Purlin

These pieces of lumber run perpendicular to the roof rafters and are used to support the roof framing.

Corbel

A decorative piece of wood or stone used to support an opening.

Not to be confused with Corbelling, which is the process of laying bricks so they are offset, creating a shaped edge.

Quoin

Corner block on masonry or stucco houses.

And if your house didn’t come with quoin blocks, you can now use the stick-on version!

Reglet

The groove into which counter flashing is inserted on a masonry wall.

Plenum

The space above the furnace through which warm air passes to be distributed to the ductwork.

Cripple Wall

A short framed wall between the foundation and first floor framing.

Weir

The highest point of the bottom of the trap arm (also called the trap weir or the crown weir).

Drip Leg

A short length of pipe extending below the natural gas intake on a furnace. Designed to catch dirt or impurities in the gas before they reach the furnace.

Ufer

A type of grounding system whereby metal rods are incorporated into the footings, rather than having copper pipe or connection to the water supply pipe.

I.       To be assured the inspector is objective in his or her reporting and will not knowingly understate or overstate the significance of reported conditions.

II.      To be assured the inspector’s opinion is based on genuine conviction within the scope of his or her education and experience.

III. To be assured the inspector stays current with the industry’s body of knowledge through continuing education.

IV. To be assured the inspector will not disclose inspection results or client information without client approval.

V. To be assured the inspector has not accepted any form of compensation for recommending contractors, services or products.

VI. To be assured the inspector will not offer to repair or replace for compensation any component covered by the ASHI Standards of Practice for one year after the inspection.

VII. To be assured future referrals to the inspector from real estate agents are not dependent on the inspection findings or the sale of the property.

VIII. To be assured the home inspector has no financial interest in the transaction.

IX. To be assured the inspector is not receiving compensation for the inspection from any other party.

X. To be assured the inspector did not compensate the real estate agent or other party for the referral to the client.

We abide by all of these items, which were set down by the American Society of Home Inspectors (ASHI) as the Gold Standard for Home Inspectors.

The best Home Inspectors have their clients’ best interests at the forefront. Be sure to ask any Home Inspector you are considering if they subscribe to the ASHI Code of Ethics and Standards of Practice. If they’re not, you won’t know if they’re putting someone else’s interests ahead of yours.

Radon is a colorless, odorless gas that is created by the breakdown of Uranium. It is the only gas in the Uranium-238 decay series. The entire breakdown cycle takes billions of years, going from uranium-238 all the way to Lead 206, which is stable.

Radon has a short half-life of only 3.8 days (half-life is defined as the amount of time it takes for half the nuclei in a sample to undergo radioactive decay). It takes billions of years for Uranium 238 to decay in a five-step process into Radon, but only about 23 years for Radon to decay through eight steps into stable Lead. During each of these decay steps, a radioactive particle is emitted, which can lead to cellular damage that can cause cancer.

On average, about six atoms of Radon emerge from every square inch of soil every second. Outside it is diluted rapidly, but if it enters through a basement floor and is trapped in a tight, energy-efficient house, it can reach dangerous concentrations.

This EPA map shows the radon zones for the U.S.

Maryland's Radon Zone Map shows each county's Radon risk level. The red areas have the highest Radon risk.

The big issue about Radon is that it is a gas when we inhale it, but if it decays into solids while it is in our lungs, those solids stay in our lungs for the rest of the decay cycle, emitting alpha, beta and gamma particles.

The radiation emitted by Radon as it decays would be less harmful if it were outside our bodies. The slow moving, heavy Alpha particle is stopped by the first thing it hits, such as our clothing or even the layer of dead skin on the surface of our bodies. But if Radon is inhaled, it emits the particles very close to sensitive internal tissues, and lung tissue is particularly susceptible to ionizing radiation.

Is There a Safe Level?

There really is no “safe” level of Radon, but since it occurs everywhere, the natural free-air outside level is about 0.4 pCi/L (PicoCuries per Liter). The Level of 4.0 pCi/L was established as a number at which the risk associated with radon is approaching other unacceptable levels. This level of exposure is equivalent to an annual radiation exposure of 4 rem. To put this exposure into perspective, the maximum permissible occupational exposure for persons working in radiation-related occupations is 5 rem per year.

When is Remediation Necessary?

