# NEGATIVE SIDE WATERPROOFING VERSUS ADMIX WATERPROOFING **URL:** \ **Category:** Archive - Product Discussions #6\ **Created:** [April 14, 2020, 6:52pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674 "2020-04-14T18:52:01Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![wayne\_yancey](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.4specs.com/wayne_yancey/32/228_2.png) [@wayne\_yancey](https://forum.4specs.com/u/wayne_yancey)\ **Post date:** [April 14, 2020, 6:52pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/1 "2020-04-14T18:52:01Z")
Good morning or afternoon from the Home Office. I am searching for reasons to convince others to use a negative side waterproofing membranes (verticals and under slab) versus a crystalline admmix waterproofing. Project is located in HI, on the shore of the Pacific Ocean. I wrote specs for GCPAT Preprufe 300R under the slabs and Bituthene 4000 on verticals. A contractor is pressing the owner about first cost versus performance (IMHO). Looking for empirical, non-anecdotal evidence to support our products. Thanks, Be safe. Stay home. Wander out into the kitchen for lunch. ---
**Author:** ![gretaeckhardt](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.4specs.com/gretaeckhardt/32/105_2.png) [@gretaeckhardt](https://forum.4specs.com/u/gretaeckhardt)\ **Post date:** [April 14, 2020, 7:09pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/2 "2020-04-14T19:09:20Z")
Not wanting to nit-pick, but as a terminology-obsessed specifier I want to be sure you mean “negative” and not “positive”. If you are using GCP; Prepruf below the slab and GCP; Bituthene on foundation walls, presumably on the exterior face, those are positive-side applications. Is the question meant to be about those applications? Or is someone proposing waterproofing on the interior face of foundation walls and the top of the floor slab, in which cases it would be negative-side? ---
**Author:** ![wayne\_yancey](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.4specs.com/wayne_yancey/32/228_2.png) [@wayne\_yancey](https://forum.4specs.com/u/wayne_yancey)\ **Post date:** [April 14, 2020, 7:34pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/3 "2020-04-14T19:34:46Z")
Me bad, Positive side waterproofing. I was having a negative thought. ---
**Author:** ![jpjordan](https://avatars.discourse-cdn.com/v4/letter/j/67e7ee/32.png) [@jpjordan](https://forum.4specs.com/u/jpjordan)\ **Post date:** [April 14, 2020, 10:58pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/4 "2020-04-14T22:58:52Z")
I always tell people that there are two things that you can count on about concrete. It will get hard and it will crack. The admixes say that they will bridge “hairline” cracks, but not anything any greater. There are lots of downsides to trying to save money on waterproofing. Depending on which island you are on, you may get minor cracking from seismic activity. My vote is not only no, but hell no! If I was the Architect, I would threaten to not stamp the Drawings or get a written release from the Owner for any water infiltration problems. ---
**Author:** ![michael\_chusid](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.4specs.com/michael_chusid/32/211_2.png) [@michael\_chusid](https://forum.4specs.com/u/michael_chusid)\ **Post date:** [April 14, 2020, 11:15pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/5 "2020-04-14T23:15:38Z")
I have seen impressive results with waterproofing made with Type K cement instead of portland cement. It is slightly expansive and creates a prestressed condition that substantially makes the concrete waterproof. Contact me off line if you want copies of the reports I have written on the topic. ---
**Author:** ![mark\_gilligan](https://avatars.discourse-cdn.com/v4/letter/m/f05b48/32.png) [@mark\_gilligan](https://forum.4specs.com/u/mark_gilligan)\ **Post date:** [April 15, 2020, 4:07pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/6 "2020-04-15T16:07:39Z")
I suggest that the concern about cracks and Xypex type treatments is related to the amount of reinforcing steel in the concrete. If you have sufficient reinforcing then the size of the individual cracks will be small. You are not concerned about the total amount of cracking but rather the size of individual cracks. ---
**Author:** ![Unregistered\_Guest](https://avatars.discourse-cdn.com/v4/letter/u/74df32/32.png) [@Unregistered\_Guest](https://forum.4specs.com/u/Unregistered_Guest)\ **Post date:** [April 16, 2020, 12:14am UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/7 "2020-04-16T00:14:31Z")
There is a limit to what degree concrete will crack after placement, and not a concern with regard to waterproofing treatments because NO waterproofing manufacturer will warrant products against a structural crack. The “concrete will crack” line is nothing more than a scare tactic used by WP manufacturers to negative sell competitors products and WP consultants that want to scare clients into hiring them. Crystalline WP works incredibly well. Negative side, positive side, and as an integral admixture. I have specified it for decades with great success - no call backs, no complaints. I swear by it. One word of caution, however, the brand of crystalline matters - not for the functionality necessarily, but for the product support and warranties offered. I have settled on one manufacturer that offers incredible technical support, detailing help, etc. and a 10 year installation warranty. None of the other manufacturer’s offer this. Because many posters on this forum have complained when a product is mentioned alleging that anon posters are just shills for the company of product(s) being mentioned, I will not name the product. But you’re a smart guy, Wayne, you can probably google it and figure it out. ---
**Author:** ![jpjordan](https://avatars.discourse-cdn.com/v4/letter/j/67e7ee/32.png) [@jpjordan](https://forum.4specs.com/u/jpjordan)\ **Post date:** [April 16, 2020, 2:49pm UTC](https://forum.4specs.com/t/negative-side-waterproofing-versus-admix-waterproofing/3674/8 "2020-04-16T14:49:11Z")
If the concrete cracks bad enough, then no waterproofing is going to work; however, most membrane systems are capable of spanning larger cracks than crystalline waterproofing. I will specify crystalline waterproofing as a last resort (like when the Contractor “forgets” to install what has been specified).