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Here's the 30 most recent of over 1,600 home inspection blog entries. You can also use the Blog Index link above, or Google Custom Search box below, to find the article with the info you need. Also, our Blog Archive lists all the articles, including a reposting of earlier blogs from www.mcgarryandmadsen.com dating back to 2011.

5

How To Look at a House

recent blogs

Can you use PVC pipe for the water heater temperature pressure relief (TPR) discharge pipe?

Tuesday, October 15, 2019
Can you use PVC pipe for the water heater temperature pressure relief (TPR) discharge pipe?

No. PVC pipe is not rated by the building code for use with hot water, so the installation shown above is wrong and unsafe. If the temperature and pressure relief (TPR) valve opens because the water heater is overheating, the water will be over 200º F. This will cause the PVC pipe to first deform, and then collapse, which constricts the flow and defeats...

What is a "dead front GFCI" or "blank face GFCI"?

Tuesday, October 15, 2019
What is a dead front GFCI or blank face GFCI?

It looks like a push-button wall switch to some people, but is actually a Ground Fault Circuit Interrupter (GFCI) device that provides shock protection for a remote appliance or receptacles, and is called “dead front GFCI” or sometimes “blank face GFCI.” One is shown above at left, next to a regular GFCI receptacle on the right side.

...

What factors can change radon test levels up or down?

Monday, October 14, 2019
What factors can change radon test levels up or down?

Radon is a naturally occuring radioactive gas that is a byproduct of the atomic decay of radium in the ground. It has about a 4-day half-life, so the radioactivity of radon emitted a month ago is pretty close to zero today. But, while it is fresh, the radioactivity of the gas can damage your lungs and increase your risk of lung cancer. See our blog...

Does the receptacle outlet in a garage for a sprinkler control panel have to be GFCI-protected?

Sunday, October 13, 2019
Does the receptacle outlet in a garage for a sprinkler control panel have to be GFCI-protected?

Because a sprinkler control panel mounted on the wall of a garage is considered by the National Electrical Code (NEC) to be a dedicated appliance that is not easily movable, it was allowed an exemption for many years from the requirement for GFCI-protection for garage receptacles. But the receptacle that it was plugged into had to be a single-outlet...

SPRINKLER SYSTEMS

Sunday, October 13, 2019
SPRINKLER SYSTEMS

Here’s links to a collection of our blog posts about “SPRINKLER SYSTEMS":

• Why is a backflow preventer required on lawn sprinkler systems?

• What is the difference between regular tap water and recycled/reclaimed water for landscape irrigation? 

 • What problems does a landscape sprinkler system have when it is not...

What is the NEC disconnect requirement for permanently connected appliances rated at not over 300 volt-amperes (watts) or 1/8 horsepower?

Saturday, October 12, 2019
What is the NEC disconnect requirement for permanently connected appliances rated at not over 300 volt-amperes (watts) or 1/8 horsepower?

Small motorized appliances such as a ceiling fan or a gas tankless water heater formerly required a disconnect device, but it was not required to be within sight of the appliance. The disconnect could be a switch or the branch-circuit overcorrect device (circuit breaker). 

    But the 2017 edition of the National Electrical Code at 422.31...

Is a ceiling receptacle outlet for a garage door opener required to be GFCI protected?

Thursday, October 10, 2019
Is a ceiling receptacle outlet for a garage door opener required to be GFCI protected?

It is now, but was not previously required. The issue is not that it is for a garage door opener, but that the receptacle is on the garage ceiling. And there is also a little twist in how it must be GFCI-protected. Here is a National Electrical Code (NEC) timeline:

• 1978 NEC - Garage receptacles first required to be GFCI-protected. But...

What are the problems with underground return air ducts?

Wednesday, October 9, 2019
What are the problems with underground return air ducts?

Under-floor-slab return air ducts were briefly popular in our North Florida area during the late 1950s and early 1960s. They were usually in upscale, midcentury modern homes. We guess it was considered cutting edge technology at the time, but now these old underground ducts are a liability for two reasons: 

Corrosion and settlement have...

What is the minimum slope of a flat roof?

Wednesday, October 9, 2019
What is the minimum slope of a flat roof?

Minimum slope is 1/4” vertically per foot (12”) horizontally, according to both the International Residential Code (IRC) and the Residential Edition of the Florida Building Code (FBC). Roofs that are often called “flat” are actually very low slope, to promote water runoff and avoid standing water, which is called “ponding.” To learn more, see our...

