we don't see zip commonly in my area.
best practice is foam/foil sheathing with seams
taped. as with zip the correct tape must be used
& surfaces clean & dry for tape to adhere.

even with foam/foil sheathing, some builders refuse
to "rely" upon it and put housewrap next to studs
with sheathing on top.

to me, in the business I'm, that is a red flag that
a battle will be waged to do anything outside of
that builder's comfort zone.
he doesn't learn new stuff, doesn't trust it, has
no experience with it & doesn't want to do anything
differently.

for the same token when a builder says doing certain
things will make the house "too tight", that is a big
red flag for me.

I'm all for tight houses & introducing a dedicated fresh
air intake system.
build tight and ventilate right.

while you like this builder, it may be a battle to get
him to incorporate efficiency into the house.
I'd keep a close eye on the hvac too, these guys
tend to hire hvac companies that put in really
oversized hvac systems.

I like the foam sheating, conventional insulation
& air tight drywall approach for wall construction.
spray foam at roofline if equip & ducts are in attic.

where are you located?

best of luck

Here is a link that might be useful: perfect wall

Your builder's concerns over the longevity of the ZIP tape are not unfounded. Even Huber's 30-year warranty on the tape is full of holes, points out Martin Holladay in the linked article. Properly lapped Tyvek will allay that concern. For the same reason, I use lapped felt (brick paper) over shiplapped XPS sheathing.

However, your builder's concern over the house being "too tight" betrays his age--he started building when energy conservation was a minor concern, notes Holladay. "Your house needs to breathe," was the answer to all problems. In fact, building science has shown that what needs to be done is to control the air flow and the moisture. That conserves energy, protects building materials and ensures a healthy atmosphere for the residents.

I think Johns Manville would not be happy to see its blown fibreglass (Spider) system touted because it's not tight!

This post was edited by worthy on Fri, Dec 26, 14 at 17:51

Surprisingly, the builder isn't an old timer and builds some very impressive homes. We just toured an 8,500 sq foot home that he is currently building and left feeling very good about what we saw. My only question mark was the resistance to using Zip. I think the spider insuation is a good product and I would be happy with that or open cell in the walls. I'm very interested in building a tight but well ventilated house that will be energy efficient.

We are located in Eastern PA.

This post was edited by BobbyV43 on Sat, Dec 27, 14 at 23:27

I'd opt for conventional insulation over foam
in walls. save foam for the roofline.

please expalin the following excrept:
" tight but well ventilated house "

One must always remember that the first order of business in designing an exterior wall system is to keep water out of the wall assembly not to make it air tight, that is secondary.

Tyvek was invented and marketed to make houses more air tight but that feature has never been able to compensate for it's ability to trap water behind it. Any plastic siding underlayment that must be mechanically attached has the potential to trap water if it gets through the exterior cladding in the presence of a pressure difference.

The video linked below shows an extreme test condition but it demonstrates which system is inherently more watertight.

Here is a link that might be useful: Zip vs Tyvek video

Great questions and responses! Interesting points on the details that I can hopefully confuse and complicate even more.

I like ZIP for its air barrier properties. Its clearly better than a weather resistive barrier that is not fully adhered (tyvek). As for its superior water intrusion properties, that video looks promising but weve had water leaks through ZIP too (not from failed tape) and it leads me to caution there are more important details than comparing these two products in this way.

Siding details, flashing, sloped sill pans and rainscreens are likely to have much bigger impacts as far as water intrusion. I think ZIP sheathing covered with a more drainable version of tyvek (stuccowrap) creates more of a rainscreen and gives you the opportunity for mechanical, shingle-style laps over vulnerable transitions. So to me, the best applications would involve both products and I would highly prefer the crinkled stuccowrap tyvek product for its increased drainage and drying potential. Even better would be a thicker ventilated rainscreen with furring strips and coravent.

As for failing tapes, I think most people's negative experiences come from improper application, a real concern when dealing with framing crews more concerned with production than quality. If the tape is not stretched, and rolled over a relatively clean substrate, its not coming off without physical destruction if it sits for very long. I find the chemistry technology of these newer acrylic based tapes amazingly effective.

If you are AT ALL concerned with indoor air quality, durability and energy efficiency there is no such thing as "too tight". Beauty is only skin deep and while the finishes may have been pretty, it sounds like there may not be much attention to detail payed to the things that matter behind the finished surfaces like durability, healthy indoor air and energy performance.

I would caution anyone watching that video that situation is unrealistic at best.

First with ZIP "experiment" red paper was installed on outside of zip sheathing, and with tyvek between sheathing and wrb. For water to penetrate zip it would have to pass threw the protective layer and 1/2 sheathing, with tyvek all it had to do is pass tyvek wrap. Additionally doubtful that in any circumstances water will be sprayed at 60 psi directly at the nail.

If you are installing 1/2 sheathing staggered joins with rigid foam (+tape) + tyvek (WRB) it will act far superior to zip sheathing imho.

