Prudent home inspectors in Austin, Texas always seek to present all view points when inquiring a new topic that arises such as radon gas in granite counter tops.  Since I do not test for radon, I will not offer my opinion to the validity of this article, but will let the reader be the judge. What about radon in granite countertops? Answer.. Does the EPA believe there is a danger of radon gas or associated radiation being emitted from granite countertops? Granite is a naturally occurring igneous rock, meaning that it was formed by the cooling of molten rock.  It is quarried and processed to produce commercial products such as countertops. It is possible for any granite sample to contain varying concentrations of uranium that can produce radon gas, a source of alpha and beta particles and gamma rays. Some granite used for countertops may contribute variably to indoor radon levels.  At this time, however, EPA does not believe sufficient data exist to conclude that the types of granite commonly used in countertops are significantly increasing indoor radon levels. Some granite may emit gamma radiation above typical background levels.  While radiation levels are not typically high, measurement of specific samples may reveal higher than expected levels on a case-by-case basis.

While natural rocks such as granite may emit radon gas, the levels of radon attributable to such sources are not typically high. EPA believes the principal source of radon in homes is soil gas that is drawn indoors through a natural suction process. To reduce radon risk you should first test the air in your home to determine the radon level. There are many home radon test kits available at the retail level and on-line, starting at about $25.

ASHI HOME INSPECTOR - AUSTIN TEXAS

Austin Home Inspectors don’t encounter radon much because we seldom have basements with trapped air that would cause high levels or radon to sit without air drafts from moving them along.  Recently an article was written by Kate Murphy on “What is Lurking in Your Countertops?  This article is worth reading if you have granite counter tops to know what questions to ask & where to go to for more information.  As  an Austin Home inspector, I do not personally inspect for radon, but if you are concerned if radon is present in your house, then call the EPA.

July 24, 2008 What’s Lurking in Your Countertop? By KATE MURPHY

SHORTLY before Lynn Sugarman of Teaneck, N.J., bought her summer home in Lake George, N.Y., two years ago, a routine inspection revealed it had elevated levels of radon, a radioactive gas that can cause lung cancer. So she called a radon measurement and mitigation technician to find the source. “He went from room to room,” said Dr. Sugarman, a pediatrician. But he stopped in his tracks in the kitchen, which had richly grained cream, brown and burgundy granite countertops. His Geiger counter indicated that the granite was emitting radiation at levels 10 times higher than those he had measured elsewhere in the house. “My first thought was, my pregnant daughter was coming for the weekend,” Dr. Sugarman said. When the technician told her to keep her daughter several feet from the countertops just to be safe, she said, “I had them ripped out that very day,” and sent to the state Department of Health for analysis. The granite, it turned out, contained high levels of uranium, which is not only radioactive but releases radon gas as it decays. “The health risk to me and my family was probably small,” Dr. Sugarman said, “but I felt it was an unnecessary risk.”

Home inspectors in Round Rock, Texas are expected to know how heat pumps work so they can advise their clients of evaluation needed before the problem becomes the buyers problem.  The following article is good information I can pass on to you for information how heat pumps work for your personal benefit.

The easiest way to recognize a heat pump is at the thermostat. When you remove the cover from the thermostat, you will have dual bubble mercury tubes controlling the heat. These bubbles or mercury tubes are mercury switches, similar to a single pole light switch. The top bubble controls the compressor; the bottom bubble controls the back-up or supplemental heat. The bubbles operate in tandem with the top bubble being engaged about 2 degrees before the bottom bubble. The air conditioning is usually controlled by one mercury tube on the right side of the thermostat. If you see a second pair of bubbles, the air conditioning system has dual compressors, which operate on demand and can operate at lower demand level, which could reduce operating costs. Dual compressors are usually found in commercial units. When inspecting a heat pump, turn the system off. Then move the thermostat up slowly so only the top mercury tube is engaged. You must have the cover off to see this. If you allow both switches to become engaged, and the unit is on, you may have to wait for a time delay to release the supplemental heat or check the supplemental heat first. Once you have the thermostat set properly, turn the system on. Assuming the outside temperature is above the balance point (32 to 40 degrees), with only the compressor engaged (top bubble), and after about 5 to 8 minutes, measure the difference in temperature between a supply and return. The temperature difference should be 18 to 30 degrees Fahrenheit in the heating mode. The outside temperature will have some impact on this temperature. If the temperature difference is not high enough, the probable causes are a laboring compressor or low freon charge. If it is a laboring compressor, figure about $500 to $600 per ton, plus $250 to $350 if the condensing cabinet fan and coil are replaced. If it is a freon charge, figure $125 to $175 for a charge and service.