FLAT ROOFS (LOW SLOPE)

Wednesday, October 9, 2019
FLAT ROOFS (LOW SLOPE)

Here’s links to a collection of our blog posts about “FLAT ROOFS (LOW SLOPE)":

• What causes bubble-like blisters in a built-up and gravel roof?  

• Why does it cost so much more to replace a steep roof than a low slope roof? 

• What is "ponding" on a flat roof?

• Why is there no attic access hatch in the...

When did circuit breakers replace fuses in homes?

Tuesday, October 8, 2019
When did circuit breakers replace fuses in homes?

Although circuit breakers for residential panels were available in the 1930s, the earliest examples we have seen date from the 1940s. The one shown above is a Westinghouse from a house built in 1947. Based on the thousands of older homes we have inspected in Florida, it appears that the switch began to surge in the 1950s and was complete by the late-1960s.

How did people stay cool in Key West before air conditioning?

Monday, October 7, 2019
How did people stay cool in Key West before air conditioning?

The “Conch House" is a unique, traditional way of constructing a home for the year-round hot weather of Key West that dates back over 100 years. It’s wood-frame, tin-roofed and has multiple passive cooling features. Until recently, most architects considered them to be charming but antiquated relics.

    Luckily, during the mid-twentieth...

Can circuit breakers be installed upside-down, with the breaker "ON" in the down position?

Monday, October 7, 2019
Can circuit breakers be installed upside-down, with the breaker ON in the down position?

No, to avoid confusion, breakers mounted vertically cannot be “ON" in the down position according to the National Electrical Code (NEC 240.81). But there are two reason why you may see it anyway:

The NEC requirement did not enter the code until sometime in the 1970s. There are plenty of older panels that predate the code change, with two...

What does "maximum sum of breaker ratings per stab" mean in an electrical panel?

Monday, October 7, 2019
What does maximum sum of breaker ratings per stab mean in an electrical panel?

It is the maximum allowable total amperage of the two breakers, or possibly three or four if tandem, breakers that are connected to a single “bus stab,” which is a metal finger bent outward from the bus bar in a panel. The bus stab is a connection point through which the current flows into the breakers. For a more detailed explanation, see our blog...

What is a "high drain loop" or "air gap" in a dishwasher drain hose?

Sunday, October 6, 2019
What is a high drain loop or air gap in a dishwasher drain hose?

They are the two ways to prevent backflow and get good drainage between a dishwasher and the drain connection at the sink tailpiece or disposal. It’s your choice of which one to use, but the code requires one or the other. 

   The Residential edition of the Florida Building Code, at 802.1.1.6, states that “the waste line of a domestic dishwashing...

How far away from the sink can I install a dishwasher?

Sunday, October 6, 2019
How far away from the sink can I install a dishwasher?

Most manufacturers specify a 12-foot maximum. Some state it as “distance to drain,” while others specify it as the length of the drain hose, which is more restrictive because the hose must rise up to the bottom of the counter top for a “high drain loop” or “air gap,” and then back down to the drain, which uses additional hose length.

...

Can a dishwasher drain hose be connected after the sink trap (to the trap arm)?

Saturday, October 5, 2019
Can a dishwasher drain hose be connected after the sink trap (to the trap arm)?

No, the dishwasher discharge must be connected before the trap. According to the Florida Plumbing Code it must "discharge into a wye branch fitting on the tailpiece of the kitchen sink or the dishwasher connection of a food waste disposer.” The International Plumbing Code citation is similar. 

    There is also an alternate method allowed,...

When is safety tempered glass required by code for glass near a door?

Saturday, October 5, 2019
When is safety tempered glass required by code for glass near a door?

Any glass within 24-inches of a door along the same wall as the door or perpendicular to it that is less than 60-inches above the floor must be safety tempered glass. There are also four exception allowed, as noted below in the citation from the Residential edition of the Florida Building Code (FBC), and the International Residential Code (IRC) is...

What are the code requirements for safety tempered glass for doors?

Saturday, October 5, 2019
What are the code requirements for safety tempered glass for doors?

Doors are considered a "hazardous location” for the purpose of where safety/tempered glass is required in a home, and all door glazing is required to be safety/tempered with only two exceptions: a glass panel so small that a 3” ball cannot go through it or if the glass is categorized as decorative. All standard French doors would not pass the 3” ball...

HUD-CODE FOR MOBILE HOMES

Sunday, September 29, 2019
HUD-CODE FOR MOBILE HOMES

Here’s links to a collection of our blog posts about “HUD-CODE FOR MOBILE HOMES":

• What are the HUD requirements for site drainage when installing a mobile/manufactured home?

