Thread: Odor only noticeable when doors opened

Potential client called and asked if I could detect what kind of odor and where it was coming from in the house he purchased 6 months ago. He gave me the details of what he has done up to his calling me, ie call the gas company, have his HVAC checked, plumbing, etc. Nothing found. Here is the interesting part, the very strong odor only is noticeable when the doors are opened. And no you cannot smell anything like it on the outside of the house.

When I arrived the house had been closed and the HVAC unit off. I walked around and did not smell anything toxic as they discribed. Then he opened the door and withing 5 minutes you could smell a faint pungent smell that overtime got worse and was noticeable in most of the house. It smelled acidic and a little rotten eggish. I thermal imaged the entire house looking for moisture and found none. Indoor humidity was an average of 35%. I use a combustible gas sniffer and it did not detect anything. I walked outside the front door and the smell actually seemed to come from the inside as I stood just outside the door.

Has anyone experienced this? I am IAQ2 certified but do not think any sampling I can do will indicate anything definite. Could it be VOC's possibly? We are in California and I doubt it is Chinese drywall. If you have suggestions I am open.

J. A. Wood Construction, Inc, J. A. Wood Const, Inc. Home Inspection Service | Home Inspections in Visalia, Tulare, Hanford, Exeter, Kingsburg and Fresno Areas

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Very strange. I am not sure if there is ant scientific way of tracking the odor.

Does it happen all the time?

Since you stated it seems to be coming from outside when you are inside, and visa versa, just to satisfy myself, I think I would open a small hole or 2 in the bays on both sides of the door. I would then sniff out the holes to see if something is originating from in the walls.

It's a long shot, but I would rule it out.

I had a similar situation.

First the drain was blocked because previous home owners covered the basement floor over it.

Second, I did a thermal check and found nothing.

Third, the odor did seem to be more present in the basement.

Last, we opened part of the basement floor. And we found that the sub floor was rotting due to a leak. The thermal scan didn't pick anything because it was a tile floor. Plus, the top of the floor was not humid, just the sub floor.

This is where a good quality pinless humidity meter makes a big difference. I used Extech MO297

Hope this helps

Zane

The smell being noticeable when the door is opened might suggest that a draft is require to draw the odor from its location.

Try closing all doors and blocking bottom with towel or tape seams/bottom.
Seal all duct work also.
Then use a fan in window to ventilate(to exterior) each room. Looking to generate odor by isolating location.

It is a start.
Dead rat in wall probably not visible to IR.

I'll never forget my first dead rat. Nor the smell.

Mogolianian drywall?

If there is a positive pressure between the house and the outdoors, the positive pressure could be keeping the smell back into where it comes from, sewer drain, sulfur water, bacteria in the water heater, outgassing from building materials, etc.

When the front door is opened that positive pressure between the inside and the outside is neutralized and becomes equal over a short period of time. No positive pressure and any of the above mentioned items could cause a problem.

Just a thought.

We had a similar problem and odor at my place of employment.. Finally found it was an old hidden floor drain. When the trap dried out we would get an odor back from the sewer lines. A bucket of water in a floor drain fixes the problems. Installing a drip trap would be the sure cure...

Originally Posted by Bob Boepple

We had a similar problem and odor at my place of employment.. Finally found it was an old hidden floor drain. When the trap dried out we would get an odor back from the sewer lines. A bucket of water in a floor drain fixes the problems. Installing a drip trap would be the sure cure...

My friend is a plumber and told me exactly what you just said.

Zane

Thanks for all your input, I am thinking through each suggestion you all made and will investigate further. This house is a slab on grade with no basement. I was also thinking about the pressure difference from inside to outside. A thought I have now is to have a door test done to force the pressure difference to a higher level and see what happens with the odor.

I did talk with the client today and he had a neighbor in to see if the neighbor had experienced the smell in his house. Today it took 20 minutes for the odor to show up and only was in one room. He said he opened up just as he did yesterday when I was there. Very strange.

Originally Posted by James Wood

Thanks for all your input, I am thinking through each suggestion you all made and will investigate further. This house is a slab on grade with no basement. I was also thinking about the pressure difference from inside to outside. A thought I have now is to have a door test done to force the pressure difference to a higher level and see what happens with the odor.

Have an energy auditor do a blower door test where they depressurize the house ... if it is what we are all thinking, that blower door test will suck that smell out in no time at all.

