I'm sorry to hear about this issue! It could be many things, I would recommend getting a home inspector or general contractor inside to do a walk through. My initial thoughts are: plumbing problem or something got into the house and died. We had the same problem in our home, it's older than yours. Good luck to you, hope everything works out!

We had the same experience with an old-lady-smoker-cats-dogs-vermin house. Walls down to studs or further, floors down to joists or further, all new insulation, new rafters some places and new roof. And we still get residual odor in one room sometimes.

Sadly I think your scope of work is bigger than you anticipated.

Our "old house" had smokers and pets before us. After we tore out the carpet and tiled the floors, replaced the window screens, had the duct system cleaned, painted the entire interior and exterior, put on new roof, replaced the kitchen ceiling and all appliances and exhaust systems, and tore out and replaced bathrooms we still smelled the odor. We finally removed the entire fireplace and chimney, sealed the roof and patio flooring....and poof, the smell was gone. BTY, our huge lawn and sunsets were spectacular!

Check beneath the floor of your home for dampness and mold and check for venting for the area beneath the home.

Some old homes used particle board as a sub-floor - that would have absorbed the smell from pet urine even more than plywood or boards.

If you haven't found the cause of the smell by now, you should probably rip out all the carpeting and make sure the smell is not from the wood subflooring itself, and then replace the carpeting with wood plank flooring. If the problem is not the carpeting, you may be able to keep the carpeting and have the edges hemmed as floor sized rugs.

Hope you find the problem soon if you haven't already.

In the meantime, see if you can find a banana nut bread scented candle. Open it but don't light it. You might also be able to find the 1" square cubes six-packs of wax; if so, just open one and place it in an unobtrusive place in each room about shoulder height, if possible.

Alternately, an aluminum pan filled with a better quality cat litter and/or baking soda placed under furniture might help absorb some odors while you look for the cause.

Let us know how this turns out.

We are looking at buying a house with 2 occupants that smoke. Ugh. Painter recommends ripping up carpet and shellacing the wooden subfloor with Zinsser Primer. He said otherwise the smell can come up through the new carpet. He also said the smell will not come up through vinyl flooring.

He will also spray the popcorn ceiling and paint the walls with it before painting. Washing with TSP will likely not cut it.

You can also contact ServPro or a carpet cleaner that specializes in odor elimination or remediation. One locally has an ozone machine we can rent for $150/day that gets into the air ducts.

http://www.naturallivingideas.com/zeolite-rocks/

Don't buy it you will regret it. We moved into a short term rental that had a long time smoker. The new owners did everything, new paint, carpet, b
duct cleaning, etc. After a few months the ninotine started coming through the paint and the smell was horrible.We moved, it was disgusting.

So we had the floors replaced. The only thing on the floor is sub floor and hardwood. We sprayed the sub floor with a bleach solution.
Anyway; our house still smells!!!! We spent a fortune on the floors. And it’s still there- I’m so lost on what it could be. Unless the smell is just lingering in the house - it’s been about 2 months

It is more than likely soaked I to the subfloor and possibly the floor joists. We had some joists that had stains down a couple inches.

And bleach is unfortunately not very effective. It doesn't actually kill all the microbiology that is stinking and it doesn't lift out the materials that are creating a breeding ground. Some methods that actually change the chemistry of the area or absorb and hold the odour like activated charcoal, tea tree oil, compost tea (really) can work but if your problem is as bad as ours was I fear the whole subfloor just needs to be out of there.

Bleach solution only makes pet odors worse, I believe. OdoBan or something like it is what you would have needed to use. You need an enzymatic based product to break down the urine.

You will need an ultraviolet light to detect any place you have missed, baseboards, etc and spray those with the enzyme based product.

https://www.thebalance.com/how-to-get-rid-of-dog-urine-and-cat-urine-odors-1799052

Did you shellac the subfloors? I havent found anything that is a true substitute for shellac. Oil primers are better than latex which is better than not doing anything. Unfortunately, homeowners who want to do the additional details like removing stained drywall or damaged subfloor get pushback from their family or contractors who just want to get the job finished. All those people who are claiming that the work is overkill aren't the ones who willing be bothered if the issue returned.

