Mildew and type of house construction (Hilo: how much, houses, refrigerator)

[hotzcatz]

Aloha Forum Folks!

As a draftsperson, I'm always drawing up blueprints for folks to build houses with. I've been doing it for quite awhile now and I've watched how the houses have changed over the years. Most of the houses used to be single wall type construction without much effort to create a "building envelope". In the past decade or so, I've seen an increase in many mainland construction methods being used locally. Folks are using house wrap, completely airtight windows, sealing up the roof eaves, etc. Since that has started, I've noticed a huge increase in complaints about mildew.

I live in a really old house - single wall construction with loads of intended and perhaps not so intended ventilation. We have very little mildew in the house. Lots of dust but very little to almost n o mildew at all. My neighbor just build a new garage - double wall construction with air tight house wrap, air tight windows, etc. He went on vacation for a month and shut his muscle cars up in the airtight garage and came back to find them both covered in mildew. It took him about a week to clean them up.

I was wondering how much of a correlation there is between mildew and house construction methods and it occurred to me that this forum might be able to help with the investigation. I guess the questions to ask (unless someone can think of some better ones) would be:

1. Does your house have mildew problems?
2. Is your house in an area where other houses have mildew problems? (Basically, are you in a humid area?)
3. What type of construction is your house? Is it double wall (walls made with 2" x 4" studs with exterior and interior siding) or single wall (walls where the outside of the board is the outside of the house and the inside of the same board is the inside of the house)
4. Was house wrap used when your house was built?
5. Is your house in a well ventilated location? Does it get the tradewinds or is it in a windless area?
6. Is there a lot of ventilation in your house? Windows on different walls for cross flow ventilation, vents up in the roof, vents in the floor, up near the ceiling, etc.

Anyone have any good ideas on how to prevent mildew by using a specific type of construction method?

[Balad1]

I live on Kauai in an area that gets much less rain then Hilo (70"+-). My house was built in the late 70s and is double walled construction with windows and sliding doors everywhere. We have the normal trade winds but still have a mildew problem especially in the winter months. Other than to move to the dry side of the island I don't think there is any way to totally avoid it.

PS: What has helped me the most is the use of semi gloss paint with additives to prevent mildew; flat paint here is a breeding ground.

[cynmkolohe]

Hi hotz, thought I'd bump up your thread by adding that our Hilo house is also single-wall, but we have problems during rainy season (not this year, but in the past) even though we generally get good breezes.

When you get 7 or 8 days of blowing rain in a row, you're going to shut windows to keep rain out, and then you have the same problems anyone else will...

I know you've seen me post this before, but the last two years we used a dehumidifier on the worst days, when we had windows and doors shut tight, and that made a world of difference in how much mold we had to deal with during the worst of the rainy season--almost none, compared to the years before we bought the dehumidifier. (Helps on voggy days too, at least it seems so to me!)

[whynot?]

Ringing in from West Maui (Ka'anapali), let me say that we have a problem with mildew on the wood trim of our eaves. They overhang irrigated beds, so there is moisture, but we do live on the dry, hot side of the island where we have to water our plants.

Our house is double-wall, with one of the commercial stucco-board (I think) exteriors. We keep it pretty closed-up and run A/C twelve months. The only interior mildew I've noticed is (oddly) inside cabinets and on the refrigerator/freezer gaskets. Our cabinets have a gasket, too, but if we put damp glasses top-down, we occasionally get rings of dry mildew on the shelves. I almost always air-dry now before putting away. The refrigerator mold/mildew is more common, I think, but annoying. We clean with a bleach solution, but can never really get rid of it.

I'm not really certain of the small differences between mold and mildew. I know they are both fungal. The issue on the trim could be mold, I suppose. Either way, we paint it white and after a while it has an icky, dirty look. (West Maui dirt/dust is typically red-brown from the volcanic oxides, so we know it's not that.)

Great question, though. The kind of thing that points up the practicality of traditional ways of doing things here that we don't appreciate until AFTER we've bought and lived here for a while.