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EIFS Wall Drainage Systems Avoid Moisture & Mold Troubles - Best Practices Guide
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InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
EIFS Drainage systems: this article discusses in-wall drainage systems introduced to avoid moisture and mold problems in EIFS synthetic stucco wall systems, and the role of weather and moisture in stucco wall installation, durability, and painting success.
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Drainage Systems for EIFS "Stucco" Walls to Reduce Leak Damage
This article series discusses best practices construction details for building exteriors, including water and air barriers, building flashing products & installation, wood siding material choices & installation, vinyl siding, stucco exteriors, building trim, exterior caulks and sealants, exterior building adhesives, and choices and application of exterior finishes on buildings: paints, stains.
At SIDING EIFS & STUCCO and also cited at STUCCO WALL METHODS & INSTALLATION we discussed the history of leaks, water, mold, and rot damage that ensue when some EIFS wall systems were installed with details that permitted leaks into the wall structure. Usually these installations were not according to detailed manufacturer's specifications. Continuing from from Best Practices Guide to Residential Construction we discuss the introduction of drainage systems intended to reduce or avoid these EIFS difficulties.
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This article series includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons.
In response to these problems, most
EIFS manufacturers have introduced new “drainage” or
“water-managed” systems, which require the same type of
waterproof drainage plane found behind traditional stucco
systems (see Figure 1-30)
As with traditional stucco, layered building paper or
plastic housewrap protects the framing and sheathing, and
all exterior openings and penetrations are flashed to conduct
any water to the outside of the sheathing wrap.
Since
window leakage was the single biggest contributor to EIFS
failures, pan flashing is recommended at windows.
Rather than gluing the EPS foam to the sheathing, the
new drainage EIFS typically use mechanical fasteners and
are designed with a capillary break between the back of
the EPS and the sheathing wrap to promote drainage.
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Some
EIFS contractors use special corrugated or wrinkled sheathing papers to create
the drainage space, while others have vertical grooves
cut into the back face of the foam insulation.
In all cases,
the drainage plane leads to a perforated weep flashing at
the foundation to drain away any trapped water.
Workmanship & EIFS Exterior Stucco Wall Success
The backup drainage layer, however,
should not provide an excuse for sloppy workmanship on
the exterior skin. The new kinds of EIFS should still be
made as waterproof as possible, since any water that leaks
past the skin may be slow to dry out. EIFS consultant
Russell Kenney, who has worked with these systems for
nearly 20 years, recommends exceeding the minimum
specs required by EIFS manufacturers.
On the other hand, our EIFS damage photograph (left) shows how water or moisture traps can form in an EIFS wall even in a building interior, leading
to substantial damage. (Photograph courtesy of home inspector John Rudy).
Kenney
recommends a higher-density EPS foam with only 2%
water absorption by volume instead of the 4% allowed by
ASTM C584. In addition, Kenney recommends a heavier
6-ounce reinforcing mesh versus the typical 3-ounce cloth,
as well as special high-impact mesh in high-traffic areas.
He also recommends a 3/32-inch base coat applied in two
layers, with the first layer used to partially embed the
fiberglass reinforcing and the second layer to fully cover
and protect it.
These steps will significantly improve the
impact resistance of EIFS, but it is still less durable than
traditional stucco or thin-coat stucco.
See details about the cause, diagnosis, cure, or prevention of paint failures on stucco exterior walls, found at STUCCO PAINT FAILURES.
Apply Sealant to EIFS Base Coat
As with the original
barrier EIFS, all penetrations require a high-quality elastomeric
sealant. The sealant needs to be applied to the base
coat since the finish coat tends to soften when wet, providing
a poor substrate for sealant. For the caulk joints to last,
they must be wide enough to tolerate the anticipated movement,
typically 3/8 to 1/2-inch, and backed up by backer rod
(see “Joint Design,” page 37 in Best Practices Guide to Residential Construction).
While control joints are
generally not needed along the length of the wall—unless
it exceeds 75 feet and is in direct sun—they are required
between floors on multistory buildings. Silicone sealant is
recommended at all joints for its longevity and flexibility
in cold temperatures.
In theory at least, drainage EIFS should function the
same as any other exterior cladding systems. Any water
that manages to penetrate the outer skin should be stopped
by the drainage layer and safely drained away. However,
given the low permeability of polymer-based coatings and
the tendency of EPS foam to soak up and hold water, EIFS
are best avoided in residential projects unless high-quality
workmanship and regular maintenance of sealants can be
assured.
-- Adapted with permission from Best Practices Guide to Residential Construction.
Exterior Insulation and Finish Systems (EIFS) Resources & Suppliers
Dryvit Systems
www.dryvit.com
Parex
www.parex.com
Senergy
www.senergyeifs.com
Sto Corp.
www.stocorp.com
-- Adapted with permission from Best Practices Guide to Residential Construction.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
- Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: info@buildingadvisor.com
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
- Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
- Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
- John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: johncranor@verizon.net
 Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
- Commercial Building Inspection Courses - protocol ASTM Standard E 2018-08 for Property Condition Assessments
- Home Inspection Education Courses including home study & live classes at eleven colleges & universities.
- Home Inspection Education Home Study Courses - ASHI@Home Training 10-course program.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
- The Home Reference Book, a reference & inspection report product for building owners & inspectors.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
- The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & Android smart phones.
Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter inspectaehrb in the order payment page "Promo/Redemption" space.
- The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.
Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
- The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones.
- Paul Galow - technical consultant on networking, LAN design, applications support. Galow Consulting Services, 914-204-1749, email: paulgalow@galowconsulting.com
- John Rudy, Advantage Home Inspections, Flemington N.J. 08822 home inspector, 908-806- 6364, Home, Radon & Termite Inspections, Central & Parts of North New Jersey, email: jonadvantage1@yahoo.com
- Malco® Products siding tools are available from that company, including the SideSwiper II SRT2 discussed at Malco's website. Websearch 09/07/2010 http://malcoproducts.com/product/roofing-siding-gutter/siding-vinyl/siding-tools-vinyl/sideswiper-ii. Malco also produces other vinyl siding repair tools such as aprons, awls, hole punches, saw blades, and tools for for fiber cement products including power-assisted cutters
- Parmetol, a wood preservative recommended by the manufacturer was used as a fungicidal additive to paint on the Blue Poplar wood sculpture in Amsterdam, by artist Mari Shields [ - art conservation consult DJF-artist MS 2010]
- "Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
- "Flashing: the plain solution to leaky walls", Thomas E. Remmele, Manager, Technical Services, Sto Corporation, Building Standards, November/December 1999 p. 21-25.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
 The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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