If the smell is in the joints of the floor than we are SOL, we spent a lot of money on our new floor and aren’t ripping them up.
Any suggestions other than tearing up new floor?

Can you remind me, did you use hardwood? It's possible to lift it up very carefully so it can be reused.

Go under the joists, I am assuming the crawl space? and spray enzymatic odor eliminators.

Following

It’s the old hardwood floors under the carpet.

You’ll have to rip it all up, plus subfloor.

I had a friend who lived in a house that had been an old folks home - you could smell the urine on certain days, despite the floors being thoroughly cleaned.

Ozone air cleaning machine is your last hope. Did you get your air ducts cleaned?

NOBODY really knows the answer to eliminating the damage to a house by smoking in it for years. They are just guessing. I feel for you Lindsay.

We dont have carpet anymore. we have hardwood throughout the house. Its just the subfloor - which is plywood and then the hardwood.

The smell still radiates through out the house. We put in new duct work and HVAC system when we moved in.

Would we need the air ducts cleaned if we just got new duct work a few years ago?

I dont know what kind of specialist to call. I have tried servpo, they said they dont know what it is.

Out of the other ideas suggested here, what have you tried?

I would have a reputable pest company come out and do a very thorough inspection of the attic and crawl space to rule out rodents or their droppings or carcasses.
I would also call a home inspector and be sure to write down anything that makes the smell better or worse time of day weather etc
You may also want to call a reputable mold inspection company who have infared cameras which might help figure things out too? They also would have ozone machines to install which are also a help

You mentioned a crawl space under the home. Of all the comments and great suggestions here, only one briefly touched on the subject of sewer lines. If you are located in a freeze/thaw area of the country, you have a cracked pipe or two. Have you had a plumber out to check for any cracks in the lines or blockages in the lines or soil stacks? There may be a sewer gas (just smelly air) coming thru the lines which will come up thru the drains in sinks, floor drains, etc. permiating the air. From your local hardware stores (or thru your plumber) there are additives that can be poured into your drains to help break down waste as well. When nature's water table is very low and weather is damp this can often be a time you notice this more. Try a few cups of bleach in a bucket of water and pour into any floor drains. Do the same for your sink drains. Now call a good plumber to check all your stacks, piping, and venting. Good luck! If this is not the problem, at least you know your plumber won't need to be called in the middle of the night for something!

After catching up on this thread, I have a question about your crawl space. Have you checked the foundation vents to ensure they are working properly? We had to replace ours when we moved in, as they were original to the house, and most were sealed shut. The new ones have a built in thermostat, so they open and close on their own depending on the temperature to allow fresh air to flow under the house. They're under $20 and very easy to install.

Kaye mentioned zeolite rocks. I know that won't solve the problem, but they could very well help until you can eliminate it. I would use them in all the closets and other small enclosed spaces that trap the odor. They seem gimmicky, but they do work, and all they need are a few days of fresh sunshine to "recharge" after absorbing odors.

Any luck eliminating the mystery smell?......

I bought a house with a bad smell that emanated from the carpeting and drywall. Part cigarette smoke and part pet urine. Just lovely. For the drywall, I had to scrub with detergent, then shellac the drywall to seal in any odors the scrubbing didn't remove, then paint with a special smell-reducing paint. For the floor, I pulled up the carpeting, scrubbed the concrete slab, then sealed it also with oil-based sealer, then a couple of coats of a special concrete paint, then installed the new flooring. Big pain in the neck, but worth the effort.

NO... smell is still here. With the weather being nicer, i smell it through the vents.
I appreciate all your comments.

We do not have a crawl space, so we can eliminate that.

All duct work is new.

The only insulation we have left is in our attic.

Im not sure what kind of contractor to call, i dont think any specialize in 'smell'

Im just still completely lost on what to do!

I didn't read comments, but is it at all sewer gas smell.... mold behind walls, bathroom maybe, can start to smell in nearby room.

Lindsay, did you try the suggestions here regarding activated charcoal, etc?

Is the attic insulation new? Old insulation especially when rodents are/were present is rank.