The primary advantage of Zip sheathing is that the sheathing is the weather/air barrier and therefore there is no space created that can accumulate water or allow it to bypass the window jamb flashing. If the weather condition is so severe that Zip will not be adequate and you can justify the cost of additional protection, rather than add a redundant layer of wrap with all of its drawbacks, IMO it would be better to field apply a liquid barrier on bare sheathing.

Creating a drainage plane is an additional protection for the cladding but IMO vertical strapping would be better than plastic drain wrap but whatever wraps into the wall openings should be fully adhered to the sheathing and framing.

DuPont's standard Tyvek installation technique of cutting a Y in the sheet and wrapping it into openings is appropriate for an air barrier but it is a sloppy waterproofing technique. DuPont provides an alternate technique where the wrap is installed after the windows which should be the standard technique IMO.

This post was edited by Renovator8 on Sat, Jan 3, 15 at 11:06

Bumping this topic back up. We chose a builder... Not the one I mentioned in my original post. He does use the zip system. I'm still up in the air about what type of insulation to use. I'm also interested in an HRV system, but know very little about them and I'd be willing to bet my builder doesn't as well.. Do t have access to natural gas so I'm really unsure about what kind of heating system to use. Heat pump? Propane Furnace?. Energy efficiency is a big deal for us.

check this blog post out. for full disclosure, this builder also prefers tyvek, but seems to me that the zip system hold up really well as shown in the research at UT.

http://mattrisinger.com/fluid-applied-wrb-testing/

That research is about fluid-applied weather barriers because institutional and commercial building owners and designers have never considered loose plastic wraps adequate protection for these expensive long life-cycle buildings.

When home builders become familiar with fluid-applied systems and want to buy enough of it to interest the manufacturers, home wraps will become a thing of the past.

Actually, they also looked at tyvek house wrap, the zip system and some peel and stick systems. I agree that it would be better to go fluid applied, but the research shows that not all of the fluid applied products are great. For example, stoguard seems to be doing very poorly. seems like you would be better off with a zip system than stoguard.

The test appears to be pointess because it exposes weather resistive barriers to UV radiation of intense sunlight as if that would be a way to see how they would perform over an extended period of time. Of course, these membranes would only be exposed to UV radiation for a week or two and then covered for the life of the cladding.

There is no information in the test that could help a designer determine how well a system would perform after 20 years. We already know from testing by the manufacturers that none of the non-metallic membranes will be able to survive exposure to sunlight for very long so it can't possibly matter which one outlasts the other during that short time period. Why not test the membranes under water or exposed to fire?

i've removed clapboards from a 120 year old house and found the red rosin paper to be perfectly preserved. That same paper probably wouldn't survive a year exposed to sunlight and rain.

Sure, it must be pointless. never mind the fact that the pictures show a portion of the barriers to be covered under hardie or something similar, while a portion remains exposed. i guess testing manufacturers claims for UV resistance is pretty pointless, because as everyone involved in the construction industry knows, everything in the construction industry works perfectly on schedule - there are never any delays, so the exterior cladding will always, as a rule, be installed within a week or two of the barrier's installation. plus, unless something has been tested for 20 years (nevermind that some of these products weren't available 20 years ago), the results of the test are meaningless. The standards at the Journal of Light Construction must have really fallen - those hacks will publish anything written by any idiot who knows the alphabet.

thank you, sir, for clarifying that.

Your link was not to the JLC but Matt Risinger's blog where he personally observes the Univ of Texas Austin test offering his own photos and personal observations like "first' let's start with the losers (my opinion only)". He then points out that "tar paper" (his terminology) was "looking terrible" and then points out that STO Guard had peeled UNDER the bottom edge of the test panel (where it had obviously not been applied over the required mesh tape) although it looked fine on the face of the panel. He then says the Zip System (with the Zip tape properly applied over all edges of the panel) looks "very impressive".

You have then used this blogger's field observations as the basis for recommending that I would be better off with a Zip System than STO Guard. I appreciate the offer of advice but I think you need considerably better information before making such a statement.

I finally found the JLC article and discovered it was a survey of available wrb's not a discussion of system durability with only a mention of the Texas test at the end of the article where Risinger concludes, "... the thicker, commercial grade fluid-applied WRB's have performed the best." However, when the test was published in The Construction Specifier, no such conclusions were mentioned.

For Risinger or you to draw conclusions that the testers have not made is at best presumptuous. Risinger's "thicker is better" observation only tells me some un-named company must be selling a new, thinner fluid-applied system for residential use. That's good to know but beyond that, so far, this test only confirms the obvious.

I know this thread is a little old, but if anyone still checks it I was wondering about house wrapping the zip system. We are currently building a house with the zip r system. The framing crew didn't take great care in nailing the zip system to the studs so there are puncture holes in may places. I was inquiring about putting typar around the whole outside as a second barrier. My real concern is will that be worse in the long run and trap moisture and not allow the zip system to ventilate to the outside?:

Has anyone used coravent sv3 and there 3/8 furring strips?if you combined this with 3/4 polyiso under the hardie lad siding would you run into a lot of issues around openings etc.

Also how much benifit would it be to add te 3/4 insulation board under the siding in (zone 3)Oklahoma,we will have 2x6 walls with r21 in th already.