Generally, a Radon level of 4 pCi/l is considered “actionable”. The highest level of Radon Bob has seen during his inspections was 44 pCi/l. The highest level ever recorded in a residence was an astonishing 2700 pCi/l (this was revealed when the home’s owner showed up to work at a nuclear power plant, and set off the radiation alarms when he entered the facility). The average Radon level in homes throughout the western world is about 1 pCi/l. As such, 3.99 pCi/L is not ‘safe’ per se, but it is under the EPA’s “threshold,” and below that at which most contingencies kick in.

Inspections by Bob strongly suggests that ALL homes be tested for Radon as part of the Real Estate transaction, and that everyone understand the risks associated with whatever values are returned.  Obviously, we strongly suggest remediation for values above 4.0 pCi/L, but also suggest that ANY level above ambient be thoroughly understood.

Want To Know More?

Read our FAQ about how we perform Radon tests.

Environmental Protection Agency (EPA)

http://www.epa.gov/radon/index.html

Maryland Geological Survey

http://www.mgs.md.gov/esic/brochures/radon.html

This simple tool costs about $10 and will tell me if the outlet is live, whether it is grounded, if the polarity is correct, and will test a Ground Fault Circuit Interrupter (GFCI) as well.

Hot and Neutral wires are reversed (reverse polarity)

No ground

Lights indicate the wiring is correct

Sometimes I will only get one light, which means that someone replaced a 2 wire outlet with a 3-wire and didn’t wire anything to the ground pin.  This can leave 3-wire grounded appliances ungrounded, presenting a potential shock hazard.

Why is Polarity Important?

Circuits have (or should have) three wires: hot, neutral and ground. Plug something in, and the current flows out from the hot plug to whatever you plugged in, and back via the neutral wire. Until the 1950s [check date], electrical outlets had plugs with identical slots, so you had no way of knowing the polarity. Nowadays, all outlets have different-sized slots, and you can only plug things in one way.

So why is this important? Let’s take a light socket as an example. If the polarity is correct, the current flows in from the bottom of the socket, out of reach. But if the polarity is reversed, the current flows in through the socket, so if the bulb is switched off, the socket is still “hot” and it’s possible to get zapped by the current.

Beyond the Basics

Occasionally I will use my fancier circuit tester when I suspect there may be problems that my go/no-go tester can’t see.

This tool is quite a bit more expensive – around $200 – but it can spot major wiring issues quickly and accurately.

False Grounds

Sometimes people will replace 2-wire outlets with 3-wire outlets and just use a jumper to attach the ground pin to the Neutral wire. This is unsafe and illegal, but standard testers can’t see it. The Fancy tester will report it as a “False Ground”

Undersized Wires

In older homes, sometimes the wires are not the size they should be.  The Suretest can check for voltage drop with a 15A and 20A pulse to make sure that a 20A circuit really is a 20A circuit.

AFCI Tester

The Suretest can also simulate an arcing circuit to test an Arc Fault Circuit Interrupter (AFCI). However, as not all manufacturers agree on how to test AFCIs, the recommendation is to rely on the test buttons in the Circuit panel.

The Suretest can also test GFCIs as well, reporting on more information than just that it has tripped.

Cheap Insurance

For a very small investment, you can check all the outlets in your home to make sure they are wired correctly. If you find there’s a problem, contact a licensed electrician for a complete evaluation of your electrical system. Otherwise, the only indication of a problem might result in the fire department showing up at your house.

This is not as easy a choice as it may seem, as the options are seemingly endless. So how do these models compare? One way to explain the differences is to tell you about my own search for the Perfect Flashlight.

The Flashlights in My Toolbox

Before I began my Home Inspection business in 2003, I had the privilege to attend the ITA school in Manassas, VA with Mike Casey, and got to ask lots of questions about tools. At the time one of the flashlights ITA was offering was the StreamLight Ultra Stinger. That became my “starter” flashlight.

What a place to start! It had a 20W halogen bulb that put out an impressive 75,000 Candle Power (about 260 Lumens) for an hour of continuous use. An hour run-time would easily make it through an inspection and since when I began I rarely had two inspections in a day, the run time didn’t become an issue.

As I got busier, I added a car-charger that would “top-off” my Ultra between inspections and would allow me to make it through the day’s inspections with one battery. Adding a second flashlight allowed me to rotate the usage and, when necessary, send the unit back for repairs of the switch or front glass.

