| Author |
Message |
David R. Combs, CSI, CCS, CCCA (Unregistered Guest)
Unregistered guest
| | Posted on Tuesday, September 23, 2003 - 11:01 am: |    |
Okay, time to tap into this vast resource of knowledge, experience, and wisdom . . .
I'm trying to find out what methods are being employed or specified throughout the industry to guard against moisture-related flooring problems and failures. Specifically, resilient flooring (both sheet and tile) over concrete subfloors (both slab-on-grade and elevated slabs over occupied spaces).
Our firm has had two projects recently where sheet vinyl flooring on second floor slabs has had problems (too much moisture in the concrete leading to re-emulsification of the adhesive).
According to the mix design, our W/C ratio was .46, which is not excessively high. And the flooring was installed a good three months after the building was dried in. Moisture tests were performed and, according to the contractor, the results were satisfactory for the flooring installation. And curing compound was not used. Not applicable to this particular scenario, but we also specify a 15-mil polyolefin Class A vapor barrier/retarder.
I've heard of products like CreteSeal CS2000, Concure, and others being applied to the fresh concrete and acting as a vapor barrier to prevent water vapor transmission. But has anyone else out there had any real experience and success with either of these products? Has anyone heard of any potential incompatibility problems with either of these products and fly ash in the concrete? Or is there some other product or method that has been met with some success?
We are investigating mandating a maximum W/C ratio of .45 for floor slabs, and moist or sheet-membrane cure only, for a minimum of three days. Our structural engineer's only concern is the increased cost for the concrete, and possible poor execution of the curing process.
Comments, criticisms, feedback, and witty quips are welcome.
Thanks. |
Ronald L. Geren, RA, CSI, CCS, CCCA
Senior Member
Username: Specman
Post Number: 14
Registered: 03-2003
| | Posted on Tuesday, September 23, 2003 - 11:51 am: | |
The technical committee of the CSI Phoenix Chapter has prepared a green sheet on moisture vapor emission for concrete slabs. I don't know if this is exactly what you're looking for, but you can go to the chapter website for information about obtaining a copy:
http://www.csiphoenix.org/Newsletters/sept2003/layout.php |
Anonymous
| | Posted on Tuesday, September 23, 2003 - 01:53 pm: | |
David:
You mention that a 15 mil poly material was specified. Was it used on the projects you mentioned?? This type of material is a vapor retarder - that means it will slow down moisture transmission, not completely remove it. There is another material that will eliminate moisture transmission. It has a WVT rating of 0.00045 g/sqft/h and a perm rating of less than 0.002 perms. The lowest available. It is a seven ply, weather coated, perminently bonded, semi-flexible bituminous core board that has been designed for underslab applications and has been continuously manufactured for 57 years. IT WORKS!!
This type of material along with properly installed and specified concrete will eliminate your headaches... |
Anonymous
| | Posted on Tuesday, September 23, 2003 - 02:28 pm: | |
for surface applied vapor barriers/retarders go with Floor Seal Technology - they are the best.
A w/c of 0.46 should have been low enough to not have to worry about flooring coming up, but this is no guarantee that water was not added during placement, curing, etc. It takes a long time for concrete to dry in ambient conditions in many climates.
We have had great success using dessicant dehumidification equipment during and after construction to get the slabs dried to acceptable levels - and the cost for doing so was far less than using a quality surface applied vapor retarder. Look in to the Munters Corp for this type of equipment.
A note of caution - calcium chloride tests only measure surface moisture and are not conclusive evidence of overall slab dryness. Another test that actually measures moisture at center of slab and used in Europe is gaining acceptance in the US as well - much superior to the other tests being used.
Anon
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Curt Norton, CSI, CCS
Senior Member
Username: Curtn
Post Number: 26
Registered: 06-2002
| | Posted on Tuesday, September 23, 2003 - 02:54 pm: | |
Things to consider:
1 Did the contractor add water to the batch before the pour?
2 How was it cured? Some curing/sealing compounds work so well that the moisture level doesn't drop below 3lbs for months.
3 Did the contractor test for pH before installing the flooring?
But its a suspended slab, so if the moisture tests are correct, maybe the Owner's maintenance people are using too much water on the floor and it isn't the contractors fault at all. (Ouch, it hurts when I say things like that) |
David Combs, CSI, CCS, CCCA (Unregistered Guest)
Unregistered guest
| | Posted on Tuesday, September 23, 2003 - 04:35 pm: | |
Thanks, Curt. Some answers:
1. Not sure, but I suspect so (before and during?). I've recommended that a Petrographic Analysis be performed on the in-place concrete to verify.
2. They used CreteSeal CS2000, which is a topically-applied, curing, vapor barrier product, appied in the presence of the manufacturer's technician. It comes with a 10-year warranty against flooring delamination. But the product appears to have failed for some reason and we're trying to figure out why. Its not a C-309 membrane-forming curing compound.
3. They were supposed to, and we're in the process of trying to obtain copies of the test reports.
4. Owner hasn't moved in yet. (Ouch, indeed!)
To Anon. #1: We specified 15 mil polyolefin, not polyethylene. Manufacturer reports WVT at 0.006. Moot point, though, since the problem is on the second floor.