Hard to say without more information...age of home might narrow scope...WAGs & thoughts to ponder:Municipal sanitary system connection or private/septic? Water supply (public/private), on-site treatment systems?Storm water/surface water interconnection to sanitary?Dry trap (DWV) or water or other offal/fouling in under/in-slab HVAC.Clogged, rotting matter in eavestroughs (gutters) and/or downs. Rain barrels or other storage, cistern, etc. water collection/storage system?Punctured or broken plumbing vent(s) in wall cavities...(recent use of chemical drain clog treatment products?). Partially clogged drains/traps?Is there a Fireplace? Chimney? Fouling perking from earth's crust below -- normally venting up through wall cavities - wind/stack effect perking through cracked slab or btwn it and footing.Local fracking, fluid injection, fault movement, mining or drilling activities? local agricultural activities?

Originally Posted by Scott Patterson

Mogolianian drywall?

Too funny Scott ! Good luck on this witch hunt. Negative pressure, positive pressure, doors opened, closed etc. I started a question post about the same time as yours, concerning sulphur in the water, ( the rotten egg oder ). I'm learning it is far more common than I realized. Ever walk into a home from outside and the interior oder is pungent, ( to you ), ?. My theory is the water and the occupants are so conditioned to it's presence they do not notice it. When the doors are opened there is more air movement, but more importantLY, there is now a comparatively different olfactory environment to stimulate the sniffer. Final answer.

I am not an inspector but the home owner James Wood is trying to help with a mystery smell. In my free time I try goggling different smell phrases and happened across this one. James-I'm not trying to step on you toes but I wanted to list a few more facts. From what I have read there are some great minds here and we may be able to get to the bottom of this.

The house was built in 04. It is semi-custom (nothing crazy but not a tract home). We are the second owner.

Before we moved in we installed all new carpet, new glue down wood floor in living room, all new paint (everywhere), and had the tile professionally cleaned. The previous home owners did not appear to be the type that cooked drugs (but they were filthy).

As James said, the house is on a slab. The smell appears in the room closest to the open door or window to out side. If the laundry room door to the outside is left open the smell appears in the laundry room. If you leave the door to the back bedroom door open to the outside, the smell appears in the bedroom. These rooms are on complete opposite sides of the house.

Same goes for the kids bedrooms, living room and playroom. If a window or door is left open to the outside the smell is pulled from its source?

The really tough thing is the way it smells. I have had 10+ people in the trades come to my house to try and find the smell. No one has been able to put there finger on it. It only shows up when doors or windows are left open which pulls the smell out.

I do not think the smell is in the ducts but I have a ger burning a hole in my pocket so I am going to have it done this week. At this point, I do not know what to do. We had our insurance company come out and they said unless the smell is causing damage there was nothing they could/would do.

Thanks to all of you for your input and thoughts. My wife is ready to move because of this smell.

Matt

Any indication what the site was prior to houses being built?
Toxic dump, garbage dump, marsh...?

As you have discovered, finding the source of odors is not always an easy task. Based on the fact that you have a slab foundation my bet guess would be a open plumbing vent stack in a wall. You might want to have a plumber perform a smoke test to see if it can be located.

Originally Posted by Scott Patterson

Mogolianian drywall?

Could be? Check the elec panel & wires to see if any corrosion?

Similar thread?

http://www.inspectionnews.net/home_i...tml#post211458

Thanks for the replies.

Before the home was built the site was a walnut Orchard. I have looked at Google earth as far back as it goes which is the 80's and it shows mature walnuts.

We have thoroughly inspected the drains and have dumped 5 gallon buckets of water down each sink.

We have checked the electrical. No signs of corrosion.

I wish it was a rug but its not.

Keep in mind that the smell appears all over the house but only at the room where door or window that is left open.

The smell does not appear to travel either. When you smell it in one room it does not linger into the next room.

Please keep the ideas coming.

Originally Posted by Matt Swanson

Thanks for the replies.

Before the home was built the site was a walnut Orchard. I have looked at Google earth as far back as it goes which is the 80's and it shows mature walnuts.

We have thoroughly inspected the drains and have dumped 5 gallon buckets of water down each sink.

We have checked the electrical. No signs of corrosion.

I wish it was a rug but its not.

Keep in mind that the smell appears all over the house but only at the room where door or window that is left open.

The smell does not appear to travel either. When you smell it in one room it does not linger into the next room.

Please keep the ideas coming.

That is all I have.... Have you had the plumbing system "Smoke" tested? This should show if you have an open vent in a wall that you can not see.

Some ideas;
1) With all windows and doors closed create a negative pressure (vacuum) in the house. Then use a smoke generator to determine where air is drawn into the house or where air movement is accruing. This may lead you to a source other than a window or door wher the oror is coming from.

