Exterior Insulation and Finish System (EFIS)

What is EIFS?

February 3, 2023
Blog, Exteriors, Stucco

When done correctly, it’s one of the best siding choices.

EIFS stands for “exterior insulation and finish system” and is often referred to as synthetic stucco. It can look like traditional stucco from outside and its main benefit vs cement stucco, is the continuous insulation value it adds to your home.

Insulating your home from the outside is more efficient than doing it from the inside, due to all the wood studs that cannot be insulated, resulting in gaps for hot/cold air to travel (known as thermal bridges).

Therefore, the insulation inside the home provides less R-value than specified, as well as a lower real R-value, which could vary depending on the design, frame, and workmanship of build.

Below is a picture of a home renovated from siding to EIFS

Why EIFS Problems Occur

EIFS are vulnerable to damage due to the combination of improper mixing and application of materials. The main components that seal, adhere, and finish the system, need to be mixed and applied according to manufacturer specifications. It is very easy to manipulate and mix these materials incorrectly, and greatly reduce the performance of the product.

Another issue is improper sealing around windows, penetrations, installation of flashings. Some of the reasons for this problem is the significant cost of materials and the consistent rise in their pricing. In addition, many contractors underbid jobs, sacrificing quality of materials or workmanship in order to make a profit. Moreover, some lack the knowledge and experience to know the harm it causes to the home/building, and believe it or not, some just don’t care. I’m amazed that the attitude of contractors that just want to get paid and let someone else deal with future issues knowingly!

Up until recently, there would be many issues with mold on oriented strand board (OSB) from moisture getting trapped between foam and sheathing, but thankfully the EIFS insulation boards are now designed with drainage, so the risk of getting mold between foam and sheathing is less likely (not impossible).

There is more to say about the subject, but these are the key components of the problem…

Problems are Becoming More Common

Every year we get increasingly more calls about EIFS issues, especially, after structures experience non-stop rainy days, or when homeowners want to buy or sell a home, and their property is looked at more carefully by home inspectors which can lead to a major repair.

Those rainy days also leave behind multiple failed condo buildings, that had their entire EIFS removed and redone under proper contractors and supervision. Since EIFS has just started to become more popular in residential homes, we expect to see more repairs and complete tear offs.
Below is a picture of a crack on EIFS Stucco which is a good indication of bad workmanship. The following picture shows what it could look underneath when moisture gets trapped, turning black and starts to rot the wood sheathing.