INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Read more

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!

• Talk With Other Members
• Be Notified Of Responses
  To Your Posts
• Keyword Search
• One-Click Access To Your
  Favorite Forums
• Automated Signatures
  On Your Posts
• Best Of All, It's Free!

Join Us!

*Eng-Tips's functionality depends on members receiving . By joining you are opting in to receive .

Posting Guidelines

Students Click Here

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Eng-Tips Posting Policies

Contact US

waterproofing membrane vs vapor barrier

2

thread256- Forum Search FAQs Links MVPs

• Forum

• Search

• FAQs

• Links

• MVPs

waterproofing membrane vs vapor barrier

waterproofing membrane vs vapor barrier

Caribbean

(Civil/Environmental)

(OP)

29 Nov 06 13:48

1.    Would you recommend a waterproofing membrane with protection board etc or a vapor barrier beneath the slab on grade in a tropical climate on very stiff clays covered with 1.5m of structural backfill compacted to 95% standard proctor. The slab is a 6" Reinforced concrete.

2.    What exactly is the difference between the two.

3.    Is visquene (plastic sheeting) an acceptable vapour barrier or waterproofing membrane?

Replies continue below

Recommended for you

RE: waterproofing membrane vs vapor barrier

SlideRuleEra

(Structural)

29 Nov 06 15:37

When using a vapor barrier, proper curing of the concrete slab becomes even more important - water cannot quickly out the bottom of the slab. Without curing, the top of the slab dries out quicker than the bottom which leads to curling upward - tending to cause cracking (even in a reinforced slab).

Polyethylene (like other vapor barriers) only slows down moisture transmission, it does not stop it. A water proof membrane essentially stops flow of both water vapor and liquid water. (It does not really stop it, but reduces transmission by several orders of magnitude more than a vapor barrier).

IMHO, if you have proper surface drainage (directed away from the building), then a vapor barrier is adequate. Polyethylene (Visquene) is a good vapor barrier. In residential construction a 6 mil thickness is the norm. For a commercial building you may want to consider something thicker.When using a vapor barrier, proper curing of the concrete slab becomes even more important - water cannot quickly out the bottom of the slab. Without curing, the top of the slab dries out quicker than the bottom which leads to curling upward - tending to cause cracking (even in a reinforced slab).Polyethylene (like other vapor barriers) only slows down moisture transmission, it does not stop it. A water proof membrane essentially stops flow of both water vapor and liquid water. (It does not really stop it, but reduces transmission by several orders of magnitude more than a vapor barrier).

www.SlideRuleEra.net

RE: waterproofing membrane vs vapor barrier

Huichen are exported all over the world and different industries with quality first. Our belief is to provide our customers with more and better high value-added products. Let's create a better future together.

Additional resources:
Valve Manufacturer China, Ball Gate Globe Check Valves ... oldestguy
Guide to oil seals for your application - ERIKs
Do Sippy Cups Cause Crooked Teeth? Separating Fact ...

(Geotechnical)

2 Dec 06 14:45

Hey guys:  Note the middle para. of SlideRuleEra.  A very true statement and I wish this was publicized more so concrete construction would not result in so many curled slabs!!.  I differ slightly in that I think the lower W/C ratio in the bottom versus top controls subsequent amount of drying shrinkage.  The wetter the mix, the more she shrinks later. Regardless, the thought is the same.

RE: waterproofing membrane vs vapor barrier

jike

(Structural)

3 Dec 06 23:33

We no longer refer to polyethylene as a "vapor barrier" since it is not a barrier. We refer to it as a "vapor retarder" since it reduces the flow of vapors thru it but does not stop it. We use 10 mil thickness for commercial applications.

RE: waterproofing membrane vs vapor barrier

Caribbean

(Civil/Environmental)

(OP)

4 Dec 06 07:23

Because we have both areas of cut and fill, the Geotech engineer has said the water table will stabilize at the new ground level in areas of cut and 2-3 m below the original ground level in areas of fill.  Despite having cut and fill areas we have placed 1.5m of fill and in some areas lean concrete ( psi mix) to underside of slab.

Is the waterproofing membrane the better choice for the 6&#; slab on grade with such varying conditions.  


  

RE: waterproofing membrane vs vapor barrier

theCorkster

(Geotechnical)

6 Dec 06 17:33

Carribean:

What's the structure to be used for, and what type of floor coverings are going to be placed on the slab, if any?  Some commerical/industrial applications can handle some vapor transmission through the slab during the structure life.  

If there are floor coverings planned that will not be permeable, capable of transferring moisture, then the quality of the barrier becomes more critical.

I have encountered visqueen degradation over a relatively short time frame; if you use visqueen, use "virign" material, not created from recycled plastics.  Go 10-mil minimum.

