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Is EIFS The Same As Stucco? The Truth Revealed


EIFS vs Stucco siding: how they differ and which is best

While EIFS and Stucco share the same sleek appearance, they are very different from each other. One consists of two layers and has a longer lifespan, and the second, although it is multi-layered, is not as sturdy. To the untrained eye, these two appear to be one and the same. However, with some training, one can learn to tell EIFS and Stucco apart. 

EIFS is not the same as Stucco. Stucco, the original hard-coated fine-grained cement, is sturdier and more durable than EIFS (also known as “synthetic” Stucco). EIFS does not provide the same dual layer of protection against water damage as Stucco. 

With a well-trained eye, one will be able to differentiate the two in a matter of minutes. To be able to do so, there is some necessary rudimentary knowledge to be learned. Here is everything you need to know how to tell EIFS and Stucco apart. 

What’s The Difference Between EIFS And Stucco?  

There is nothing on the exterior to tell these two apart when looking at Stucco and EIFS (exterior insulation and finish system). However, there are other tests that can be used to determine which is which. 

Material

Stucco is a mixture of sand, a small quantity of lime, water, and Portland cement and consists of a total of two layers. EIFS, on the other hand, has approximately six layers and offers less protection than the original Stucco. 

They Sound Different

A good way to test a wall to see whether it is EIFS or Stucco is by knocking on it. Since EIFS is made up of six soft layers, the inside of the wall will sound hollow. Stucco, on the other hand, sounds solid, despite only having two layers. 

Moisture Barriers

In Stucco, the exterior layer serves as a primary barrier from water, and a concealed, water-resistant interior redirects any stray moisture. 

Despite their similar appearance and installation, one of the barriers of the EIFS doesn’t allow moisture to leave through its coating in a gaseous form. Stucco, with its porosity akin to that of cork, allows for water to freely flow in and out of the wall. This is yet again a result of the different materials used in the two, one allows for breathability while the other is completely sealed.

Installation 

Additionally, to different materials, these two also have slightly different installations, which is yet another easy way to tell them apart.

When installing EIFS, first, a base and finishing coat that is applied over an EPS board that is directly attached to the sheathing of the house using strong adhesive or fasteners. Because of the installations, EIFS has nowhere for the water to run out. 

In comparison, the stucco installation process allows for the water to drain out; this is a result of the Stucco being directly applied on a wire mesh and secured with standoffs. 

Be on the Lookout for EIFS In Your Home

EIFS are commonly used to cut costs in construction. Many homeowners purchase their house thinking it was Stucco but then are shocked to discover it is not. 

Some realtors purposefully withhold from mentioning the use of the material. So, it is important to know how to differentiate them to be certain that one can make sure they are getting what they are paying for. Even though at first glance, EIFS and Stucco appear to be the same, it is not the case for what lies beneath. 

Stucco consists of two layers that work together to keep water out, while EIFS consists of six slimmer layers that are not as effective. So do not be fooled by the near identical first appearance.

The Hidden Layers 

Beneath the surface, the differences between the two finishing coats is glaring. Stucco consists of two thick layers of the original Stucco spread over a mesh wire.

EIFS on the other hand consists of a total of six different layers. 

The first layer is any approved substrate which is then coated with adhesive. The adhesive is used to hold the third layer, EPS. A base coat and a reinforcing mesh are placed onto the EPS respectively, making up the fourth and fifth layers.

The sixth and final layer is a finishing coat that gives it the sleek appearance that is often mistaken for Stucco. 

Despite having four more layers than Stucco, EIFS is the considerably weaker of the two. This is a result of “synthetic” Stucco being softer than the original. Unlike original Stucco, the EIFS uses a higher ratio of cement than lime is one of the reasons for the weaker coating EIFS has. 

The layers behind these two finishing coats are what make all the difference. Stucco, thanks to its unique composition, is both sturdy and porous, yet it allows water to flow freely.

Since the formula of Stucco was altered to create EIFS, other features and components had to be added in to meet the requirements for outdoor coating for houses.

Test Types

From the difference in materiality to porosity and installation, these two finishing coats can be distinguished by using some of the following tests. These tests were designed specifically for this purpose and have been used successfully over the years.

The first test that can be done is the knock test that had been briefly discussed earlier in the article. While from afar EIFS and Stucco look alike, they are made out of different materials.

Since the EIFS is lighter and softer, the knock will resonate as hollow while knocking on Stucco would have resulted in a nice solid, full sound. This is an easy and fool-proof way to check what material is on the walls. 

Another test that has proven to be accurate is the penetration test. This test relies on the different installations to work, since EIFS has so many layers, it can be tedious to leave pre cutout places for fixtures. 

The penetration test works by unscrewing either a light switch or an outlet and looking at how the interior of the wall is.

If the interior of the wall has a foam board anywhere inside it, that is a dead give away of EIFS. If there is no foam board visible behind the fixture, the wall had been constructed from the original Stucco. 

Another installation checking test is called the gap test. When Stucco is installed, there is a sliver of space left between the stucco wall and the foundation that is aligned with each other.

However, if this is impossible to do and only a lip of material can be felt, it is most likely that the wall was made out of EIFS. This test however can be difficult for beginners to grasp, most experts suggest the knocking test and the penetration test for less-experienced people. 

With two easy and sure tests, one can determine if the home they are buying is worth the price. After all, this is not a small investment, it has to be well thought out to make sure it doesn’t become a regret.

While there are many different siding options to choose from, most people prefer to know exactly what material is in their house.

This YouTube video discussed in detail how to tell these two materials apart and why you need to know which one you have:

How to Tell Synthetic EIFS From Real Stucco

Paul

As a homeowner, I am constantly experimenting with making the structure of my house more energy-efficient, eliminating pests, and taking on DIY home improvement projects. Over the past two decades, my family has rehabbed houses and contracted new home builds and I've learned a lot along the way. I share my hard-learned lessons so that you can save time and money by not repeating my mistakes.

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