However bright that 20W halogen was, it had one major flaw: it could burn out without any warning. Filaments do burn out, and Murphy’s Law says you will be at the other end of a crawl space or attic when it does! When my flashlight suddenly burned out, I was indeed in the attic, but was lucky enough to be able to see the attic hatch when it got very, very dark!

As a result of that experience, I added a small 1W LED flashlight to the other side of my belt. As time progressed, I found I was using the small light flashlight more and more, for under cabinets, sinks, furnaces as it was so much smaller and lighter than the Ultra Stinger, and lasted WEEKS on a set of AA batteries. But I still carried my Ultra Stinger for attics, crawlspaces and outdoor work where I wanted lots of light.

As technology progressed, I upgraded to a 3W LED, and now the Ultra Stinger spent more and more time in the car. I also found a TeraLux LED bulb for a 3 C-cell Maglight. Now I had almost as much light (140 Lumens) as my Ultra Stinger with the run-time of a 3C LED package.  My halogen Ultra Stinger was moving farther and farther back in my vehicle.

I still carried two flashlights at all times, as it can get very dark in an attic if the batteries die, or (it happens) you drop your primary flashlight and can’t find it in the insulation. It’s easy to find a dropped flashlight if you can see the glow, but if it has turned off, forget it!

Attending Inspection World, the annual Home Inspection Conference, brought a host of new flashlights to consider. Many of my colleagues would talk about their “special” flashlights and others would bring theirs to ASHI Chapter meetings and pass them around for all to review. One thing was common though: almost everyone carried a “backup” flashlight, even if it was a tiny keychain unit.

After dragging out the Ultra for what seemed like a darker than usual attic, I decided it was time to seriously look for a new flashlight again. The Ultra’s batteries were starting to lose their charge faster. But rather than start searching at random, I had a list of requirements.

• I wanted at LEAST the same light as My Ultra-Stinger (75,000 candle power or 300 Lumens)
• It should be an LED system
• It HAD to use standard batteries readily available at common retailers
• It should not rely on rechargeable batteries, as these may be difficult to switch out in the field.

Google was my friend as I continued my search many nights after finishing other paperwork.

I found LOTS of flashlights that promised LOTS of Light, but they used C123 cells or 1829’s or some other strange cells that I never saw in stores. The Ultra Stinger’s proprietary 5-cell ‘stick’ was about $40 and I didn’t want to go that route again. C123 batteries are about $3.50 each for the good ones.

My wife found an interesting flashlight at an alternative energy fair: the Solar Goose Ultimate 3-Watt Flashlight. While not as bright as I wanted (120 Lumens), it had the distinct advantage of not requiring a charging cable: I could simply leave it on my car’s dashboard. The flashlight head can be removed and the base can be used as a charger for many different devices: it came with plugs for just about any electrical device (except an iPod). My wife also bought a very handy attachment for the base: an inspection mirror with a flexible neck and an integrated LED light.

Then I stumbled across a brand I had never heard of before: Fenix. I wrote them a short note outlining my specifications, and they quickly responded with several choices. The best fit was their TK40 that ran on (believe it or not) AA cells, and produced an astounding 640 Lumens, more than DOUBLE my Ultra Stinger’s. Yes it uses 8-AA cells, 4 in a pinch, but it is BRIGHT! Holy cow, is it bright. But, unlike my Ultra Stinger, my LED Maglite, or my 3-AA LED Mini-Mag, you can adjust the brightness. It has four settings: low, medium, high and turbo. It has a couple of other neat features such as “Dazzle,” which is a fast strobe-like blink meant to disorient an attacker. It also has an SOS mode which automatically blinks SOS in Morse code.

The Fenix TK40 is now my primary flashlight, and my 3W-3AA LED Mini-Mag is my backup. The Fenix is not cheap at $124, but is in line with the Ultra-Stinger and other premium flashlights.

Side-by-Side Comparison

To show the illumination capabilities of each flashlight, I did a “real life” test. I set up a camera in my attic and took all of my flashlights up with me one night. Each flashlight was either freshly-charged or had a new set of batteries installed, and each picture was taken with the same camera settings (shutter speed, ISO and aperture).

