I’m fairly new to the home building business and have yet to get a solid answer on the use of house wraps. Code in NC does not require them and my suppliers make no commitments on there effectiveness. The builder I first got into this business with didn’t believe in them so we’d sheath the walls and then install either vinyl or cement board directly to the OSB. The majority of houses I see going up have a house wrap of some sort installed. Every now and then you’ll see a house wrapped in felt – commercial structures seem to always have felt. What’s the best option for stopping infiltration and protecting the structure???
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This question comes up about once a week. Try searching the archives and you should get enough reading to put you to sleep or drive you nuts.
Women need a reason to have sex. Men just need a place. - Billy Crystal
A structure should have some sort of wrap to help shed water that gets behind the siding.
Plastic siding is about as water tight as a collander. Anyone who puts vinyl directly over sheathing doesn't belong in the construction business.
Under cedar claps? It's finally been recognized and accepted that cedar should not be in direct contact with spun-poly housewraps.
It's ironic that the spun-poly products were not initially intended for use as a housewrap. Not only have they evolved into that use, but it's perceived that they are far superior in that role over old-fashioned felt.
If it's new, it must be better. Those advertising dollars were well spent.
If forced to choose one or the other I'd choose felt.
I don't do brick, stucco, or vinyl. I do cedar. Under cedar, good old tar paper gets my vote. Even with a rain screen. A spun-poly wrap only if the cedar is backprimed, and even then, it's not preferred.
Under fiber cement or vinyl I'd say either could be used.
Under stucco or brick, I have no practical experience.
I like to think of housewrap as insurance.
It is there for when leaks occur somewhere (and they will always occur, somewhere, sometime, even on the most carefully constructed house), to protect the sheething and insulation from getting wet.
It is not likely to help with air intrusion, at least nothing like the way that densly packed cellulouse or more expensive Icynene type foam will, so I don't think of it as a windbreaker (although some advertising would love for you to think so).
Felt is proven, and durable, so is often prefered by some.
New, synthetic stuff like Typar, Tyvec, and so on, have had, on occasion, gotten in trouble when used with tannin rich woods (Cedar).
HOpe this helps (check the archives for more, lots more!).
Norm