2) Seal plumbing vents and make sure all traps have water in them. Pressurize wast system with smoke and look for smoke when you open the door or window. Fan sealed into window is good way to create a vacuum needed.

Assume that you have inspected the attic for a source of odor.

My guess is that there is a dead animal in a heating duct. Hopefully the duct cleaning will take care of it. Let us know.

I forgot to mention. When the smell is very strong in the house there is absolutely no smell in the attic. I have never experienced the smell in the attic and I have spent hours in there trying to find a clue (seriously hours).

I have the duct cleaning scheduled for next tuesday. They will also use the disinfectant.

My thoughts: The smell appears in rooms that do not have plumbing (bedrooms) but it also appears in rooms that do have plumbing. Couldn't plumbing be rulled out?

If the source is in the ducts (I am praying it is) wouldn't you smell it when the AC or heater is on. I may not have mentioned this. If the doors or windows are shut, and the AC or heater is on, no smell. This is why I am not getting my hopes up about the ducts.

Garry- How do I pressurize the waste system? If the duct cleaning does not work I am going to try the reverse whole house fan with card board and fan to pull air out of the house. I will have to buy a smoke generator..

Thanks,

Matt

Some people prefer to use peppermint oil instead of smoke.

James

A long shot, as I see you mention Fresno area.

Acid Sulfate Soils
Understanding Soils Risks and Hazards
ftp://ftp-fc.sc.egov.usda.gov/NSSC/S...sk_low_res.pdf
See page 7.

Back fill for development in the former Walnut grove?

Matt,
It is much like performing a test on the vent system by the plumber when the house was built. There is a balloon seal that goes in the waste line. then cap the vents on the roof. Inject smoke into line and see what happens. A plumber would be a good source to help you out. I say pressurize an in pump smoke into the system, will not be a lot of pressure but it will give you possibly a way to locate a leak.

Where is Rub Goldberg when you need him. Think outsidde the box....

I had the ducts cleaned yesterday.

I got in the attic and followed the brush/sucker device as it went through the vents. I did not notice it getting stuck or hung up. There was nothing removed from the ducts that would have caused the smell.

The cleaning company used the sanitizer at the end. I then left doors open to see if the smell would appear.

It did. I am beyond frustrated.

This is a serious thought. Run some sort of add for an inspectors challenge. Have an "open house" night for certified inspectors. Offer a lump sump if someone can figure it out. I think $1,000 would spark some interest.

Too bad all of you are all over the US.

Sorry to hear about your frustrations with this nuisance.
I would tend to side with Scott about having the plumbing checked. A loose or broken connection in a wall; or even a penetration of the plumbing pipes through the slab may allow air flow to be drawn through the soils up into the house???

Gunnar had a problem house once with odd smells - turned out to be carpeting. You ruled out carpeting, but should you not until the actual problem is located?

Good morning, Gents –

My take on this is a little different (HA! Imagine that….)

I was first struck with the notion “Why would somebody call a Home Inspector to identify an odor in the home?”

I have never heard of “IAQ2 certified” but your post is evidence of the lack of credibility for the “certification.” After all, if “IAQ2” actually meant something, you wouldn’t be posing the question.

On Tuesday of this week I had a similar call – a chap selling a (BEAUTIFUL) 1920 house with a foul odor that was blocking the sale of the home. He told me he had hired three consultants: a plumber, a “critter-gitter” and an HVAC technician to find the odor. I was first struck with the notion “Why would somebody call these individuals to identify an odor in the home?”

I entered the home and within three minutes, my field tech and I had mapped the odor profile in the home. Within seven minutes, we had isolated the two areas in the home with the odor. Within nine minutes we had identified the source of the odor; by the eleventh minute we had identified the mechanism of fugitive migration from the source to the room with the odor.

We spent the next 30 minutes trying to disprove our findings.

We took ZERO samples.

We performed ZERO tests.

The problem is now corrected.

I am not “IAQ2 certified” (I am “Certified Active Shooter” does that count for anything?) Has the role of the Home Inspector changed? I would NEVER accept a job as a Home Inspector, (since I'm not competent to so do), do you guys also get into dentistry now, cuz I've got this pain in the back of one of my molars... just askin'


Cheers!

CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

Yes and I bet you didn't get your IAQ certification on-line either.

So what did you attribute the fugitive odour to?

I was first struck with the notion “Why would somebody call a Home Inspector to identify an odor in the home?�

Sooo......'Who you gonna Call? Gas Busters!"

