Inspecting Modular Built Homes

 

Inspecting Modular Built Homes

Many people confuse modular homes with manufactured homes. Mobile or manufactured homes are built on steel frames called chassis and they cannot be removed. The chassis are used to support the homes and transport them to their permanent locations. These homes can either be placed in “parks” where other manufactured homes are also placed or be fixed on a permanent foundation, which may qualify them as traditional homes.

Modular homes are built in units that are joined together on-site and, unlike a manufactured home; they can be built as a multiple story house. Modular homes are built with wooden beams that use steel supports which make it possible for the modules to be stacked, allowing the homeowner to have a basement and multiple stories.

Modular homes are built with a process that involves the construction of components in a factory. It starts with a wood frame floor built to attach the wall panels later. The builders will then use fasteners to attach the wall panels. The window openings are already cut out before they are attached. As the structure is built, the drywall, ceilings, plumbing, and electrical wiring are installed under the close supervision of inspectors.

The roof is attached in one of two ways depending on the builder. Some manufacturers will build the roof and then set it on top of the walls. Other companies will send the roof separately and attach it on-site.

The final step is adding the exterior and interior finishes. The buyer can customize their own finishes such as the siding, the cabinets, flooring material, backsplash, vanities, countertops, and many other finishes.

The modular units, are usually shipped with a layer of plastic wrap suitable for transportation purposes only. Failure to erect these assemblies on a timely basis may result in serious weather damage and molded areas. Modular homes are inspected like a “stick built” house; however there are some areas that an inspector should pay close attention to:

- An energy seal should be installed by the factory around the perimeter of the marriage wall.

- To ensure an energy-efficient seal between the modules, a foam gasket or other sealant should be used for this insulating process.

- The perimeter rail of the structure is nailed to the sill plate with 16d nails @ 12” O.C. (For basement sets, all lally columns are located per the recommended schedule and lagged to marriage wall floor rails/girders with four 3/4” x 4” lags each one preferably into each rail. Additional columns are required under each side of marriage wall opening in excess of 52”.)

- The first two modules are bolted together, using 1/2” through-bolts.

- If the home is a two story, the rails of the first floor are bolted together with 1/2” bolts @ 4’ O.C.

- The third module should set on top of the first module, in the same manner as the first. The second floor rails should be fastened to the first floor ceiling rails with 16d nails @ 12” O.C.

- Spray foam is put in place around the marriage wall perimeter.

- Roof center beams must be nailed with a 16d nail @ 8” O.C. in height and 12” O.C. in length, staggered, after leveling the beams to each other.

-  Fire stop should be installed in chase areas to assure a maximum of eight feet of vertical distance.

- For an open roof system; fasten truss knee wall to ridge or rafters as per plans.

- Ensure floors are level and not damaged

- The center beams should be bolted together per specifications

- Check factory installed interior / exterior doors for proper working order.

- Drywall cracks, especially at marriage wall openings.

- Check the connection of water lines between modules

- Connection of electric panel to main service and between modules. There may be electrical connection junction boxes where the modules are joined

- Connection of hot water heater to main plumbing pipes.

- Connection of mechanical equipment, furnace, air conditioning, etc., to main systems.

- Ensure there is a bottom sheathing board that completely covers the sill plate

- Examine sheathing splice at marriage wall openings.

- Examine marriage wall doors and cased openings.

Inspecting The Square D QO Electric Load Center

 

Inspecting The Square D QO Electric Load Center

The Square D – QO and Homeline load centers have some unique features. It is important to note the proper breakers must be used. I know you are thinking; load centers should always have proper breakers, however these breakers are different than ones you are used to seeing. The Neutral Load Centers are specifically built for Arc Fault, Ground Fault, and dual function breakers. Pig tails on these types of circuit breakers have been eliminated using the Square D Plug-on Neutral breakers. This also reduces clutter and additional connections in the panel. These new circuit breakers also have special diagnostics to identify the type of fault that last occurred by holding the test button down. If the breaker trips immediately, it is detecting a fault. If the breaker trips after a 2 second delay, it is detecting an Arc Fault. If the breaker trips after a 5 second delay, it is a thermal overload or short circuit. This is great technology and identifies an issue on the circuit. So what should a home inspector be looking for:

 

• The QO load center will have an extended neutral lug on both sides of the panel (this can be seen in the picture above)
• The specific “Plug-On Neutral” circuit breakers for this load center connect at the rear of the breaker to the extended neutral lug
• Neutral pigtail’s are not present on these breakers
• If you see a AFCI or GFCI circuit breaker with a pigtail connection, it is not the proper breaker
• The Quick-Grip Wire Management System eliminates most knockout removal
• The Quick-Grip Management system is UL Listed and Code Compliant
• Eliminates most box connectors
• Wires connect from the front of the panel and are covered by a protective shield.
• There is less of a chance of conductors shorting on the panel
• Quick-Grip connectors can hold up to 5 NM-B wires

Why Are The Air Conditioning Ducts Sweating?

 

Why Are The Air Conditioning Ducts Sweating?

We are conducting an inspection on a hot day and the air conditioning is running; which is something I am always grateful for. In the basement, attic, or crawl space we see the ducts or the air handler sweating. Sometimes we see the copper suction line sweating. Our client asks; “why is there water droplets on the ducts (or unit)”? I have heard home inspectors give different answers to this issue. I know some say this is “normal”. Normal does not mean acceptable, and I take issue with “normal”. Sweating ducts can cause mold issues in areas we can’t see over time. I have seen ceilings covered with mold from sweating air conditioning ducts. One of the issues I see overlooked by not only home inspectors, but installers is the size of the air conditioning system. I hear installers say; “we use 3 ton units on all houses”. Sure they won’t get a call back. The homeowner sets the temperature to 60-65, and the house is cold, but not properly dehumidified. I have seen “professionals” recommend that a dehumidifier is installed to control sweating ducts. A properly sized unit should dehumidify the air. Actually this is the most important part of a properly sized system. I have seen people set the temperature at 60 degrees F! Air conditioning is about humidity reduction. A 78 degree, 48% humidity house will feel great. A house at 60 degrees and 90% humidity will feel cold and clammy because the humidity has not been properly reduced. An oversized unit will shut down long before the house is properly dehumidified. An air conditioning system that is too large will run in shorter cycles of less than 12 minutes. This is because the system will quickly cool the air and shut the thermostat down without properly cooling the entire space. This causes the system to shut off without running long enough to cool the furthest rooms in the house and properly dehumidify. The thermostat should be set around 78 degrees F. If you set the air conditioning temperature higher, then the temperature of the return air will also be higher and there will be less chance of sweating. Short cycles will cause temperature variations and areas of the house that are not properly dehumidified. 1 ton of cooling (12,000 BTU’s) should be adequate for every 1000 square feet of well insulated space. This number could be higher or lower depending on many factors including; house layout, insulation, air leakage, etc. Always recommend your client seek the advice of a qualified HVAC contractor. So what else may cause air conditioning ducts to sweat?

1.     Duct Insulation – Duct insulation is most important. We have cold, dehumidified air traveling in a space that is hot and humid through a thin metal duct. The same analogy applies to a cold glass of water sitting on a table on a hot summer day. All ducts should be properly sealed. Gaps or missing insulation will cause air loss and moisture.

2.     Sealing a Crawl Space – If the crawl space is not properly insulated, including a proper vapor barrier on the floor that will increase the chances of condensation on the ducts.

3.     Proper Attic Ventilation – I know many individuals don’t recommend attic ventilation anymore (which I disagree with), however a very hot attic, with cold ducts running through it, will cause condensation.

4.      Poor Air Flow – The biggest reason for this is a clogged or dirty filter. This is the easiest fix of all. I have seen furnace heat exchangers ruined because of a clogged filter. Damaged, dirty, or blocked vents can also cause improper air flow.

5.     Icing of the Evaporator Coils – Causes of this are a clogged air filter, dirty coils, or an undersized or improperly functioning system.

