to be insulated, but they should still
be sealed off from air passageways that connect to unheated areas. Drywall- to-ductwork connections should be inspected
because they are often poor (or nonexistent) and lead to unwanted air flows through wall cavities. If the return air ducts are located
in an unconditioned part of the building, they should be insulated.
Look at your pipes. If water pipes run through unheated or uncooled spaces in your home, such as attic or crawl spaces, then the
pipes should be insulated.
Air Sealing
Air sealing is important, not only because drafts are uncomfortable, but also because air leaks carry both moisture and energy,
usually in the direction you don't want. For example, air leaks can carry hot humid outdoor air into your house in the summer, or
can carry warm moist air from a bathroom into the attic in the winter.
Most homeowners are aware that air leaks into and out of their houses through small openings around doors and window frames
and through fireplaces and chimneys. Air also enters the living space from other unheated parts of the house, such as attics,
basements, or crawl spaces. The air travels through:
- any openings or cracks where two walls meet, where the wall meets the ceiling, or near interior door frames;
- gaps around electrical outlets, switch boxes, and recessed fixtures;
- gaps behind recessed cabinets, and furred or false ceilings such as kitchen or bathroom soffits;
- gaps around attic access hatches and pull-down stairs;
- behind bath tubs and shower stall units;
- through floor cavities of finished attics adjacent to unconditioned attic spaces;
- utility chase ways for ducts, etc, and
- plumbing and electrical wiring penetrations.
around windows and doors. Since many of these leakage paths are driven by the tendency for warm air to rise and cool air to fall,
the attic is often the best place to stop them. It's important to stop these leaks before adding attic insulation because the insulation
may hide them and make them less accessible. Usually, the attic insulation itself will not stop these leaks and you won't save as
much as you expect because of the air flowing through or around the insulation.
We talk about moisture control in an insulation fact sheet because wet insulation doesn't work well. Also, insulation is an important
part of your building envelope system, and all parts of that system must work together to keep moisture from causing damage to
the structure or being health hazards to the occupants. For example, mold and mildew grow in moist areas, causing allergic
reactions and damaging buildings.
When Is Moisture a Problem in your Houston Home?
When moist air touches a cold surface, some of the moisture may leave the air and condense, or become liquid. If moisture
condenses inside a wall, or in your attic, you will not be able to see the water, but it can cause a number of problems. Adding
insulation can either cause or cure a moisture problem. When you insulate a wall, you change the temperature inside the wall.
That can mean that a surface inside the wall, such as the sheathing behind your siding, will be much colder in the winter than it
was before you insulated. This cold surface could become a place where water vapor traveling through the wall condenses and
leads to trouble. The same thing can happen within your attic or under your house. On the other hand, the new temperature profile
could prevent condensation and help keep your walls or attic drier than they would have been.
Four Things You Can Do to Avoid Moisture Problems:
1. Control liquid water. Rain coming through a wall, especially a basement or crawlspace wall, may be less apparent than a roof
leak, especially if it is a relatively small leak and the water remains inside the wall cavity. Stop all rain-water paths into your home
by:
- making sure your roof is in good condition,
- caulking around all your windows and doors, and
- keeping your gutters clean - and be sure the gutter drainage flows away from your house.
- If you replace your gutters, choose larger gutters and gutter guards to help keep rain from dripping onto the ground near the
house.
watering systems for your lawn or flower beds do not spray water on the side of your house or saturate the ground near the house.
It is also a good idea to check the caulking around your tub or shower to make sure that water is not leaking into your walls or
floors. You can place thick plastic sheets on the floor of your crawlspace to keep any moisture in the ground from getting into the
crawlspace air, and then into your house.
2. Ventilate. You need to ventilate your home because you and your family generate moisture when you cook, shower, do laundry,
and even when you breathe. More than 99% of the water used to water plants eventually enters the air. If you use an unvented
natural gas, propane, or kerosene space heater, all the products of combustion, including water vapor, are exhausted directly into
your living space. This water vapor can add 5 to 15 gallons of water per day to the air inside your home. If your clothes dryer is not
vented to the outside, or if the outdoor vent is closed off or clogged, all that moisture will enter your living space. Just by breathing
and perspiring, a typical family adds about 3 gallons of water per day to their indoor air. You especially need to vent your kitchen
and bathrooms. Be sure that these vents go directly outside, and not to your attic, where the moisture can cause problems.