ASHI HOME INSPECTOR - Austin, Cedar Park, Georgetown, Leander & Round Rock

In Central Texas we have many varieties of soils that the Austin home inspector should be aware of before he sets out for the home inspection.  Expansive soils can play havoc on a foundation regardless of the design.  This should be known before the potential buyer signs a contract on a new or existing home.  Existing homes most likely will show the evidence of foundation movement if the home has been built over ten years.  However, that is not the case with new homes.  The structure has not had time to settle thus the buyer cannot foresee what may await when he has lived in the house ten years.  By that time a structural engineer may be needed to assess the damages & recommend foundation repairs.  Don’t let this happen to you.  Do your home work ahead of time.  Talk to your home inspector in Austin, Texas & ask him for information on soil conditions in the area you want to buy.  If he does not know, then the home inspector should guide you to the Soil Conservation Service or a state agency that can help.

Expansive Soil   �
Soil is an essential component in the construction and stability of a house that is often overlooked by homeowners and home buyers. Since the house is built on soil, structural damage to a house can occur if the soil expands, contracts or slides.

Expansive clay soils

Throughout the United States, particularly in Texas, California, Virginia and Colorado (though not exclusively in these locations), expansive or reactive clay soils are known to cause adverse effects on residential structures. Expansive soil expands and contracts due to changes in the moisture content of the soil, causing structural problems through differential movement of the structure. If the moisture content and or soil type differs at various locations under the foundation, localized or non-uniform movement may occur in the structure. This isolated movement of sections of the structure can cause damage to the foundation and framing, evidenced by cracking of the slab or foundation, cracking in the exterior or interior wall covering (indicating movement of the framing,) uneven floors and/or misaligned doors and windows. This type of movement is usually associated with slab on grade construction that is common in the previously mentioned regions of the country. However, this type of movement also occurs in structures with basements and crawlspaces. The following image of a moderately reactive soil sample illustrates its effect when moisture is introduced.

A second effect of expansive soils is additional horizontal pressure applied to foundation walls found in basements and crawlspaces. Increased moisture in the soils adjacent to the foundation wall will cause the soils to expand and increase the lateral pressure applied to the foundation wall. If the foundation wall does not have sufficient strength, minor cracking, bowing or movement of the wall may occur. Serious structural damage to, or failure of, the wall may also occur.

A third effect associated with claystone soil (a type of expansive soil) is the movement of soils on unstable slopes. Expansive claystone soil, found as a layer under a more rigid top layer of soils, become unstable as the moisture content increases, allowing the claystone and the top layers of soils to move. If the soil is located on a slope, the top layer of soil can creep (slow movement) down hill or even cause a landslide (sudden and dramatic movement). Consequently, a house with an inadequate foundation built on unstable slopes can be subject to creeping of the structure down slope, or to failure of the structure in a landslide.

Possible Solutions
Pre-construction solutions: Prior to building the structure, a soil test of the site should be performed to ensure the soils are stable or to determine the approximate effect the soils will have on the structure. This will assist in determining if the soils are capable of properly supporting the structure. In addition, information on the soils can ensure that the foundation is designed to withstand the effects of the existing soil conditions, and assist in the development of plans for long-term maintenance.

Post-construction solutions: For structures already in existence, several possible solutions to counter the effects of expansive soils are available. Common preventative solutions include proper soil maintenance such as maintaining a uniform and constant moisture level in the soil. This may involve introducing moisture into the soils continually and uniformly to prevent shrinking; and/or preventing excessive or isolated saturation of the soil through proper drainage and grading techniques that prevent swelling. For structures affected by expansive soils, further movement can be prevented by providing additional strength and support to the foundation. This may include various methods of underpinning (to prevent vertical movement and/or sliding) and/or reinforcing of the foundation walls (to withstand lateral pressure).

