What does EIFS stand for?
Exterior Insulation and Finish System. A basic EIFS system consists of 4 components:
- Polystyrene or polyisocyanurate foam insulation board.
- Glass fiber reinforcing mesh.
- Weather barrier composed of a durable, water-resistant base coat applied to the insulation.
- Acrylic co-polymer technology, colorfast and crack-resistant finish coat.
What is the difference between PM and PB EIFS?
PM: Polymer Modified: Thick cementitious base coat applied over glass fiber reinforcing mesh.
The joints in this system are similar to that in traditional stucco. This system uses a standard finish however a elastomeric finish can be used to fill any hairline cracks that could occur with the thickness of the base coat.
PB: Polymer Based: This system typically uses adhesively fastened, expanded polystyrene (EPS) insulation as well as fiber reinforcing mesh embedded in a nominal 1/16 inch base coat. PB EIFS may include additional layers of base coat and reinforcing mesh in order to create a higher level of impact resistance. An EIFS finish coat is applied over the entire base coat.
What is the maximum thickness allowed for foam shapes to achieve architectural treatments such as accent bands and cornices?
The national model building codes generally limit foam thickness to a 4-inch maximum. However, precedence exists for using thicker expanded polystyrene foam insulation when acceptable to local authorities having jurisdiction. [top]
Are control joints necessary?
Yes. Control joints are normally grooved in the system for aesthetic reasons but also to provide the tradesman applying the finish reasonable areas for completing his work without creating dry joints.
How do you repair smaller damaged areas of the EIFS?
Be sure to establish and correct the cause of the damaged area. Assuming the substrate is sound, proceed as follows:
- Cut out and remove a rectangular section of the EIFS extending approximately 3” on each side of the damaged area to expose the substrate.
- Grind off a band of acrylic finish at the perimeter of the hole to a minimum width of 2 1/2” exposing the system’s basecoat.
- Apply adhesive to the back only of a tight filling piece of insulation and install where the damaged area has been removed, making sure that the substrate is clean and sound. Sand the edges of the board so that it is flush with the surrounding insulation.
- Mask around the repair area and apply adhesive and reinforcing mesh so that the mesh overlaps the existing exposed basecoat 21/2”. Ensure that the mesh is completely embedded. Allow to cure for a minimum of 24 hours.
- Remask and apply the same color and texture finish over the patch. Remove the mask and using a damp brush feather the perimeter of the patch into the existing finish.
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- Can weather conditions during application affect the performance of EIFS coatings?
- Yes, EIFS adhesives, basecoats, and topcoats can all be affected by the air temperature and humidity at the time of application. Long-term performance may suffer if coatings are applied when it’s too cold or damp, or if uncured coatings are not protected during such weather.
What happens if it is too cold?
Polymer latexes used to make 1-00% acrylic coatings that have what is called a “Minimum film formation temperature” (MFFT). Above the MFFT, the latex will form a clear film with good-binding action. Below the MFFT however, the latex will dry to a white powder and no film will form.
Is mechanical attachment of EIFS recommended to resist high wind loads?
In general, adhesive attachment of the EIFS sound supporting construction provides superior wind load resistance in comparison to mechanical attachment. It is important in an adhesively attached system that the supporting construction is sound-free of surface damage, defects or contamination, and, in the case of sheathing substrates, that they are attached with fasteners.
Fastener spacing must be capable of resisting wind loads. It is recommended that mechanical fastenings of the insulation to the substrate only be considered where adhesive attachment cannot be used.
What materials can I use to recoat my EIFS?
There are a number of acrylic finishes that can be used for this purpose, including both standard acrylic and elastomeric coatings. A top quality acrylic latex paint is also acceptable.
What type of sealants are recommended for use with EIFS?
There are a number of acrylic finishes that can be used for this purpose, including both standard acrylic and elastomeric coatings. A top quality acrylic latex paint is also acceptable.
What type of textures are available?
90% of the Acrylic Finish sold is Medium texture. The popularity of this texture can be attributed to:
- Additional coating thickness.
- Ability to cover minor ridges or defects in the substrate.
- Longer open time and workability compared to the thinner coatings.
For the reasons above, use a medium texture finish over Portland Cement Plaster (Stucco) substrates, particularly in larger wall areas. The fine finish is more suitable for small area and detail work over stucco, or on smooth planer surfaces.
Using Flashing with EIFS
For the wall to resist water penetration, particularly at transition areas such as decks or roof/wall intersections, flashing must be installed to divert water beyond cladding not into or behind it. Similarly, if windows are expected to leak, sill flashing beneath them is important to divert water away from and not into the wall assembly.
The Cost of an EIFS Inspection
The cost varies from home to home and is dependent upon location, size, configuration, wall square footage, complexity of the EIFS, and access to the structure itself. A basic EIFS (and Stucco) inspection and report begins around $500. The cost of inspecting a residence with complex design features can exceed $1,000. Commercial inspections, due to larger structure sizes, are usually more expensive.
The cost of inspections are minimal especially when compared to stripping and replacing the EIFS and wall structure of a home which may run into tens of thousands of dollars if moisture intrusion is ignored. Moisture damaged wood is somewhat akin to cancer. You have to stop it from spreading, or cut it out. The first step to stopping it is to have a survey performed.