6.     Blocked Condensate Discharge – Chilled condensate water will back up into the condensate tray in the air handler mixing with the warmer air creating condensation.

Common Code Misconceptions & The Home Inspector

 Common Code Misconceptions & The Home Inspector

I know what you are saying; “why is he talking about building codes”. You are right. A home inspection is not a code inspection. But there are many areas where the two do intersect. Here are some issues I would like to address. I know some of my clients have asked me some of the following questions, and I must admit I was caught off guard at times. I never like to be caught off guard!

• You see a joist hanger where the wood member is not tight to the back of the bracket.
• Is there a difference between a stair railing and a guard railing?
• How should plywood or OSB be installed for a roof deck or floor structure?
• Insulation with exposed kraft paper vapor barrier
• CSST Bonding

 Many times I see wood members that are not fully seated against the back of a joist hanger or other metal bracket. Sometimes we see a complete structure where the members are not fully seated. Many staircases, especially in older homes actually have a “guard” being used as a railing. To ensure the structural integrity of walls and roof systems, there is a proper way to install plywood or OSB. Many times we see very small pieced sections. We regularly see exposed kraft paper insulation in different areas. So what should a home inspector be looking for:

 Joist Hanger Installation

-        The connection between the structural member and the joist hanger should be tight. This included trusses. Sometimes the lumber may have been wet and has shrunk. Anything more than 1/8” gap may decrease capacity or strength intended. Some manufacturers have resources that include repair techniques and load reduction based on the gap or connection. 

What is the Difference Between Stair Railings & Guards?

-        A railing is for “gripping” or “grasping” and must extend from the top step to the bottom step. A railing must be easy to hold on to where you can close your hand around it. A railing should be continuous. You should not have to let go of it and re-grasp. The ends of a handrail should be turned back to a wall or post. It should not contain open areas that may catch clothes or anything else being carried. A guard wall is built at the edge of a elevated surface to prevent someone from falling. Guards could be decorative like a bench or row of cabinets. A guard could be also be used as a hand railing, however the requirements for a hand railing must be met.

How Should Plywood or OSB be Installed For a Roof Deck or Floor Structure?

-        Most accepted standards recommend sheeting extends over three rafters or floor joists. This standard applies to sheeting that is at least 24 inches wide. Smaller panels require solid blocking and or “H” clips.

Insulation With Exposed Kraft Paper Vapor Barrier

-        The paper facing is combustible and must be covered by an acceptable material like drywall. It should not be exposed to air. This warning is printed on the face of the paper: “WARNING: This facing will burn. Do not leave exposed. Cover with approved building material in contact with facing. Keep open flames and other heat sources away from facing. See package for warning, fire hazard and installation instructions…”

CSST Bonding

-        CSST must be bonded to the electric service grounding with at least a number 6 AWG copper wire or equivalent. This requirement is for every section of CSST if not connected to a bonded section.

Direct Vent Gas Fireplace Clearances

 

Direct Vent Gas Fireplace Clearances

                                       

I see many wood burning fireplaces converted to gas units. I prefer vented gas units instead of “unvented gas logs” for many reasons. Sometimes we see the vent located in areas that may seem unacceptable. Venting from the unit will differ depending on the manufacture. However there are some requirements that most manufacturers recommend. The use of flexible metal pipe is acceptable. Metal vent pipe that penetrates a wall must have an approved sleeve. Sometimes called a through the wall thimble. Horizontal and vertical termination caps are different. I have seen them improperly installed. The length of the vent pipe will be diminished by the number of elbows used. These units cannot be joined to any other appliance. If you notice the flame burning blue and appear to be “lifting off” the burner it may indicate blockage, vent pipe leaks, or improper vent cap installation. So what else should a home inspector be looking for:

•  Horizontal and vertical termination caps are different. (Refer to the diagram)
• 3 feet of vent length should be subtracted for every 90 degree elbow
• 1 ½ feet of vent length should be subtracted for every 45 degree elbow
• Horizontal termination clearances should be 3 inches at the top, and 1 inch on the other 3 sides
• The heat shield should be flush with the wall
• Horizontal installation requires ¼ inch of rise for every 12 inches of travel

