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New Year

Residential Roof and Floor Framing Systems, Part 2: Conventional Framing

Submitted by Geoffrey D. Lowrey, National Property Inspections Franchise Owner, Winter Haven, Florida

In my previous blog article, I talked about prefabricated metal plated wood truss framing. This time, I will be discussing conventional roof and floor framing. I will describe the different components used in conventionally framed roof and floor systems, give a quick explanation on how these framing systems work, and I will describe some common issues that may be found during a home inspection.

I would like to note that conventional framing techniques also apply to both structural and nonstructural wood wall framing. I will not discuss these components in this article.

Conventional Roof and Floor Framing
Conventional framing is referred to as “conventional construction” in the International Building Code (IBC). The IBC defines conventional construction to be, “A type of construction whose primary structural elements are formed by a system of repetitive wood framing members.” These framing methods are based on time-tested prescriptive methods. In short, conventional construction does not require design or engineering, but it must be installed using proven construction techniques and methods.

Conventional framing members consist mainly of rafters and joists. These members are supported by and transfer loads through other members such as headers, beams and girders. Conventional framing members are usually rough-sawn or dimensional lumber. Member sizes are based on span tables.

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Figure 1: Common Conventional Construction Roof Framing Techniques

 

Figure 2: Conventional Construction Floor Framing System

Figure 2: Conventional Construction Floor Framing System

Conventional framing is more common in homes built prior to 1980, though it is still commonly used, at least in part, in modern homes. It is often used to create more complex roof profiles.

Bracing
Bracing is required in roof and floor framing systems for structural stability and to help transfer loads through the systems into the walls and, eventually, down to the foundation. Bracing in wood framing systems typically consists of dimensional lumber.

Common bracing used in conventionally framed roof systems includes collar ties and vertical/diagonal braces. Collar ties are horizontal members that tie rafters on each side of the ridge together to resist horizontal forces on the rafters that try to spread them apart. Vertical/diagonal braces are used to transfer loads from the rafters back to interior load-bearing walls.

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Figure 3: Typical Bracing for Conventionally Framed Roof Systems

Bracing used in conventionally framed floor systems is called bridging. Two types of bridge can be used, diagonal bridging and solid bridging. Bridging is used help distribute the load on a floor joist, helping the floor system to act as a unit; in other words, it keeps the floor from feeling like it is bouncing under foot. Bridging also prevents racking, or twisting, of the joists in the system by providing lateral support.

Figure 4: Bridging Details – Diagonal Bridging on the Left, Solid Bridging on the Right

Figure 4: Bridging Details – Diagonal Bridging on the Left, Solid Bridging on the Right

The following is a list of common problems that may be found during a home inspection:

  • Damage.
    • Broken, cracked or split rafters, joists, bracing, or support members or loose connections. These types of damages undermine the structure of the roof or floor and could lead to structural failure. Since conventional framing does not require engineering analysis, repairs do not necessarily require an engineer, but rather, can be installed by a qualified licensed contractor. If your inspector sees any of these conditions and it does not appear that a repair has been applied, then it should be reported in the home inspection and your inspector should recommend further evaluation by a qualified licensed contractor. Common repairs that may be visible during an inspection include scabbing or sistering of members to repair a broken member and headers to repair cut or missing framing.One instance I can remember where I saw damage to a conventional framing system is shown in Figure 5. The photo shows series of jack rafters attached to valley rafter (refer to Figure1b for a schematic of this framing configuration). The circled area shows a failed connection at the end of the jack rafter where it should attach to the hip rafter — the end of the jack rafter has been pulled away from the hip rafter. There is also some staining in this area, indicating a possible roof leak and perhaps some dry rot or decay in this area (refer to the next section). In this example, this damage was caused by a falling tree. This corner, obviously, was never properly repaired after the damage. From the exterior the roof surface in this corner appeared un-level, giving me the clue to concentrate on this area when in the attic.
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Figure 5: Example of Damaged Conventional Framing