How do I maintain the exterior of my house?
1. Physical Damage – Patching and Small Repairs
It takes time, skill, experience, proper techniques and the correct material to make a good repair. Both color and texture must be blended for the area to look good.
Holes, cracks, wrinkles, and bulges should all be corrected to prevent additional damage. Some are easy to repair and some very difficult. Most repairs may still be slightly visible unless the entire panel is recoated. Even then, a badly worked patch may still be seen.
The time required to repair EIFS depends on the size and depth of the damaged area. Most installers do not have personnel available to repair a small area. With the expense of travel time, etc. repairs are expensive. Many owners object to the high cost they are charged when they can find someone to do the repairs. Time is money. Repairs are often difficult and expensive.
2. Cleaning EIFS
Keeping your house or building clean is vital to curb appeal. Whether you are trying to draw customers or clients, selling a house or doing spring-cleaning a positive first impression depends on a clean exterior.
EIFS, which rarely needs to be painted, must be cleaned occasionally to maintain its like-new appearance. Each manufacturer has cleaning instructions that should be followed to prevent surface damage and color fading.
Various kinds of stains and discoloration can occur on the surface. Each has its own characteristics and remedial cleaning processes.
WARNING: Many firms use high pressure (3500psi+) to remove stains and mildew. High pressure washing may easily damage various surfaces including brick and concrete. Overzealous individuals can ruin mortar joints, caulking, masonry surfaces, paint and wood decks with a high pressure washer. High pressure has its applications, but only when used carefully with damage prevention in mind. There is a preferred low pressure option for cleaning EIFS, which can accomplish the same results without the danger of damaging the surface.
3. Mildew
For mildew removal, use the EIFS manufacturers recommendations or have the house professionally cleaned. Please see “WARNING” in No. 2 above.
4. Painting EIFS
Painting EIFS is normally unnecessary unless a color change is wanted or unusually stubborn stains cannot be removed.
EIFS buildings cannot be painted like most surfaces. Picture framing, streaking, and flattened textures are the results of inexperienced painters using improper or inappropriate procedures required on EIFS. Proper painting is not more difficult, but it is different. Don’t hire someone to learn on your project.
Some coatings will change the sheen or gloss. Most will change the texture enough that an entire elevation must be painted to be aesthetically acceptable.
Contact the manufacturer for advice or call a professional in the EIFS coating business to do it correctly. Some coatings can change the water vapor transmission characteristics of the EIFS and trap moisture inside. Solvent-based coatings can dissolve the EPS Insulation board and cause delamination of the outer layers of the EIFS.
If the EIFS surface is an elastomeric or silicone based coating, regular latex paint will not adhere properly and peeling may result.
Although top-quality exterior acrylic latex paint is often used on EIFS material, coatings other than those provided by the EIFS manufacturer may void the warranty.
Why do small cracks appear in my stucco finish?
As stucco cures some of the water it contains evaporates. This causes the stucco to shrink slightly. As it shrinks, small cracks called “check cracking” might appear. Applying stucco finishes in hot, dry weather could contribute to check cracking in stucco. During periods of hot dry weather conditions, a light spray (mist) of clean water is recommended over the stucco finish. Some check cracking in stucco is normal.
I have noticed slight color variations, or “blotches” in my stucco finish. What caused this and how can I even out the color?
Usually, spotty or “blotchy” stucco color is a result of variations in the thickness of the cement “base coat” beneath the stucco finish. Slightly thicker areas can retain moisture longer. This drying pattern can cause the slower-drying areas to appear darker. Typically, this happens more during winter months, and on shaded surfaces.
What is the white powdery substance I have near the base of my stucco wall?
How can I remove it?
This is probably “efflorescence,” also known as “alkali.” Efflorescence or alkali consists of salts leached from cement-based materials when exposed to excessive, saturating moisture. It appears as a whitish powdery “bloom” on the surface of the wall. A wash down with white vinegar or another approved dilute acid solution, followed by a thorough flush with clear water will usually remove efflorescence. Taking care to direct sprinklers, irrigation systems or other sources of water away from stucco walls will help prevent it.
REMEMBER: always keep acids and other chemicals away from children, and ALWAYS use the proper safety equipment – including eye protection – when working with any hazardous substance!
My house is several years old. How can I “freshen” its stucco color?
Most stucco colors darken slightly over time because they contain natural all-mineral ingredients. Unlike painted surfaces that have only a thin layer of paint that can fade, chip and/or peel, stucco color is “integral.” This means stucco color extends through the entire stucco layer instead of only on the surface. Properly maintained exterior stucco can remain attractive for many years with only minimal changes. However, exposure to dust, dirt and air pollution over time can slightly change its color.
How can I change the color of my stucco? Is it ok to paint it?
Although stucco, like other masonry surfaces, can be painted this is neither the best nor the most economical way to change color. Over time, paint tends to fade, chip and peel away from stucco walls.
It is recommended that you contact a professional EIFS installer before performing any maintenance or repairs on your home.
