by Carey, James
Cellulose: Cellulose insulation is an organic, loose-fill material made from recycled paper chemically treated to resist moisture and pests. Moisture absorption can make cellulose heavier, causing it to pack down and lose its insulative value.
If you have cellulose insulation in your walls or ceilings, the insulative value has probably diminished substantially since it was first installed. When loose-fill insulation compacts in walls, it should be vacuumed out so that fresh insulation can be added. Cellulose in the attic can be left in place and simply covered with new insulation.
Many insulation materials can irritate your skin and lungs, so whenever you work with any type of insulation, be sure to use gloves, a fabric mask, protective clothing, goggles, and a hat to reduce exposure. In addition, some insulation is manufactured with formaldehyde — when buying insulation, check to ensure that the insulation you choose does not contain this nasty chemical.
Understanding R values
Insulation value is measured using what is known as R value. The higher the R number, the better the insulative value. R values vary widely between climate zones. Whereas an R value of 11 (R-11) may be recommended for your floor, your walls may need R-13, and your attic may need R-38.
Over the years, insulation requirements in homes have changed. R-19 was once sufficient for use in attics. Today, in moderate climates, R-30 is required. In extreme climates, R-60 may be necessary.
Check with the building department in your area to determine the correct R-value for each area of your home.
Adding insulation all over your house
We had been away from home for over three weeks. Before we left, we shut down all the mechanical systems — the water heater, air conditioner, and so on. The day we returned, the temperature was 104 degrees. But when we walked in the front door, we discovered that that house was cool and comfortable. We turned to each, making the same comment at the same time: “Good insulation.”
When it’s done well, nothing keeps on working — for free — like insulation. In this section, we walk you through all the parts of your home that should be insulated and tell you how to fill in the gaps.
Where to start: The attic
When you’ve got a problem with your insulation, the attic is the first place you should look. Believe it or not, most heat is lost through the ceiling — 60 percent or more. Properly maintained insulation can significantly reduce this heat loss.
The nice thing about attic insulation is that it doesn’t have to be glued, nailed, stapled, or otherwise held in place. All it does is lay there.
So if all it does is lay there, why would you ever need to do anything with insulation after it’s installed? Powerful air currents are created in your attic as air enters through eave vents and exits through higher vents. Natural air currents can actually move loose-fill insulation as if it’s being swept by a broom, resulting in piles of insulation in some areas and none in others. If you have loose-fill insulation, check to see if the insulation in your attic has shifted; if it has, you can use a plastic lawn rake to gently move the insulation from high spots onto the bald areas.
Notice that we said a plastic rake. With electrical wires present in the attic, you don’t want to use a metal rake.
You also can use a piece of batt insulation to fill a gap or a hole. Hey, it would save raking, and it can’t be easily blown out of place again. Just measure the approximate area to be filled, use a razor knife or a pair of scissors to cut pieces of batt insulation to the approximate length required, and lay the material in place.
If your insulation appears to be in good shape, but you still feel a chill, you may need to add more. Check with your local public utility or your local building department for advice on what to do.
Whether you’re filling holes or adding more, be sure to keep attic insulation clear of light fixtures. Light boxes covered with insulation can overheat and result in a fire. And don’t plug your attic vents. An attic must be able to breathe; otherwise, hot air trapped in the attic can convert even the best-insulated home into a sweatbox on a hot summer day. Plus, a buildup of humidity can occur, which, over a long period of time, can result in wood rot, mildew, mold, and fungus growth.
If you have traditional wood-framed skylights in your home, then you have skylight chases. A skylight chase is the walled area that immediately surrounds the skylight between the roof and the ceiling — it’s a vertical tunnel that runs through your attic from the ceiling to the roof. Skylight chases should also be insulated.
The walls
If mildew is growing on the inside surface of your exterior walls or if your exterior walls are sweating (you see excessive condensation), it may mean that there is no wall insulation or that the insulation has settled and is no longer effective. In either case, you need to add insulation.
Adding insulation to a wall is a bit more difficult than adding it to an attic (see the preceding section) because in a wall, the insulation is hidden between the interior and exterior wallcoverings. Removing the wallcovering to insulate the wall cavity just isn’t cost effective. It’s cheaper and easier to create small penetrations in the wall so that the insulation can be blown in. For that reason, blown insulation is usually the preferred choice when you have to re-insulate a completed wall.
