Barrie Home Inspector

Home Maintenance and Tips for Home Owners

Tag: soil

Understanding Your Septic Tank

Plumbing

Understanding Your Septic Tank – Information on the construction, operation and maintenance of your rural homes septic tank system.

Septic TankThe septic tank is buried, watertight container typically made of concrete, fiberglass, or polyethylene. It holds the wastewater long enough to allow solids to settle out, forming sludge, and oil and grease to float to the surface as scum. It also allows partial decompositions of the solid materials. Compartments and a T-shaped outlet in the septic tank prevent the sludge and scum from leaving the tank and traveling into the leach field area.The most common leach field consists of a series of trenches containing perforated pipe surrounded by septic rock, or gravel, and covered with mesh and dirt. The effluent entering the leach field is partially absorbed into the soil and partially evaporated. the leach field should not be driven on or covered by a driveway or patio.

If your home‘s plumbing system does include an on-site septic system, it is incredibly important to be aware of the signs of possible damage, along with the maintenance needed to prevent it. A damaged or clogged septic system can be costly to repair. It can also impose possible health risks for homeowners, tenants and neighbors. A failing septic system could be responsible for releasing wastewater and harmful bacteria and viruses, including E. coli.

There are many different types of septic systems ranging from what are called conventional in-ground systems to sand mounds and from spray irrigation systems to stream discharge systems. There are also seepage pits, cesspools, and homemade systems. This booklet is not intended to cover every situation, but is intended to give the homeowner an understanding of the concept of how a septic system works and a better understanding of a septic inspection.

The in-ground type of septic system uses a series of perforated pipes located below the ground surface. These pipes are placed in a bed of crushed stone or aggregate. The sewage flows over the crushed stone or aggregate into the underlying soil. The condition of this soil determines how well your septic system will operate and how large the absorption area needs to be. If the absorption area is too small and the soil is too tight as with clay soils, the liquid cannot soak into the soil fast enough causing the waste to either back up into the home or emerge at the ground surface. An early sign of waste emerging at the surface is “lush growth.” The saying “that the grass is always greener over the septic tank” isn’t true when it comes to a properly operating septic system.

How often should a septic tank be cleaned or pumped? The frequency for pumping a septic system depends on a number of factors; the average frequency is between two and four years. You can, in some cases, abuse a septic system and neglect to pump it for 10 or 20 years without any apparent problem. This would be like driving your automobile for 50,000 miles without changing the oil. You might get away with it, but you would certainly cause undue wear and tear on the engine. The same is true with a septic system. You may get away with not pumping the system for many years, but you will pay for it in the end by having to replace the absorption area.

When the soil conditions are right, an area of active microorganisms is formed where the waste enters the soil. As the waste slowly percolates through the soil the microorganisms continue to grow and feed on the harmful bacteria and viruses in the septic waste. The underlying soil continues to absorb and filter the waste. Four feet of soil is all that is needed to treat the septic waste in good soil conditions.

Concrete – Strength in Knowledge

Basements, Exterior

Concrete – Strength in Knowledge.  Concrete is used more than any other man-made material in the world.  As of 2006, about 7.5 billion cubic meters of concrete are made each year-more than one cubic meter for every person on Earth.

In evaluating concrete problems, one of the important decisions home inspectors must make is determining whether a problem is the result of conditions that have stabilized with a low chance of continuing future problems, or whether the conditions that caused the problem are such that there is a high probability that problems will continue or worsen.

Concrete powers a US $35 billion industry, employing more than two million workers in the United States alone. More than 55,000 miles (89,000 km) of highways in the United States are paved with this material. Reinforced concrete, prestressed concrete and precast concrete are the most widely used types of concrete functional extensions in modern days.

Concrete, as the Romans knew it, was a new and revolutionary material. Laid in the shape of arches, vaults and domes, it quickly hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick.  Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice, often consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.

Combining water with a cementitious material forms a cement paste by the process of hydration. The cement paste glues the aggregate together, fills voids within it and allows it to flow more freely. Less waterin the cement paste will yield a stronger, more durable concrete; more water will give a freer-flowing concrete with a higher slump. Impure water used to make concrete can cause problems when setting or in causing premature failure of the structure. Hydration involves many different reactions, often occurring at the same time. As the reactions proceed, the products of the cement hydration process gradually bond together the individual sand and gravel particles and other components of the concrete, to form a solid mass.

