The Department of Energy developed an excellent graphic of exactly where you should insulate your house. [1] the attic space that are unfinished—insulate between floor joists or insulate the rafters if you intend to use the space; [1A] any door that accesses the attic should get insulation; [2] unfinished rooms in the attic whether or not there is a dormer; [2A] knee wall studs get insulation; [2B] all exterior walls in the attic; [2C] if you have ceilings in the attic with cold spaces overhead, insulate the ceilings; [2D] cut air flows in the attic where possible by extending insulation into all joist spaces; [3] around the house, all exterior walls; [3A] seal those space between living areas and garages; [3B] insulate foundation walls to block the cold; [4] all floors above cold spaces such as crawl spaces; [4A] if a space is catilevered beyond the exterior wall where it is exposed to weather conditions in the floor; [4B] all slab floors built on the ground; [4D] block cold air by insulating all joists; [5] insulate band joists; [6] block heat loss from windows by adding storm windows and block air flow with caulking for all windows and doors. These are the recommendations of the Oak Ridge National Laboratories in Oak Ridge, Tennessee

The Department of Energy developed an excellent graphic of exactly where you should insulate your house. [1] the attic space that are unfinished—insulate between floor joists or insulate the rafters if you intend to use the space; [1A] any door that accesses the attic should get insulation; [2] unfinished rooms in the attic whether or not there is a dormer; [2A] knee wall studs get insulation; [2B] all exterior walls in the attic; [2C] if you have ceilings in the attic with cold spaces overhead, insulate the ceilings; [2D] cut air flows in the attic where possible by extending insulation into all joist spaces; [3] around the house, all exterior walls; [3A] seal those space between living areas and garages; [3B] insulate foundation walls to block the cold; [4] all floors above cold spaces such as crawl spaces; [4A] if a space is cantilevered beyond the exterior wall where it is exposed to weather conditions in the floor; [4B] all slab floors built on the ground; [4D] block cold air by insulating all joists; [5] insulate band joists; [6] block heat loss from windows by adding storm windows and block air flow with caulking for all windows and doors;

Weather Barriers
Insulation is a key ingredient to big energy and dollar savings in the home. If no insulation now acts as a weather barrier in the unit, then the addition of even a little will dramatically reduce fuel bills. In homes which contain some, the addition of more insulation will result in a substantial savings.
In all likelihood the house you live in or are about to buy needs more insulation if it is a few years old. If you spot a house during snow season and the roof is clean, beware of those heating bills because the heat is going out through the top of the house. The insulation is not effective: heat is rising right through the attic roof and melting the snow.
The National Bureau of Standards (NBS) reported that 40 percent of the energy (and dollars) consumed in home heating and cooling are wasted. Inadequate insulation is the major culprit. Most homes, even today, lack sufficient insulation because energy conservation has never been a top priority for the government, the building industry, or the homeowner.

Before 1940 no insulation was required by major building codes. Until recently, the Minimum Property Standards (MPS) of the Federal Housing Administration (FHA) required only l1/2 inches of insulation in the attic, the most important area in the home for insulation.

Federal codes have been updated so that today 6 inches of attic insulation are required. An estimate by the NBS indicated that by investing in those 6 inches a person living in a relatively mild climate who has no attic insula­ tion can get all of his or her money back in one heating season in saved energy bills. This, of course, is only a minimum. In extreme climates, 12 inches of attic insula­ tion should be installed.

Investing in insulation pays for itself heating season after heating season. A homeowner who invests in the minimum 6 inches, spending between $100 and $200, will save about $100 to $200 the first year. But over the next ten heating seasons the savings will mount to be­ tween $1,000 and $2,000-the price of a grand vacation or the downpayment on a new car.

And this comes only from adding insulation inthe at­ tic. Greater savings can obviously be obtained from add­ ing insulation to the walls and floor. For maximum dollar savings on heating and cooling bills, the entire roof, wall and floor area exposed to outside temperatures and weather conditions should be insulated. You should use weather barriers to protect you·r entire house. Just as an insulated jug is used to keep hot drinks hot, and cold drinks cold, so your house must reach for this type of efficiency.