Insulating a completed wall is easy. You need an insulation blower (kind of like a giant tank-type vacuum cleaner that blows instead of sucks). You can rent insulation blowers, but some stores provide the machine at no charge when you purchase your insulation from them. In addition to an insulation blower, you need these tools and materials:
A stud finder
An electric drill
A hole saw (slightly larger in diameter than the tip of the insulation blower)
Blue masking tape (which is easier to remove than the regular kind of masking tape)
Several bags of blown insulation
Should you blow the insulation in through the inside or outside walls of your home? It depends. Attacking the project from the interior is a bit messier but also less expensive. Plus, a perfect repair normally can’t be made to the exterior wallcovering — regardless of type. However, if some portions of the interior side of the wall are covered with tile or other expensive finish, your next best bet is insulating from the outside.
Follow these steps to blow in insulation:
1. Use the stud finder to locate each stud and any horizontal blocks that exist at or near the center of the wall’s height; then mark each stud center and horizontal blocks with a piece of blue masking tape.
Some homes have a horizontal block midway between the top and bottom of a wall cavity. Some have a diagonal row of blocks. Others have none.
2. Use the drill and hole saw to make a penetration (on center between each pair of studs) into the top of the cavity approximately 6 inches below the ceiling.
Because studs are spaced every 16 inches or so, penetrations to add insulation must be made at the same intervals, filling one cavity at a time.
Save the discs of wall-covering material removed by the hole saw. When the project is complete, you (or a wallboard contractor) can use them to quickly patch the holes.
3. If the wall has horizontal or diagonal blocking, make an additional (second) penetration (on center between each pair of studs) an inch or so beneath the block.
4. If you find old compacted insulation within the wall, remove it with a vacuum.
5. Blow in the new insulation.
6. Repair the holes and clean up the mess.
Consider hiring a wallboard contractor to repair the holes. In an average home, they can be repaired for a few hundred dollars, and you’ll never be able to tell that the holes were there.
The floor
An insulated floor substantially reduces the loss of heat (thank you, energy gods), helps to eliminate mildew- and rot-causing condensation, and generally helps to keep your tootsies warm when you go barefoot through the kitchen. If you have hardwood floors, you should be especially int
erested in maintaining your floor insulation because lack of floor insulation can cause planks of hardwood flooring to twist, buckle, and curl.
Periodically (at least once a year), crawl beneath your home with a flashlight to check the condition of the floor insulation in your basement or sub-area to ensure that it’s properly positioned. Here, sagging is the biggest problem.
Floor insulation is normally held in place with netting or bailing wire attached from one joist-bottom to another. If the insulation netting sags, you need to reattach it or replace it:
To reattach insulation netting, you can use nails or staples. Nails hold better but are hard to drive in tight spots. Staples are easier to install, but you may need to buy a tool (a construction-grade staple gun — known as a hammer tacker, which you can find at your local hardware store or home center). If the paper has become brittle and tears, staple or nail directly through the insulation.
To replace insulation netting, lightning rods (named for their speedy installation) are a handy alternative to netting or bailing wire. These lightweight, flexible steel rods hold the insulation in place by spring tension. Just place one end of the rod against the side of a floor joist and bend it slightly so that the other end is forced into place against the face of the opposite joist (see Figure 6-1). Use one hand to hold up the insulation and the other hand to whip the lightning rod into place. Lightning rods are available at hardware stores and home centers.
Figure 6-1: Lightning rods are a great alternative to traditional insulation netting, but both do the job.
Pipes
Putting insulation around all accessible water pipes (see Figure 6-2) saves energy, prevents freezing during most moderate to medium chills, and reduces condensation when pipes flow through attics and crawlspaces. It’s also cheap insurance. A pipe that bursts in the crawlspace is no joy to experience or repair, but it’s bearable. A pipe that bursts in the attic is an altogether different story. We know. Years ago, long before we were old enough to spell contractor (let alone be one) a pipe in our attic burst. What a mess!
Figure 6-2: Insulate your pipes to prevent them from bursting in cold weather.
Be sure that the tape that holds the insulation in place and the insulation itself are in good shape. If either the insulation or the tape crumbles to the touch, replace it. You can remove crumbling insulation with nothing more than a gentle tug. With the insulation removed, all you have to do is slip a new piece in place.
If you live in an area where temperatures frequently reach below freezing, and you’ve installed pipe heaters (wire or tape), don’t insulate these pipes without first getting the approval of the company that manufactures the pipe heaters. By the way, pipe heaters also deteriorate. If you see signs of deterioration or fraying, it may be time for replacement.
Heat ducts
As with other kinds of insulation, the material that surrounds your heat ducts reduces energy costs while improving the effectiveness of your central heating and cooling system. It also helps prevent unwanted condensation in attics and crawlspaces, thereby reducing the chance for mold, mildew, and the foul odors associated with them.
