| Author |
Message |
Tracy Van Niel
Senior Member
Username: tracy_van_niel
Post Number: 212
Registered: 04-2002
| | Posted on Wednesday, April 04, 2007 - 10:53 am: |    |
One of the project architects came up to me this morning to talk about a project that is currently under construction. This project has a brick exterior skin and apparently when the joint sealant contractor applied the exterior joint sealant around the exterior openings (louvers, storefront, etc.), he went back and applied some kind of sand to the sealant before tooling it. According to the PA, the contractor told him that it doesn't affect curing, helps with tooling and the PA loves it because it looks like the adjacent mortar joints. Has anyone else used this process before? Any pros or cons (because the PA would love to use this process in the future)?
Thanks much. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 344
Registered: 05-2003
| | Posted on Wednesday, April 04, 2007 - 11:56 am: | |
Tracy
Adding sand to a joint sealant would probably void the warranty. If the PA likes the look of the sand, try specifying a textured sealant, i.e.Sikaflex Textured Sealant: http://www.sikaconstruction.com/tds-cpd-SikaflexTexturedSealant-us.pdf |
Nathan Woods, CCCA, LEED AP
Senior Member
Username: nwoods
Post Number: 194
Registered: 08-2005
| | Posted on Wednesday, April 04, 2007 - 11:58 am: | |
Sanded joints are very common in hardscape work, and I have also seen it used at the cove base joint in tiled restrooms to mimic the grout.
I would not see a particular problem with using it at the face of brick, but I agree that checking with the MFR is best. |
Lynn Javoroski CSI CCS LEED AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 541
Registered: 07-2002
| | Posted on Wednesday, April 04, 2007 - 12:01 pm: | |
Yes, I have seen it before. On a historical preservation pre-bid walk-through, an experienced mason told me about this practice. (He probably used "mason's sand" - at least that's the term my friendly mason used.) There is a manufacturer of sealant that makes a "pre-sanded" sealant, too. I'm not sure which manufacturer, but it's a common one and you can probably find it. |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 503
Registered: 07-2002
| | Posted on Wednesday, April 04, 2007 - 01:08 pm: | |
sanding sealant joints is the ZGF standard and it is used on every project. you have to use smooth silica sand, it has to be done when the joint is tooled and still tacky and it has to be "thrown" or hand patted in. you can't pat it in too much or it looks like a sealant joint. the point is that its supposed to look like a mortar joint.
it doesn't void anything, but I would suggest getting about 5 mockups because if they aren't used to doing it, they won't do a very good job at first.
and no, the textured sealants don't look the same. |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 504
Registered: 07-2002
| | Posted on Wednesday, April 04, 2007 - 01:12 pm: | |
in fact... I have the sealant manual from UniPro Sealants in Seattle and their spec for sanding the joint is:
"use nothing larger than 45-55 mm aggregate. sand should be equal in size to prevent settlement. it should be water washed, dust free and kiln dry.
there are many ways to install the sand after tooling the joint:
"cup a handful of sand in your hand and rub it across the joint"
"use a 4" dusting brush, piling a mound of sand on the brush and rub it across the tooled joint"
"simply grab a handful of sand and throw it on the sealant like throwing a baseball. make it look uniform in appearance"
if you mix sands, be sure to mix them often because they will settle in the bucket." |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 505
Registered: 07-2002
| | Posted on Wednesday, April 04, 2007 - 01:26 pm: | |
It was just called to my attention that 45-55 mm sand is about 2 inches wide. I'm guessing that's the screen size used to sort it, but I will send a correction to UniPro for their next manual..... |
Bob Woodburn
Senior Member
Username: bwoodburn
Post Number: 174
Registered: 01-2005
| | Posted on Wednesday, April 04, 2007 - 01:58 pm: | |
Are the decimal points missing? Does 0.45 - 0.55 mm seem about right? |
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