Plastic cracking occurs prior to concrete curing. Autogenous shrinkage is caused by internal drying.  Since there is no loss of water to one exposed surface, autogenous shrinkage is more uniform than plastic shrinkage. However, tensile stresses still develop, and embedded steel can cause anomalies in an area of concrete with relatively uniform stress. These anomalies can cause variations in stress within the concrete that are relieved by cracking.  Autogenous shrinkage cracking will be shallow and is not a structural issue. The cracks may look similar to those formed during plastic shrinkage and are often propagations of cracks created during plastic shrinkage.

The advantage to inspectors in being able to accurately determine the source of cracking is in understanding whether the condition that caused the cracking has stabilized so that it is no longer likely to cause additional cracking or encourage the propagation of existing cracks. Many cracks, like those caused by concrete shrinkage, are shallow cracks caused by forces that allow conditions to stabilize relatively quickly and do not lead to structural problems. Others, like those caused by soil subsidence or changes in soil volume, are caused by forces that can continue to affect concrete for a long time. This long-term instability can continue to cause serious structural problems over the long term.

When investing in a new property it is important to have the building inspected by a qualified residential or commercial inspector.  Visit www.barrie-home-inspector.com to learn more about the Barrie Home Inspector, when purchasing Commercial or Residential Properties.  With over 4,000 inspections, experience and knowledge can help protect your investment.

What is Radon – Is It in Your Home

Home Inspection

What is Radon –  Is It in Your Home
Radon is a gas produced by the radioactive decay of the element radium. Radioactive decay is a natural, spontaneous process in which an atom of one element decays or breaks down to form another element by losing atomic particles (protons, neutrons or electrons). When solid radium decays to form radon gas, it loses two protons and two neutrons. These two protons and two neutrons are called an alpha particle, which is a type of radiation. The elements that produce radiation are referred to as radioactive. Radon itself is radioactive because it also decays, losing an alpha particle and forming the element polonium
Elements that are naturally radioactive include uranium, thorium, carbon and potassium, as well as radon and radium. Uranium is the first element in a long chain of decay that produces radium and radon. Uranium is referred to as the “parent” element, and radium and radon are called “daughters” or “progeny.” Radium and radon also form daughter elements as they decay. The progeny of radon are called radon decay products, or RDPs.

The decay of each radioactive element occurs at a very specific rate. How fast an element decays is measured in terms of the element’s “half-life,” or the amount of time for one-half of a given amount of the element to decay. Uranium has a half-life of 4.4 billion years, so a 4.4-billion-year-old rock has only half of the uranium with which it started. The half-life of radon is only 3.8 days.

If a jar were filled with radon, only half of the radon would be left after 3.8 days. But the newly-made daughter products of radon (or RDPs) would also be in the jar, including polonium, bismuth and lead. Polonium is also radioactive. It is this element which is produced by radon in the air and in people’s lungs that can hurt lung tissue and cause lung cancer.
Radioactivity is commonly measured in picocuries (pCi).

Because the level of radioactivity is directly related to the number and type of radioactive atoms present, radon and all other radioactive atoms are measured in picocuries. For instance, a house having 4 picocuries of radon per liter of air (4 pCi/L) has about eight or nine atoms of radon decaying every minute in every liter of air inside the house. A 1,000-square-foot house with 4 pCi/L of radon has nearly 2 million radon atoms decaying inside it every minute.

Radon levels in outdoor air, indoor air, soil air and groundwater can be very different. Outdoor air ranges from less than 0.1 pCi/L to about 30 pCi/L, but it probably averages about 0.2 pCi/L. Radon in indoor air ranges from less than 1 pCi/L to about 3,000 pCi/L, but it probably averages between 1 and 2 pCi/L. Radon in soil air (the air that occupies the pores in soil) ranges from 20 or 30 pCi/L to more than 100,000 pCi/L; most soils in the United States contain between 200 and 2,000 pCi of radon per liter of soil air. The amount of radon dissolved in groundwater ranges from about 100 to nearly 3 million pCi/L. Natural Radiation Exposure

Since the beginning of time, all living creatures have been exposed to radiation. We live in a radioactive world. There are many natural sources of radiation which have been present since the Earth was formed. In the last century, we have added somewhat to this natural background radiation with artificial sources. However, the naturally occurring sources contribute about four to five times more radiation than human-made sources.

