Let's Fix Construction
  • Blog
  • Why & Who?
  • Workshops
    • Upcoming Workshops
    • A & E Coordination
    • CDT Education Program
    • Let's Fix Construction
    • Social Media & AEC
    • Specifier/Product Rep
    • Specs 101
    • Young Professionals
    • Past Workshops
  • Contributors
  • Submit
  • Accolades
  • Donate
  • Contact

Air Barrier Problems Arise With Wet CMU

7/8/2019

3 Comments

 
Picture
Contributed by ​Roy Schauffele
​Late fall and during all winter, concerns and problems arise with air barrier applications on CMU (Concrete Masonry Unit). I know because I get the phone calls. Generally speaking, the fluid applied water-based vapor permeable air barriers go on OK but take a long time to cure or set. 

Additionally, I’ve observed a myriad of job site problems with self-adhered vapor impermeable sheets, flashings and tapes. The vapor impermeable materials were applied properly but exhibited blistering and lack of adhesion within days. When investigated there was always liquid water on the adhered side of these sheets.

Observations of quite a few jobs leads me to state that, in this investigation, the vast majority of “problem” jobs had the following in common:
​
  1. New construction projects with …..
  2. The top of the CMU wide open with nothing to prevent rain entry …..
  3. Unheated and wide-open interiors of the building
  4. Located adjacent, within 30 miles, to a coastal condition with dew and fog.

OK, let’s deal with what will lead to an excellent new construction air barrier installation and long-term performance:

1. If the Architect/Specifier has specified a dry water repellent in the CMU, it is already causing a potential problem with the adhesion of a water-based air barrier or primer. This issue has been written about previously in an article in Coatings Pro Magazine July 2018 “Legacy Specifications, Wall and Air Barrier Performance”. The Air Barrier installer absolutely needs to make the Architect/Specifier aware of this prior to bid.

2. If the project is wide open with doors, bay doors and windows not finished or openings not protected from water entry, then a tremendous amount of water can enter the CMU causing some of the problems referenced above. The top of the walls and window openings should be treated in such a way as to prevent water from running in to these open areas.
One of my friends and great technical writer in Austin, TX, Mr. Dave Watts, RA, has the following statement in his specifications: Section 04 20 00, 3.18 PROTECTION OF FINISHED WORK, 3.18.e “Protect tops of masonry with waterproof coverings secured in place without damaging masonry. Provide coverings where masonry is exposed to weather when work is not in progress.”
​3. If the construction site is not conditioned then it is up to the General Contractor to provide some type of interior heating to prevent the build-up of moisture in the CMU wall.

4. “Hand Damp”, a widely used term that is non-quantifiable and can lead to problems as it is never indicative of how internally wet the CMU may be. Real world is that I know of a multi-generation family business that was put out of business as the air barrier placed on the “hand damp” CMU never cured out as the interior of the CMU contained a ton of moisture. Yes, they were being pushed hard by the GC, who was already behind schedule and they acquiesced.

Perceptual statements were made to me that today’s CMU is too “open” or “porous” compared to what was made a few years ago. Upon research, I have found no information to confirm or disprove these statements. I’ve checked project specifications that were 20 years apart and all specify CMU to the ASTM C90 - Standard Specification for Load-Bearing Concrete Masonry Units. 

As of the writing of this article, there are no CMU manufacturers that are members of ABAA.

It is this authors opinion that perhaps it is time for the ABAA (Air Barrier Association of America) to research these concerns and to either lay this concern to rest or have a proactive technical approach to answer the preceding perception(s).
3 Comments
MICHAEL QUARANTA link
7/9/2019 03:37:26 pm

A lot more details are necessary to address the problem. There is a clear coat, water based, water extended, proven waterproof coating available known as a white label with millions of square feet installed. The current offering is a Veteran Owned Business (VOB) product known as "StarGard© Veteran Coatings with a 10 year warranty for concrete floors.

Reply
Trish B link
7/19/2019 01:04:00 am

Too bad for the family business who lost their business. Too often the "get it done now" wins over "it's not ready" arguments. Thank you for writing about this issue.

Reply
Drywall Bend Oregon link
1/7/2022 09:59:59 pm

We will look forward for your future updates.Thanks!

Reply



Leave a Reply.

    About

    Let's Fix Construction is an avenue to offer creative solutions, separate myths from facts and erase misconceptions about the architecture, engineering and construction (AEC) industry.


    Check out Cherise's latest podcast
    Picture


    Get blog post notifications here

    Enter your email address:

    Delivered by FeedBurner

    RSS Feed


    Archives

    March 2022
    May 2021
    May 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016

    Categories

    All
    Architecture
    Certification
    Collaboration
    Communication
    Concrete
    Construction
    Construction Administration
    Contract Documents
    CSI
    Education
    Estimators
    Fabrication
    Fix
    Manufacturing
    Misconception
    Myths & Facts
    Podcast
    Refresh
    Specifications
    Subcontractors
    Technology
    Training

    Tweets by FixConstruction
© COPYRIGHT 2021. ALL RIGHTS RESERVED.
  • Blog
  • Why & Who?
  • Workshops
    • Upcoming Workshops
    • A & E Coordination
    • CDT Education Program
    • Let's Fix Construction
    • Social Media & AEC
    • Specifier/Product Rep
    • Specs 101
    • Young Professionals
    • Past Workshops
  • Contributors
  • Submit
  • Accolades
  • Donate
  • Contact