You poor thing.....but the insulation may well be the culprit....if there were ever rats in the attic or if there possibly still are rats in the attic? Dead bodies and feces or urine trapped in the insulation esp since insulation can be close to the air vents? Could be the culprit. It really really stinks :(
I would call a very reputable pest control company to determine if there is a rodent issue and I would also call an insulation company to come in behind them and make sure it's clean up there and have them replace any insulation they find that is compromised....
Other thoughts:
Did you have the house tested for mold? Could be a source.

Was possibly any part of the house remodeled in 2005/2006? Do you also have allergic reactions or headaches you can't explain? I'm asking because Chinese drywall was an issue during these years and it can give off a very strong sulfur smell. A reputable home inspector can tell you if you have it or not but its only likely a source if any drywall was put in during those years as that is when it was used by some contractors as there was a drywall shortage during that time and some was imported from China

You shouldn't have to live with a smell. Don't give up yet....there must be an answer hidden somewhere :)
Good luck!

Did you pay the carpet over the word floors? Wood is extremely porous you would never get the smell out. You would have to remove carpet which can be salvaged, rip out the wood and then reinstall carpet. My neighbor have me a beautiful wood 2-drawer file cabinet when she moved. I was thrilled. Then I opened the drawers and nearly fell over. The time it would take to clean this with everything under the sun people and pros recommend would take months and lots of hard labor..... 2 drawers inside out and backwards as well as underneath. No thanks, threw it out. Nothing comes out of wood.

You might try ozoning the house. It is a form of bleaching that is air born and used to be used in hotels to eliminate cigarette smoke in rooms. It can be quite effective in eliminating odors. It may not do the trick if the problem is urine in the hardwood and subfloor however. If that is the case, you may have to follow Fla_chic's advise first and even then before putting down a new subfloor I would use a sealer like kilz to block the smell from seeping out.

Most larger disaster restoration companies will have ozone machines if you are wondering.

Ugh! Do not use charcoal to absorb odors and then use it to cook food on the grill! That is a disgusting idea! Good luck to you!

Have you tried ripping up the carpet in one room (or even a closet) then painting the floor with several coats of sealant? If you have one room you could sacrifice, paint the floor, and then seal the door up, you might be able to tell if that fixed the problem in that one room. If the sealant worked you would have your answer - smelly floors. And by the way, a painted wood floor can look nice with a nice rug placed on top, although you could also use clear polyurethane.

A family member gave me a very nice oriental rug that had pet stains. Over the course of several years I washed it myself with mild soap and hung it outside for a few weeks - no luck with the smell. I sent it to several different commercial rug cleaners and those didn't work either. I rolled it up with baking soda and that didn't remove the smell.

Finally I used liquid soap and a curry comb (rubber brush used to clean horses) on both sides, scrubbed, washed and rinsed both sides several times, and hung it out in the sun for a few weeks with a sheet on top to prevent sun bleaching. That finally worked and I have a lovely non-smelly rug.

The point of this story is that pet urine is very smelly and if the smell is in wood floors, you will never get it out. I do think, though, that you could encapsulate it with paint or polyurethane.

"Ugh! Do not use charcoal to absorb odors and then use it to cook food on the grill! That is a disgusting idea! Good luck to you!"

No one suggested this...

Is it possible that you have some animals living in/under/over your home -- in walls; in attic; beneath floor, perhaps even in the insulation between the floor joists or even in the hollow spot beneath a bathtub?

Before you start ripping out anything/everything, call a pest pro and see if they can find the stink for you.

If you do rip out your flooring, replace any carpeting with something other than carpeting.

U could try damprid through out the house and see what happens

Lindsay - I cannot believe everyone recommends thousands in house remodeling - I don't think all of that work is/was necessary at all. I had a similar issue and fixed it with an Ozone generator. Buy one from Amazon for $100, run it overnight (leave for the night). Air out the place the next day and your smell issue will most likely be resolved.

reading through.... bemused.... we bought our vacation house in 2000. since then we've removed carpeting and replaced with hardwood and tile, rebuilt the stairs, have painted several times, redone all 3 bathrooms and the kitchen.... and you know, it still smells like a beach house. hard to put a finger on what it is... not pets, not smokers...we dont even notice it when we enter the house but when we get home on sunday night all of our clothes we bring home smell like... beach house. we're currently having a screen porch and deck built and some rot was found when the side of the house was opened up. maybe that was the source, we'll see.

