Which Products Should I Use: Positive Side vs. Negative Side vs. Blindside Waterproofing

I’m sure someone has “an app for that,” but this article is your checklist to help you identify which waterproofing products to specify or apply to the positive, negative or blindside of a building envelope, because it can be confusing.

Your first task will be essential: a full site inspection. This will determine some of your site concerns when you’re selecting your waterproofing system. Having this intelligence upfront enables you to identify the most durable long-term solution.

Here are W. R. MEADOWS’ recommendations for below-grade waterproofing:

POSITIVE SIDE: All forms of waterproofing products can be used on the positive side—sprayable and self-adhesive membrane sheets.
NEGATIVE SIDE: Brush-on waterproofing products only. No sheet goods. Our recommendation: flexible, fiber-reinforced, hydraulic cement-based materials, or Portland cement-based coating (a.k.a. “slurry”) comprised of silica-based materials.
BLINDSIDE: Sheet membrane products only.

Other Factors:

Building Code Requirements
Groundwater Conditions and Drainage Changes
Seasonal or Thermal Variations
Dynamic Movement–If the potential for substrate cracking exists, you’ll want to use a flexible system with self-sealing characteristics
Soil Conditions Impacting Your Concrete—Consider the type of soil and if there are any contaminants within the soil that could affect the waterproofing system or the concrete

Which Products Do I Use for Poured-in-Place Concrete?

You can use either any of the above materials for your poured-in-place concrete waterproofing projects, but here are the factors you’ll want to consider:

Contractor Preference—Contractors have their go-to methods and crew, which can impact your decision
Surface Conditions—Fluid-applied material is more forgiving on some substrates
Labor Costs—Sprayable will save you some money on labor if you have the ability to spray
Thickness Consistency– Membrane sheet goods always give you consistent thickness, whereas with fluid applications, it is dependent upon the applicator
Timing—For green or eco-friendly concrete, some emulsion fluids can be applied on green concrete, but you’ll have to wait a few days for membrane sheet goods
Detailing—Fluid applications can be easier to detail