When putting on a housewrap, we make the effort to ensure that it it installed prperly. Wrinkles and bulges get smoothed out while seams, tears and rips get taped. The goal is to have an applied housewrap with out holes in it.
So, what is the affect on the intregrity of the housewrap when siding is installed? The siding can’t go up without hundreds or thousands of nails punching through the warp. Just curious!
In certain scenarios, flat roofs make more sense than pitched roofs (and vice versa).
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Replies
If you use an "unwoven
If you use an "unwoven fabric" wrap such as Tyvek, the nail point pushes the fibers apart and they "hug" the nail fairly tightly and seal the holes about as well as one could hope.. Dunno about other styles of wrap.
Nails are leak points, spun fiber or woven. The worst is cultured stone. So many nails to put up the wire mesh and no drainage plane to allow free movement of the water. It rots sheathing faster than no siding at all. We are completely moving away from house wraps and moving toward xps foam over our structural sheathing. It seals nail penetrations better and leaves the wet side far enough away from the structural sheathing that it won't wick water in. I think the butyl wraps they are bringing out now are too pricey. I don't think they will adhere over time as much as we are lead to believe. When we put the foam on, we spray foam the seams too. We don't use the tape because we haven't found one to stay stuck over time.
Nails are leak points, spun fiber or woven. The worst is cultured stone. So many nails to put up the wire mesh and no drainage plane to allow free movement of the water. It rots sheathing faster than no siding at all. We are completely moving away from house wraps and moving toward xps foam over our structural sheathing. It seals nail penetrations better and leaves the wet side far enough away from the structural sheathing that it won't wick water in. I think the butyl wraps they are bringing out now are too pricey. I don't think they will adhere over time as much as we are lead to believe. When we put the foam on, we spray foam the seams too. We don't use the tape because we haven't found one to stay stuck over time.
Whether or not you need a drainage plane depends on the siding. There are many forms of siding that do not pass significant amounts of water and require no drainage plane.
I have, over the decades, run into lots of "authorities" who don't know what they're talking about. Being an "authority" is mainly a matter of collecting a sufficient number of "true believers".
How is your authority derived?
Actually, being an authority usually means having a learned degree from an accredited university and/or extensive application knowledge. Mr. Lstiburek has both.
DanH's definition of an "authority" sounds supspicoulsly like an evangelist. Which is no coincidence because that seems like someone he might be getting his knowledge from.
holes are holes
Sure the wrap gets penetrated by the nail, but the nail essentially fills the hole that it creates in the wrap.
And how many holes are there? A bunch. Assume I'm hanging cedar claps with a fairly typical 4-1/2" exposure on 16" framing. That works out to about two nails per square foot of wall. Your putting holes in about one one-hundredth of one percent of the wall. And again, the nail pretty much fills the hole that it created.
Housewraps have a pretty high perm rating to begin with. Nail holes really don't copromose a housewrap's ability to perform.
Tears in housewraps are essentially big holes. So are lapped seams. So it makes sense to repair and tape them. Nail holes made by a nail that fills the hole? Not much of a problem.
Mongo is spot on.
....and I beg to differ with the O.P.
The goal of a house wrap is not "to have it installed without any holes in it". As Mongo stated, it already has holes in it (microscopic) when manufactured, and will invariably have more in application. I believe the goal of any WRB application is simply to install it in a continous manner that facilitates the proper management of external bulk water.