3AA MiniMag LED Flashlight

3 C-Cell MagLite with LED Bulb

SolarGoose Ultimate Flashlight

StreamLight UltraStinger

Fenix TK40 on Low

Fenix TK40 on Medium

Fenix TK40 on High

Fenix TK40 on Turbo

A round-base meter usually means electrical service of only 50 to 60 amps.

With few of today’s modern conveniences, a house could easily get by with only 50-60 Amps of electrical service, and even today this level of service does not pose a problem, as long as electrical devices are kept to a minimum. However, when homeowners with such basic service start adding modern appliances, they quickly run out of electrical capacity, which can result in local brownouts, blown breakers or fuses, or overheating of wires and a possible fire hazard.

A meter with a small square base is also common with feeds of 50 to 60 amps. Also, noice the frayed service entrance cable on the left.

Computers don’t take much, but they don’t like brownouts or flickers in power. For any type of computer or computerized appliance, it’s a good idea to use surge suppressors and uninterruptible power supplies to prevent damage. This includes computerized sewing machines, exercise equipment, TVs, digital video recorders, and cable boxes.

A large rectangular base usually means a home is supplied with 150A to 200A.

Another consideration when with older homes is that many of the wires coming from the poles to the house, and then down the house to the meter, are 40-50 years old and are now frayed. Often the wire wrapped around the central conductors is now showing through. Contrary to common belief, that is not a ground, but a current-carrying conductor, often carrying substantial current. Although wrapping with tape is acceptable by some, most electricians agree that frayed Service Entrance (SE) cables should be replaced for safety. At a minimum, that wire needs to be replaced so that it is safe and it is a good opportunity to UPGRADE the entire service to a more modern 150-200A service. Most municipalities won’t install less than 125-150A, and most times 200A service is the same price as the lower, so 200A is installed. Even Townhouses and condominiums now are provided with 125-150A service per unit.

This extra-large rectangular meter enclosure is an indication that the service to the house is 400A.

Some all-electric homes, or homes with lots and lots of circuits, may even need a larger service (400A) because of the requirement for no more than 42 circuits per panel, and 150-200A per panel.  With the new rules, the number of circuits per panel is being relaxed, but homes with multiple air conditioners, water heaters, second kitchens, clothes dryers, guest quarters and other large users of electricity may still need the larger electrical service.

Modern Life Consumes Electricity

Here are typical amperage requirements for some common household appliances.

Electric Range:  40A

Wall Oven: 40A

Modern Electric Clothes Dyer: 30A (min.)

Air Conditioner, outside unit: 25A (min.)

Air Conditioner, inside unit: 15A

Microwave: 12A

Toaster: 12A

Hair Dryer: 12A

Dishwasher: 15A

To calculate how many amps an appliance needs, divide the wattage by 120 (normal household voltage). For example, a microwave oven that uses 1800 watts needs a 15 amp circuit. (Amps = Watts/Volts)

Safety Note

The service entry cable should always be protected from the elements, and from the possibility of abrasion or fraying. Soil settling around the foundation of a house can pull the cable conduit away from the meter box, with potentially disastrous consequences.

This cable could rub against the meter housing and lead to a house fire.

Air Leaks

Some common sources of air leaks

Unintentional air leaks can suck cool air out of living spaces, drawing in more hot air from outdoors. Even tiny gaps around recessed light fixtures, vents and other penetrations can add up to a lot of leakage. A simple way to track down air leaks is to light a stick of incense and go through the house, checking around every wall penetration (electrical switches and outlets, exterior doors and windows, ceiling lights, etc.). When you find a draft, plug it with insulation, caulk or weatherstripping.

Insufficient Insulation

Insulation was swept aside for access and not replaced.

In the DC area, the minimum recommended insulation level is R-38. R-40/50 is better, and that is 14” of Fiberglas or 10” of cellulose at a minimum, with no paths, gaps or voids. A single small void can reduce the overall R value in the entire attic.

Contractors working in attic spaces sometimes clear footpaths through insulation and fail to replace it or fluff it back up as they leave. Settling is also an issue; you should inspect your attic regularly to make sure the insulation is in place.

One common weakness in attic insulation is the access hatch. It rarely has the recommended insulation, and that means a big reduction in overall attic protection. One way to insulate the hatch is to construct a simple open-bottomed box out of rigid foam insulation and silver foil tape (which is rated up to 150 degrees). This keeps the access hatch insulated, and is easily moved aside when you need to get into the attic.