Reattaching and adjusting insulation
Insulation is wrapped around and around the duct in a corkscrew fashion (see Figure 6-3). Air currents, rodents, house movement, and vibration in the heating system can cause the insulation to loosen and fall away from the ducting. Reattaching or adjusting the insulation to cover the ducting is a good thing. While you’re there, add an extra layer — it couldn’t hurt.
You can “stitch” a nail into insulation to hold it together. You do this in the same way that a seamstress uses a sewing pin to hold two pieces of fabric together.
Figure 6-3: Heat-duct insulation keeps your energy costs low.
A thin layer of plastic, which acts as a vapor barrier, surrounds modern insulated ducts and prevents moisture from attacking the insulation and the ducting. If rodents or sloppy workers damage the thin plastic vapor barrier, use plastic sheeting (any kind) and metal tape to fix the barrier.
Metal tape looks like duct tape, except it’s shiny and won’t rot in moist areas where duct tape can. Actually, for small tears, just tape over the damaged area in the same way that you’d cover a cut with a Band-Aid. For areas of larger damage, use a piece of plastic as a patch held in place with metal tape. Make sure the tape seals all four sides of the patch.
Performing a duct leak test
Those same workers, house shifts, and pesky rodents also can cause duct damage that creates air leaks. This condition can result in major heat or cooling loss and can substantially increase your energy bill. Therefore, checking for duct leaks can pay off big time. Because most ducting is covered with insulation, leaks can be hard to find.
Here are a few signs that may indicate a leak:
Ducting that is crushed or badly bent
Insulation that has darkened
An area around the ducting that is warmer than normal in the winter or cooler than normal in the summer
If none of these conditions exist and you aren’t happy with your energy bill, hire a home-comfort specialist — a heating contractor — to perform a duct leak test. He’ll cap off all register outlets and pressurize the duct system. If pressure loss occurs, the contractor will search out the leak using smoke and then repair it.
Controlling air leaks in your ceilings, walls, and floors
There’s more to the energy envelope than maintaining insulation. You also need to perform another maintenance step, known as infiltration control (controlling air leaks through penetrations in ceilings, walls, and floors). No matter how much insulation you have in your home, if major air leaks exist, your insulation won’t work effectively.
Locating leaks
Unwanted air can leak into your home from all sorts of places: at weather stripping, door and window frames, attic and sub-area plumbing and electrical pen-etrations, heat registers, yes, and even electrical switches and receptacles. Infiltration also occurs where pipes and wires in walls penetrate into the attic or sub-area.
Here are tips for finding leaks in different areas of your home:
In an attic or crawlspace: Finding a penetration in an attic or crawlspace isn’t terribly difficult when it comes to plumbing pipes, flues and ventilation, and heating ducts. Just check the point where a pipe or duct penetrates the ceiling or floor and look for gaps.
Around wiring: Finding penetrations around wiring — especially in an insulated area — is a challenge. Short of removing the insulation, you can’t see where penetrations exist because the wiring normally doesn’t stick up beyond the insulation like a pipe or a flue does. Therefore, you have to search through insulation until you find a point where a wire travels down through the top of a wall.
In walls, ceilings, and floors: The amount of infiltration from walls, ceilings, and floors is simply amazing. Fortunately, you can easily locate these leaks in the myriad of places that they occur: around light switches, electric plugs, drain and water pipes, heat registers, thermostats, wall and ceiling light fixtures, smoke and carbon monoxide detectors, floor plugs, door bell chimes, doors, and windows. Just light a smoky incense stick — if leaks exist near the stick, the smoke flickers.
Around windows and doors: When it comes to leaks, doors and windows are major culprits. Even the slightest amount of house shift can cause a previously well-maintained and properly adjusted door or window to leak like a sieve. Check the weatherstripping on doors and windows twice each year: once during mid-spring when the soil around the house dries out and begins to shrink and the house begins to shift, and again during mid-winter when the soil around the house swells from moisture retention and the house begins to shift. Here’s an easy way to check for air leaks at the bottom of a door. At night, and from the outside of the door, point a flashlight toward the bottom of the door. If light can be seen from inside, an adjustment is needed.
Stopping infiltration
In the days when we were the maintenanc
e men aboard the ark, we filled small cracks (no wider than 1/4 inch) with caulking. For larger openings, we stuffed insulation or steel wool into the gaps. For the largest and most gaping of holes, we used tin plates or wood covers.
Today, things have changed. Expanding polyurethane spray foam in a can is now available. No more time-consuming tin-plate installations or replacing insulation or steel wool that has fallen out. Simply spray a little expanding foam into the gap, and it immediately expands to permanently seal the hole (see Figure 6-4). Home maintenance in a can. What a country!