There is a great deal of stress today to add insulation· in accordance with the climate in which you live. To be on the safe side, add as much insulation as you can to your house. There is a good reason for this. Recent inter­ views with government energy officials and building industry research people reveal that home energy costs will rise between 10 percent and 12 percent a year, well into future years. This means that if you currently pay $800 a year for energy, in ten years you could be paying at least $1,600. Add inflation to this and you could well be pay­ ing $2,000 a year to heat and cool your home. Investment in adequate insulation today will reap rewards for years to come.

Energy awareness can resuIt in secondary benefits as well: financial columnists and consumer groups are now urging people to check energy bills as standard operating procedure when buying a home. If your energy bills are outlandishly high, you may have to cut the price of the house. So plan ahead for the sake of your home’s resale value.


Not only do you save on lower bills, but the federal gov­ ernment has added an extra incentive! Pending federal legislation provides the homeowner with a tax credit of 30 percent of the first $750 of insulation expenses, up to
$225. This credit is not a “tax deductible expense” that you take off the short or long form-it is an amount that can be directly subtracted from the total tax amount you owe, at the bottom line. In effect, money in the bank!

All materials conduct at least some heat. Silver, copper and similar metals conduct heat rapidly and are, there­ fore, classified as “heat conductors.” Wood and other fibrous materials conduct heat more slowly and are con­ sidered “heat insulators.’ Materials used in building insulation are of course heat insulators, but they have other characteristics as well: they are fireproof, vermin proof and moisture-resistant.

The very best insulator we have available is air. Building insulation uses “trapped air” to achieve an ef­ fective heat barrier. In standard building insulation, air is trapped between miIlions of tiny fibers packed to a proper density. Proper density is the key: material packed too loosely will allow air to circulate and be dissipated by convection (convection is the transfer of heat through fluids). Material packed too tightly will allow heat loss by conduction (conduction is the transfer of heat through solids).
Besides greater energy and dollar savings achieved by adequate insulation, the material works in other ways to keep all of us more comfortable. During the winter, an uninsulated wall facing onto the exterior can be between eight degrees and fifteen degrees cooler than an insulated wall. By placing your hand on such a wall you can actu­ ally feel the cold. Through radiation all warm bodies lose heat to cooler bodies. This means the occupants sitting in a room with uninsulated exterior walls will actually lose heat to these walls even though the room temperature is 70 degrees. This phenomenon is known as the “cold wall effect,” and occupants will turn the thermostat higher to feel comfortable. People sitting in a room with insulated walls will feel more comfortable with the same thermo­ stat setting of 70 degrees.

The opposite occurs inthe summer. Even though you may have the air conditioner runningfull blast, occupants in a room with uninsulated walls will absorb heat from the walls and possibly turn the thermostat lower to feel comfortable.

Besides causing discomfort, juggling the thermostat up and down can greatly add to fuel bills. If you can keep your thermostat three degrees lower in winter and three degrees higher in summer, you can save at least 5 percent on your annual fuel bill.

Another function of insulation is to keep the entire room at about the same temperature. In an uninsulated room, heated air near a cold wall will cool off and move to the floor while hot air will rise to take its place. This continuous circulation of air causes drafts. A room with well-insulated walls will, obviously, have fewer drafts.

Insulation Placement

As mentioned above, insulation must be placed in every area of the home which is exposed to the exterior. Ali lo­ cations which will reduce heat loss in the winter will pre­ vent heat gain in the summer as well. No insulation is needed between two rooms within the house so long as both are kept at about the same temperature. The only time insulation is needed between two interior walls is when one room is left unheated or is only heated in­ frequently.

