Calling house detectives: just HOW is the smell of next door's weed coming into my son's bedroom?

[MamaChocoholic]

We live in a 30s semi. The boy next door smokes weed. Sometimes its smell comes into my son's room, so strong it's as if he is smoking in there himself. (he's not, he's 5). We can't work out how. There are no holes in the walls. There is a vent, but we have covered this, and for it to be that, the smoke would have to perform a u turn on exiting from next door. What else could it be?

We are not going to approach next door and ask them to smoke elsewhere, neither of us have that kind of confidence, so we need to work out how it's getting in to fix it. Have left a message for friendly builder, but sometimes the collective wisdom of mumsnet can deduce incredible things.

Floorboards???

In my defence I have no idea how a semi fits together and if the floorboards and cavity beneath would be connected.

Could be the floor but also the loft - have you looked to see if the joining wall up there is complete? Some older places they didn't brick up the whole thing. Our old 30s house had this - much to our neighbours distress as we smoked at the time!

I don't know either! But the connecting wall must carry a lot of weight, so assuming the wall is solid. Certainly it is downstairs because I've seen under there. But need to investigate every possibility. Perhaps we'll try covering boards with rugs.

Smoked cigarettes - not weed

Are you completely sure it's not the vent?

We live in a flat and can sometimes smell weed from upstairs in our bathroom. I can only think that it somehow comes through the xpelair. I'm pretty sure they're not smoking it in their bathroom so dread to think how strong it must be in their flat!

Are you sure they are only smoking it and not growing it?

I am guessing that you can't ask the lad to stop smoking weed in his room?

It was certainly only partially bricked, but we've now had the loft converted, and there's no smell up there. would also have to get through plasterboard ceilings on both sides. Is that likely?

We had this back in the day. Environmental health came round to try and work out how the smell was getting through but found that it was just so potent it was coming through the ceiling.

We ended up using air fresheners and opening the window as much as possible. Fortunately we didn't live there long! It became a ghost room, I was always so worried people would smell it on us and think we smoked it.

Have no idea if they're growing it, but would expect the smell would be constant then, when it's now 2-3 times a fortnight.

Not completely sure it's not the vent Twentieth. Not completely sure of anything! Perhaps we need to cover it with more layers.

Interesting, and worrying, to know it's come through your ceiling Caja. How can we seal the ceiling?

I'm so glad you put his age. I read the thread title and thought hmm your son either needs to stop or be more discrete.

Do you know how your floor joists are laid? If they are shared, it could come in that way.

Is it a popular design of house? If so you might be able to google structural information that could help?

Definitely a popular design - lots of council/ex council in this area with identical builds. How would I know what structural information to look for?

How do I know which way the joists are laid? The floorboards are at right angles to the shared wall, does that mean the joists have to be parallel, and therefore not shared?

IME (am not a builder) floorboards are laid perpendicular to joists, so sounds like the houses probably don't share.

At a guess I suppose you would be looking for shared air space? So anywhere in the design that the houses aren't separated by a solid structure?

It does sound like a lot of hassle and even if you find something you may not be able to block it up. Could you not just steer the conversation round? Do you have a good relationship with your neighbours?

They keep themselves very much to themselves. The mum is nice enough when we have spoken (to warn her about loft conversion), but otherwise doesn't even glance our way when we pass in the morning. The younger son smiles and nods, but the older boy (the smoker) won't even manage that. He's mostly up at night, sleeps in the day, proper dopehead hours. Certainly, no chance to steer any conversation round, we'd have to approach them specifically.

We have this, but in our case I think the smell comes in through the vent in the boiler cupboard and the lad also has his window wide open so the whole street stinks. Very annoying so I feel your pain! We also don't want to approach the neighbours about it.
We also put insulation under the floorboards by the adjoining wall, had thick underlay and carpet put down, just in case, but am pretty sure the smell is coming from outside in, rather than from their house directly through. Could that be the case with you?