Inadequate Ventilation

A powered attic fan can help your HVAC efficiency

If the attic is 150 degrees, and you want the living space at 72, the insulation better be in really, really good shape. I have recorded temperatures above 150 during my inspections. The passive ridge vents just don’t hack it in our area; you really need active ventilation, meaning a powered fan, to keep the attic between 110 and 120 degrees or cooler.  Look at it this way: If you have an AC/Heat pump in the attic, and its metal chassis is at 150 degrees, how is it going to pump out 65 degree air without spinning the electric meter really fast?

Lack of Maintenance

If your HVAC unit is in the attic, it needs regular attention. Air filters need to be changed every 30 days.  AC units must be serviced each spring to make sure they have the right amount of coolant or you will have high electric bills and the unit won’t stand a chance of keeping up on these triple-digit days.

Design Considerations

The design temperature in the DC area is 95 to 100 degrees. This means that units are designed to be working at 100% capacity when the outside temperature is 95 to 100degrees and the inside “middle of the room” temperature is 78 degrees. If your unit is cycling on and off on a day like today, there is a problem. This could indicate that the unit is too big and is cooling the house too fast and not dehumidifying the house, so it will be cold and clammy because it is not running long enough to remove the humidity. Units need to be running 14-20 minutes before they reach peak dehumidification. If it cycles before that, you have a problem.

If your unit is undersized, you will not be able to cool the house down no matter how long the unit runs. This is why it is critical to have a properly-trained technician assess your home’s heating and cooling needs. Ask for a “Manual J” assessment; this is an industry standard survey that measures the square footage of window and wall space, along with other factors, to determine the house’s requirements.

A lot of the efficiency of an HVAC unit also hinges on proper installation; I have seen too many houses with improperly installed systems and/or faulty ductwork.

Practical Issues

The temperatures we’re seeing in the DC area are outside the normal range, and it really isn’t practical to install HVAC systems that can handle occasionally extreme temperatures. Doing so means the unit won’t operate efficiently on the more normal days, and will just increase the operating and maintenance costs.

1. Do you live in an area prone to serious power outages (for example, have you had two or more outages lasting at least twelve hours in the past year)?
2. Do you rely on an electrically-operated well pump or water purifier for fresh water?
3. Do you rely on a sump pump to keep your basement and its contents dry?
4. Do you rely on a home medical device powered by electricity?

If you answered “yes” to any of these questions, you should seriously consider a backup power system.

Home generators are becoming popular options, especially in rural homes where above-ground power supply lines are more susceptible to falling trees and other weather hazards. And if you rely on well water, a power outage means you also lose your water supply once your holding tank is depleted.

Calculating Your Power Needs

It’s important to get the correct size generator for your needs. Make a list of the crucial circuits in your home: well pump, furnace, refrigerator, freezer, stove, and a few key lighting circuits. Add up the wattage for all these needs and that will give you the minimum capacity to shop for.

There are web tools available that allow you to check off which appliances you want to be able to use with a backup system, and help you calculate which size system is appropriate, such as this one from Gillette Generators. You can also download a PDF file from Generac which lists the power requirements of many common appliances. Note: We are not affiliated with either of these companies.

Keep in mind that for anything with a motor, you need to allow for how much energy is required to start the motor, since that is what pulls the most power. Several motors starting at once can cause even a large generator to stall.

A back-up power system should be large enough to power the essential systems in your home. You could certainly put in a system that is powerful enough to run the entire house, including big energy users like air conditioners and clothes dryers. But most of the time you just want to keep the basics running.

If you rely on medical equipment, such as nebulizers, oxygen concentrators or power stair lifts, you need to make sure your backup system is up to the task of running them.

Types of Generators

Portable

Portable Gasoline Generator

If outages aren’t frequent, then a portable generator could be an option. It is crucial to keep portable generators at least ten feet away from the house, to prevent carbon monoxide poisoning. Just recently, three people in Maryland were killed by carbon monoxide poisoning due to a portable generator running in the basement.

You need to use heavy-duty extension cords to connect your appliances directly to the generator. A portable generator isn’t suitable for use with hard-wired appliances. Also, since they tend to sit idle for long periods, the gas can go stale and gum up the engine.

Installed

The generator (1) connects to the power inlet plug (2) and feeds the transfer switch (3) off the main power panel (4).