I agree Caiomhin that I am not qualified to deduce this quandry on a home inspection......but while inspecting a house with a noticeable smell that is noxious, unpleasant, out of the ordinary or otherwise regugnant, I
would make a comment, if not an issue, of the assault on the senses.
" I smell something unpleasant - source unknown. If this is an issue for you Mr Buyer, I recommend you hire a competant professional [Gas Buster] to locate the problem and mitigate the issue to your satisfaction."
He might question "Who is this gas buster?" Environmental hygenist? or is there a specific category you might recommend?

......oh....and yes, what where your findings on that 1920 house?

Hello Raymond! and Hello Chris!

Men and women detect and characterize odors differently. All our odor projects in include a male (me) and a female. (Back in my old laboratory QA/QC days with General Foods in Ireland, I had my nose “certified” and I was an official taster and “sniffer” of fine General Foods products).

The structure was a dug out basement with a very odd and convoluted configuration – 1/2 of the basement was poured concrete floors with brick and block foundation walls (and unknown footer construction).

One half of the basement was a multilayered earthen structure covered with poly (the owner told us the critter guy recommended installation of the poly to fix the odor problem.

During our odor profile, we identified the odor of “old sweat and cat pee” exclusively in a parlor. We identified an odor of cat pee in the unfinished basement. The parlor is directly above the earthened portion of the basement. The owner doesn’t have cats. There is a passive return plenum in the floor of the parlor.

We made the initial hypothesis that an animal spent many years peeing in the dirt in the basement. This became the working hypothesis – now we set about trying to disprove the hypothesis.

The owner told us that a previous owner many years ago had cats. The owner told us he had no olfactory sense. The odor only appeared 18 months ago. The man just got married… guess when? 18 months ago.

We pulled back the poly got down on our hands and knees and sniffed the dirt in the basement (YUCK) cat pee. A quick dig around revealed considerable deposits of (very old) mammalian faeces the size of which was about right for a cat. Therefore, we have a tough time disproving our hypothesis and must therefore accept the hypothesis in the absence of contradictory facts (objective or subjective).

With odors, we are exclusively dealing with three things:

1) A source
2) A recipient
3) A pathway (route of migration) from the source to the recipient

The pathway is exclusively (in real life) pressure differentials. If one addressed any one of the elements (source, pathway, or recipient) one can solve the odor problem, usually removing the recipient isn’t an option. So we focus on the other two.

In this case, we identified the source, but corrected the problem by interrupting the route of migration (the pathway).

It is very seldom useful to test the air to find out “what the smell is” since odors are complex soups of chemicals, many of which are far above the odor threshold, but far below the analytical detection limit. I.e. We can smell it, but we cant objectively measure it or identify it. Similarly, odors have “notes” and “tones” which can change with very small changes in the actual chemical soup causing the odor.

Therefore, when most “certified” IAQ guys perform sampling, then end up with chemical analysis reports that they can’t interpret.

With a single sniff, I can often quickly identify a class of chemical (terpenes, aromatics, aliphatics, esters, amines, ketones, etc). Most people reading this can as well, which is why getting the person’s subject description is important – then use their subjective comparative description to identify the chemical class.

In fact, nobody really cares WHAT it is, they just want it gone! Unless someone can come up with a really good reason for performing a chemical analysis for an odor, then why waste time, effort and money? It all has to do with hypothesis testing, not air testing. About 80% of the odor issues we deal with are solved without the need for sampling or testing of any kind.

When we do “air testing” usually it is in the form of pressure differential mapping. Working backwards from the recipient. We have tracked down some amazingly convoluted pathways through structures. Puzzles iz wot we do! Mind you we solve only about 85% of all odor problems within the alloted budget. (With enough money, all odor issues can be resolved.)

Cheers!

CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

Hey CaoimhÃ*n

Thats a great explanation and sage advice as always!

Cheers,

Personal experience with a simular smell in older home was due to glue used with vinyl flooring. Moisture had collected under the vinyl and the water soluble glue became ransid.

No IAQ cert and have a head cold so take it for what it is worth!

Yes, Cheers, Caiohmin.

I do enjoy your posts. I read and believe that you are fully professional in your line of work, and you are generous enough with your time to educate us inspectors in your areas of expertise - although we are in the early learning stages of many of these complex issues. I learn much valuable information and gain understanding enough to know where to draw the line - in that I am not qualified to evaluate, just report.
You give information that is beneficial to my understanding of the interpretation of the processes of indoor air and odors (also mold, radon, drug lab chemicals, etc.)

