[cam_l]

Fwiw, most mould is caused by buildings. Poor ventilation, leaks, no waterproofing, substandard building materials.

Yes, you can avoid mould in older buildings by carefully airing out rooms and keeping things dry and away from walls. But not if the previous three tenants had a mould issue and the landlord just painted over it.

[GJim]

> most mould is caused by buildings.

An honourable mention to fitting Cavity Wall Insulation, heavily sold and encouraged by UK government energy saving schemes thorough the 1990's and 2000's.

Except by stuffing the wall cavity, you provide a nice moisture bridge to outside whilst simultaneously stopping air circulating in the cavity and whipping away moisture; thus an explosion of mould.

The policy was a disaster, as getting the stuff removed costs a small fortune.

[zrail]

I think this depends on the construction of the rest of the house. A typical stack built house in the US will have extensive insulation in the exterior walls, but it's paired with a number of different layers intended to expel moisture.

As a retrofit without those things I guess I can see it being problematic.

[skyberrys]

Maybe everyone here can help me. I bought a house with an accessory addon already built, but it's walls and roof are very cheap aluminum. It's a constant source of mold. I'm at the point where I want to demolish it and rebuild properly. Some contractors I've spoken with instead encourage me to just frame out inside the existing aluminum box and get double pane windows instead. I don't think that will solve the problem though, these cheap aluminum panels are so full of mold now how would putting fresh wood over the panels solve anything, in 4 years I'll just have more mold growing over the interior frame out if I don't demolish and rebuild the whole thing with proper moisture barriers on the exterior and underside of the accessory room.

[IIsi50MHz]

The walls are getting below dew point when they cool and/or the humidity is too high for extended periods. And the walls have dust or other surface accumulations conducive to mold. Insulating the exterior and keeping the interior humidity low will help. Thoroughly clean and dry the interior walls, removing all mold and all other surface accumulations. Keep the interior above dew point.

[sidewndr46]

The walls are aluminum? Where do you live?

[skyberrys]

Trailer park in California. It's a prefab kit built accessory room. The main part of the trailer is normal, just this accessory room is built out of aluminum panels (about 3' x 9' per panel) and then plenty of single pane windows.

[zrail]

Mold growth is a moisture problem which can either be because of condensation or because of leaks. I agree with the contractors, properly framing out and insulating the interior would probably help a lot with condensation on the inside of the aluminum, as would double pane windows. Ventilation is also important for stopping mold growth.

[IshKebab]

Who has cavity wall insulation removed? The effect on your heating bill is going to be much worse than a small amount of mould, and I'm unconvinced that it makes it worse anyway - one of the main causes of mould in my experience is poor insulation! It makes the walls cold, which means you get condensation on them, and if you have poor ventilation in the rooms then you get mould.

If you have this problem, then the only thing I found which helps is fungicidal wash, and keeping furniture away from the problem walls (especially north facing corners of the house). I suspect wallpaper would also help but I never tried it.

[EliRivers]

Who has cavity wall insulation removed? The effect on your heating bill is going to be much worse than a small amount of mould

Some of these houses have been transformed into being unfit for human habitation due to the damp and mould. In some cases, the botched insulation has resulted in an increase in heating costs (along with the damp and mold). Some have suffered structural damage due to the botched insulation, costing tens of thousands to repair.

[IshKebab]

How did they botch it? Definitely a [citation needed] here...

[amluto]

Here’s an extremely snarky take, from an author who is very much an expert in the field:

https://buildingscience.com/documents/building-science-insig...

[GJim]

> The effect on your heating bill is going to be much worse than a small amount of mould

A small amount of mould?

Oh you sweet summer child! You really need to see the damage it can do.

[InsideOutSanta]

It's definitely true that not all apartments are equally prone to mold, but individual behavior also has a huge effect on mold. If you know that you're living in a place that's susceptible to mold, you have to take that into account when deciding how to furnish your place and how to manage humidity.

[phantom784]

Even if you're renting, it's worth keeping an eye on the humidity and setting up dehumidifiers if it's consistently getting high.

[W3zzy]

Yes, but no. We have historic, sometimes even mediaeval buildings. They weren't built with the current energy efficiency in mind. Leaving the bathroom door open after showering. Not putting furniture flus against the wall are simple measures you could take that don't need structural adaptations. I know there are plentiful of technical options but some common sense goes a long way.

[stefan_]

It infuriates me to no end that we are expected to put up with building design and technology from 1900 as a consequence of the obsession with "property values must go up" (notwithstanding the property) and a healthy helping of "regulations are only ever added to, everything old is forever grandfathered".

Like, central ventilation is not magical unobtainable technology. Simple heat recovery even vastly improves heating costs in a way insulation never can.

[sokoloff]

What’s the alternative? Governments pass regulations and all buildings must be adapted within 12 months? 36 months?

What of the buildings that don’t comply in time? Or can’t find trades to do it in time? Or we notice to our eternal shock that projects to ensure code tracking are priced at a serious premium?

Or, how many improvements to code would we decide weren’t desirable because of the costs of retrofitting, so now we lose even the low slope of improvement versus today.

[mrngld]

This is a fairly well-trod path in economic policy circles, especially in Europe. You can either grandfather in buildings, perhaps with rules that line up with maintenance schedules anyway so that when something breaks anyway you replace it with the new standard (the HVAC world understands this well with refrigerants), or you sign yourself up for stunning, astronomical expense.

Not to mention, a lot of places around the world care about the look and character of historical locations. If a structure wasn't designed for central HVAC, for example, then there's often nowhere to hide the condenser units, air handle units or the ductwork. Same with insulation -- if that exterior wall wasn't intended to have it you've got a couple options and they both hurt.

Last of all, I'll mention labor. The type of skilled labor that can do any specific trade at all is relatively rare in the aftermath of the "college-or-bust" era, but the kind of labor you'd want for renovation work (fast, efficient, can tackle multiple different aspects at once without calling in different trades, and gets it right the first time to minimize disruption/call backs) is even more rare. To carry out some kind of massive renovation project at a national level even with infinite money you're talking about a generational timeframe just due to labor constraints.

[Pragmata]

Government removes regulations and let property owners make whichever decisions they feel is best for them individually.

[Natfan]

consider Japan's housing market for ideas

[W3zzy]

Who's talking about 1900? We have a part in the city that was built in the 1600's. These buildings have thick stone walls that are prone to condensation during the summer. It's easy to deal with when you open a window in the morning or keep the bathroom door open after showering.

These buildings will have ventilation eventually but the code needs about 20 years to take full effect.

Mind you that people have been living in those buildings for hundreds of years without issues but tennants these days don't seem to have the basic skill of airing their place.

[blitzar]

My home from the 1700s would have been demolished and rebuilt from scratch dozens of times if this was the reality we live in.

Not everyone lives in a disposable McMansion in a gated community.

[inglor_cz]

A large-scale overhaul of the entire country's housing stock is not realistic for multiple reasons, including shortages of qualified people.

There is a lot of old buildings out there.

[Hnrobert42]

Yeah. The last two apartments I've been in have had leaks. I begged the landlord to open up the walls and dry them out. They just painted over it, so I moved out. Sadly, that means two other people now in apartments can never figure out why their place smells musty and they feel a bit congested all the time.