Does your house need “bypass surgery?”

Many do.

Air bypass into the roof structure (attic) is one of the biggest challenges to the home’s roof structure–from the “inside” that is. Everyone is aware of the damage that can occur from failed roof coverings and roof flashings, but most are not aware of air by-pass issues. Certainly most home owners are not aware enough.

When we heat our homes, the warm air takes on moisture due to the simple fact that warm air can hold more water (as vapor) than cooler air can. As an example the cooler you keep your home the more condensation will form on your windows. When you warm the house up, the condensation magically disappears. This of course assumes there is not so much moisture being produced that no amount of warming can hold all the moisture–we call this rain.

Any place this warm moist air can find a way into the roof structure we call “air bypasses.” Think of them as paths of moisture vapor transfer–a moisture vapor transfer system. Obviously this is a waste of heat and is a huge problem in itself in terms of energy efficiency, but this air movement can also result in ice dams and other problems in the roof or attic structure. The movement of water vapor with this air is problematic because it can result in wood decay rot in the roof structure as well as mold growth in the attic.

For the most part, stopping the air movement will stop the vapor movement. In really cold climates it is a good idea to have a vapor barrier on the insulated ceilings to prevent moisture vapor from migrating to the cold roof surfaces by means of temperature/pressure differentials–vapor drive. But this could be the subject of another post.

Back to bypass surgery.

Where do these bypasses occur (and this is by no means a complete list)?

1. Improperly sealed (gasketed) attic accesses.

2. Openings around plumbing pipes, electrical wires and HVAC ductwork.

3. Inadequately sealed skylights.

4. The spaces or chases around chimneys and b-vents.

5. Ceiling electrical junction boxes.

6. Can-lights–especially when the lights are turned on.

7. Kitchen, dryer and bathroom exhaust fans–even if the units have dampers.

Think of each one of these paths of air movement as little exhaust vents–with no damper–essentially working 24/7–in an attempt to destroy your roof structure and empty your wallet.

Stopping all means of air movement is critical to solving a lot of the attic’s health problems–and can result in avoiding surgery altogether. A little preventative medicine goes a long way.

Some types of insulation, like cellulose fiber, are more forgiving of some of these bypasses because they essentially do a very good job of stopping air movement. If you have any type of fiberglass insulation you can pretty much include everything on the list as a functional air bypass.

I came across a great example of can-light bypass the other day. Granted, this is considerably more egregious than most can-lights but it is a perfect example to illustrate what we have been talking about so far.


First of all, note the location. These two can-lights above the tub are in a location that likely requires sealed covers (and certainly would require fixtures rated for a damp location if not a wet location). So, besides the air bypass issue these would be considered wrong regardless. Of course the exposed bulbs being CFL’s adds another interesting dimension to the installation.

These can-lights are installed in what might be considered the area of highest moisture vapor in the home. It is a good thing there is a vent fan right there between them to help with the moisture. Too bad the fan vents directly into the attic!


Here is a picture of one of the can-lights as seen from inside the attic.


Can you see all those round holes in the fixture? The circled hole, and others in the fixture, are what make this thing a bathroom vent as much as a light fixture.

This next picture is what the fixture looks like if you were a mouse in the attic and the lights were turned off.


Can you see the cute curls of the CFL through the holes? The mouse can.

So what kinds of “obvious” air bypasses do you have into your attic?

By Charles Buell, Real Estate Inspections in Seattle

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Even showering together won’t fix this problem!

I have done posts in the past about the importance of the home inspector checking the water temperature at all points of use in the home.


161+ Degrees F

While outside the Standards of Practice for many home inspectors, in Washington State, we have a sort of Left Handed approach to this issue (we are on the left hand side of the country after all). Our Standards of Practice merely state that we are to report: “whether or not the water temperature was tested and state that the generally accepted safe water temperature is one hundred twenty degrees Fahrenheit.”

Scalding is not a laughing matter, and as a Seattle Home Inspector I routinely find the water temperature above 120 degrees Fahrenheit.

Whenever I start to whine about the water being too hot, I sometimes get a response like: “I like my water hot!” The truth is that human skin will not tolerate even 120 degree water without pain and discomfort. Prolonged contact with even 120 degree water will result in injury.

What I think people are really saying is that when they take a nice long shower, the water temperature cools off to a point where it does not feel hot enough. This is usually due to inadequate volume of hot water (water heater possibly too small—-or too slow of a recovery rate). It is more of a case of the water not being hot enough “any more.” All of this semantics is wasted on anyone that just wants to have a nice long shower however.

