Joel

And this is the downstairs (with the same overlay)

This is the layout of the upstairs (with the ducting overlay)

Hi Mike, thanks so much for your reply -- sorry it has taken me a while to respond. Ah cool! I'll take a look and see if I can incorporate them into my design. I suppose with my radial design this would also help with muffling sound between roo ms. I guess these would fit on the comfowell system after the air has come through the MVHR unit from the outside. Should I be worried about large dust particles coming into the MVHR system from outside or is that handled by the MVHRs own filters? In my spreedsheet I linked above there are some embedded images with floorplans. I'll include them here in followup posts. They're a bit crude but hopefully they're sufficient.

Hi there. I am planning on installing an MVHR system in my two-floor (ground and first floor) maisonette apartment, and I was hoping I could get some feedback on my design from the experts here before I proceed. Here is a link to my calculations, along with some images of my design. It's a small place so the design is not very complicated. Some background: The motivation for installing the unit is that I have cigarette smoke and food smells entering the apartment through multiple party walls (see here for some more discussion of this). Between the ceiling and the upstairs floor boards there is exposed brickwork and holes in the wall which allows air to flow, which is the most likely source of the majority of the fumes. I plan to seal all of this up, along the entire perimeter of the apartment, as well as some other unplastered portions of wall. My hope is that this will stop all major sources of airflow between my apartment and my neighbours'. We don't have any damp or mold problems, likely due to good ventilation, so I want to supplement this loss of air flow with a mechanical ventilation system. My hope is that I can also affect some positive pressure in the apartment through the mechanical ventilation system to help keep the fumes out. An additional motivation is to improve air quality in general, as my partner is sensitive to alergens. I appreciate that MVHR may be considered an extreme approach, but my strategy here is overkill -- I am more concerned about good air quality than expense, and I'd rather have a solution that works the first time round. An overview: I'm installing an upright Zehnder Comfoair in a closet that opens onto the landing on the second floor. I plan to run 7.5cm semi-flexible ducting under the floorboards -- supplying the living room, bedroom, and office, and extracting from two bathrooms and the kitchen. The back wall of the closet adjoins the bathroom, and I plan to have the intake and exhaust ducts, as well as the water condensation pipe, run through that wall and under the bathtub and out of the building (the water condensation pipe I plan to connect to the drain under the tub). Some specific questions and concerns: -- I still have to include baffles in my design. Since I have a very simple radial design is it possible that the flow can just be controlled at the grilles? -- I am trying to fit the silencers and insulated ducting down the sides of the unit, all in the closet, with u-bends coming out the top to connect everything. I have calculated the size I need to fit everything and I think it will fit with space to spare, but please let me know if my design is not accounting for something that might foil my plans. -- I am trying to figure out the design for the outdoor intake vent. I understand I might want to include some kind of filter for large particles, and also a preheater to prevent frost. I'm wondering if there is a standard design for this that I can copy? -- Since the ducting is coming up under the floor on the second floor, I'd like to have the ducting connect to wall grilles near the floor. I have thin solid walls that I don't think I can just run pipes into, and so I'm trying to understand what the installation of this part of the system will look like. I expect I need to cut a hole in the wall and inset a piece of ducting with custom dimensions -- but I can't find good resources for how to do this. I'm happy to hire a builder to do this, but I want to understand what's required. -- since the unit is right in the middle of the home, should I be worried about noise? Would it make sense to surround it with noise insulating foam? Please let me know if there's anything you spot that I should account for. Thanks for your help!

I believe the apartment block was built in 1957

This is under the floor board just above the stairs on the first floor. The wall is not party to the smoking neighbour but party to our neighbour on the other side. I can only assume that the smoking neighbour party wall is similar.

No perpendicular. I'll probably just have to pull them all up I think.

I pulled up a floor board that was loose and I think you're right.

Yes that's right, between the ground floor and first floor. In particular where the living room light fixture is and also up from between the floor boards on the first floor.

I had thought PIV as well. I toyed with the prospect of it being a simple job ( ie not pulling up floors), but after discussing with my partner we decided we wanted to take an overkill approach. The reason is because both of us have health issues which can be exasperated by cigarette smoke, so we decided it was a priority to do everything we could to address the problem. Given the house needs renovating anyways I don't mind pulling up the floors (most of the boards are exposed at the moment anyways). The last thing I want is to do renovations only to discover that PIV isn't sufficient and so have to pull up new floors anyways. So my plan has been to get under there and see how comprehensive a seal I can create. But then my second thought was that currently the flat has no mold or moisture buildup problems, and this is almost surely due to very good air flow within the building, so this is leading me to seriously consider a mechanical ventilation system. I understand this could also have the effect of introducing a positive pressure in the flat. I have money saved for renovations, so I don't mind investing in a permanent fix. Can you elaborate on what you mean by an absence of perpend? Also where might I find the air bricks? The flat is two storeys, and most if not all of the smell is coming from under the floorboards of the second storey (and out from the light fixtures in the ceiling of the first floor), so I can only conclude there are gaps or porous wall exposed in that space. To seal things up I had been recommended applying Aerosana Vsiconn and using fibre paint for bigger voids and air tight tape for joints etc. The food smells are actually usually some kind of ragu -- I don't mind it so much, it usually makes me hungry!

Thanks for the welcome We have spoken to him about it and he admits that he smokes, but he insists it's not possible it's coming into our home. He is a bit volatile so we have resolved not to try and push him on it. It seems unlikely we'd convince him to quit smoking, and the alternative is him smoking in the neighbouring garden or outside our front door which would actually be worse for us since we wouldn't be able to open our windows 😅. It seems to me that there are other good reasons to try to stop air coming from neighbouring apartments ( I think the upstairs neighbours smoke too, and sometimes we get food cooking smells as well ), and the benefits of an air ventilation system ( removing alergens, fresh air etc.) seem to me to be worth the effort anyways. So I thought why not do it and see if it solves the problem before escalating things with our neighbours. As my dad always said -- good fences make good neighbours.

Hi there, this is my introduction post. I recently purchased a 1960s ex-council flat which is in need of some renovations. I've never done anything like this before so I've been browsing this excellent forum to learn what I can. Currently I'm dealing with smoke ingress from the neighbour's apartments. I assume this is coming from porous wall sections hidden under the floorboards. I have resolved to pull up the floors and try my best to seal things up before installing a mechanical ventilation system. I would be grateful to hear thoughts or advice for dealing with a situation like this.