Seattle Home Inspector's Blog

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Crossing the line

Why is there a black line on the carpet in this doorway?

This “ghosting” on carpets is pretty common in homes.  It merely shows you where there is a great deal of air movement.  It is typically worse where there is inadequate clearance under the door and the door has been kept closed a lot.  It is also more noticeable in homes that are not cleaned regularly---but even in well maintained homes they can be difficult to eliminate entirely.

For the inspector it is a clue.

The inspector will want to know why the air is moving here and at the very least recommend that the door be cut off to allow for air flow to improve.  Because, even with inadequate clearances, this is the path of least resistance, air will be sucked through the carpet and the carpet is acting like a filter.

In this case, the furnace was located in the room and this was the only means of providing combustion/dilution air to the furnace.  More often it is air moving from the room as heated air comes into the room and must return to the air return that is on the other side of the door.  When combustion air is involved it is a little bit more problematic because it could mean that the appliance is not getting enough air and could become and health and safety concern related to oxygen depletion.

In this case it most certainly was a safety issue because the room where the furnace was, was also being used as a bedroom.  The sleeping room with the door closed could result in a lack of oxygen in the bedroom---let alone the risk of combustion by-products being introduced into the room.

Definitely crossing the line.

P.S. Crushing those wires repeatedly is likely not a good thing either.

 

Charles Buell, Real Estate Inspections in Seattle

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Seattle Home Inspector

 

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WA State, Home Inspector Advisory Licensing Board

Comment balloon 20 commentsCharles Buell • December 21 2013 06:03AM

Comments

Hi Charles,

Picky, Picky and more picky. LOL I bet the owners never gave this a second thought.

Uncle Bob must had been out in your area in the past couple of years. He seems to really get around.

Have a Great Christmas in Seattle with family and friends.

Best, Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) almost 5 years ago

What a mess. I do have a slight bit of ghosting under the guest room door - we keep it closed when visitors aren't here - wondering if I should keep it open. I do vacuum a LOT.

Posted by Debb Janes EcoBroker and Bernie Stea JD, REALTORS® in Clark County, WA (ViewHomes of Clark County - Nature As Neighbors) almost 5 years ago

Clint, I have been asked how to clean it but never why it was there in the first place.

Debb, unless there is something wrong with the heating system or LOTS of dirt in the air these lines usually won't develop if there is adequate clearance under the door.  There should be a 5/8 to 3/4 inch gap.  Of course if one does not clean in 100 years they will develop anyway.  Also rooms with multiple supplies will never get enough space under the door and other means of increasing the size of the return to the furnace may be necessary.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

Charles - this is what being knowledgeable means. And the more I read, the more i was lost :)

Tells you something about my being not knowleadgeable in these issues at all.

Posted by Jon Zolsky, Daytona Beach, FL, Buy Daytona condos for heavenly good prices (Daytona Condo Realty, 386-405-4408) almost 5 years ago

Jon, in a nut shell:  do not have open flame combustion appliances in bedrooms and make sure the air coming into the room can get back to the air return to the furnace.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

I have been asking this questions for ages... thanks for the explanation.

Posted by Nina Hollander, Your Charlotte/Ballantyne/Waxhaw/Fort Mill Realtor (Coldwell Banker Residential Brokerage | Charlotte, NC) almost 5 years ago

YOu always have great posts and your pix speak a thousand words too!

Posted by Kristin Johnston - REALTOR®, Giving Back With Each Home Sold! (RE/MAX Realty Center ) almost 5 years ago

I can hear the whistling sound of the air squeezing under that door to get out.... from here!

Posted by Fred Hernden, CMI, Albuquerque area Master Inspector (Superior Home Inspections - Greater Albuquerque Area) almost 5 years ago

Nina, now you know

Kristin, thanks--just having fun

Fred, there indeed can be quite a draft under the door

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

Hi Charles, I see this a lot where the carpeting meets the wall but I've yet to see a line like that under a door. Now I'll at least have some knowledge as to what it is. This is why I prefer wood flooring to carpeting.

Posted by Cindy Westfall, ABR,GRI Your Tualatin & Portland Metro Real Estate (Premiere Property Group,LLC Portland Metro & Suburbs Oregon) almost 5 years ago

Charlie, Such a great illustration of what the air movement in the home. This was very important in this case. Hey whatt is a gas appliance anyway ;)

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) almost 5 years ago

Cindy, yes very common at walls but created by different forces.

Don, to you--an automobile

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

Well that sucks. Or does it blow?

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) almost 5 years ago

Jim, I am guessing both

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

Charles - I learned something new from your post, and I thank you for that.  :)

Posted by Jason Crouch, Broker - Austin Texas Real Estate (512-796-7653) (Austin Texas Homes, LLC) almost 5 years ago

Jason, you are welcome, hope you have a great Christmas and New Year.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

Now I have a clue how to find "drafts" under a door and other places inside the house.  Thank you! 

Posted by Fred Griffin, Licensed Florida Real Estate Broker (Fred Griffin Real Estate) almost 5 years ago

Fred, you are welcome

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

Hello Charles, I learned something important, and it takes a good inspector to find all the hidden things.

MERRY CHRISTMAS TO YOU AND YOUR FAMILY 

Posted by Barbara Hensley, Homes for Sale in Rockwall County, Texas (RE/MAX Properties) almost 5 years ago

Barbara, well "close" to everything or a least the important things :)

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 5 years ago

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