Why and How Did This Deck Fail Prematurely? Deck Expert Autopsies a Dead Deck

As an estimator selling deck coatings for new home construction, I always had a hard time getting the  job. The short simple reply to my question “Why didn’t I get this job?’ was usually “Your quote is  to much compared to X.” Of course it wasn’t an apples to apples type bid. My competitors all use different materials than I, many of which are not as detailed and have as many steps to install as Desert Crete is. Fewer steps to install means less labor, and that means a lower cost. The contractor doesn’t care, he’s thinking profits ahead of great waterproofing.

I never sold on rock bottom pricing and I still don’t, even in this economy. Cheap waterproofing is cheap waterproofing. Period. I provide high quality and high end service with high end waterproofing products backing me up. I have very few go backs and a near zero warranty claims record because of this.
Anyway, I get this repair job over in Shell Beach;  a roof top deck. I go look at it, and as soon as I walked in the house, I knew I’d been here before some years ago when it was being built.
My inspection finds a few cracks at flashing edges that need repairs as well as a larger/longer cracks in the field of the deck and the surface needs to be cleaned and resealed. At least, that’s what we think… Well we started yesterday with demo’ing some of the decking. I could not believe what we found!
This job has defect written all over it…
The cracks were opened and we found the deck was not stapled down as it should be-these metal lath based systems usually require typically 20+ staples per square foot. So we found DEFECT # 1. Stapling of lath not done as directed in the ICC report and the manufacturer’s installation instructions. The pictures clearly show that there’s maybe 7/8 per square foot. The decking came up fairly easily and it shouldn’t have, but that’s what happens when your deck is done wrong.Strangely enough, the deck material just peeled right up, not sticking to anything…

 

Then we found a membrane applied to the deck substrate. It”s an asphalt based membrane. Looking closer at this membrane, I note that it’s very shiny. Run your finger over it and it’s smooth & waxy feeling. I look at it again; I realize that the shiny stuff is a film. I get a fingernail under a piece, I peel it back. Underneath is the membrane and it feels smooth to, but not waxy. I call a manufacturer that I know makes this decking product. Technical service says oh yes, that film has to be removed before stapling lath down. It’s on to protect the membrane up until it’s ready to be covered. Ohhh, that’s why the deck material peeled off so easily. When I staple my lath/put down our cement, it’s stuck! Usually the only efficient way to get it off is to just saw off all the plywood!
So DEFECT #2 is not taking off the protective film, which prevented proper adhesion to the membrane.
Defect 3 may be in play if the plans/specs for the house call for a Class A/One Hour Fire Rating. The assembly described is not an approved method under the ICC report of the two manufacturer’s who make this type of product. Building codes typically call for Class A/One Hour roofs as they are very vulnerable to fire. Class A rated assemblies resist fire.
Peeling back the decking, we get to the edges where the flashing’s are under the coating, meeting the deck/wall and allowing the decking to terminate. The flashing’s are found to be nailed off in a manner that is not consistent with code requirements and the manufacturer’s instructions. We are supposed to nail flashing’s so they lay flat without distortion or movement, in a W pattern. This was not done as required. So we have DEFECT # 4. Looking again at the flashing’s, I see they are bright shiny metal-the coating peels off easily from the flashing.

 This is because the installer did not wipe down his flashing’s with a solvent to remove film oils that bright flashing’s have on them. So we have Defect #5.

And the final Defect, Defect #6, is the drains, or more precisely, the lack of. We have 6 pipes stubbed up through the floor of the deck, but where are the drains? We use Thunderbird Products drains, a flat plate allows us to terminate the coating and run the waterproofing into the drain pipe. Not here…no drain, just use caulk and say a prayer…

This job was doomed to fail from the day it was put down…a big thank you to my competitor for the work! Keep up the bad work!

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