0 Helpful?

Fully applied membrane substitute

When applying exterior insulation, the PERSIST method specs a fully adhered membrane covering the sheathing to control air, moisture and water. These self adhered membranes can be costly, so I'm wondering if there is any risk in using the peel and stick membrane where it's needed and then less expensive draining type house wrap in the field of the wall.

This might be trickier to install but right now I'm just interested in the performance of these materials - would it matter that the house is wrapped in 2 materials with very different perm ratings?

Thanks

Asked by Mark Fredericks
Posted Jul 8, 2014 9:41 AM ET

Tags:

1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.

Mark,
Your question is addressed in this document: REMOTE: A Manual.

That document was written for Alaskan builders. It notes, "Self-adhering waterproofing membranes, i.e., Grace Bituthene, were used in early REMOTE construction due to their impermeability and ability to seal around fastener penetrations. Covering an entire house with these materials is extremely effective but typically more expensive. As an alternative, 6-mil polyethylene sheeting has been used with good results and meets Fairbanks building codes which require the use of a vapor retarder with a permeability (perm) rating of .06 or less. It is worth noting that 6 mil poly is more susceptible to physical damage during installation, and breaks down after extended exposure to sunlight. Another product that is showing promise as an exterior membrane and is particularly well suited to wet climates is Tyvek DrainWrap, a vapor-permeable air barrier."

Mixing and matching your air barriers at different locations of your building shouldn't cause any problems, as long as you pay attention to airtightness. If you expect a layer of Tyvek to be your air barrier, I would verify that it works with a blower door.

Answered by Martin Holladay
Posted Jul 8, 2014 10:04 AM ET

Other Questions in Green products and materials

1 1/2 story farmhouse in British Columbia

In Plans Review | Asked by Michael Blake | May 22, 18

Spray foam questions

In General questions | Asked by Stanger133 | May 20, 18

Is it worth creating a conditioned attic for my house?

In Energy efficiency and durability | Asked by CGFears | May 23, 18

Spray foam from crawlspace onto bottom of plank subfloor in Pacific NW?

In Energy efficiency and durability | Asked by Frasca | May 21, 18

Fasteners for concrete, brick, and CMUs

In General questions | Asked by Martin Holladay | May 23, 18
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!