  • Wood Destroying Organism (WDO) damage.  This can include anything from dry rot fungus in the wood truss members due to a roof leak or damage caused by wood destroying insects such as termites or carpenter ants.  If these conditions exist and there is significant section loss, the framing may no longer be able to function as intended.  Again, these conditions should be reported in the home inspection report.  The recommendation should be two fold.  First, recommend further evaluation and remediation by a licensed pest control operator to kill any living WDO – this recommendation would mainly be for wood destroying insect damage.  Second, you should recommend further evaluation and repair by a qualified licensed contractor.Figure 6 shows what WDO insect damage may look like.  The members shown here are floor joists as seen from a crawl space.  There appears to be significant section loss here, so repairs will likely be required.
Figure 6:  Example of Apparent Wood Destroying Insect Damage in a Conventionally Framed Floor Joist System

Figure 6: Example of Apparent Wood Destroying Insect Damage in a Conventionally Framed Floor Joist System

  • Missing framing members.  This condition my not be as apparent in a conventional framing system as it would be in a trussed framing system because there are no plates at joint locations.One instance where I’ve seen this is where an opening was installed in a framing system for attic access.  The opening required two ceiling joists to be cut in the process.  To do this properly, a double header of the same size and grade as the cut ceiling joists should have been installed at each end of the opening spanning between the adjacent un-cut joists.  These headers were not present.  Figure 7 shows a detail of the proper installation for this condition.
Figure 7:  Proper Framing Around an Opening in a Conventionally Framed Joist System

Figure 7: Proper Framing Around an Opening in a Conventionally Framed Joist System

  • Numerous Shiners – Shiners are nails that missed their mark when the sheathing was attached to the rafters or joists.  A few shiners here or there are probably not a big deal, but if there are long lines of shiners along the sides of several framing members, there is a problem.  This means the sheathing is not properly attached and the framing in these areas are not properly braced.  Depending on the severity of this condition, this can lead to structural failure.  If you see an excessive number of shiners during a home inspection, you should report this condition and recommend repair by a licensed roofing contractor.
  • Improper Bridging / Blocking – Most of the time, this is not something you will see, but rather feel.  Most of the time, floor framing systems are obscured by the floor and floor covering above and by the ceiling drywall and finish below, so the bridging / blocking is not visible.  Even if they were visible, a home inspector is not technically qualified to determine if there are enough of them or if they are spaced properly.  However, if you walk into an upper story room and you feel like you are walking on a very stiff trampoline, it is very likely the strongbacks were not properly installed.  Often, this is not a structural issue, but it is a serviceability issue since it gives an uncomfortable feeling to those walking through the room.  If you experience this issue during a home inspection, you should report the floor in that upper story room feels “bouncy” underfoot and recommend further evaluation and repair, as needed, by a qualified licensed contractor.  Figure 7 shows installation details for blocking/bridging in conventionally framed floor systems.

Final Thoughts
I hope this article was informative.  For more information about conventional framing practices and details, please refer to the American Forest & Paper Association’s Details for Conventional Wood Frame Construction at http://www.awc.org/pdf/wcd1-300.pdf.

Please note that I am writing this article from the perspective of a Florida home inspector.  If there are regional differences in my observations compared to what you are used to in your area, please forgive them.  I tried to be as general about this as I could.

Finally, because we are in the holiday season, I want to wish everyone a happy holiday season and very prosperous 2015!

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Ice Damming Spells Trouble for Your Home

Submitted by Scott Ward, NPI Franchise Owner, Southern Johnson County, Kansas

Winter House_shutterstock_93938941In parts of North America that are now experiencing accumulations of snow and ice, ice damming can cause water damage and stains on both exterior and interior walls and ceilings. Ice damming occurs when snow and/or ice builds up in gutters, roof valleys, and roof-to-wall intersections and then begins a series of freeze/thaw cycles. Snow and ice melt, typically in daylight hours, can be combined with heat radiated from the home itself, then refreezes at night when temperatures drop. The melted snow travels downward until it hits the ice-filled gutters or valleys and begins to back up and refreeze.

This moisture can actually work uphill, refreezing under roofing and flashing materials. Later, when warmer conditions prevail, this ice buildup melts, many times draining back through the roof and walls.

One indication of ice damming is large icicles forming from gutters or roof edges. Water stains that mysteriously appear in the winter along exterior walls and ceiling can usually be traced back to ice damming. Ice can also accumulate in attic and wall cavity areas that are not easily visible.

Once the ice is formed, it is usually not practical to attempt to melt it away due to the inherent danger of snow, ice and roofs and ladders. If the problem is chronic, as it may be in the northern sections of North America, gutter heaters are available at many home improvement retailers. Most use a heat tape type strip, similar to heated pipe wrap, to increase the temperature in the affected gutter or valley to prevent ice from building up. Some are even equipped with thermostats that will turn them on and off as temperatures fluctuate.  These are fairly easy to install and simply plug into an exterior outlet.