The next type is the Installed Gasoline Generator. This tends to be a larger unit, on wheels, possibly with an electric starter. A sub-panel for the supported circuits is wired into the house, and a special connection plug is installed outside the house to connect the generator to the panel. This type of unit still has the same issues with gasoline as the smaller portable unit, but is located outside and eliminates snaking extension cords.

Whole-House

A Whole-House Generator is permanently installed.

Larger generators can be permanently installed, with automatic transfer switches and weekly self-testing cycles. They will start automatically, usually within a minute of the power failure, and shut down when the power is restored. They can be powered either by natural gas or hooked up to a propane tank. These units can be large enough to power an entire house if desired, and can cost several thousand dollars. They are installed in weatherproof cabinets and make less noise than the average lawnmower.

Some generators are actually just super-sized battery backups, which can keep systems running for up to a day or two before needing to be recharged. These are fine for short outages, but won’t last long during a multi-day outage. The advantage of such a system is that it switches over almost instantly, so you don’t have to wait for a generator to power up. Another plus is that these systems are virtually silent.

Some Things to Consider

When planning for a generator, think about how it will be used and who will likely be operating it. When we were in our first house, we chose a small stand-alone gasoline-powered generator just big enough for the furnace, well pump and a light circuit. To use it, you had to go outside and start the generator manually with a pull cord, then go inside and throw switches. Easy for my husband to do; however, we failed to consider that he might not be home when a blackout occurred, and didn’t take into account that I might have to start it in the pouring rain, while leaving our two small children alone inside the house. For our next house, we got a fully-automatic system.

Have More questions?

If you have questions about home generators, or any other Home Inspection issue, we’re happy to help. Just give us a call at (301) 208-8289.

Lead paint chips and dust can contaminate the air and water.

Federal law requires that individuals receive certain information before renting or buying pre-1978 housing:

• LANDLORDS have to disclose known information on lead-based paint and lead-based paint hazards before leases take effect. Leases must include a disclosure form about lead-based paint.
• SELLERS have to disclose known information on lead-based paint and lead-based paint hazards before selling a house. Sales contracts must include a disclosure form about lead-based paint. Buyers have up to ten days to check for lead hazards.

As of April 22, 2010, federal law requires that contractors performing renovation, repair and painting projects that disturb more than six square feet of paint in homes, child care facilities, and schools built before 1978 must be certified and trained to follow specific work practices to prevent lead contamination.

The Environmental Protection Agency (EPA) has extensive information on their website regarding these new regulations, along with information about how to hire a certified professional.

We can check for lead paint during a home inspection by using chemical swabs. However, more sensitive testing is required to reveal lead paint hidden under wallpaper or repainted surfaces.

The EPA’s Lead Information brochure (in PDF format) is available for download from our website.

Does your house have problem drywall? If so, you'll need to remove it... along with a lot of other stuff.

The U.S. Consumer Product Safety Commission (CPSC) and US Department of Housing and Urban Development (HUD) have issued interim remediation guidelines regarding the issue of problem drywall imported from China, which has been associated with corrosion of metal parts such as pipes and electrical components.

The cause of the corrosion was found to be a high level of hydrogen sulfide.

Based on scientific study of the problem to date, HUD and CPSC recommend consumers remove all possible problem drywall from their homes, and replace electrical components and wiring, gas service piping, fire suppression sprinkler systems, smoke alarms and carbon monoxide alarms. Taking these steps should help eliminate both the source of the problem drywall and corrosion-damaged components that might cause a safety problem in the home.

To read the full text of the remediation guidelines, visit the federal Dryall Information Center website (PDF).

How to Identify Problem Drywall

The affected drywall was installed between 2001 and 2008, with most occurring between 2005 and 2008. The most obvious sign is blackening of copper electrical wiring and/or air conditioning evaporator coils. Chemical analysis may be required to confirm the specific chemical emissions from the drywall.

A full text of the identification process can be obtained from the CPSC website (PDF).

Most of the problem drywall was used in Florida and the Gulf states, during the building boom following hurricanes Katrina and Rita. However, there have been reports of it in Virginia, and on the Eastern Shore.

Now What?

If you suspect your property has been affected by this issue, you should contact the CPSC by calling 800-638-2772, or visit the Drywall Information Center.