I, and most of us (I would guess) can determine what is an undesireable smell - “old sweat and cat pee� but not be able to take it to the level of your certified nose - (terpenes, aromatics, aliphatics, esters, amines, ketones, etc) - not that I want to.
I would be satisfied to take it only as far as letting the buyer know there is a smell. If you, the buyer, also find the smell undesireable, then you need to take it from here.
As an inspector I would like to help to find the source of a problematic smell, whether it be chinese drywall, or a skunk in the crawlspace. I always bring my part of the odor detecting process with me - the other 1/2 of the odor detection process is usually the lady buyer or wife of the buyer. That's an interesting point, Caiomhin. Thanks for that also.

Come on now. I would not waste my time or the time of all of you for a cat pee smell. I called an inspector because I am a pretty handy person and tried and checked everything I could think of. VOC testing was done because I wanted to eliminate the source being from something I did after buying the house (new carpets, paint, wood floors, etc.) I am also worried about the health and welfare of my family.

Just curious Mr. Connell, what type of budget would need to find my smell source? Did you read the description of how the smell will appear in any part of the house but only when a near by window or door is open. And then the smell just hangs out in that room.

Please keep the useful suggestions coming.

Matt

Hi Chris –

The flip side of course is that I would NEVER buy a house without having my trusty Home Inspector by my side. Since I am not competent to perform the job, I bring him in. When I buy a house, I hang my hat on his opinions, because he IS the professional upon whom I am trusting.

Hello Matt – VOC testing was a complete waste of money. VOC testing will not address health and safety of your family, toxicology will. VOC testing will not eliminate something you did (carpets, etc); sounds like you were sold a bill of goods. My initial services cost my Client $135. Waddaya think? Money well spent? What did the VOC testing cost? What was the benefit? (I.E. what did the testing tell you?) BTW, are you aware of the fact that if you did the same testing again the day before and then the day after, you would get different results?) I'm going to guess the "testing" was useless, and I'm going to guess the interpretation was faulty.

Post your report here, or send it to me and I will provide (FOR FREE) a critical review, and post it here. (Careful, my critical reviews make waves - see Mould Hazards in Marijuana Grow Operations for example or http://www.forensic-applications.com...cal_review.pdf

Cheers!

Edit: Oh BTW, nobody but us actually identified "cat pee" until we were brought in. The odor was described by many people in many ways, but not a single person mentioned "cat pee" until we raised the issue. (Wearing my other hat, I have obtained many search warrants based exclusively on my sense of smell...)


CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

I inspected a home with a odor problem most prevalent in a room with a large jetted tub a while back. The realtor and home owner had candles, several heat scent devices deployed and planned a seance in frustration and and desperation. This home had pier and beam construction. Before entering the crawl space the owner informed me that a unsolved murder had taken place in the home and if I saw a bullet while in the crawl space please recover it for the authorities. The bullet had passed through the victim and floor but was not recovered. I searched but could not help on that request but found a very large cat deceased in the crawl space over a beam.You never know what to expect.

How about the house being "possessed" and the spirit does not like the doors to be opened. Thus causing the odor and the increase of the odor for the increased length of time the doors are open. Need to have a Priest Inspection OR ;

Instead of :Gas Busters" maybe the answer is to call "Ghostbusters " .

Originally Posted by Matt Swanson

Before we moved in we installed all new carpet, new glue down wood floor in living room, all new paint (everywhere), and had the tile professionally cleaned.
the house is on a slab.

This is my first post here and I joined today just to add my two cents to this thread, I am not a HI but have been a developer/builder/landlord my whole adult life and seeing everything that has been tried I am guessing at this point the source of the smell is coming from concrete slab itself.

I am guessing that because it is present in every room that has an opening to the outside. What is causing the smell? My first guess would be some kind of moisture issue. If it were my house I would start be pulling up a small area of carpet and take a moisture reading and sniff a little LOL. You would be surprised how much of a smell, carpet and a pad can block/ slow down

Another uninformed 2 cents from the peanut gallery:

Given the facts described, the only things all rooms have in common are the attic and slab.

As the owner has been all over the attic and never detected the smell, that only leaves the slab as the culprit.

I'm not sure how you'd test this theory without just going for it, but given everything you've tried so far, it doesn't seem like too much of a reach... presuming the smell is coming from beneath the slab, you could install a sub-slab depressurization system (commonly used for radon abatement) to ventilate the sub-slab area to the atmosphere and to prevent the pressure differentials that are allowing the gasses to permeate the slab and enter the living space.