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A Special Message From NPI and GPI

Happy Holidays

What You Need to Know About Fire Extinguishers

Submitted by Jon McCreath, NPI Franchise Owner, Emerson, Georgia

Fire Ext 1The vast majority of today’s modern homes have smoke alarms, whether they are hard-wired and battery-operated or simply battery-operated. Current guidelines require smoke detectors in all bedrooms, in central halls outside bedrooms, and a minimum of one on each floor, including basements.

But what about fire suppression, i.e., fire extinguishers? While fire suppression systems may be required in certain types of buildings or in some new construction, there really isn’t any current standard for placement of fire extinguishers in homes. The National Fire Protection Association (NFPA) does recommend having a fire extinguisher on each floor of your home, as well as having a fire plan, which would include making sure that the family knows escape routes, where to meet outside and how to call 911.

Fire extinguishers can provide for emergency situations by allowing you to extinguish small fires, or suppress the flames prior to arrival of fire department. So, what information should you know before purchasing a fire extinguisher(s) for your home?

  1. Is bigger better? Not necessarily. In most cases a bigger extinguisher will be heavier and could make it more difficult to maneuver. Generally, a 2- to 5-lb. extinguisher is adequate for most homes. Remember, the weight on the extinguisher refers to the amount of chemical inside, and the canister may add several pounds.
  2. Rechargeable vs. Disposable. Rechargeable extinguishers have metal valves and cost more. Disposable extinguishers have plastic valves and are less expensive. However, refilling a rechargeable extinguisher once the contents are low may still be less expensive than replacing with a disposable extinguisher.
  3. What do the numbers and letters mean? The letters indicate what type of fire the extinguisher is rated for. Class A extinguishers are designed for ordinary combustibles, such as wood, paper, cloth and plastics. Class B extinguishers are designed for flammable liquids, such as gasoline, oil and grease. Class C extinguishers are designed for electrical fires.Fire Ext 2The numbers that may precede a letter indicate the extinguisher’s effectiveness against each type of fire, regardless of its weight or the chemical it uses. Higher numbers mean more effectiveness, although you won’t see a number preceding the letter C — the C simply means that the extinguishers chemicals won’t conduct electricity. A 4A rating means that it will put out twice as much fire as a 2A. You should look for an extinguisher that has an ABC rating. Lastly, make sure that the extinguisher has a UL (Underwriters Laboratories) listing.
  4. Where should I keep the fire extinguishers? It is generally recommended that that you keep one on each floor of your home, plus one in the garage. They should be easily accessible and not buried behind other household items. You may also want to consider keeping one in your vehicle. Make sure that you have an extinguisher with a BC rating in the kitchen.
  5. How often should I check my extinguishers? It is recommended that you examine your extinguishers on an annual basis. Extinguishers can lose pressure over time, which may render them useless in the event of an emergency. Rechargeable extinguishers should be serviced annually by the manufacturer. Once an extinguisher has been used, it should be discarded or refilled.
  6. How do I use a fire extinguisher? Remember this acronym: PASS. Pull the safety pin. Aim toward the source of the flame. Squeeze the trigger continuously. Sweeping motion over the flame source.
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Be Energy-smart This Winter

Infrared House_shutterstock_108938912In the Midwest and northern parts of North America, winter means higher energy costs, and who couldn’t use to save a few bucks? But regardless of what region you live in, a few simple tips can help save money on energy costs and keep your home cozy.

First, you might want to have an energy audit performed on your home. Performed by a professional, an energy audit typically checks for leaks, examines insulation, inspects the furnace and ductwork, performs a blower door test and uses an infrared camera to determine points of heat loss on your home. After the audit, you’ll have a report listing areas where heat is escaping.

One of the easiest ways to save energy is to be sure you have the appropriate amount of insulation in your attic. Fourteen to 20 inches is usually recommended. If you have less, then you’re wasting energy in both the winter and summer months. An insulation company can easily blow in more insulation to get you where you need to be.

Another simple way to reduce energy costs year round is to caulk and seal gaps and cracks around windows and doors.