LOCATION CLEARANCES (see diagram)

·         Above grade, porch, deck, & balcony – 12”

·         Operable window – 9-12”

·         Fixed window – 12” (to prevent condensation)

·         Vinyl siding – 12”

·         Ventilated soffit- 24”

·         Unventilated soffit – 12”

·         Outside / inside corner – 12”

·         Electric meter – 3 feet

·         Gas meter – 3 feet

·         Combustion air supply (non-mechanical) – 9-12”

·         Mechanical air supply (including HRV) 3 feet above if within 10 feet

·         Above paved sidewalk or driveway – 7 feet

·         Under porch, deck, & balcony (must be opened on at least 2 sides) – 12”

·         Between two horizontal terminations – 12”

·         Between two vertical terminations – 12”

·         Above another direct vent gas appliance termination – 12”

·         ALWAYS check the manufacture recommendations and local municipality requirements

The Mysterious Oily Green Residue On Electrical Equipment

The Mysterious Oily Green Residue On Electrical Equipment

This may be an old topic for seasoned home inspectors, however I feel it is worth taking another look at this issue. I first noticed this several years ago, and am not to proud to admit that I thought it was dielectric grease. After further research I discovered that this is actually the breakdown of a “plasticizer” used for the wire insulation. They added this to make the wire more flexible. Elevated temperature and possibly humidity can cause the plasticizer compound to separate from the insulation on the wire. The plasticizer can then travel along the wire and be visible on the exposed part of the wire or on a device like a circuit breaker or receptacle. Common wire insulation has an outer nylon jacket. The plasticizer cannot penetrate this jacket, therefore it runs down the wire strands or conductors. This is why it is most noticeable where the wire conductors are exposed or at a termination. The effects of this process cause the wires to become less flexible and more brittle. Residue on devices may also cause connection issues and possibly failure. What should a home inspector be looking for and how to advise your client:

 

• Green oily residue – this should not be confused with dielectric corrosion
• The surfaces should not be cleaned
• This may be confused with lubricant use to pull wires.
• The oily residue is normally found on the ends of the wires or where the conductors are connected to a device, NOT on the outside where a lubricant may have been applied in order to pull wires through conduit
• If this residue is observed, the electrical equipment and devices are probably damaged. The residue may have entered the inside of the components
• The “plasticizer” is a petroleum based product and may cause deterioration to insulation used in some electrical devices
• Recommend your client seek the services of a qualified electrician to evaluate and replace any areas where this has taken place

Cantilevered Areas

Cantilevered Areas

Cantilevered areas and “allowable spans” are always of concern to home inspectors. For a couple reasons: 1 – many times we are unable to view the structure where these cantilevered areas are. 2 – There seems to be confusion on the requirements for cantilevered areas.

The distance your joists can safely cantilever or overhang is determined by the size of the joists, the wood type and grade of the lumber and the spacing between joists. Many building departments limit joist cantilevers to 24" maximum. Cantilevered areas are also prone to damage at the area where they exit the structure. The American Wood Council states that cantilevers are limited to 1/4 the span of the joists, (refer to the chart above). Specifically the joist must back space at least 3 times the distance of the cantilever if the cantilevered area is supporting a wall or roof. The member should back space at lease 2 times the distance of the cantilevered area if not supporting a wall or roof structure. What should a home inspector be looking for;

• A general home inspector rule of thumb in the field; cantilevered distance should be no more than 2 times the width of the joist. For example a 2x10 joist actually  measures 9 ½”. Therefore the cantilevered distance should be no more than 19 inches.
• Examine both areas inside and outside of the house for damage or deflection
• Joists or members should be installed “crown up”
• Maximum allowable overhang cannot exceed 1/4 of the actual main span.
• Evidence of leaks  / moisture at the house insertion, inside and outside
• Proper flashing and counter flashing should be visible
• An adequate drainage plane ensuring water is drained away from the structure
• If possible, check the basement structure to ensure the cantilevered section is properly installed
• A minimum of 5 framing nails should be used to attach the joists to the rim joist