Here are specific areas which require insulation

o Exterior walls-all exterior walls; sometimes over­ looked are walls between the living space and un­ heated garages or storage areas.
o Ceilings-facing on cold spaces above.
o Knee walls-when attic isfinished as a livingarea.
o Around perimeter of slab- if house is slab-on­ grade.
o Floors-facing on cold spaces such as over ga­ rages, crawl spaces or porches when house is can­ tilevered.
o Basement walls-when area is heated or used as living space. When basement is unheated, the floor over the basement should be insulated.

“R” Value

To compare apples with apples, all insulation is given an “R” value or “Resistance to Heat Flow” value. All insula­ tion commercially available will be marked with an “R” o value. On a typical insulation package, you will either see an R-6, R-11, R-19 and so on. This R value is given for a certain thickness of material or the way in which it is used. The higher the R value, the better insulator it will be.

Never underestimate the real value of insulation. It is often heard that an 8-inch concrete block wall, typically found in basements, does not need insulation because the blocks are insulation enough. The fact is, it would take a wall four concrete blocks thick to provide the same weather barrier obtainable with just one inch of properly applied mineral wool insulation. A typical wall hasabout3 Y2 inches of mineral wool insulation; now calculate how many con­ creteblocksyou would needtoobtain that insulatingvalue.
Buying Insulation

Today, typical insulation for the home is made from min­ eral fiber in batts or blankets, mineral fiber loose fills (these are either pneumatically installed by machine or spread by hand), cellulosic loose fills (machine-applied), foamed plastics (usually but not always in board form) and aluminum foil sheets.

Mineral Fiber. This has been on the market for a long time and is one of the oldest forms of modern insulation. Originally manufactured by melting down slag as a by­ product of steel production, this material today is made of either rock wool or fiberglass. The materials are melted down and extruded as fibers. These fibers are joined to­ gether and with air trapped between fibers it makes an excellent and versatile insulating material.

Always use gloves and old clothes (which can be discarded later) when pushing and shoving this material into place. Some of the fibers break off and become air­ borne. For this reason, always wear a respirator when ap­ plyingthe material. A simple respirator can beobtained at local hardware outlets for under $3.

Cel/ulosic Fiber. Made from wood pulp. Although wood itself is not fire resistant, this material has been treated so that it is both fire and moisture resistant. Unlike mineral fiber, this insulation can be handled without in­ jury to the skin but inhaling any type of insulation mate­ rial should always be avoided.

Foamed Plastics. Includes substances such as poly­ urethane, polystyrene or urea formaldehyde. Some of these substances are used as packaging materials. For building insulation, they come in rigid boards which can be easily cut with a knife and put in place. These materials are usually more efficient per inch of thickness than fi­ brous insulation. Polystyrene for example has an R value of 4 per inch and polyurethane is 6 per inch. The mate­ rials are often used where space is at a premiumsuch as in a refrigerator or freezer wall. Although fireproof, in a very hot fire these materials melt and give off a thick, toxic smoke. These materials should never be used as a finished surface for a room in a living space. They must always be covered with at least 1h inch of gypsum wallboard to assure fire and smoke safety.

Expanded Mineral Materials. These are loose fills usually blown or poured into place. Popular fills include both vermiculite and perlite.
Refer to the following table for various R values of different insulation, according to thickness.

What Insulation for Where

Insulation not only comes in a variety of materials, but these materials are used in different forms. Certain forms of insulation are more effective in certain areas of your home.

Batts. These sheets are of matted glass fiber or rock fiber insu1ation, and are used in the floors of unfinished attics, unfinished attic rafters and the underside of floors. This insulation is best suited for standard joist or rafter spaces either 16 inches or 24 inches o.c. (on center). And it usually comes in sections 15 inches to 23 inches wide, 1 inch to 7 inches thick and 4 feet to 8 feet long. It is available with or without a vapor barrier (see section in this chapter on vapor barriers), depending on your needs. This material is relatively easy to handle because of its size, and excellent for areas where you can lay insulation in place. There is usually more waste in trimming batts to fit areas than with blankets.

