Spay applied sealants

[StrEng007]

Has anyone here had much luck with specifying a spray applied waterproofing membrane? More specifically, spraying directly to the cementitious material that is the walking surface?

I have a situation where it is too costly to get down to the waterproofing membrane of an exterior stair slab. Looking for solutions to try to use a spray applied finish to the existing system.

My only concern is creating a way that moisture gets locked in or a walking hazard.

 

[Enable]

Can you provide a quick sketch of the elevation? I'm envisioning a stair landing consisting of topping over granular material placed on protection board over hot applied waterproofing adhered to the structural slab. Not entirely sure though. Also can you expand on the requirements for a spray applied coating? Some do exist but they are almost never used and unless it's not possible to get to the surface (it must be because you're worried about people walking?) then you want to go with a pedestrian traffic topping.

At any rate, what we use for waterproofing concrete in pedestrian areas is a traffic topping. The topping has sand broadcast into it during placement (either broadcast and backroll or fully saturated) for traction. We typically use MasterSeal 1500 but you can also use the 2-component 2500 series for a quicker turnaround or any other similar type product from Tremco and the like. Note: You will want the UV stable top coat if exposed to direct sunlight. If it's entirely covered then you can use the regular topcoat.

If the situation is as I envisioned above your problem will be a tie-in to the membrane on the suspended slab unless the traffic topping covers the entire surface. Otherwise water will get down to the lower level and be an issue if the hot applied waterproofing is not satisfactory. This can be done with a mix of epoxy and sand broadcast (you create a shoulder with epoxy on top of the topcoat and overlap with the hot applied waterproofing) but each manufacturer will have their own particulars here. For epoxy we tend to use MasterSeal 350.

As far as moisture is concerned there is no concern as long as the concrete is below the required moisture levels during traffic topping placement (assuming it has air entrainment and your waterproofing job is satisfactory).

 

[dik]

I've only used a real membrane... because of the brittle nature of concrete, I would not be looking at a liquid sealant. There are numerous types, depending on the use. A parkade deck sealant would be different than a foundation wall waterproof membrane sealant.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Ingenuity]

Spray applied 2-component polyurea?