As noted by sliderulera, the w/c ratio of concrete and curing have impacts on the long-term performance of floor covering, regardless of the barrier.  The entire floor covering process needs to be considered since each aspect, if not done properly, can result in floor covering failure.





 

RE: waterproofing membrane vs vapor barrier

tpmanzi

(Structural)

19 Mar 07 10:42

does anyone have a suggestion for a watertite membrane to be used under a slab and on foundation walls for an application ~3 ft below water table?

RE: waterproofing membrane vs vapor barrier

SlideRuleEra

(Structural)

19 Mar 07 20:20 http://www.cetco.pl/e/panels.htm

www.SlideRuleEra.net

RE: waterproofing membrane vs vapor barrier

jike

(Structural)

20 Mar 07 12:40

Don't forget that if you have a slab on grade that it will not be able to resist hydrostatic uplift greater than it's own self weight unless it is designed as a structural slab.

Volclay panels work great and we have used them in many commercial applications.

RE: waterproofing membrane vs vapor barrier

golf39

(Structural)

26 Mar 07 15:42
http://www.post-tensioning.org/pdfs/sog-faq3.pdf
Concrete In Practice CIP29, Vapor Retarders Under Slab on Grade.
ACI recommends vapor retarders for all slabs which recive moisture sensative flooring, which to me includes most carpets, VCT, etc. The first two references recommend vapor barriers be installed for all interior slabs on grade, which I concur with.
Hope This Helps.

See Structural Thread 507- Concrete Cover w/Vapor Barrier. Here are some references that address this issue. http://www.nrmca Concrete In Practice CIP29, Vapor Retarders Under Slab on Grade.ACI recommends vapor retarders for all slabs which recive moisture sensative flooring, which to me includes most carpets, VCT, etc. The first two references recommend vapor barriers be installed for all interior slabs on grade, which I concur with.Hope This Helps.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login

News

With all of the products on the market today that offer moisture control in some way, selecting the correct product for the job is not always an obvious choice. When choosing these types of products, certain questions arise: What exactly are waterproofing membranes and moisture-reduction barriers? What is each made of? Why would I pick one over another? The short of it is that it will vary a bit from job-to-job, but here are some general details to keep in mind:

What is a Waterproofing Membrane vs. a Moisture Barrier?

Waterproofing is just that, it stops liquid water from moving from one space to another; it does not stop water in a vapor form completely (though it can slow it down). Waterproofing and moisture barriers are completely different products with different jobs. You would use a waterproofing membrane to contain water in a certain area, like a shower pan for example. 

Moisture-reduction barriers control moisture in a vapor state. These membranes fill the pores of the substrate, typically with epoxy or a polymer, and keep virtually all vapors from passing through within the specific products limits. These types of products are well-suited for treating high-moisture slabs, or where a concern of high moisture conditions in the future exists.

What are the differences in composition of the products?

Waterproofing membranes are typically a liquid-rubber type material that is applied similar to traditional wall paint. Mapelastic AquaDefense for example, is rolled onto the substrate with a 3/8&#; nap paint roller in two coats. There are other types that require reinforcing fabrics and meshes or application with a trowel vs. a roller; though roller-applied membranes are most common. There are also cement-based waterproofing membranes like our Mapelastic 315, which is a cement powder that is mixed with a supremely flexible additive, and is then trowel-applied in conjunction with a reinforcing fiberglass mesh for added strength. 

Moisture-Reduction Membranes can vary in composition quite a bit, but the three most popular types MAPEI manufactures are epoxy, polyurethane, and polymer-based. First, epoxy (the most popular choice) does a phenomenal job of filling open concrete pores and making a monolithic membrane to guard against vapor transmission. Epoxies can be a touch difficult to work with, and most of these types of membranes will have moisture vapor emission limits. This brings us to products like our Planiseal PMB, which is polyurethane. Polyurethanes like Planiseal PMB can be applied easily using a paint roller, and are already pre-mixed saving time and frustration. Some of these products have moisture limits, but Planiseal PMB does not (so long as the slab has no standing water on it). Finally, polymer-based moisture-reduction membranes like our Planiseal MSP are inexpensive, easy to apply, and are typically very available in the marketplace. These products fill a great niche, but do not have incredibly high moisture limits.

So, how do you choose? Decide if you need to stop &#;water&#; or &#;Water Vapor&#;. If you need to stop water from moving to one area to another, like creating a basin to keep water in a fountain, you need a waterproofing membrane. If you are dealing with a high moisture concrete slab, and need to install solid sheet vinyl, then a moisture-reduction barrier would be the ideal choice.

If you want to learn more, please visit our website waterproof vapor barrier.