And to add to my post above, nothing like good air/dryer vent cleaning as well. $400 max? Some activated charcoal for $27. Ozone generator for $100? Guaranteed the $527 investment would have fixed all. No need to completely tear up the house, unless of course this was an excuse for a remodel. Just saying :)

"and you know, it still smells like a beach house. hard to put a finger on what it is..." --> Do you have wet suits?? Because I finally figured out why my garage smells like weed -- it's that neoprene/salt-water/seaweed combo. :P

could be! not wet suits, but wet suits.... we don't dive but always lots of wet bathing suits. eau de sand, sunscreen, chlorine, salt, bugspray, charcoal smoke, mixed with morning and afternoon fog, sprinkle in just a hint of mold/mildew. you could bottle it but no one would buy it!

we're having the big construction project still going on, so beachyfug is still overwhelmed by sawdust inside, and portapotty and construction dumpster in the front yard. maybe the thing to do is have someone come over every week and saw up some boards in the downstairs den. i love the smell of sawdust....

We had something similar...moved into a brand new house. After a couple of years, we noticed a strong musty smell on the main level. Worse on hot humid days. Turns out crows had made their way into a bathroom vent through the “cage” on the exterior of the house. Built a nest, had babies and it goes from there...some of the babies died.
We couldn’t reach the nest from in inside vent. Had to get it from the exterior, using a vacuum and very long sticks/poles. What they pulled out was disgusting!!!
The cages are suppose to prevent this from happening but after years they get holes/cracks. And I don’t think they are a requirement.
Seems like you’ve tired just about everything but wanted to pass along our experience.
Good luck!

Omggggg! Story of my life. My clothes smells when i leave the mobile home. I have two smells going on here. I have old wood smell and a moist/damp/humid disgusting smell i cannot seem to fine whar is causing this. Just like you I’ve done several things but I cannot get rid of it. Any update on your house smell?

Lindsay,

My daughter purchased a home from an investor who did cosmetic changes only. We noticed a smell and asked what it was and was told that the previous owner had a lot of animals in the home. So we asked that they do a ozone air cleaning prior to closing. Thinking that would help she purchased the home. Now its been a year and the smell is still there. Her home is on a slab, we have repainted, replaced all of the flooring and done tons of others things. So after reading all of this I was hoping that you found some sort of resolution to how you stopped your smell. We are at a loss and have spent thousands of dollars with no end results of what the smell is or where it is coming from. My daughter and grand baby clothes smell terrible. Have you had any luck on your end or have any suggestions? The only thing that I haven't done is cut out the walls and baseboards.

Hi I have same problem 1950s house suspect leaking roof into cavity wall and treat under sides of floorboards and joists at ground level and loft seal roof to prevent water ingres to cavity lot of work hope this helps a am half way started with roof

Smell issues in your home: Resources y'all might try could be your "county extension agent" or state sponsored college . They tend to deal with agricultural issues but if there is any chance the smell is an animal, they might be able to help or point you in.

For anyone living in a model home: Older model mobile homes had something that might have been a particle board cover that looked like cardboard that would crumble after getting wet under the flooring to hold the insulation and hide the pipes and animals really liked to chew an opening and crawl into that space near plumbing pipes.

If the issue is mold, no matter how it got started (dead animal or water problem) that is a health issue that needs to be addressed, especially if there are children or elderly or members of the family with health issues involved.

We just purchased a home built in 1976 with slab foundation and that's where the HVAC ducts are place. There's a septic tank and water damage from a roof leak. The house and the garage have a strong smell that reminds me of yeasty smell of vitamins. Not sure where to start. To me its weird that the smell is also in the garage which is not near the area of water damage.

Did you ever find the culprit?

Faced a similar problem. We bought a house, but at first we didn't care for the smell of cigarette smoke and various bongs, maybe something else we don't know much about. More precisely, we asked about this issue on what we were told, paint on the new ceilings, throw out the mats and everything will be fine. This is what the previous owner told us, who claimed that only e-cigarettes were smoked. Learn the truth about vaping. So we calmed down. But now that we have done all the cosmetic repairs, we spent a lot of money on it. And the smell is still there. What advice do you have? It seems to me that we have to dismantle the whole house and build a new one.