The following was written by our competitor here in the SLO area…a layperson reading through it and viewing the pictures might get the false impression that all the coatings discussed are bad…and that their only salvation lays with Deck Tech’s Granite Deck membrane.
But nothing could be further from the truth. All the pictures do show deck with problems…but in my opinion, all of them, have failed due to a secondary cause other than the deck coating membrane being faulty. I always say any deck coating membrane is only as good as the installer assembling the pieces and how well built the deck framing was built.
The best installer in the world could have done the best possible job assembling his materials, but if he’s going over a deck with no blocking at plywood seams, or where they use regular bright shiny nails instead of barbed ring shank nails or screws, well that deck is probably going to fail.
The best deck framing contractor can be hired and he can build you the best deck substructure the world has ever seen, but if a poor job is done installing the flashing, or the minimum thickness of the coating isn’t applied or any number of things done wrong, that deck will rot out just as surely as if it wasn’t waterproofed at all. So we encourage you to read their article, then read our response down below and continue to read our articles on this site’s pages and at our sister site www.deckexpert.com.
Why Coating Assemblies Fail
As a waterproofing contractor specializing in failure I give little merit to manufactures and their claims regarding the durability or longevity of their deck coating assemblies. All these assemblies have issues and the proof is seen in the photos below which were taken from inspections Decktech has provided to our clients. The key to a durable and long-lasting deck is finding an assembly that meets the specific needs of the project environment and then ensuring fundamentals are sound prior to any application.
READ ALL OF THIS AND VIEW THE PICTURES BY CLICKING HERE
Read my response below to the article…DeckTech of course won’t approve the comments I submitted
It seems that most of these failures are not coating failures but rather are failures caused by one or more underlying reasons.1.) The framing and substrate are sub-standard.
Nail pops are caused by the framer using smooth shank nails instead of ring shank or screws. That’s not a coating failure.
Straight cracks at edges and the inside wall indicate that the flashing wasn’t nailed properly or laying flat.
The edges of the deck from 2728 barcelona are to high. Either the fascia board is high or more likely the gutter installer forced his gutter up underneath the flashing, causing to raise up slightly and cause a dam. Not the coatings fault.
The pic from the Beachcomber is a plywood substrate issue. Moving seams of plywood will create a crack in any coating over time when maintenance or repairs aren’t undertaken.2.) The coating wasn’t installed properly.
Proper coating application is essential and when not done properly, the coating won’t last.Part of that problem is caused by3.) Sequencing- the construction of a building needs to be done in a certain order. When flat decks are part of a new construction project, it is essential that the flashings and construction coat of waterproofing be installed first, before walls are closed in. If coating materials are not lapped up the vertical rise of the flashing and building paper lapped down over it, water can seep past small openings left at the edge of the weep screed and cause flashings to rust. Not the coatings fault.However, even if the sequencing is in order, the complete system must be installed. Often on new construction I find that the system as designed and specified by the mfg wasn’t installed completely. Seams showing through a polyurea deck or polyurethane deck is usally because they weren’t resealed as they need to be, the UV burns up the coating and the seams are the first to split because of the movement between the sheets of plywood. Not the coatings fault.I’ve seen this occur on NCS Granite Deck, Tufflex, Polytuff and other thin membrane systems.The separation in the first pic of a Life Deck system is probably because the installer used bright shiny flashing instead of the industry accepted “bonderized “or “phosphated” flashing. Bright shiny flashings MUST be weathered for 12-18 months, cleaned using specialty cleaners or blasted. That cause of failure would NOT be the coatings fault, but rather, applicator error.NCS Granite Deck, made of polyurea, has not been tested under AC-39, the acceptance criteria from ICC that is issued for strict testing of materials claiming to be suitable for decks must pass before being listed in ICC-ES’ Div 7 Pedestrian Traffic coatings section. Most of the above coatings you mention-Life Deck, Westcoat, Desert Crete, Mer-Kotehave been tested and accepted under the rules of AC-39.
They are all Class A fire rated, something that NCS is not from my research and inquiries. Please correct me if I’m wrong by forwarding a ICC report, or a copy of the testing results performed under UL 790, ASTM E-108, or UBC requirements.