Blankets. Available in glass fiber or rock wool, as above, and can be used in an unfinished attic floor, un­ finished attic rafters, the undersides of floors, and in ex­ terior walls. Standard rolls are 15 inches to 23 inches wide, 1 inch to 7 inches thick, and come in a variety of lengths. They come with or without vapor barriers. There is usually less waste with blankets than batts, but the ma­ terial is more difficult to handle because the rolls are much longer than are batts.

Foamed in Place. Insulation is usually urea formal­ dehyde and can be used in unfinished attic floors and in finished frame walls. This form of insulation has a higher R value per inch thickness than the above-mentioned types, but it must be contractor-installed, and so is more expensive. A shoddy job is possible unless you hire a qualified contractor.

Rigid Board. Made of extruded polystyrene bead board, urethane board or fiberglass. Extruded polystyrene and urethane are vapor resistant, but bead board and glass fiber are not. All these materials come inthicknesses from % inch to 4 inches and in widths from 24 inches to 48 inches. Materials can be used to insulate basement walls in existing homes. They have a high R value and are easy to install but must be covered with wall boards (be­ cause of the smoke danger). If you cannot install the wallboard yourself, hire a contractor- it will push the cost up, but installation of the wall boards is mandatory.

Loose Fill. Comes in several materials that include glass fiber, mineral wool,cellulosic fiber, vermiculite and perlite. Cellulosic fiber has about 30 percent more in­ sulating value than rock wool for the same installed thickness, but may break down in a hot attic (see Chapter . 4 to avoid a hot attic). You can pour it yourself on un­ finished attic floors; it is especially suitable where joist spacing is irregular or where there are many obstructions. Loose fill can also be blown into finished walls and attics which have no insulation. This is an excellent choice for hard-to-get-to places. A reliable contractor must be used because if the spaces are nottotally fi!led, you wiIInot get the insulating value you desire.
… How Much Insulation?

You can select the amount of insulation on the basis of climate, fuel cost, and type of heating system. The ac­ companying maps and tables can give you a rough esti­ mate. In some parts of the country, where higher priced fuels are used, R-38 insulation in the attic is recom­ mended for best results.


Assume your house is guilty of inadequate insulation until proven otherwise. The first place to check is your attic.


They come in every shape and every stage of completion. Your attic may be completely finished, or it may be un­ finished to the point where roof rafters are showing and no floor boards are in place. Regardless of the stage of completion, it must be insulated. But you must make a decision. If your attic is unfinished, and you plan to keep it that way, you can insulate between the floor joists. If, however, you intend to convert your attic to a living space (see chapter 8 for details), you should insulate the roof raf­ ters and sidewal Is and dormers (if you have them) instead. If you’re not sure, opt to insulate the attic floor. This is a smaller area and will be less expensive and easier.

An unfinished attic, obviously, is the easiest place to check the insulation-either it’s there or it’s not; either there’s enough or theFe’s not enough. If “some” insula­ tion is apparent, take a ruler and measure its thickness. Then look at the table on p. 12 to estimate the R-value of your attic insulation. If it is less than R-18, some additional insulation should be added.
In finished or semi-finished attics, the search may be a bit more difficult. There are two areas your insulation could be: either in roof rafter, end walls and dormers, or under the floor boards.

If the attic is finished, insulation has been installed in the roof rafters, end walls and dormers. Usually in a finished attic, closets might be unfinished.This might be a good place to check the quality of insulation. If closets are finished, you will probably have to remove a portion of wall board or paneling to determine if insulation is behind it. If there are electrical outlets in the attic, you might be able to remove the switch plate and shine a flashlight in to determine the amount of insulation. (Always turn electrical power off before removing switch plate.) In anyevent, the roof rafters, side walls and dormers must bechecked separately.

If upon investigation there is no insulation in those areas, then check under the floor board. The easiest way is to slip a ruler in between a crack in the floor boards and shine a flashlight in to determine the extent of insulation. The most accurate way to measure the insulation is to re­ move a floor board with a pry bar and measure carefully.