Duct sealing is another way to improve energy efficiency and reduce energy bills in the summer and winter. Many homeowners choose to hire a contractor to seal their ducts, as the entire duct system will need to be checked and sealed. If you choose to seal your ducts yourself, start by sealing all leaks using mastic sealing or metal tape (NOT duct tape, as it isn’t long-lasting) and insulating all the ducts that you can access, including those in the attic, garage and crawl space. Then, make sure that the connections at the vents and registers are well-sealed where they meet floors, ceilings and walls. For more information about duct sealing, visit http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_ducts.

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What’s Wrong With This Photo?

Furnace ventingA. Duct tape can be used to seal joints for PVC connections on condensing furnaces.

B. This installation passed city inspections.

C. PVC vent pipe connections must  be glued together and not duct-taped together.

D. Foil tape is a better choice for sealing these types on connections.

Correct Answer: C. PVC vent pipe connections must  be glued together and not duct-taped together. True story, an elderly lady died from carbon monoxide poisoning as a result of a negligent HVAC contractor.

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What Will My Inspector Check on the Furnace?

FurnaceThere are a lot of different ways to heat our homes: solar, hot water circulating, steam, wood-burning, oil furnace, gas furnace and heat pumps, just to name a few. There are pros and cons to each, and geography plays a role. For example, electric radiant heat in the ceiling is probably not the best choice for northern Michigan, but might be a reasonable choice for a temperate climate like Tennessee. Most of us think of heating our homes with a furnace. (Collectively, some people refer to furnaces as “air-handlers.”) A good inspector will first identify the type of furnace and then will focus on specific things relative to that type of furnace.

A gas furnace is one of the most common and, although there are numerous things an inspector will look for, three of the most common are the following:

  1. Is there enough combustion air and where is it coming from?
  2. The condition of the furnace flue and whether the burned gases are venting properly to the outside.
  3. Are there any gas leaks?

One of the most important components of a gas furnace is the heat exchanger. In short, this is a sealed chamber where combustion takes place and the burned gases are directed to the furnace flue, to be safely vented to the outdoors. Inspecting a heat exchanger is difficult because it’s mostly hidden/enclosed inside the furnace cabinet. Determining whether there is a crack in the heat exchanger is a difficult task, but it can be done using certain gas detectors, carbon monoxide detectors and chemical tests.

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A Better Inspection for Your Dream Home

Couple in house + inspection reportAfter carefully searching for just the right home, you’ve found one that fits the bill — your dream home. You’re excited about the move, but also a little unsure. How can you be certain that you’re making the right decision?

One way is to have the home inspected by a professional home inspector. This will help you understand the condition of the property and avoid unwanted surprises. When looking for an inspector, seek someone has experience, and ask them about their training and background. They should be professionally trained, and they should be certified or licensed where applicable. (Not all states and provinces require certification/licensure.) The inspector should be able to answer your basic questions, such as whether they are insured and bonded.

Keep in mind that a home inspection is a comprehensive visual assessment of the home and all of its systems and components at the time of the inspection. But not all home inspections are created equally.

Why Our Inspectors Are Better
Founded in 1987, NPI and GPI are proud to be among the oldest and most widely respected names in the home inspection industry. Our professionals have assessed more than 2 million properties in the United States and Canada, focusing on detailed, quality inspections and customer service.

NPI and GPI inspectors attend an intensive two-week training course at our home office in Omaha, Nebraska, and then they attend about 80 hours of field training with another NPI/GPI inspector. Keep in mind, too, that our inspectors are backed by a national company, and they have tech support available seven days a week from our home office should they have a question about something on your home.

The NPI and GPI Home Inspection
For your peace of mind, it’s important to understand everything possible about the home you are about to purchase. NPI and GPI inspections are designed to meet strict industry standards (such as ASHI and InterNACHI) and cover the home from roof to foundation:

  • Lots and grounds, including grading, walks and driveway
  • Roof
  • Exterior surfaces and siding
  • Garage (attached or detached)
  • Attic and insulation
  • Bathrooms
  • Electrical system
  • Lighting control systems
  • Fireplace(s)
  • Kitchen
  • Structural components
  • Heating system
  • Air conditioning
  • Plumbing system and fixtures
  • Windows and doors
  • Interior rooms
  • Basement/crawl space

You may attend your entire home inspection or just the summary at the end. Your NPI or GPI inspector will provide you with a written inspection report that gives you a complete and accurate account of your home’s condition. The easy-to-read inspection summary and report lay out information for your use today and in the future.