Remember that a vent does not work unless you turn it on; so if you have a vent you are not using because it is too noisy, replace
it with a quieter model. If your attic is ventilated, it is important that you never cover or block attic vents with insulation. Take care to
prevent loose-fill insulation from clogging attic vents by using baffles or rafter vents. When you think about venting to remove
moisture, you should also think about where the replacement air will come from, and how it will get into your house. When natural
ventilation has been sharply reduced with extra air-sealing efforts, it may be necessary to provide fresh air ventilation to avoid build-
up of stale air and indoor air pollutants. Special air-to-air heat exchanger's, or heat- recovery ventilators, are available for this
purpose.
3. Stop Air Leaks. It is very important to seal up all air-leakage paths between your living spaces and other parts of your building
structure. Measurements have shown that air leaking into walls and attics carries significant amounts of moisture. Remember that if
any air is leaking through electrical outlets or around plumbing connections into your wall cavities, moisture is carried along the
same path. The same holds true for air moving through any leaks between your home and the attic, crawlspace, or garage. Even
very small leaks in duct work can carry large amounts of moisture, because the airflow in your ducts is much greater than other
airflows in your home. This is especially a problem if your ducts travel through a crawlspace or attic, so be sure to seal these ducts
properly (and keep them sealed!). Return ducts are even more likely to be leaky, because they often involve joints between drywall
and ductwork that may be poorly sealed, or even not sealed at all.
4. Plan a moisture escape path. Typical attic ventilation arrangements are one example of a planned escape path for moisture that
has traveled from your home's interior into the attic space. Cold air almost always contains less water than hot air, so diffusion
usually carries moisture from a warm place to a cold place. You can let moisture escape from a wall cavity to the dry outdoors
during the winter, or to the dry indoors during the summer, by avoiding the use of vinyl wall coverings or low-perm paint. You can
also use a dehumidifier to reduce moisture levels in your home, but it will increase your energy use and you must be sure to keep it
clean to avoid mold growth. If you use a humidifier for comfort during the winter months, be sure that there are no closed-off rooms
where the humidity level is too high.
Insulation Installation in your Home, the Retrofit Challenges
Whether you install the insulation yourself or have it done by a contractor, it is a good idea to educate yourself about proper
installation methods because an improper installation can reduce your energy savings.
Also, if your house is very old, you may want to have an electrician check to see if:
- the electrical insulation on your wiring is degraded,
- the wires are overloaded, or
- knob and tube wiring was used (often found in homes built before 1940).
around the wires because that could cause the wires to overheat. THIS IS FOR FIRE SAFETY. The National Electric Code forbids
the installation of loose, rolled, or foam-in-place insulation around knob and tube wiring.
Adding thermal insulation to the ceiling or walls of a mobile home is complex and usually requires installation by specialists.
If adding insulation over existing insulation, do NOT use a vapor barrier between the two layers!
Attics
On unfinished attic floors, work from the perimeter toward the attic door. Be careful about where you step in the attic. Walk only on
the joists so that you won't fall through the drywall ceiling. You may need to place walking boards across the tops of the joists to
make the job easier. Remember that it is important to seal up air leaks between your living space and the attic before adding
insulation in your attic.
Installing batts and rolls in attics is fairly easy, but doing it right is very important. Use unfaced batts, especially if re insulating over
existing insulation. If there is not any insulation in your attic, fit the insulation between the joists. If the existing insulation is near or
above the top of the joists, it is a good idea to place the new batts perpendicular to the old ones because that will help to cover the
tops of the joists themselves and reduce thermal bridging through the frame. Also, be sure to insulate the trap or access door.
Although the area of the door is small, an uninsulated attic door will reduce energy savings substantially.
In some Houston houses, it is easier to get complete coverage of the attic floor with blown-in loose-fill insulation. It is best to hire
an insulation contractor for this job. Loose-fill insulation must be prevented from shifting into vents or from contacting heat-
producing equipment (such as recessed lighting fixtures). Block off those areas with baffles or retainers to hold the loose-fill
insulation in place.
When you stack new insulation on top of existing attic insulation, the existing insulation is compressed a small amount. This will
slightly decrease the R-value of the existing insulation. This effect is most important if the new insulation is more dense than the
old insulation. You can compensate for this stacking effect and achieve the desired total R-value by adding about one extra inch of
insulation if the old insulation is fiber glass, or about 1/2 inch if the old insulation is rock wool or cellulose.
Reflective Systems are installed in a manner similar to placing batts and blankets. Proper installation is very important if the
insulation is to be effective. Study and follow the manufacturer's instructions. Often, reflective insulation materials have flanges that
are to be stapled to joists. Since reflective foil will conduct electricity, avoid making contact with any bare electrical wiring.
