GRACE I&W vs other like membranes
saundersjordan
| Posted in Green Building Techniques on
Because I plan to build a perfect wall/roof or PERSIST house I’m looking for alternatives to Grace Ice and Water Shield for the entire WRB as it’s pricier and seems to be hard to get locally. Will most Ice and Water Shield SA membranes work? I can get GAF Stormguard for example. Thanks.
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Saunders, there are many vapor permeable, waterproof, self-adhering membranes now that weren't available when the PERSIST method was developed. I recommend using one of them. If you really want to use a bituminous, impermeable material other than Grace brand, there are many equivalents. Many of the builders I work with use Protecto Wrap. GAF Stormguard also looks equivalent. Just check out the warranties of any you are considering to make sure they have reasonably similar terms.
SaundersJordan,
I agree with Michael. Being entirely waterproof like I&WS is a great attribute for roofs, sill-pans and the like, but doesn't add much on walls under exterior insulation. I'd consider Henry's Blueskin vp100.
Thanks for the input guys. Would you recommend a SA membrane due to penetrations of it was your build? Or tape the plywood sheathing as air control layer and use a building wrap and then seal penetrations from the inside if needed? If apples to apples on performance I’m looking for cost effectiveness and buildability.
It depends on the situation. In most cases, the most affordable way to build airtight is probably using Huber's Zip System, taking care to tape all joints and transitions, and rolling the tape to get full adhesion. But it's not the most robust system available.
There have been hundreds of discussions here on this topic. Try searching for "wall assemblies" or something like that.
saundersjordan,
Maybe I'll come around in time, but I still prefer to separate the primary air-barrier from the WRB. For both ease of installation in any conditions, the amount of wall area you cover quickly, and the flexibility allowing you to lap things like head-flashing after the WRB is up, I like using a robust house-wrap like Tyvek Commercial.
Thanks for the feedback. I feel like I’ve read every article there is on this site on the topic and it still seems to come down to context for each job and assembly.
Huber Zip isn’t available locally and my personal preference is plywood over osb sheathings.
I like the idea of taping the plywood joints which could largely be done on the flat before lifting the walls for ease of install. I guess the stigma of standard building wraps lives strong in me when I see them so commonly poorly installed I connect that to inferior product but I’ll look into the Tyvek commercial wrap.
I’m going to be monopoly framing so the trickiest transitions will be taken care of with full continuity. I’m hoping the product I choose will last in the hundred of years as opposed to decades. It’s why I’m framing with 1800msr Douglas fir as well.
Thanks again for the feedback.
Taped plywood can work great. The tightest house I've designed had taped plywood sheathing and came in at 0.12 ACH50. Just pay attention to voids at the edges, which may need some additional tape or sealant, and be prepared to possibly need to replace some sheets if they delaminate.
I haven't used Tyvek commercial wrap but I'm sure it's good quality. My standard specification is Siga Majvest or Pro Clima Mento, both of which are easy to get online, both made in Europe and both are very durable.
saundersjordan,
Regular Tyvek tears or pulls through staples if you even just look at it the wrong way. Tyvek Commercial is a lot more robust. It is about 28 perms, which is about half of the regular one, but still high.
The mod bit based peel and stick also don't adhere well to vertical surface without a primer. I would stick something with an arylic adhesive, these work great on walls and can be installed in any weather.
For roofs, there is also grace select which is a lighter/cheaper version of their I&W. Not a fan of granular stuff unless it will get shingles over it after.