As an Austin ASHI Home Inspector, I am a huge fan of radiant barrier in the attic under the roof decking. The big reason, my utility bills are below $175 per month in the hot summers of Austin. Home inspectors are in hot attics every day. The sweat that pours down my face from the time I enter the attic is from poor ventilated attic space & no radiant barrier. Radiant barriers are great because they reduce the amount of heat transfer from roof surface into the attic. Therefore a/c ducts do not get excessively hot so the a/c has to work less to cool the house. The following article will help you to understand why your attic should have radiant barriers.

Radiant barriers are materials that are installed in buildings to reduce summer heat gain and winter heat loss, and hence to reduce building heating and cooling energy usage. The potential benefit of attic radiant barriers is primarily in reducing air-conditioning cooling loads in warm or hot climates. Radiant barriers usually consist of a thin sheet or coating of a highly reflective material, usually aluminum, applied to one or both sides of a number of substrate materials. These substrates include kraft paper, plastic films, cardboard, plywood sheathing, and air infiltration barrier material. Some products are fiber reinforced to increase the durability and ease of handling. Radiant barriers can be used in residential, commercial, and industrial buildings. However, this fact sheet was developed only for applications of radiant barriers in ventilated attics of residential buildings.

How are radiant barriers installed in a residential attic?

Radiant barriers may be installed in attics in several configurations. The simplest is to lay the radiant barrier directly on top of existing attic insulation, with the reflective side up. This is often called the attic floor application. Another way to install a radiant barrier is to attach it near the roof. The roof application has several variations. One variation is to attach the radiant barrier to the bottom surfaces of the attic truss chords or rafter framing. Another is to drape the radiant barrier over the tops of the rafters before the roof deck is applied. Still another variation is to attach the radiant barrier directly to the underside of the roof deck.

How do radiant barriers work?
Radiant barriers work by reducing heat transfer by thermal radiation across the air space between the roof deck and the attic floor, where conventional insulation is usually placed. All materials give off, or emit, energy by thermal radiation as a result of their temperature. The amount of energy emitted depends on the surface temperature and a property called the “emissivity” (also called the “emittance”). The emissivity is a number between zero (0) and one (1). The higher the emissivity, the greater the emitted radiation. A closely related material property is the “reflectivity” (also called the “reflectance”). This is a measure of how much radiant heat is reflected by a material. The reflectivity is also a number between 0 and 1 (sometimes, it is given as a percentage, and then it is between 0 and 100%). For a material that is opaque (that is, it does not allow radiation to pass directly through it), when the emissivity and reflectivity are added together, the sum is one (1). Hence, a material with a high reflectivity has a low emissivity, and vice versa.

Radiant barrier materials must have high reflectivity (usually 0.9, or 90%, or more) and low emissivity (usually 0.1 or less), and must face an open air space to perform properly. On a sunny summer day, solar energy is absorbed by the roof, heating the roof sheathing and causing the underside of the sheathing and the roof framing to radiate heat downward toward the attic floor. When a radiant barrier is placed on the attic floor, much of the heat radiated from the hot roof is reflected back toward the roof. This makes the top surface of the insulation cooler than it would have been without a radiant barrier and thus reduces the amount of heat that moves through the insulation into the rooms below the ceiling. Under the same conditions, a roof mounted radiant barrier works by reducing the amount of radiation incident on the insulation. Since the amount of radiation striking the top of the insulation is less than it would have been without a radiant barrier, the insulation surface temperature is lower and the heat flow through the insulation is reduced. Radiant barriers can also reduce indoor heat losses through the ceiling in the winter. Radiant barriers reduce the amount of energy radiated from the top surface of the insulation, but can also reduce beneficial heat gains due to solar heating of the roof. The net benefits of radiant barriers for reducing winter heat losses are still being studied.