The solution to this problem is to crank up the water heater so there is more to dilute. Then there might be enough for one really long shower or even enough for two people to take showers one right after the other. Of course showering together might solve the problem too–assuming there is not too much fooling around.

The solution of “cranking-up-the-temperature-on-the-water-heater” is problematic in that we are then going to have hot water at above the recommended high limit of 120 degrees. However there is another good reason to have the water temperature of the water heater at 130 degrees besides creating more volume to dilute. At temperatures below 130 degrees we create an environment conducive to certain bacteria–including Legionella. The point of this post is not to go into all of these aspects of heating water. Just suffice it to say that your water heater should be set to about 130 degrees and then there should be a tempering valve installed to adjust the outgoing water to safe levels below 120 degrees. Pretty simple really.
Under no circumstances should you adjust your water heater to above 120 degrees if you do not have a tempering valve.


Tempering Valve

Now I want to get back to why inspectors should be checking the water temperature at all points of use.

First and foremost we should be doing it because the temperature at the start of the inspection will often be lower than at the end of the inspection when the water heater has kicked-on and has heated the water to its high limit. This is why the temperature at the last fixture we check should give us the best idea as to what the actual highest water temperature is.

I have found the water temperature at the kitchen sink to be 118 degrees F and by the time I got to the laundry sink in the basement it was 140 degrees F. I for one would not want to have stated in my Inspection Report that the water temperature was 118 degrees–or worse yet, said nothing at all. It is not within the scope of this post to go into all the reasons for these variations in temperatures. I have posted about that in the past.

Here is another reason why inspectors should be checking the water temperature at all locations.

The other day at an inspection the water at the kitchen sink tested at 145 degrees Fahrenheit. “Holy Crap Batman,” I said to myself, “–what the heck is the temperature going to be at the last fixture?” While it is a general rule that that Generals rule, in this case the temperature was not higher at the last fixture as one might expect. It turned out that the water temperature at the Master Bathroom shower was 97 degrees F. Now let me see–what is human body temperature again?

It is no wonder that the home owner was complaining about running out of hot water before he could finish his shower!

What was happening was that the bottom heating element was not functional—either the element was bad or the thermostat was bad, which caused the upper heating element to attempt to compensate. The upper heating element clearly was not up to the task as it could only heat the top few gallons to a very high temperature and then was quickly used up. Even showering together would not fix this problem.

It is time to call the plumber and have the water heater fixed.

By Charles Buell, Real Estate Inspections in Seattle

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The tale of a trail of tails

When I was in high school the guys with the hot cars and the wild girls were called “greasers.” They could easily be recognized by their leather jackets and “DA” hair cuts that they would continually be slicking back with the combs they kept in their back pockets. The slicked back hair style did indeed look like a duck’s ass.

rodents-in-the-NWFor some reason whenever I think about rodent body grease, I can’t help but think how humans leave the same sorts of marks and that to deliberately add oils to our already oily hair seems kind of odd. I am sure that rats groom themselves, even without combs, but what would they call a “DA?” The mind wants to go to “RA”—but politely stops itself.

If people had any awareness of this body grease they would know how important it is to keep vegetation adequately cleared away from their homes—especially the roof.

Rodents will use vegetation as a pathway to the roof.

If they can get to the roof and gutters, they will find a way into the attic.

The gutters can make a perfect highway where rodents can travel around the roof unnoticed. If they can find a little opening they can make it bigger—and the homeowner would be none the wiser.

At a recent inspection I was walking around the house and noticed some black marking on the electrical conduit and surrounding wood structures. I remarked to my buyer that this was an obvious rodent access point to the attic and I could anticipate a mess in the attic. It takes a considerable amount of time to accumulate this much body oil on a rodent trail. They are truly greasers.

Here is the picture of what could be seen from the ground.


Can you see the black shadowing of rodent body grease?

The “high-lighted” areas in the next picture are the body grease marks left by years of rodents coming and going from the attic.


Here is what the attic looks like at the access point.


Before I entered the attic I laid out my biggest tarp. As expected, it was a good idea as rodent feces rained down when I opened the hatch.

Much of the insulation throughout the attic was totally trampled and covered with rodent feces. The insulation was installed 7 years ago and now it will all have to be removed and replaced again.

Naturally there will be concerns about the condition of wiring as a result of the infestation and that will all have to be evaluated after the insulation is removed.

Are the greasers hanging out at your house?

When was the last time you checked your attic?

By Charles Buell, Real Estate Inspections in Seattle

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