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The Importance of Stair Nosing in Waterproofing Systems


by Steven Dolan

Exterior stairs and landings are the most abused portion of any waterproof deck coating system, and all too often, the stair landings and stairs are built without having proper stair nosing installed. Of course, per manufacturer specifications, this is OK, because the stair nosing is listed as an option or an upgrade.



When stair nosing is not installed, the nose of the stair or landing is extremely susceptible to kicking and added downforce pressure causing increased movement. Over time, the movement causes the waterproofing system to breakdown and crack. When water penetrates the cracks it causes either mold or dry rot, often resulting in all or part of the stairs needing to be rebuilt. In extreme cases that are not caught in time, dry rot from lack of stair nosing can extend to adjacent walls or decks, causing even more costly damage.


If this is occurring, contact WICR immediately to prevent additional damages. As more time goes by, and the system is continually being abused, the system will chip away, leaving nothing at the edge but the metal flashing which is not waterproof by itself.


There are ways to prevent this from happening, such as installing proper stair nosing.

There are two (2) two types of nosing: Integral nosing and topical nosing. The integral nosing is a piece of extruded aluminum that has a 4” flange to mount to the stair tread after the membrane is installed by prior to texture and color of the system. It is then re-waterproofed with the membrane over the flange, then continuing with the finish texture and ultra violet resistant color coats.deck repair The benefit to the integral nosing is that It provides additional stability on the deck, so that when the pedestrian steps on the nose going down, it has a thicker, stronger piece of metal fastening to the structure and limits the movement. Additionally, It is waterproofed over the fasteners, meaning, although it penetrates the first membrane, the secondary strip of liquid membrane and fabric is placed over the flange, covering the fasteners.


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The second type of stair nosing is a topical nosing which comes in a variety of colors, finishes, style and mediums such as aluminum, wood, and vinyl. We would never recommend a wood or vinyl nosing on an exterior stair; however, they do exist and people have asked for them in the past. A topical nosing is one that is fastened on top of the system using a thick bead of sealant and nails. Each nail used to fasten, which is typically about 4 per nosing, will be penetrating the system and relying on the use of caulking. Over time, the nails can come loose, losing the seal within the sealant and causing a leak but it’s still better, and an easier repair, then if the nosing wasn’t there to begin with.

deck repair waterproofing


To ensure your stairs are properly waterproofed, make sure to use stair nosing. Although it will cost more money up front, it’s less cost later on!