I just bought a condo which is a three-level townhouse and was built in 1980.

I am adjacent to my neighbor and share a common wall. My neighbor, an older couple, smoke weed frequently and do not air their home.

The smoke gets to my side and it is gotten so bad that I have left my condo and live elsewhere. Are there any products out there like drywalls or sealer that could prevent the smoke from coming to my side? How effective are the options available? I am just thinking about redoing my walls by bricks, thicker dry walls, waterproofing, etc.

  • 17
    How did the realtor get you to visit and not notice the smell...
    – Solar Mike
    Jan 12, 2020 at 16:57
  • 6
    Other options would include taking this issue up with your landlord or law enforcement.
    – René Roth
    Jan 12, 2020 at 17:20
  • 24
    I would definitely take this up with your landlord: an inter-condo demising wall should not be allowing smoke to penetrate it, irrespective of the source, as that means that if your neighbors light their couch on a fire with a stray blunt, the smoke from the couch will get through, not just the smoke from the blunt! Jan 12, 2020 at 18:11
  • 8
    Positive air pressure is the ticket I think. Suggested sealing things up thinking it might improve things enough to get by on the cheap. Likely there are significant leaks between the two units.
    – gnicko
    Jan 12, 2020 at 23:41
  • 6
    @ThreePhaseEel If OP bought a condo that means OP has no landlord?
    – gerrit
    Jan 13, 2020 at 8:25

5 Answers 5


I would consider adding a positive pressure to your living space with the fresh air being pulled from a wall on the opposite side of the house. I have installed this type of fan in several multi-family dwellings to keep smoke stink out. The ones I have used are quite small squirrel-cage blowers that operate with a pressure switch; I think it was based on 2 or 3” water column.

The slight positive pressure pushes air out through light fixtures, switches and outlets. The only downside I remember: because these are small, if you open a window or door for long you lose the advantage of the positive pressure. I did a handful and put each one in a wall next to an existing outlet so no new circuits needed to be run.

I don’t know if you can really seal things but the positive pressure fan worked. I had 1 customer have me install them in 3 different houses; the last one was a single-family home but she said she liked the fresh air (that house had no make up air electric baseboards) and it made her feel better, so those little positive-pressure fans do work.

  • 1
    by reconstructing the wall i am trying to block the smoke getting to my unit. the smell is disgusting.
    – Na Sim
    Jan 13, 2020 at 1:55
  • did you install in a house with a marijuana smoker, and did it work?
    – Na Sim
    Jan 13, 2020 at 2:04
  • 1
    I have used these and they help. I upvote a lot of your answers but can't on this one. Yea it helps but it doesn't take away to smell. I guess it depends on the OPs threshold is and their expectations. I tried doing these on a few units and sealed the hell out of them and still had tenants complain after spending thousands.
    – DMoore
    Jan 13, 2020 at 4:24
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    My experience is it keeps the smell from getting in we did try sealing and did spend a huge amount the only problem we find was when someone was smoking close to the intake the fan picks it up from there so I guess there is no fool proof method.
    – Ed Beal
    Jan 13, 2020 at 14:12
  • 1
    A small square cutout inside and a 2” round hole in the wall. Some have nice outside covers some cheap sheetmetal. I get the ones with a filter that can be replaced or washed. they do have activated charcoal filters available. There are larger units but I thought that would not be a good idea once the house is closed up after a minute or so you can’t even hear it but it maintains 2-3” of water column if memory serves it’s not a lot but keeps the flow exiting where the stench was entering.
    – Ed Beal
    Jan 13, 2020 at 17:07

I just had a friend that went through this about 8 months ago. This is not really a DIY question if you want a long-term answer. I will get back to how his situation turned out...

Your answer is to stop your neighbor from smoking. Let's just take weed off the table. Let's talk cigarettes or vaping which is not considered a controlled substance. It is illegal in every single state to emit smoke (cigarettes) onto another dwelling. Second hand smoke can cause major health concerns and if you can smell it it can harm you. I mean you know the fart smell is just you taking in tiny vapors with poop in them right? Same thing for cigarette smell, vaping smell, pot smell.

So pot would be met with double the attention because more than just the negative health side effects you are in fact giving someone a dose of an illegal substance. It does not matter how small it is, it is illegal.

