protecting tyvek from uv?
user-7601308
| Posted in General Questions on
Hello, I am about to install tyvek on my house and then install my windows and doors so I can close my building in. The problem is that I don’t have my siding ready yet, and it may be a few more than 3 months before I do have it ready. I am milling and drying it at my sawmill. What’s the best way to protect tyvek from uv? Should I just put a second loose layer of tyvek over top? is tyvek opaque enough to block UV? or should I do something else.
Thanks,
Forrest
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Replies
Forrest,
Dupont allows regular Tyvek to be exposed for four months, and Tyvek Commercial can go nine months before being covered. Another alternative is to install the windows and doors and hold off the house-wrap.
https://www.youtube.com/watch?v=SqP4liutJFs
We had another thread about this on hear a few months ago (might have been longer than that, I don't really remember exactly). A second layer of Tyvek should be plenty of protection if you need more than the four months Malcolm mentioned. Black polyethylene is another option, but it has the downside of being a vapor barrier so it won't breath -- this can sometimes result in excessive dampness and mold issues, especially if it's rainy and humid for a while.
If you only have a little area to deal with, see if you can just shadow it with some scrap materials that you have on hand. It's most important to protect things in direct sunlight. Stuff that isn't in direct sunlight (Northern wall, things that are mostly shaded by a tree, etc.), are less of an issue.
If the surface of the Tyvek starts to seem a bit chalky, that's from UV exposure. A "little chalky" is usually OK, but if it keeps going, it will eventually get damaged enough be weakened from exposure. I've seen Tyvek last entire seasons before without any issue though, so I think their ratings are pretty conservative in terms of UV tolerance. I'd still try to stay within the ratings though just to be safe.
Bill
Typar Metrowrap is rated for 12 months. It's much sturdier stuff than the typical house wrap as well.