| Author |
Message |
Lynn Ostenson (Unregistered Guest)
Unregistered guest
| | Posted on Monday, January 17, 2022 - 03:12 pm: |    |
Curious: If membrane installation on CMU stipulates that joints be struck flush, what do you stipulate for *existing* CMU joints that are concave? |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 633
Registered: 10-2003
| | Posted on Monday, January 17, 2022 - 05:03 pm: | |
parge coat. not necessary to cover full surface. use trowel fill joints with a mortar or a concrete repair compound
Michael Chusid, RA FCSI CCS 1-818-219-4937
www.chusid.com www.buildingproduct.guru |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 1428
Registered: 12-2006
| | Posted on Monday, January 17, 2022 - 05:42 pm: | |
After that, surface prep is always the critical aspect. Considering the number of failures I've had to deal with over the past few years, I suggest getting an independent BEC onsite before membrane application to ensure that someone on-site knows what they're doing. It seems like fewer people know or care anymore and it's a lot easier to catch failures before they happen. |
Brian E. Trimble, CDT
Senior Member
Username: brian_e_trimble_cdt
Post Number: 130
Registered: 08-2005
| | Posted on Tuesday, January 18, 2022 - 10:58 am: | |
Agree with Michael. |
(Unregistered Guest)
Unregistered guest
| | Posted on Tuesday, January 18, 2022 - 12:38 pm: | |
Michael - Any prep work required on the existing mortar to ensure bond? |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 634
Registered: 10-2003
| | Posted on Tuesday, January 18, 2022 - 03:05 pm: | |
Basically, the CMU needs to be free from anything that would interfere with bonding. I suspect that the surface prep requirements for the membrane will be sufficient for the membrane.
Depending on the membrane, you may have to wait 28 days for the mortar to cure before applying a covering. (Or use a quick setting product such as those offered by CTS Cement).
If the anticipated hydrostatic pressure is trying to force the membrane away from the CMU, then you may want to investigate further.
Also be sure to consult with the membrane manufacturer to see what their recommendations are.
I call your attention to an article In the Construction Specifier about the preliminary selection of waterproofing. I helped write it as part of the LA CSI Technical Committee.
https://www.constructionspecifier.com/preliminary-selection-of-exterior-waterproofing-systems-2021/
Michael Chusid, RA FCSI CCS 1-818-219-4937
www.chusid.com www.buildingproduct.guru |
(Unregistered Guest)
Unregistered guest
| | Posted on Wednesday, January 19, 2022 - 12:08 pm: | |
Hi Michael - I was referring to the bond of the new mortar to the existing mortar. |
Michael Chusid, RA FCSI CCS
Senior Member
Username: michael_chusid
Post Number: 635
Registered: 10-2003
| | Posted on Wednesday, January 19, 2022 - 12:46 pm: | |
Try contacting https://ncma.org National Concrete Masonry Assoc. for assistance.
Michael Chusid, RA FCSI CCS 1-818-219-4937
www.chusid.com www.buildingproduct.guru |
ken hercenberg
Senior Member
Username: khercenberg
Post Number: 1429
Registered: 12-2006
| | Posted on Wednesday, January 19, 2022 - 01:17 pm: | |
Depends on your project and conditions.
At CMU, see https://ncma.org/resource/maintenance-of-concrete-masonry-walls/ as Michael suggested.
In general here's a good primer: https://www.nps.gov/tps/how-to-preserve/briefs/2-repoint-mortar-joints.htm |
Phil Kabza
Senior Member
Username: phil_kabza
Post Number: 697
Registered: 12-2002
| | Posted on Wednesday, January 19, 2022 - 04:27 pm: | |
Consider a fluid applied product rather than parge + sheet goods.
Phil Kabza FCSI CCS AIA
SpecGuy Specifications Consultants
www.SpecGuy.com
phil@specguy.com |
Dan Helphrey
Senior Member
Username: dbhelphrey
Post Number: 79
Registered: 12-2018
| | Posted on Wednesday, January 19, 2022 - 07:08 pm: | |
Budget permitting, I'd still do a parge coat with a fluid-applied barrier. |
Ron Beard
Senior Member
Username: rm_beard_ccs
Post Number: 482
Registered: 10-2002
| | Posted on Friday, January 21, 2022 - 01:35 pm: | |
In line with Michael's early post, "...use trowel fill joints with a mortar or a concrete repair compound...": try a surface bonding cement. It is a superior structural project, bonds well other mortar, inexpensive, and dries in a couple of hours.
"Fast is good, but accurate is better."
.............Wyatt Earp |
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