Most homes are constructed with wood frame walls. Here the siding and interior finish are attached to 2 x 4 inch support members called studs, which are either 16 inches or 24 inches o.c. This type of construction is used even in houses which have an exterior brick or stucco finish.

The simplest way to check wall insulation is to turn off the electrical power coming into the house, then re­ move the switch plate. Shine a flashlight into the space and see how much (if any) is there. Another way to check for adequate insulation if you’re in the heating season, is to feel the inside of an exterior wal I. If a wall is adequately
insulated, it should be about room temperature. If not, it
will feel cold to the touch. If your walls feel cold, don’t

despair! Methods will be fully described in a following section for insulating these walls.

Electrical outlets themselves can be a problem with reference to wall insulation. The electrician who installed wiring in your house may have pulled the insulation away from the area where he installed the electrical fixture. This might cause a draft. A quick check of all switches and outlets in your house will pay off in lower heating or cool­ ing bills. If it is a cold day you may be able to feel a distinct draft while standing in front of the outlet without even removing the switch plate! This is easily rectified by re­ moving the plate and stuffing some fibrous insulation around the unit.

·Basements and Underside of House

Regardless of the type of house you have, considerable money can be saved on fuel biIls by insulating the under­ side of your house whether it has a full basement or crawl space.

In an unfinished basement it is easy to determine the amount of insulation. If the area is unfinished and bare masonry walls are showing, you have zero insulation. Now check the basement ceiling. If you don’t see it, you don’t have it. In a heated basement you definitely need insulation in the walls and not in the ceiling. (Remember, to gain the insulation qualities of 1 inch of mineral fiber insulation you would need a masonry wall 4 blocks thick.) In an unheated basement, you do not need insu­ lation in the walls unless you intend to use the area as a living space. You must, however, insulate the ceiling to prevent heat loss.

If the basement is finished, make a careful check of walls to see that insulation is installed. Do this by remov­ ing a portion of the wall finish. Use the switch plate tech­ nique if you don’t want to bother removing a piece of wall. In both finished and unfinished basements you should have at least 1 inch of rigid board insulation in walls or 334 inches of batt or blanket insulation in the ceiling.

Houses without basements will either have a crawl space (opened or closed) or slab-on-grade. Houses with an open crawl space will have insulation (if there is any) between floor joists directly above the space-either batt or blanket. Houses with a closed crawl space will have insulation either in the floor joists or on the sidewalls of the crawl space as in the accompanying illustration

When checking the crawl space you should look for a minimum of 6 inches of insulation. If your house has less than that, add insulation following the directions in the next section of this chapter.

With homes built on a slab, it is impossible to tell if there is insulation under it. But one check you can make is the insulation around the footings. As a minimum, there should be rigid board insulation completely around the perimeter of the house at the footing going into the ground down to the frost line (usually 18 to 24 inches).

But sometimes this insulation is run vertically under the baseboard to the depth of the slab, and then horizontally under the slab for 24 inches or more.

Hot Water Pipes and Heating Ducts

Often ducts and pipes from your heating system pass through uninsulated areas of your home, such as an unin­ sulated crawl space. Inthis situation, the air or water you pay to heat is being dissipated before it enters the living space. To check this, follow the ducts from the furnace. If a duct or pipe passes through an uninsulated area, it should be insulated with material wrapped around it. The same is true for water pipes.

Duct insulation comes generally in blankets 1 or 2 inches thick. Getthe thicker variety, particularly if you’ve got rectangular ducts. For air conditioning ducts make sure you get the kind of insulation that has a vapor barrier. Seal the joints of the insulation tightly with tape to avoid condensation.


Before putting any insulation in the attic, all water leaks must be sealed. Even if the weather is dry when you begin this task you can still discover water leaks. Portions of the roof board, rafters or perhaps the floor immediately adja­ cent to a water leak, will be discolored by the moisture. If the condition has persisted for a while, deterioration of the wood cou Id be apparent In most cases the repair of the leak can be accom­
plished by replacing a few shingles. If numerous leaks are apparent, your entire roof might need replacing. Call in a qualified roofing specialist or repair the roof yourself be­ fore you begin insulating.