Here is what my friend did:

  1. Talked to neighbor. This did not help and neighbor continued.
  2. Warned neighbor they were going to get sued if they continued.
  3. Wrote a letter to the HOA. Advised them that if they deemed it legal to do in their facilities then the liability of the home owner would be at least partially passed to them.
  4. File a suit in small claims court against home owner. Filed a motion asking board to act as witness and to testify on their HOA rules. The suit was to pay them 20k+ for renovations that would allow for zero smoke to enter their home.
  5. Friend called cops each time smell got bad. After the 5th time the cops issues the other home owner a public nuisance ticket.

After the ticket was issued his case was basically won for him - judge would look incompetent not favoring him and he could just keep sueing as each light up is a different offense. So HOA lawyer basically told other homeowner this. She put her condo up for sale within a few weeks and moved out... HOA made it against their rules to smoke weed (as much as it can be smelled).

These steps were outlined to him by case law that he found on home owners with similar issues. He did not think of any of these things himself. He also researched remedies like positive pressure and filling in gaps. Most of the people experienced the same thing - they spent tons of money for some remedy but still smelled the smoke. My recommendation is that you talk to neighbor and HOA board before doing anything. I have worked on condos and apartments with lots of smoke damage. There is no way you are sealing off an adjoining wall from a non-commercial building without ripping the whole thing apart.

Here are some other things to think about:

  1. If it is weed or cigarette smoke these smells can basically get trapped by your house. In severe cases I have had to rip out drywall and start over. Someone other than the homeowner is liable for this for sure (HOA and other home owner). This is destruction of property. Let's just say the homeowner seals their home "adequately" where it isn't making them upset. There is a high chance that they just got used the smell. What if that smell has infiltrated the walls. Think about the dog/dog-pee smell you smell when at a friends house and they smell nothing. So now even if homeowner is sort of happy short-term they could be out potentially tens of thousands if trying to sell.

  2. What would your reaction be to a house that installed positive pressure or some funky air traps and filters? Cliffhanger... I would buy something else. Most people would react the same. Spend a bunch on fixing house so 80% of the smoke smell doesn't get in and prove to potential buyers that the condos were not made well in the first place AND that there is/was a big problem.

  3. This is not a new problem. Don't let uninformed people fool you. There is no right to smoke marijuana even for medical purposes if smoking will effect others. The law is crystal clear in every state.

  • 9
    At some places smoking weed is legal. It has been proven that weed helps to anticipate Parkinsons, for exmple. Both slowing the propagation of the syndrome and preventing it. Your suggestion may be sort of taking their cure off them.
    – Crowley
    Jan 13, 2020 at 6:52
  • 28
    @Crowley No one has the right to make someone else take their medicine too. If they need canabinoids or something else from the cannabis they could eat it.
    – ian
    Jan 13, 2020 at 7:03
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    @Crowley - you have the right to smoke weed all you want in your house. You have zero right for the smoke from your weed to effect others. If a home owner had kids you could (and it has happened) get brought up on child endangerment charges or giving an illegal substance to a minor. I wrote this answer because I have seen too many people spend too much money without it helping in the end for something that is illegal in every case on the other end.
    – DMoore
    Jan 13, 2020 at 8:29
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    @DMoore: Sorry, that's not true. It's a generally accepted legal principle that people's behavior can bring them in conflict, and each case needs to be considered on its merits. A standard of reasonableness usually applies - a minor nuisance to you may be justified by a larger benefit to the other party. Medicinal use for Parkinson could be such a benefit. Recreational use would fail the same test, as it lacks the medical benefit.
    – MSalters
    Jan 13, 2020 at 9:40
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    @rath - yes legal requirements are a big part of this site. We don't tell a homeowner to make a repair that another should be making. If this homeowner repairs their house they are in fact making it harder to enforce the law or recoup expenses. It's illegal in all states to emit smoke onto another dwelling sorry if some misinformed comments confused you - and this has nothing to do with weed.
    – DMoore
    Jan 13, 2020 at 15:48

I'd go with aerobarrier which can help to seal your unit extensively. Then as suggested by Ed add positive pressure fans.