The system basically amounts to knocking a hole through the slab, excavating a bit, fitting a standard ABS sewer pipe into the void, backfilling with gravel, sealing the slab opening and then running the ABS pipe through a fan and up above the roofline.

The fan looks something like this:
FANTECH Radon Fan 4-1/2 In, Duct , 163 CFM - Radon Fans - 6KWA4|HP 2190 - Grainger Industrial Supply

Originally Posted by Mike Pagozalski

This is my first post here and I joined today just to add my two cents to this thread, I am not a HI but have been a developer/builder/landlord my whole adult life and seeing everything that has been tried I am guessing at this point the source of the smell is coming from concrete slab itself.

I am guessing that because it is present in every room that has an opening to the outside. What is causing the smell? My first guess would be some kind of moisture issue. If it were my house I would start be pulling up a small area of carpet and take a moisture reading and sniff a little LOL. You would be surprised how much of a smell, carpet and a pad can block/ slow down

Originally Posted by thaddeus cox

Another uninformed 2 cents from the peanut gallery:

Thaddeus,

You were giving your 2 cents as change for the 5 cents he put in?

I would not rule out what Mike said, and to call it "Another uninformed 2 cents from the peanut gallery" makes it seem like *you* shortchanged *him* when giving your 2 cents worth, I think you still owe him at least 1 cent, maybe even 2 cents - was your 2 cents Canadian? That might account for the difference in value.

Nothing negative intended toward our Canadian friends and inspectors here.

Originally Posted by thaddeus cox

Another uninformed 2 cents from the peanut gallery:

y

who was that directed at?

Originally Posted by Jerry Peck

Thaddeus,

You were giving your 2 cents as change for the 5 cents he put in?

I would not rule out what Mike said, and to call it "Another uninformed 2 cents from the peanut gallery" makes it seem like *you* shortchanged *him* when giving your 2 cents worth, I think you still owe him at least 1 cent, maybe even 2 cents - was your 2 cents Canadian? That might account for the difference in value.

Nothing negative intended toward our Canadian friends and inspectors here.

Jerry - how did you know I was Canadian?

Seriously though, you misunderstand. I neither replied to Mike's post nor was my "2 cents" comment directed at him. Note the colon at the end of the sentence which indicates that the 2 cents follows!

(yes I know this is a building inspection board, not a grammar nazi board, so I'm willing to let this one slide... )

Hello to you both, Mike and Thaddeus.
I think you are both onto a possibility of probable cause(s). Hope you don't mind a little ribbing from the other posters. Some of these guys are pretty fart smellers. ooops - dyslexia

Anyway, I suspected some similar scenario, too. We wont know though until Matt the homeowner gives us the final outcome.
So Matt - have you given consideration to Caiomhens offer of a FREE review of your tests? Many of us are on the edge of our seats waiting to see whats up. .....and I did not intend to minimize the post by quoting about the 'old sweat and cat pee' . That is only to reiterate that I only have a limited sense of what a smell is - compared to the sophisticated and educated olfactory organ of a certified smeller

Originally Posted by thaddeus cox

Jerry - how did you know I was Canadian?

Seriously though, you misunderstand. I neither replied to Mike's post nor was my "2 cents" comment directed at him. Note the colon at the end of the sentence which indicates that the 2 cents follows!

(yes I know this is a building inspection board, not a grammar nazi board, so I'm willing to let this one slide... )

sorry, I took that a different way, its cool

to add to my guess, the fact that the carpet and wood floors went in after they bought it, and before they moved in.........glued down wood floors, and perhaps glued down carpet pad could be alot of glue thrown down on a slab that might not have been properly prepped.........again just guessing blindly from 1000 miles away

Have a bunch of people all stand in different rooms, open doors and windows and whoever smells it first yells. Keep narrowing down and repeating same.

Originally Posted by thaddeus cox

Given the facts described, the only things all rooms have in common are the attic and slab.

Hello Thaddeus –

Actually, your observation is not correct. A home, like most structures is incorrectly viewed as a bunch of discrete, isolated areas, assembled into a super-structure.

In fact, an home, like other structures, is a unit, a complex integrated system. If I go into a house, or an apartment complex, or a strip mall, and release a tracer gas in any one area, I will quickly observe the tracer in all areas of the structure.

The tracer will migrate along paths described by the pressure differentials in the structure, and then, eventually, it will exfiltrate from the structure into the “building envelope.� (My, “building envelope “ is different from the concept of “building envelope� used in the construction trades.).

The building envelope is a nebulous pocket of air that surrounds a structure and is coupled with the structure. Anything that enters the building envelope can be reintrained back into the structure through infiltration.

