Is your home a sieve?

We can never totally stop air movement in and out of homes. Not only are our attempts to seal homes never perfect, materials change over time and sometimes create new gaps where there were none to begin with.air-infiltration2  Some homes are more forgiving than others because of the choice of materials used.

air-infiltration1In this first picture we can see the very common black staining that happens around the edge of the carpet where air is finding its way in and out of the living space at the wall bottom plate.  The carpeting is merely acting as a filter.

In this next picture the black staining on the soffit around this beam of a home, with a flat roof, is where air is leaking in and out of the building.

air-infiltration3I have long held that since it is going to be difficult to completely stop air movement, why not do our best to at least torture the heck out of it as it moves?  In other words make it difficult for air to flow.  We can do this by choosing really good quality insulation like cellulose fiber insulation–it gets into every little nook and cranny making a very good barrier to air movement.  We can caulk the connection of bottom plates and sub-floor.  We can use weather-stripping on doors and windows and access hatches. We can glue drywall to studs and top & bottom plates. We can seal around pipes and ductwork that penetrate the building thermal envelope.

If we can stop or significantly slow down air movement something else happens in the process.  One of the major ways moisture moves through the building envelope is in moving air.  If we can stop air movement we can eliminate or greatly reduce moisture movement as well.

Fiberglass insulation is notoriously bad at stopping air movement–and thus moisture movement.  In fact, in the early days (early 1970’s) of making homes more energy efficient, one of the main reasons we went to such great lengths to install plastic vapor barriers behind the drywall was because fiberglass insulation could not do the job adequately.  Everyone has experienced the cold drafts that can occur around electrical outlets of homes insulated with fiberglass insulation.  This does not happen with cellulose fiber insulation.

In my opinion stopping air movement is perhaps the single most important quality of insulation. Its “R-value” is a moot point if it can’t stop air movement.  How much money are we really saving by insulating our homes if we cause structural damage by moisture related to air movement?

Your home inspector will often be on the lookout for signs of air infiltration/exfiltration during the inspection.  An important thing to keep in mind is that air moves both in and out of homes depending on atmospheric conditions.  At times your house can be pressurized and at other times depressurized–close to “neutral” is ideal but not always easy to manage.

For example, if you turn on all of your exhaust fans, where will air come into the home that is being displaced by the exhaust fans? 

Well, if it can’t “easily” find a way in, a negative pressure in the home will be created and the fans will actually not move any air–won’t do their job.

As an example of this effect, my sweetie and I had checked into a little motel a few years ago and experienced this first hand.  The motel was brand new and very well built.  The motel had a little kitchenette and when my sweetie decided to make toast in the morning, she did her typical method of making toast–which is to have the smoke alarm tell here when it is done.  Well, NOT REALLY wanting the entire building’s alarms to go off, I thought it more prudent to turn on the kitchen exhaust fan and get rid of the smoke before the alarms went off.  I turned on the fan and the smoke just sat there like a dense motionless fog.  It occurred to me that perhaps if I opened a window it would help and immediately the fan became functional and pulled all the smoke out of the unit and the alarms never went off.

In most homes, air does find a way in-somewhere, but fans will be much more effective if they can obtain air easily.  Air will find its way into the home around poorly sealed doors and windows, around the bottom of walls, around electrical outlets, around crawl space access covers, down the chimney or even back in through un-dampered exhaust fans.

Another important factor to remember is that we want air to come into the home–we just want control over how, where, when and how much.

Energy efficiency is compromised when we lose control.

Take this picture of a heating system supply-air duct in a crawl space.  This is a great example of how inadequate fiberglass insulation is as an air barrier, as well as a good demonstration of air movement at a location where we don’t want to see air movement.


All duct connections should be air-tight and on my planet ductwork would not be allowed to be installed outside the building’s thermal envelope.  If the connections are not air-tight, when the heating system is operating, warm air will be pushed into the crawl space–right through the insulation.  When the system is not running, these leaking ducts will become a place for air to enter the home when the home is under negative pressure (as when exhaust fans are operating or due to the home’s stack effect).  As you can see from the black band around the ductwork, the yellow fiberglass insulation is acting like a “filter” as air moves through it.

These are just a few of the “visual” indications of poor control of air movement in the home.

By Charles Buell, Real Estate Inspections in Seattle


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They do their best work in the dark!

Your house is DIRT!

We have lots of wood destroying organisms it the Northwest.  Wood Decay/Rot, Carpenter Ants, Dampwood Termites, Sub-Terranean Termites, Anobiid Beetles and Moisture Ants are always looking for ways to return your house to where it originally came from–dirt!

Good building practices are put in place to slow this process down as much as possible.  Most of us would agree that, given the sizable investment our homes represent, this is a pretty good idea.

And yet, we install finish grade too high, let our homes become overgrown with vegetation, don’t control roof water drainage, and in general, we seem to do what we can to assist the bugs.  We are sort of co-conspirators with them–and they seem to know this.

In a recent crawl space I came across this installation of the plastic ground cover/moisture barrier.  This is an open invitation to wood destroying insects.  You might as well put up a big sign that says
“Bugs Welcome!!”–have at it!


We need to put ourselves in their place.

Think like a Termite.

Think like a Carpenter Ant.

Be one with Rot.

When we do this we can learn how to keep them out–or at least slow them down.  When we run the plastic ground cover up the foundation and attach it to the wood rim joist we create a nice protected area for the bugs to do their thing un-noticed.