As mentioned previously, you must decide on future use of the attic. If the attic is unfinished and you intend to keep it that way, it is cheapest and easiest to insulate the floor. If you intendto finish off the attic into a livingspace, do not insulate the floor, rather insulate the roof rafters, side walls and dormers.


One of the easiest do-it-yourself tasks for a bill-conscious homeowner even if he or she is not especially handy around the house is to insulate the floor of an unfinished attic. To estimate the amount of insulation you will need multiply the length by the width. Then you must adjust this number to allow for the area taken up by floor joists. In your attic, your joists wi 11 be either 16 inches o.c. or 24 inches o.c. If 16 inches o.c., multiply length by width by
.90 to arrive at the number of square feet you need. If 24 inches o.c., multiply length by width by .94 to total.
If you plan to use either blankets or batts, purchase insulation in the width you need plus length enough to satisfy the square footage. If you are going to use loose fi II insulation, the bag will tell you the number of square feet it will cover to achieve a certain R-value.

· Once you know the square footage of insulation needed, estimate the R-value you wish to achieve. For example, if you have 4 inches of mineral wool insulation in the attic floor, by checking the table on p..12 you will quickly see that you have a value of approximately R-12. If you wish to boostthis to R-30, subtract R-12 from R-30, which equals R-18.Therefore you wil Ineed to add about 6 inches of mineral wool to achieve the value of R-30. It must be remembered,however, that to obtain the proper weather barrier, the insulation must be properly installed. Insulation rated at R-3 could act as a better barrier than poorly installed R-6 insulation.

Installing Vapor Barriers
If no insulation is present in the attic floor,vapor barriers must beadded. As can beseen inthe illustration, a plastic vapor barrier must be stapled on the heated side of the in­ sulation before the insulation is added,unless insulation incorporating a vapor barrier is used. If some insulation is present, a vapor barrier is also probably there, do not add another. Usebattsor blankets or loosefill without a vapor barrier. If your insulation has a vapor barrier, cut holes in it as in the illustration. Failure to do so may cause an accumulation of moisture between the two layers of insulation.

The following illustrations detail the proper way to install insulation in the attic floor. You will need only a few tools to complete this task. These include a sharp knife, a straightedge ruler, measuring tape and a rake (to stuff insulation into tight corners and walk boards).

If the unfinished attic is partially finished with floor boards in place, insulation can be completed by removing several floor boards and stuffing insulation under others.

apart (see illustration). Cut the blanket to fit tightly against the framing at the bottom (see illustration). If more than one piece of blanket or batt is used in the same stud space, butt the ends tightly together.
Because insulation comes in standard lengths to fit cavities either 16 inches or 24 inches o.c., it may be necessary to cut the insulation to fit it into a tighter or an

If you plan to finish your attic and want to insulate for it, install insulation in the rafters and walls. Installing blankets or batts between roof rafters or end walls is ac­ complished in a similar manner to floors. Fit one end of the blanket or batt snugly against the top piece of the framing (as in the illustration) with the vapor barrier fac­ ing into the heated attic space. Working down, staple the flanges to the sides or the faces of the studs about 8 inches

irregular wall space. To do this, cut the insulation about 1
inch wider than the measured space. Staple the flange to one side of the stud wall, then pull the vapor barrier on the other side to its stud and staple, through the barrier.

These walls can also be insulated with unfaced insu­ lation, in which case a separate vapor barrier must be added. Using either 2-mil or thicker polyethylene sheet­ ing, press the material flat against the studs and staple about every 8 inches. Take care when handling material so that it is not punctured. If an accident does occur, tape the tear or puncture with electrical tape.