Strangely comforting to know we're not the only ones, thanks, and sorry you suffer this too. I hope it is coming from outside in, blocking the vent will be the easiest solution. Have only done it so far by taping cling film over the thing, I'm sure there's a better fix possibly there.

Obviously you can't block up the vent for the boiler, but can you make the door to the cupboard more airtight? Did the insulation/carpet make any difference?

Is he smoking out of the window?

(NC, for obvious reasons...)

I live in fear of this, as the mother of a dope-smoking teenager with an attic room, a 5 year old on one side and the family of a police officer on the other. :(

My son is banned from smoking in the house, but still does. Generally I do not smell it, because he stuffs towels under his door and opens his window. However, sometimes I do. As far as I can work out, it's more likely the smell will spread if:

• He's got friends round. Inevitably I suppose, 3-4 teens make more smell than one. I guess that explains why you only smell it occasionally.

• He doesn't open his door for a while, then suddenly does when a lot of smoke has built up. I think it's worth bearing in mind that it could be seals/air pressure differences inside their house, as much as yours.

• The wind's blowing towards the house. When his window is open, the smell then drifts back towards other open windows downstairs, rather than blowing away. It might be worth just noticing which way the wind is blowing, the next few times you smell it, because I'd guess Gently is right.

If I were your neighbour (and I sincerely hope I'm not) I would be mortified if you approached me, and hugely apologetic, and would try to do something about it... But I might not succeed, so you are wise to try to tackle it at your side. If I were you, I'd carpet your son's room, I'd re-seal the vent, and I'd think about any pipes you may have had installed or moved during your loft conversion. Is it possible that the smoke could be coming through the eaves (which are unlikely to be sealed or insulated) and then down into your son's room through a pipe hole in his ceiling that goes to a boiler or suchlike in a storage cupboard in the eaves?

I hope you get it sorted.

Just spotted that you have sealed the vent with cling film. I can tell you for sure that cling film won't stop the smell of skunk, because if any of the (visiting or resident) teens have their 'stash' wrapped just in cling film, I can smell it.

He doesn't smoke out of the window, but the window is often open when he smokes, plus he has a matching vent,adjacent to shared wall and therefore v near ours.

Anon, thanks for the open reply. Interesting what you say re eaves. On their side, there are lots of holes in the white board that runs between the top of the outer wall and the roof edge, presumably for ventilation. I guess the smoke could get in their, and come through the lightfitting on our side? There are no pipes.

Oh dear, I have 2 small boys, how do I prevent them from doing this nonsense? Sorry for the OTT just feeling really anxious about the future....

I am sorry but if someone was smoking weed in the house next to mine and it penetrated the wall into my child's bedroom I would be dobbing them into the police.

I wouldn't be spending time and effort to prevent it coming through, I would be stopping the cause.

I don't know whether you're lucky with your neighbours, Potterer, or I'm unlucky. But if I put your rule into action, I'd have to dob in at least four sets of neighbours on my street, as well as my own DS1. :( And it wouldn't stop it, either: the police generally issue only a warning for at least the first offense of cannabis possession, often the first few, and after that there's a small fine. They very often turn a blind eye, since there's so much of it about; and although they'd have to pay a visit to your neighbour if you reported someone smoking weed next door, they might well be reluctant - because they'd sooner have teens smoking it in their own homes than out on the streets. I think the OP is just being pragmatic.

I have the same problem with our neighbours not only are they the loudest people that feel the need to shout and have the TV that loud you'd think there deaf but they smoke weed now I'm not bothered what people do in their own homes but when it comes into mine it's not very nice, I've complained to council and they paid visit but said can't smell anything and they can't do anything without proof and police won't be able to do anything as it will be classed as personal use so that was not helpful, I've sealed cudboard walls etc with filler but still have strong smell of the stuff from time to time on stairs, hallway and can't work out where it's coming from