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j smith
Senior Member
Username: Specbuster
Post Number: 13
Registered: 07-2003
| | Posted on Wednesday, September 24, 2003 - 10:11 am: | |
The two types of systems that I have had great results are W.R.Meadows premoulded membrane with plasmatic core..This system is designed for applications underslab..The topical systems for existing vapor drive problems I spec SG-2 system manufactured my Aquafin inc. Links are provided for your review.
1> http://www.aquafin.net/vapor_emission.htm
2> http://www.wrmeadows.com/wrm00061.htm |
Helaine K. Robinson CCS
Senior Member
Username: Hollyrob
Post Number: 8
Registered: 07-2003
| | Posted on Thursday, September 25, 2003 - 11:25 am: | |
For underslab applications only:
ACI 302 Caution - Vapor Barriers/Granular Fill
http://www.stegoindustries.com/Stego%20Industries/aci302caution.htm
http://www.stegoindustries.com/Stego%20Industries/aciflowchart.htm
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Anonymous
| | Posted on Thursday, September 25, 2003 - 04:13 pm: | |
stegowrap is pretty spendy - I spec Raven Industries VaporBlock 10 and Fortifiber Ultra along with stego - much less $$ in my neck of the woods than the stego products and meet same performance criteria (no matter what stego tells you). so far no contractor has used the stego when given a choice of the three...
anon |
Anonymous
| | Posted on Thursday, September 25, 2003 - 09:17 pm: | |
W.R. Meadows also has a high quality polyolefin material in 10 mil and 15 mil thicknesses that is very cost effective to the Raven and Stego materials. Their premo material remains the PMPC product. It has been around since the 1940's and is the only true "Vapor Barrier" available. |
Phil Kabza
Senior Member
Username: Phil_kabza
Post Number: 20
Registered: 12-2002
| | Posted on Friday, September 26, 2003 - 08:21 pm: | |
David,
Have you gone back to the adhesive manufacturer to discuss their quality controls and presence/absence of other similar failures. It sounds like you did most things about right; I'm surprised you had a massive failure. I wonder if the goop was a bad mix. |
Dennis Hall (Unregistered Guest)
Unregistered guest
| | Posted on Saturday, September 27, 2003 - 10:36 am: | |
We are currently performing investigations on two school project with similar problems in a litigation action by a school board. We have just began an 18 point extensive testing process, however based on a lot of experience by our forensic team and preliminary testing, most tile problems are not related to moisture from below the slab. Many other factors can be the problem from incorrect adhesive, improper installation, cleaning products, dew point temperature, etc. Many moisture tests are not done properly and give false high readings.
E-mail me presonally and I will send you a copy of our report in about a month with our test proceedures and conclusions.
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David R. Combs, CSI, CCS, CCCA (Unregistered Guest)
Unregistered guest
| | Posted on Monday, September 29, 2003 - 08:51 am: | |
Phil,
We don't think the adhesive was the problem. Since it re-emulsified, that leads us to believe its a moisture problem. And since its an elevated second floor slab, we have ruled out vapor transmission typically attributed to the damp, under-slab soil. The only thing left is that there was too much water in the concrete (in spite of the .46 stated in the mix design). Its just a theoretical attribute of the recipe, not an actual measure of in-place conditions. We have no way of accurately knowing how much water was added at the site, during mixing and placement. Also, its possible there was inadequate time for the concrete to "dry" (not cure) before the floor installation began.
Thanks for the feedback all.
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Richard L. Hird (Unregistered Guest)
Unregistered guest
| | Posted on Monday, September 29, 2003 - 01:31 pm: | |
David:
I had a similar problem several years ago with a thin epoxy bonded rubber sheet over almost the total second floor slab. We had isolated bubbles in the flooring that when opened showed water had been entrapted.
The frame had been in place for an extensive period, so we discarded the unhydrated moisture in concrete idea. I believe it was the total humidity of the building during construction, a lot of it from the concrete, but not just in the concrete that was contributing the water. Anything that forms a barrier to moisture migration has the potential to create free water under the right conditions.
I feel that a building needs a lot of ventilation during construction. I have never seen any studies to support this and since we also have to heat the building this adds to the expense.
We never came to a conclusion on the precise problem, since after we fixed all the "bubbles" they quit occuring. |
Anonymous
| | Posted on Monday, September 29, 2003 - 02:13 pm: | |
It's not the heat, it's the humidity!
Again, it is important to control the humidity during construction in order to help materials dry - especially during installation of wet materials like joint compound, paint, concrete, plaster, etc...If you don't want problems with floor coverings on slabs (either on grade or suspended), you need to control the humidity. The building's HVAC system WILL NOT WORK for this.
Go to the Munters web site and learn about dessicant dehumidification. This little bit of knowledge will be invaluable to anyone faced with moisture problems in buildings. Without this information, endless, circular discussions and theories will be the rule (as I am disappointed to see going on with this thread).
anon |
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