Insulating a finished attic is a bit more difficult. If youcannot get to the unfinished part of your attic without tear­ ing up either the floors or walls, it might be best to call in an insulating contractor who can blow insulation into the required areas. He will drill relatively small holes in the wall and, using an air compressor, shoot loose fill insula­ tion into the cavities. Although this will cost you consid­ erably more than a do-it-yourself project, contractor­ installed insulation will still eventually pay for itself in lower energy bills.


Sidewalls of a house should be insulated to at least a value of R-11, which means between 3Yi to 4 inches of blanket or batt mineral fiber or loose fill insulation. For new homes or additions, the blankets are probably easiest to install for the do-it-yourselfer. For older homes, the best option is to bring in a qualified insulating contractor and have him fill the walls with one of several loose fill mate rials.
insulation in walls and other cavities because once the material is in, you will not be able to really check the work. Before you sign a contract make sure that it is clearly understood what type of insulation you want in order to achieve a particular R-value. By looking at the table on Page 12 and reading the section on insulation types in this chapter, you can speak knowledgeably to any contractor.
If you select loose fills such as mineral fiber or cel­ lulosic fiber, you can always check the bags to be sure of the R-value and to determine exactly how much insu­ lation the contractor installs in your walls. If you opt for one of the foam insulations, there is really no way to check the quality. When obtaining an estimate for the job, contractors can usually estimate within 5 or 6 bags. If the contractor is a little over or under the figure he esti­ mates, don’t be surprised. There is nothing wrong with asking the contractor to save al I empty bags for a final count.

The one problem with blowing loose fills into a wall. is the vapor barrier. There is no way to blow a vapor bar­ rier into a wall along with the insulation. Yet it is needed. To get around this, two coats of aluminum-in-varnish paint can beapplied to the walls as an effective vapor bar­ rier. Another method is to apply two or more coats of a good alkyd base semigloss paint over the primer coat of aluminum paint on walls. A good washable plastic wallpaper will also act as a substantial vapor barrier. If you have never wallpapered before, you might want to stick with paint; it’s cheaper and simpler.


If the basement is to remain an unheated space used for storage and little else, the cheapest and least time-con­ suming way to insulate is to do the ceiling of the base­ ment. Use either blankets or batts at least 4 to 6 inches thick to achieve an R-value from 12 to 18. The easiest method is to face the vapor barrier up into the house and then place insulation between the joists and secure it by stapling wire mesh to the joists.

If the basement will be used for family entertainment or a home workshop, you must insulate the walls. Before beginning wall insulation, however, you must seal up all leaks. Moisture in the basement is often a tricky problem and can affect insulation. Sometimes it can be stopped by painting the lower portion of the foundation with a waterproofing paint. If the problem is serious, you may have to call in a water-diversion specialist.

For basement walls, use rigid boards or batts or blan­ kets. Boards of 1 or 2 inches will give you adequate insu­ lation or mineral fiber batts or blankets of 3 inches will

serve also. As can be seen in the follow ing i llustration you wi ll need l umber for this operation. To support insulation in place, make a stud wall using 2 x 3 inch members either 16 inches or 24 inches o.c. Hammer a bottom plate to the floor and a top plate to the top of the masonry wall. Then insert 2 x 3s at your specified distance. The i nsu la­
tion can then be fitted between the 2 x 3s and stapled in place.

One area of potential heat loss occurs near the r i m or band joist. A small piece of insulation above the furring and against the sill wi ll i nsu late the band joist.

How to I nsu late Crawl Space

If your home has a craw l space or is located over an un­ heated garage, i nsu l ate the joists as described in the previous section. Another method for insulating an en­ closed crawl space is to lay insulation on the side of the enclosure and across the ground. Starting at the top of the crawl space wall, extend across the earthen area and up the other wall. A plastic vapor barrier shou ld be carefu ll y placed on the ground befor ework is begun. Unless you insulate the crawl space this way, it is important to h.;ive proper ventilation in the crawl space to keep moisture in check. For complete detaiIs see Chapter 4 on ventilation.