  • 1
    Wait so you are going to blow 40 mph wind into your neighbor's home and seal gaps and then they are going to do the same? I have never seen this done on a shared wall but who knows. Do they have an example of this?
    – DMoore
    Jan 13, 2020 at 4:38
  • 1
    It blows a latex aerosol mist which hardens when it is pushed into gaps. I don't see a problem with pressurizing your house and sealing any holes whether they go to the outside or to another unit. Why 40 mph? Aeroseal uses ACH50 it shouldn't have much to do with wind speed it should be a CFM over air volume. Jan 13, 2020 at 7:16
  • I agree that aerobarrier might be the best way to seal, I have only seen it done on new construction (can it be done with a finished structure ?) , we looked into it and there sales pitch was awesome but the cost was out of reach for us. + That was my last build , but we have said that before. +
    – Ed Beal
    Jan 14, 2020 at 14:31
  • 1
    You can do it on finished structure but you have to mask any horizontal surface. It isn't cheap but I think it is typically based on square footage and in a condo it should be relatively affordable. Jan 14, 2020 at 16:18
  • Thanks I did not know it could be used after finishing. It was quite expensive but we met the purchasers requirements without it , funny thing the owner required sealing and had us add make up air intakes to both sides. But she bought it before we had finished the Sheetrock so we were happy.
    – Ed Beal
    Jan 14, 2020 at 16:39

Previous advice to deal with the civil/legal side is great, here are some tips about condo smells, I am sure there are better guides on the web:

  • Tell the neighbors to buy a CARBON FILTER. activated carbon is extremely reactive with air particulates and lasts for years. You can make one by settling 2" activated carbon in a 12'' inch box and placing a 10'' PC fan / quiet fan non-stop over it. They should have multiple carbon filters going 24/7 under beds and hidden away, it costs 3 dollars per year in electricity.

  • Inform them that you will start to phone the cops if they don't install a fan blowing outside to have negative pressure, an activated carbon box, and you should have positive pressure if you can find a source.

  • Get a carbon filter for yourself for the time being, activated carbon costs 5 dollars a pound in the fish shop, put 1-2-5 filters in stragetic places / rooms where smoke can get through. An 12v 8 inch pc fan puts through 150 m3/hr undervolted to 9V AC power supply.

  • Use a joss sticks to search cracks or gaps where air is going through, alghough this should be done on the neighbors side. It's what I do to analyze draft dynamics of the home. It's all about directing flow of air into your home from a clean source, so that their air cannot physically push into your home, and getting them to evacuate their air away from residents.

  • buy one of those brushes for under the door and door sealant tape for the edges online.

  • research anti-odor paint and hermetic sealant paints, plasterboard is breathable (what kind of wall do you have?) so it's good to seal it hermetically. You may find that slow-setting plaster mixed with a chemical, PU or silicone can be used to limit scents. Plastering a wall roughly by hand is fun and it's a lot more relaxing shadow play than a flat wall for the eyes to rest on.


The cheapest technical solution might be to offer them a vaporizer. There are low-tech, efficient ones called "vaporization pipes":

A passive-convection "vaporization pipe" with flame filter

I've seen some at parties a long time ago. People were smoking right next to me and it smelled as if they were drinking tea, nothing more.

You'd have to ask your neighbors first but those pipes have objective advantages for the users too:

  • No need for tobacco
  • Much easier on the lungs than other inhalation methods
  • More efficient because THC isn't destroyed by pyrolysis during smoking.

As far as I can tell, it is legal to buy and own such a pipe. What your neighbors put inside is not your problem.

It might not be the solution you had in mind but it might be worth it to try it for $50 before investing $XXXX in other technical solutions.

  • Those with THC liquids are often highly toxic - best are those with steel sieves, starting at about 150$. While bamboo coal bags might helps to contain the smell to some degree... asking them to smoke at the window might be the cheapest, most effective, because vaporizer damp smells just the same.
    – user55391
    Jan 13, 2020 at 21:15
  • @MartinZeitler: No liquid, simply grass. Why does the lighter appear strange? It's a standard lighter, which is bought separately and isn't integrated to the vaporizer. We're probably talking about different ones. The one I've seen really didn't smell at all. Users thought it didn't work at first, mostly because there was no nicotine buzz. 15 minutes later, it was quite clear it worked fine. Jan 13, 2020 at 21:15
  • @MartinZeitler: If I remember correctly, there was a small stone which was heated on one side by the lighter and vaporized on the other side. I'll try to find a corresponding model. It was a long time ago. Jan 13, 2020 at 21:25
  • They might have used some liquid, because those which heat up flowers smell just just alike that... cold tobacco smoke might stink more than weed. There has to be some whiff and it must not necessarily go through the walls, but it can also be the floor or the ceiling (if there is some hollow space)... pumping air out of the neighbors apartment should reverse that whiff.
    – user55391
    Jan 13, 2020 at 21:43
  • @MartinZeitler no, there definitely was dry herb inside. I cannot find the model again, I sent a message to an acquaintance to know if he still remembers. Jan 14, 2020 at 3:27

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