Air-tightness and durability

[mrd999]

What happens when a modern air-tight building is abandoned for any significant time? Any minor source of moisture in the building accumulates without active ventilation/dehumidification.

Some claim an air-tight shell with vapor permeable walls will allow the moisture to escape, but how much moisture can such a solution handle?

Has anyone considered a passive ventilation system when the HVAC isn't powered? Perhaps normally-open powered dampers in some well-placed passive vents?

[Martin Holladay]

MDR999,
The fact that abandoned buildings tend to deteriorate quickly is nothing new.

In Vermont, if you abandon a building for one week during the winter, every pipe in the building will burst. As soon as the thaw arrives in April, the building will be flooded.

[jesse@kaplanthompson.com]

And those pipes might not even freeze in a well insulated, air tight building in Vermont... Without people cooking and bathing inside that abandoned house you've removed major sources of interior moisture and humidity.

[Dancing Dan]

How about opening a window?

[Allan Edwards]

How about opening a window?

I'm sorry but that violates EPA rule 53.000365.

[mrd999]

How about opening a window?

Funny, that didn't even cross my mind; though people may board up the windows to deter criminals.

[mrd999]

In Vermont, if you abandon a building for one week during the winter, every pipe in the building will burst. As soon as the thaw arrives in April, the building will be flooded.

Perhaps a frost protected shallow foundation would be more resilient? In this case passive ventilation wouldn't be a good idea.

I rarely come across discussion of the building under such conditions. Being such a large investment, it would be prudent to make it a bit hardy, no?

[Ted S.]

I'm sorry but that violates EPA rule 53.000365.

And there are no Tax Incentives for opening windows.

[Dutchman]

What happens when a modern air-tight building is abandoned for any significant time? Any minor source of moisture in the building accumulates without active ventilation/dehumidification.

I did a super tight vacation cottage renovation for some Californians a few years ago...it's visited every two or three months with no issues. My though is that the basement windows we didn't replace help the non permeable top of the building. As a check, I requested that they let me know if it was "stuffy" when they came back for a visit....never a mention and I check it myself from time to time when I'm in the neighborhood. I'm certain that no water is getting in, and if they are not there making moisture like Jesse mentioned, should be okay.

[Martin Holladay]

Yes, I know that it is possible to build a superinsulated home with a low rate of air leakage, and that such a home is much less likely to freeze than the typical Vermont home.

I just used that example of the typical Vermont home, because MRD999 seemed to think it was unusual for an abandoned building to deteriorate quickly.

Every winter, Vermont plumbers are kept busy repairing frozen pipes -- and that's in occupied homes. Every spring, Vermont plumbers are kept busy replacing cracked toilets that were left without antifreeze in summer cabins.

When it's -25 degrees F at night, and the daily high at 2:00 in the afternoon is 0 degrees F, and that weather lasts for a week, you need a very good house to keep the pipes from freezing -- assuming there isn't any heat.