And trust me–they do their finest work in the dark.


By Charles Buell, Real Estate Inspections in Seattle


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You can have “problems” and still not need a shrink

In the mid 1970’s when the United States was first awakened to the fact that oil might not stay cheap forever, Urea-Formaldehyde Insulation became all the rage.

formaldehyde11It would be nice to think that we came to an awareness of saving energy for the sake of conserving finite resources, but the harsh reality is that we only came to the awareness by how it impacted our pocket books and wallets.

It was this concern with saving money that led to many different methods of insulating homes so that we didn’t have to buy so much oil–depleting our wallet reserves.  Of course the oil companies merely charged more for the reduced amount of oil we purchased but that is another story.

Urea-Formaldehyde had a problem though.  After installation of the product, some people reportedly reacted badly to “out-gassing” of the product and it fell out of favor.  Many people spent even more money having the product removed.  Besides the out-gassing issue (which was largely exaggerated much the same way we see with mold exaggerated today), it had a much more troublesome problem over time.

  It shrank a LOT. 

The idea with insulation is that you want to fill all cavities and stop all air movement.  So now we have a cavity with this giant floating block of insulation surrounded by free air–air that is free to transport both heat and moisture through the wall.  It also made it impossible to re-insulate the spaces to make up for the shrinking insulation, leaving the only option removal and re-insulating.

Many people have heard about the past history of Urea-Formaldehyde insulation and have questions and concerns when it comes up on an inspection.  I still frequently find homes that were insulated with the material.  I find it usually extruded into attic spaces where there were small or big openings that prevented it from being contained in the wall cavity–as can be seen in this picture.


In this next picture, if you look closely, I think you can see just how much the material has shrunk away from the wall studs.  In this case as much as an inch on each side


Given the length of time since this material was installed, the EPA considers any out-gassing to be complete and not likely to represent any health concerns.

This leaves its shrinkage and greatly reduced ability to insulate the home as its biggest concerns.

By Charles Buell, Real Estate Inspections in Seattle


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Have you ever had a “snake” moment?

Everyone has snake moments.  You know, those times when something just jumps out at you and your heart sinks, your pulse rises, your knuckles turn white and your face goes ashen.  If it is a big enough snake you might even experience the taste of adrenalin in your mouth and the smell of urine in your pants.

snakes1Some people are more prone to snake moments than other people.

Home inspectors seem to be less prone to these moments than the general population and it may in fact be part of what it takes to be a home inspector.

Rats, spiders, ants, stinging insects, tight spaces, faulty wiring, sewage, flooded crawl spaces, Cujo, environmental hazards—and even snakes are some of the things that home inspectors have to deal with on a daily basis.  Most normal people do everything in their power to stay away from these things.

But when you think about it, most people have to pay to get their adrenalin rushes—home inspectors get paid to have adrenalin rushes.

The other day I had an unexpected snake moment. 

Aren’t they all unexpected?

Anyway, I had removed the cover from the electric panel when it struck like a coiled Diamond Back.

I should clarify that I have been working with residential electrical panels and wiring homes for more than 40 years, so there is not much that is likely to cause me to become unglued.  But the nature of snakes is that they quietly just show up when you least expect them.

This particular snake was observed winding its way across the live bus bars of the electrical panel—giving me an ever so slight taste of adrenalin—yet allowing me to remain continent.

The part that really got me going was not so much that wires crossed the bus bars—I see that sometimes.  But the fact that one of the wires was BARE COPPER, and only a ½ an inch away from the 4th of July, it gave me pause.


Anyone working inside this panel—especially anyone not smart enough to know what snakes might be hiding in there–could be in for a BIG surprise as the snake exploded in a flash of blinding light.

Hopefully they would live to see the light.

By Charles Buell, Real Estate Inspections in Seattle


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I bet you pee your pants before I pee mine!

I subscribe to the Electrical Currents Newsletter from the Washington State Department of Labor in order to stay “current” (no pun intended) with what is going on in the “electrical field” in Washington State.  It always has “electrifying tidbits” about what is going on with updates to the National Electric Code as they pertain to Washington State–as well as lots of other useful if not too “shocking information.”

Mouse_climbingThe newsletter always has a question of the month that is often times way over my head technically, but that is fun to read nonetheless.

This month’s question left me a little baffled as it entered into a discussion about the differences in susceptibility to electrical shock between the sexes.

The idea that I might be more inclined to pee my pants than a woman left me feeling a little uneasy.  However I was greatly “relieved” to find that it is actually women that are more likely to lose muscle control when encountering electrical current.  15 milliamperes for men and 9 milliamperes for women.

While the answer seemed clear cut and emphatic it does nothing to answer the many questions that come to mind.

How old is a “woman?”

How old is a “man?”

Is it also true of “boys” and “girls?”

Is it true regardless of weight, height, and/or size?

What if the woman was pregnant?

What if the woman was pregnant with a boy?

Another interesting aspect of the question though is, how the heck did they figure this out? I can imagine some sort of Frankensteinian experiment involving paid and/or unpaid volunteers and lots of screaming, wriggling and floor mops.

I could find nothing definitive on the internet as to why this difference between men and women is true, but it does seem to be a pretty pervasive idea in the electrical literature that I did find.

By Charles Buell, Real Estate Inspections in Seattle


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