The three major sources of naturally occurring radiation are:

• cosmic radiation;
• sources in the earth’s crust, also referred to as terrestrial radiation; and
• sources in the human body, also referred to as internal sources.

Cosmic

The Earth and all living things on it are constantly bombarded by radiation from space, similar to a steady drizzle of rain. Charged particles from the Sun and stars interact with Earth’s atmosphere and magnetic field to produce a shower of radiation, typically beta and gamma radiation. The dose from cosmic radiation varies in different parts of the world due to differences in elevation and to the effects of the Earth’s magnetic field. Cosmic radiation comes from the Sun and outer space, and consists of positively charged particles, as well as gamma radiation. At sea level, the average cosmic radiation dose is about 26 millirems (mrem) per year. At higher elevations, the amount of atmosphere shielding cosmic rays decreases and, thus, the dose increases. The average dose in the United States is approximately 28 mrem per year.

Terrestrial

Radioactive material is also found throughout nature. It is in the soil, water and vegetation. Low levels of uranium, thorium and their decay products are found everywhere. This is called terrestrial radiation. Some of these materials are ingested with food and water, while others, such as radon, are inhaled. The dose from terrestrial sources also varies in different parts of the world. Locations with higher concentrations of uranium and thorium in their soil have higher dose levels.

The major isotopes of concern for terrestrial radiation are uranium and its decay products, such as thorium, radium and radon.

There are natural sources of radiation in the ground, rocks, building materials and potable water supplies. Radon gas is a current health concern. This gas results from the decay of natural uranium in soil. Radon, which emits alpha radiation, rises from the soil under houses and can build up in homes, particularly well-insulated homes. In the United States, the average effective whole-body dose of radon is about 200 mrem per year, while the lungs receive approximately 2,000 mrem per year.

Internal

In addition to cosmic and terrestrial sources, all humans are born with naturally occurring radionuclides, such as Potassium-40, Carbon-14, Lead-210, and other isotopes. The variation in dose from one person to another is not as great as the variation in dose from cosmic and terrestrial sources. The average annual “dose” from internal radioactive material is about 40 mrem.

Ionizing Radiation Exposure to the Public

This chart shows that of the total dose of about 360 millirems per year, natural sources of radiation account for about 82% of all public exposure, while man-made sources account for the remaining 18%.

Government of Canada Radon Guideline
Did you know?
The Canadian guideline for radon is 200 becquerels per cubic meter, If the radon level is found to be high, it can be fixed.
Health Canada collaborated with the Federal Provincial Territorial Radiation Protection Committee (FPTRPC) to review the health risk from exposure to radon. The risk assessment is based on new scientific information and was the subject of broad public consultation. Using the risk assessment and feedback obtained from the public consultation, the Government of Canada is updating its guideline for exposure to radon in indoor air. This updated guideline provides advice that is more broadly applicable and more protective than the previous FPTRPC guideline.
The Minister recommends that
• Remedial measures should be undertaken in a dwelling whenever the average annual radon concentration exceeds 200 Bq/m³ in the normal occupancy area.
• The higher the radon concentration, the sooner remedial measures should be undertaken.
• When remedial action is taken, the radon level should be reduced to a value as low as practicable.
• The construction of new dwellings should employ techniques that will minimize radon entry and will facilitate post-construction radon removal, should this subsequently prove necessary.
• In addition to residential homes, the term “dwelling” in this guideline also applies to public buildings with a high occupancy rate by members of the public such as schools, hospitals, long-term care residences, and correctional facilities. The following settings are excluded from this guideline:
o Uranium mines, which are regulated by the Canadian Nuclear Safety Commission;
o Other mines (e.g., fluorspar mines), which are regulated by provincial mining authorities; and
o Other workplaces which would be addressed by existing guidelines for naturally occurring radioactive materials (NORM). Details are given in theCanadian Guidelines for Management of Naturally Occurring Radioactive Materials (NORM) and a copy may be viewed or downloaded.
• The “normal occupancy area” refers to any part of the dwelling where a person is likely to spend several hours (greater than four) per day. This would include a finished basement with a family room, guest room, office or work shop. It would also include a basement apartment. It would exclude an unfinished basement, a crawl space, or any area that is normally closed off and accessed infrequently, e.g., a storage area, cold room, furnace room, or laundry room.
• The aim is to remediate and reduce the radon concentration to less than 200 Bq/m³. If the radon concentration is found to be greater than 600 Bq/m³, the remedial actions are recommended to be completed in less than a year; between 200 Bq/m³ and 600 Bq/m³, the remedial actions should be completed in less than two years.
• “As low as practicable” refers to what can be achieved with conventional radon reduction methods in a cost-effective manner. This is consistent with the ALARA (As Low As Reasonably Achievable) principle, whereby reasonable efforts are made to maintain radiation exposures as low as possible, with social and economic factors taken into consideration. In most situations, a final level less than 200 Bq/m³ will be readily achievable. In a small number of cases, it may happen that the application of all reasonable remediation techniques will still leave a residual radon level greater than 200 Bq/m³. It is not the intention of this guideline to recommend excessive or unreasonable remediation costs in order to achieve a marginal increase in benefit. Such situations should be evaluated on a case-by-case basis.
• This Government of Canada guideline is based on the guidance approved by the FPTRPC. The guideline is based upon current scientific understanding. It will be reviewed and updated as appropriate. Further information on the Federal Provincial Territorial Radiation Protection Committee is available.
Brought to you by the Barrie Home Inspector – Your Radon Specialist for Barrie, Alliston, Orillia, Midland, Penetang, Bradford, Newmarket and Aurora

