Water Control and EIFS

The blue at the base of the wall is Dryvit Backstop Waterproofing.

I discussed the differences between stucco and EIFS in my previous post, “problematic stucco.” Improper water control is the most common reason for EIFS failure. Proper EIFS systems are expensive when compared to other cladding systems like lap siding, vinyl, or James Hardie systems.

A well designed EIFS system is composed of the following elements: a moisture rated substrate, a fluid or sheet-good waterproofing membrane, a drainage mat, foam, a base coat, and subsequent finish coat. This list of components should be used 100% of the time and will look very similar from job to job. Any time a termination point is reached, a special termination should be installed; this can be a drainage channel, drainage track, or weep track.

The before-mentioned components are required because when controlling water in a wall assembly, the name of the game is DOWN, OUT, AND AWAY! You MUST install a system that allows water to move DOWN the wall, out of the wall cavity, and then away from the wall. Hard driving rains will generate massive static pressure and force water behind an EIFS water system; however when a proper system is installed, that statically driven rain will enter the assembly and simply drain away and dry up.

In a poorly designed system, when water penetrates into the wall assembly, the water lacks a path to drain down the wall, out of the bottom of the wall, and away from the building. Moisture will become trapped behind the wall assembly and this will cause mold, discoloration, and failure of the system.

I am fascinated with EIFS and water control because of the VAST amount of dependent variables that must be accounted for to render a proper installation. Additionally, I am fascinated with watching the entire installation process. Even if a system is well designed, it is only effective if it is properly installed. A proper installation requires intensive oversight and quality control.

Whenever we begin a new EIFS installation, my first step is to setup a lawn chair… I sit down and WATCH! I answer questions from the workers. I check all of their work. I perform an intensive inspection of each component as it installed. Cheaper and faster does not exist in EIFS!