• Is a ground cover vapor barrier (plastic sheet) required under a new mobile/manufactured home? 

• What is a "HUD label verification letter"...

Why would an old, pre-1970s house have a fire place but no chimney on the roof?

Thursday, September 26, 2019
Why would an old, pre-1970s house have a fire place but no chimney on the roof?

Old brick chimneys that are in poor condition sometimes get abandoned and the brick removed down to below the roof sheathing in the attic when the house is reroofed, like in the photo above. The mantel and firebox may still be in place down below, but unusable, or it might have been converted by a remodeler to an unvented fireplace. For information...

Can you wire a electrical cord with a male attachment plug at both ends, and plug into a receptacle and a generator, for electricity in the house during a hurricane power outage?

Wednesday, September 25, 2019
Can you wire a electrical cord with a male attachment plug at both ends, and plug into a receptacle and a generator, for electricity in the house during a hurricane power outage?

You could call it “good ole Yankee ingenuity” or “white trash engineering,” depending on whether you approve or not. But, either way, it’s both dangerous and illegal. Here’s three reasons why:

1) It’s against code. The National Electrical Code [NEC 406.6(B)], states that “no receptacle shall be installed so as to require the insertion of...

Can an unused (spare) circuit breaker remain in an electrical panel or does it have to be removed?

Monday, September 23, 2019
Can an unused (spare) circuit breaker remain in an electrical panel or does it have to be removed?

Spares do not have to be removed from the panel. The National Electrical Code (NEC) simply requires that they be identified in the circuit directory. At 408.4(A) it states that “spare positions that contain unused overcurrent devices or switches shall be described accordingly.” For more details on panel circuit directory requirements at NEC 408.4,...

How safe is a modular home in a hurricane?

Friday, September 20, 2019
How safe is a modular home in a hurricane?

Although a modular home is built in a factory, it is manufactured and installed to the same building code standards as a site-built home. So in Florida that means it will conform to the extensive hurricane-resistance requirements of the Florida Building Code, and stand up to hurricane winds as well as a site-built home that was constructed in the...

How do I determine the age of an air conditioner or heat pump from the model number?

Monday, September 16, 2019
How do I determine the age of an air conditioner or heat pump from the model number?

The model number is not where you figure out the age of a unit. It’s encoded in the serial number, and each company has their own system. If you enter the name of the manufacturer in the seach box above, it will lead you to a blog with the answer you need. Only a few companies do not encode the manufacture date in the serial number, and for them it...

What is the code required minimum pitch/slope for a metal roof?

Monday, September 16, 2019
What is the code required minimum pitch/slope for a metal roof?

The traditional metal roof types, such as 5V-crimp (shown above) and corrugated, are rated by the manufacturers for use down to a 3/12 pitch—three inches of vertical “rise” for every foot of horizontal “run.” Because of the shallow height of the undulating ridges of the 5V and corrugated profiles and the use of exposed metal fasteners to screw the...

What is the code required minimum height above a toilet?

Monday, September 16, 2019
What is the code required minimum height above a toilet?

Minimum 6-feet 8-inches of height to ceiling at the center of required area in front of toilet where there is a sloped ceiling over toilet, according to the International Residential Code [IRC P2705.1(5) and R305.1(2)]. Similar citation in Residential Edition of Florida Building Code.



   Go to our blog posts What are the minimum...

Should I buy a house with bouncy, spongy, or squeaky floors?

Friday, September 13, 2019
Should I buy a house with bouncy, spongy, or squeaky floors?

Although these are three different problems, they are often interrelated and two or all three may be experienced together as you walk around a house during a showing with your realtor, especially in an older home. The flexing of bouncy floor joists, for example, can cause the subflooring fasteners to work loose and squeak. When the subfloor is plywood,...

When is a cricket or saddle required on a roof?

Thursday, September 12, 2019
When is a cricket or saddle required on a roof?

According to the Residential Edition of the Florida Building Code (R903.2.2) and the International Building Code (IBC), the high side of any chimney or other roof penetration that is more than 30 inches wide requires a cricket or saddle. Skylights installed per code are the only exception. Here’s the code citation:    Shown below is an example of...

Can I install a new metal roof over an asphalt shingle roof?

Thursday, September 12, 2019
Can I install a new metal roof over an asphalt shingle roof?

Yes, you can. It is specifically allowed in the 2017 Residential Edition of the Florida Building Code (FBC) at R908.3, Exception 1, with a similar citation in the International Residential Code (IRC):

    A separator sheet between the shingles and the back of metal roofing is often used, but not required. Asphalt or synthetic felt, or even...