The shape of the building envelope is dictated by the local topography, nearby buildings, microclimate issues, etc, and a single building envelope can surround multiple, separated buildings. Thus if one structure is dumping an odiferous material into the envelope, it can preferentially migrate to another structure sharing that envelope.

Therefore, each room in the house shares many things, including the fact that each room in the house shares the same air throughout the house.

Food for thought.

Cheers!
CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

Did anyone think about possible septic tank?? I would have a plimber run TV through drain?? my first choice.

Originally Posted by CaoimhÃ*n P. Connell

Hello Thaddeus –

Actually, your observation is not correct. A home, like most structures is incorrectly viewed as a bunch of discrete, isolated areas, assembled into a super-structure.

In fact, an home, like other structures, is a unit, a complex integrated system. If I go into a house, or an apartment complex, or a strip mall, and release a tracer gas in any one area, I will quickly observe the tracer in all areas of the structure.

The tracer will migrate along paths described by the pressure differentials in the structure, and then, eventually, it will exfiltrate from the structure into the “building envelope.” (My, “building envelope “ is different from the concept of “building envelope” used in the construction trades.).

The building envelope is a nebulous pocket of air that surrounds a structure and is coupled with the structure. Anything that enters the building envelope can be reintrained back into the structure through infiltration.

The shape of the building envelope is dictated by the local topography, nearby buildings, microclimate issues, etc, and a single building envelope can surround multiple, separated buildings. Thus if one structure is dumping an odiferous material into the envelope, it can preferentially migrate to another structure sharing that envelope.

Therefore, each room in the house shares many things, including the fact that each room in the house shares the same air throughout the house.

Food for thought.

Cheers!
CaoimhÃ*n P. Connell
Forensic Industrial Hygienist
Forensic Applications Consulting Technologies, Inc. - Home

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

Caoimhin,

If you were given the task of identifying this anomaly, how would you go about it?

Or is it simply sniff, look, think, sniff, open something, think, look, open something, sniff, sniff, sniff?

Is there a reasonable way to scientifically identify the odor, or track it to its source?

Or do you bring in a Bloodhound? (Bill Stephens, got any pictures?)

Poor mr. Wood never did he ever hear of a typo, Must be new!! make fun of people good inspector!!

If you never heard of TV ing a sewer lines you must be new!!

Originally Posted by Rolland Pruner

Poor mr. Wood never did he ever hear of a typo, Must be new!! make fun of people good inspector!!

If you never heard of TV ing a sewer lines you must be new!!

That's ok cuz we have a large "herd" of plumbers here in the Carolinas

A few days after CaoimhÃ*n posted what I felt were insults I called him because I realized his way of helping might be what I needed. We had a lengthy discussion about my problem. I do have a copy of the VOC test results and would be happy to post them but they do not show anything "smelly."

The only trade I did not have in the house was a plumber. Reading posts on here I was either going to do a Peppermint test or smoke test to see if there were any leaks in the plumbing (I was positive the smell was being pulled from the house).

I was at a local plumbing supply house getting some materials for work and I asked the old timer (Mr. Mark) behind the counter about the Peppermint test. He looked at me funny and inquired. I told him in length the situation. He gave me his 2 cents and offered to come by the house.

What the hell, I happily gave this complete stranger the directions to my home.

Sorry for the novel..

A few days later I stopped by the house and opened some doors a few hours before Mr. Mark was due to arrive. After 10 minutes he explained his thoughts. The house was experiencing a ghost. Just kidding. The house was back drafting odor from the plumbing roof vents back into the house (the smell was coming from the vents, down the roof, and into the house through the open window or door). I was not convinced because of the following: I was certain the smell was somewhere in the house being pulled out. I had been on the roof and stuck my nose on all of the roof vents and never smelled the smell. I never smelled anything outside. The smell did not smell like sewer to me.

So, Monday night I got on the roof and covered all of the roof vents with zip lock bags and zip tied them tight. I opened up the house for 2 hours last night and no smell. I had to try in the day time so I came home at lunch and opened some doors. No smell. I came home tonight and opened just the front door for over an hour. NO SMELL.

It has only been 2 days and I have only tried opening doors a three times. As soon as I am done posting this I am ordering some vent stack filters. I am not 100% convinced this is the problem but this is the closest I have been to pinpointing it. It still does not make complete since that the smell appears in the house but you don't smell it outside.

If it turns out this is not the problem I really don't know what is next. I will report back in a week or so.

I sincerely appreciate the feedback you all have given and realize some of you mentioned plumbing vents over a month ago. As Homer would say, "Duh."