Radiant barriers may be installed in attics in several configurations. The radiant barrier is most often attached near the roof, to the
bottom surface of the attic truss chords or to the rafter framing. Do not lay a radiant barrier on top of your insulation or on the attic
floor because it will soon be covered with dust and will not work.
If your attic has NO insulation, you may decide to insulate the underside of the roof instead of the attic floor. (This option is more
often used in new houses and is described in Design Option: ATTIC VENTILATION OR A CATHEDRALIZED ATTIC). If you
choose the cathedralized attic approach, all attic vents must be sealed. Spray-foam is then often used to insulate the underside of
the roof sheathing. If batts are used for this purpose, they must be secured in a manner similar to that described below for
insulating under floors. It is best to hire an insulation contractor with experience in this type of installation for this job.
Walls
Installing insulation in the cavity of exterior walls is difficult. However, when new siding is to be installed, it is a good idea to
consider adding thermal insulation under the new siding. The Retrofit Best Practices Guide provides useful information about
adding insulation when you remodel the outside of your house. It usually requires the services of a contractor who has special
equipment for blowing loose-fill insulation into the cavity through small holes cut through the sidewall, which later are closed.
It is sometimes feasible to install rigid insulation on the outdoor side of masonry sidewalls such as concrete block or poured
concrete. However, if that is not an option, you can use rigid insulation boards or batts to insulate the interior of masonry walls. To
install boards, wood furring strips should be fastened to the wall first. These strips provide a nailing base for attaching interior
finishes over the insulation. Fire safety codes require that a gypsum board finish, at least 1/2 inch thick, be placed over plastic
foam insulation. The gypsum board must be attached to the wood furring strips or underlying masonry using nails or screws.
The first-floor band joist may be accessible from the basement or crawlspace.
Floors and Crawl Spaces
If you have a floor over a crawlspace, you can either:
Insulate the underside of the floor and ventilate the crawlspace, or Leave the floor uninsulated and insulate the walls of an
unventilated crawlspace. When batts or rolls are used on the underside of a floor above an unheated crawlspace or basement, fit
the insulation between the beams or joists and push it up against the floor overhead as securely as possible without excessive
compaction of the insulation. The insulation can be held in place, either by tacking chicken wire (poultry netting) to the edges of
the joist, or with snap-in wire holders. Batts and rolls must be cut and fit around cross-bracing between floor joists or any other
obstructions. Strips of insulation may be cut off and stuffed into tight spaces by hand. Don't forget to place insulation against the
perimeter that rests on the sill plate. If you insulate above an unheated crawlspace or basement, you will also need to insulate any
ducts or pipes running through this space. Otherwise, pipes could freeze and burst during cold weather.
Reflective Systems are installed in a manner similar to placing batts. Proper installation is very important if the insulation is to be
effective. Study and follow the manufacturer's instructions. Often, reflective insulation materials have flanges that are to be stapled
to floor joists. Since reflective foil will conduct electricity, one must avoid making contact with any bare electrical wiring.
Spray-foam can be used to insulate the underside of a floor. The spray foam can do a good job of filling in the space around wires
and other obstructions and in filling any oddly-shaped areas. It is best to hire an insulation contractor with experience in this type of
installation.
When a fiberglass blanket is used to insulate the walls of an unventilated crawlspace, it is sometimes necessary to attach wood
furring strips to the walls by nailing or bonding. The insulation can then be stapled or tacked into place. Alternatively, the insulation
can be fastened to the sill plate and draped down the wall. You should continue the insulation over the floor of the crawl space for
about two feet on top of the required ground vapor retarder. Because the insulation will be exposed, be sure to use either an
unfaced product or one with the appropriate flame spread rating. When rigid foam insulation boards are used to insulate the walls
of an unventilated crawlspace, they can be bonded to the wall using recommended adhesives. Because the insulation will be
exposed, be sure to check the local fire codes and the flame-spread rating of the insulation product. If you live in an area prone to
termite damage, check with a pest control professional to see if you need to provide for termite inspections
If you are concerned are need assistance with any of the above issues - now is the time to contact Robert at ATEX Inspects, your
professional Houston Home Inspector at 281-216-1171.
New Home Construction Phased Inspections:
Residential Home (Buyers) Inspections:
Four (4) Point Insurance Inspection:
Commercial Property Inspections Services:
| General Insulation Tips To Help You Save Money With Energy Cost In Your Houston Home Or Commercial Real Estate |
| A Houston Texas licensed and certified home, building & commercial inspection company that builds customer trust through detailed, thorough and dependable inspection services. |