Radon–Characteristics

Home Inspection

Radon-222:

•    is a gas;
•    is odorless;
•    is tasteless;
•    is invisible;
•    mixes with air;
•    is chemically inert (or non-reactive);
•    is found everywhere;
•    decays by alpha-particle emission; and
•    has a half-life of 3.8 days.

Radon Decay Products, or RDPs:

•    are solids, called daughters or progeny;
•    are chemically active;
•    are electrically charged;
•    can attach to air particles and cling to surfaces;
•    have a ratio of progeny-to-radon gas ranging from 0.3 to 0.7 ER (equilibrium ratio),
averaging 0.5 ER;
•    are short-lived (from 0.2 milliseconds to 26.8 minutes);
•    include Polonium-218, 214 and 210, which are alpha-particle emitters, and
these alpha-particle emissions can cause physical cellular damage, such as lung cancer.

Risk Assessment Facts

•    The EPA’s indoor radon program promotes voluntary public actions to reduce the risks from indoor radon.   The EPA and the U.S. Surgeon General recommend that people perform a simple home test using kits which are now widely available in stores.  If high levels of radon are confirmed, it is recommended that those high levels be mitigated or reduced using straightforward techniques.
•    The EPA recently completed an updated assessment of their estimates of lung cancer risks from indoor radon, based on the NAS’s 1999 report on radon titled “The Biological Effects of Ionizing Radiation (BEIR) VI.” This report is the most comprehensive review of scientific data gathered on radon, and builds on and updates their previous findings. The NAS concluded that homeowners should still test and, if necessary, mitigate their exposure to elevated radon levels in their homes.
•    Radon is a naturally occurring radioactive gas that is colorless, odorless and tasteless.  It’s naturally produced from the radioactive decay of uranium that’s present in soil, rock and groundwater. It emits ionizing radiation during its radioactive decay, changing into several radioactive isotopes known as radon decay products or RDPs.
•    Radon gets into the indoor air primarily from soil under building structures.  Radon is a known human lung carcinogen and is the largest source of radiation exposure and risk to the general public.  Most inhaled radon is rapidly exhaled, but the inhaled decay products readily deposit in the lung tissue where they irradiate sensitive cells in the airways, increasing the risk of lung cancer.
•    The NAS BEIR VI Report confirmed the EPA’s long-held position that radon is the second leading cause of lung cancer, and a serious public health problem. The NAS estimates that radon causes about 20,000 lung cancer deaths each year. The report found that even very small exposures to radon can result in lung cancer.  They concluded that no evidence exists that shows a threshold of exposure below which radon levels are harmless. The report also found that many smokers exposed to radon face a substantially greater risk of getting lung cancer compared to those who have never smoked. This is because of the synergistic relationship between radon and cigarette smoking.

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