Matt

Have you thought of raising the vent with an extension? It is possible now that you describe the situation that the wind is creating negative air pressure as it comes over the roof pulling gasses down over the leeward side.

Is the vent closer to the ridge or down further towards the middle or lower portion near the eaves?

Does it protrude above the roof line as in the illustration?

You may want to uncover the vents before you decide that was it ... just in case it went away on its own. If you've found it, the smell should return.

I found it to be a missing trap in a bathroom off the master bedroom from a recent remodel.

They actually had a ceiling fan in the bathroom to get rid of the odor in the bath. It actually got rid of the odor altogether. The reason being, pressure.

As stated in the original post the odor was not smelled until the doors were open. Keep the doors closed and the home is more or less pressurized on most occasions.

With the fan on in that bathroom is was pushing air down the drain and up the roof vent. Without it on the smell rose in the bathroom. This was also a 1930s home and of course very leaky.

Originally Posted by Raymond Wand

Have you thought of raising the vent with an extension? It is possible now that you describe the situation that the wind is creating negative air pressure as it comes over the roof pulling gasses down over the leeward side.

Is the vent closer to the ridge or down further towards the middle or lower portion near the eaves?

Does it protrude above the roof line as in the illustration?

Raymond,

That is not a good, or accurate, drawing in that it is not the height of the vent which is the problem, but the size.

The code REQUIRES the vent to extend above the design snow load depth (which could be 4 feet), and the code also encourages the vent size be increased before it goes through the roof to help avoid frost closure.

Happy New Year. Still no smell. I purchased vent stack filters called Sweet Air filters and installed them on all of the plumbing vents coming out of the roof.

It doesn't make since to me that you don't smell the smell out side the home but since we blocked or filtered the plumbing vents and tested by leaving doors open, we have not had the smell.

I hope I don't have to report back that the smell has returned.

Matt

Matt,

Simply extending the vent pipe up several inches may be an alternative and long term solution.

Originally Posted by Matt Swanson

I purchased vent stack filters called Sweet Air filters and installed them on all of the plumbing vents coming out of the roof.

That is a no-no as the code prohibits any blocking or reduction/restriction of the vents.

Smells fishy, like snake oil to me (as the old saying goes).

Matt,
Interesting that the filters resolved the problem. Like others I am not a fan of of restricting the vent, though at 47cfm it may not be an issue.

I have another suggestion to try to correct the cause rather than treat the location of the smell. Especially since you have located the source.

From the roof top run a 1"- 2" snake down 30 ft. Idea being that there is an obstruction that may be restricting the air flow causing it to become concentrated at the stack vent as it spills out. Obstruction could be a bird or even a tennis ball or just a blockage in the waste line it self.

Good point. I have seen Hornets build nests in vent pipes almost blocking the vent opening entirely.

Dang, That was actually a very fun read of all the comments.

It also was a great way to see how everyone thinks in these situations

This is an old thread, but I suppose there are folks with current odor issues who's search's will lead them here, so I will add a comment or two.

Matt, I'm glad to hear that your odor issue has apparently been resolved. If I'm correctly following the logic of your solution, the odor was due to sewer smells exiting the vent stacks at roof level and then re-entering the house through the open doors or windows, and the odors emanating from the vents are now filtered by the Sweet Air filters and no longer offensive?

If that's the case, the smell may be less offensive, but I would think that you might also want to take additional steps to reduce the incidence of the sewer gases, odorless or not, from coming back down into the house, such as increasing the height and/or exit size of the vents above roof level as previously recommended by the very knowledgeable inspectors here.

In addition to the possible causes of clogged vent pipes already mentioned, other obstructions I have discovered include rats and squirrels that apparently entered or fell head first down the pipe, as well as tools, cut pieces of pipe material, and pieces of lead flashing trimmed off the lead roof jacks. Also, roofers are often careless about folding the lead roof jacks into the top of the pipe, but then not spreading the lead back open inside the pipe. So there many reasons why vent pipes might be obstructed.

On a humorous note, my former mother-in-law, a rather stately and proper woman who lived in a rather stately country home, once came running out of her master bathroom, underwear trailing on one foot, and with a water-logged squirrel darting past her and running through the house. She was screaming at the top of her lungs that the squirrel came up from between her legs while she was sitting on the toilet! She swore that it was not in the toilet when she sat down. We surmised that it had fallen down the vent and came out through the toilet! It's either that or she sat on a toilet and didn't notice there was a squirrel in it.

______________________
Don Putnam
Austin, Texas
www.RoofConsulting.com