Life is full of surprises, but that shouldn’t include the new home you’re purchasing. A home inspection will set your mind at ease. A home inspection by NPI or GPI is a cut above the rest.

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Perplexed About PEX Plumbing? We Have Answers

Submitted by Rodney Twyford, NPI Franchise Owner, San Antonio, Texas

PEXModern plumbing as we know it has only been around during the last 100 years and has vastly improved over the years. Initially, the first water distribution pipes were made of clay, wood and lead. In the 1950s, most indoor water pipes were made of galvanized steel, followed by copper. During the expansion of the economy, the need for better, corrosion-resistant materials and ease of installation became a necessity.

During the early 1960s, plastic piping was introduced and offered as a great alternative to metal materials. PVC (polyvinyl chloride) and CPVC (chlorinated polyvinyl chloride) were successes where others such as polybutylene piping were failures.

So, What Is PEX?
PEX is an acronym for cross-linked polyethylene. As early as the 1930s PEX materials were being developed, in the late ’50s, scientists worked on the structure of the polyethylene to strengthen the connections between the polymer chains by developing ways to create additional ties between the PE molecules through covalent or chemical bonding.

During the late ’70s, PEX was mainly used for radiant floor heating; however, PEX is now a recognized alternative to other materials and is predominantly used for domestic water distribution in most residential homes.

Advantages of PEX

  • PEX costs approximately 25 percent less than alternative plumbing systems and takes less time to install, resulting in reduced labor costs.
  • PEX is a flexible and easily adaptable plumbing system that can be bent around most wide-radius turns without the use of elbow fittings, saving time and materials.
  • PEX typically provides greater water pressure at each fixture with fewer transition fittings that cause turbulence resulting in pressure drop.
  • PEX can be connected to almost all other types of plumbing materials, making it a popular choice for repair and remodeling projects.
  • PEX is suitable for hot and cold water. It is more resistant than other materials to freezing and high-pressure expansion conditions, and it is resistant to corrosion.
  • PEX can be installed with a manifold system, making it convenient to shut off individual fixtures without the need to shut off all plumbing.

Disadvantages of PEX

  • PEX can be damaged from chemicals such as pesticides and even by pests themselves.
  • PEX cannot be installed near high-heat locations, such as recessed lights and water heater flues.
  • PEX cannot be used outdoors with direct exposure to sunlight. Most PEX products have a limited UV resistance and must be protected during storage, while on the construction site and during long transports. How many times have you seen a pickup truck carrying rolls of red, blue or white PEX plumbing and wonder if they are just transporting it short term or has it been on their truck for months just waiting to be used in someone’s home?

Not All PEX piping Is Created Equally
PEX piping is required to have a four-digit material designation code. This numeric code is located after the brand name printed lengthwise on the pipe. The codes are tested in accordance with and defined by the American Society for Testing Materials (ASTM).

ASTM F2023 is the standard required for testing for chlorine resistance. The first digit in the code is the designation for chlorine resistance. A 5 rating as the first digit is the highest classification for chlorine resistance and indicates that the PEX pipe has been tested and meets the requirements for minimum chlorine resistance at end use conditions 100 percent of the time at 140°F (60C). A 3 rating indicates 50 percent, and a 1 rating indicates 25 percent of the time at the same temperatures. A digit of zero indicates that the pipe has not been tested or rated and should not be used for drinking water.

ASTM F2657 is the standard required for evaluating the UV exposure of PEX. The second digit in the code determines the limits to UV exposure. For example, PEX with a 5106 code has a “1” in the second digit, and indicates that the tubing material meets the minimum UV resistance requirements for a period of only 30 days. A code 5206 has a “2” in the second digit, indicating the tubing meets the minimum requirements for 90 days. The highest and best exposure is a code such as 5306; this is typically a multilayer tubing and meets the minimum requirements for UV exposure of still only 180 days.

The third and fourth digits are for hydrostatic design stress (HDS) as tested in accordance with the Plastics Pipe Institute (PPI) Technical Report TR-4. A digit of 06 indicates that the PEX piping has an HDS of 73°F (23°C) at 630 pounds per square inch (psi). A digit of 08 indicates that the PEX piping has an HDS of 73°F (23°C) at 800 psi.

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