EIFS vs. Stucco: To the inexperienced and often, to the experienced eye, Exterior Insulation and Finish System (EIFS) and Stucco often appear the same. Because EIFS and Stucco seem stylistically similar, many believe that these two popular building materials have the same basic properties, one being an acrylic version of the other material.
The fact is EIFS and Stucco couldn’t be more different, starting from the most basic level to the final, completed building system.
Materials:
Stucco dates back to the Greek and Romans, composed of
- Portland cement.
- Sand and water.
EIFS is a lightweight system, introduced in U.S. in 1969, composed of
- Polystyrene insulation board attached to the exterior wall with adhesive or mechanical fasteners.
- Strengthened with an acrylic plaster and fiberglass mesh on top.
- Veneered with an acrylic and polymer coat that is both colorfast and crack-resistant.
Differences in energy and thermal effectiveness:
EIFS
- Acts as a continuous insulation system with no thermal bridging due to fasteners, reducing building maintenance costs and air infiltration (by approximately 55 percent). Produces insulation of an R-value of up to R20.
Stucco
- It is limited to the thickness of insulation and cannot come near to matching the R-values of EIFS and, as a result, cannot achieve thermal efficiency.
Design Options:
EIFS
- Has the capability to achieve infinite design options with its vast array of aesthetic flexibility.
Stucco
- Users are limited to a minimal design palette.
Because of this, EIFS can look like nearly any material on the market; something stucco cannot achieve.
See below chart to see the several features that differentiate EIFS from Stucco:
| EIFS | Stucco |
| Began in the 1950s | Began during Greek and Romans Times |
| Polystyrene insulation board, base coat applied to fiberglass mesh, finish coat | Combination of sand, Portland cement lime, and water |
| Light — 2lbs/SF (reduced structural load requirements) | Heavy — 10.3lbs/sF at ⅞”thickness |
| Attach using adhesive, mechanical fasteners, or both (Attachments designed to resist wind, gravity, & thermal movement effects) | Mechanical attachment through the metal reinforcement over most substrates |
| Installation: Trowel/spray/roller applied water-resistive barrierIntegration of flashingBack wrappingAdhere or fasten insulation board Aesthetic grooves/ featuresBase coat (reduces air infiltration & energy consumption)Reinforcing meshPrimer (promotes adhesion / improves & stabilizes color). | Installation: Building paper, polymeric wrap water -resistive barrierIntegration of flashingMechanical fasten insulation boardControl joints, expansion joints, week screedsLathScratch coat Brown coast Aesthetic features Finish |
| With the exception of water, most materials are pre-blended (Some base coat materials may require measuring cement) | Field mixing, measuring, and batching of cement, sand, lime, fibers, water (Dependent upon laborer to ensure proper amounts) |
| Maintenance:Maintains fresh appearance with minimal cleaningImpactsMedium difficult patch and repair | Maintenance:SealantsDirt can become ingrained in surfaceCracking can be particularly problematic Medium difficulty patch and repair |
| Crack resistance:Highly crack resistant and accommodates building movementCoating flexible to accept minor structural movementNotched trowel adhesions of insulation board minimizes transference of stress to coating | Crack resistance:Typically brittle, cracks if not properly jointed / curedBrittle nature subject minor structural movementMinimal fastener installation of insulation board transfers stress to coating Susceptible to shrinkage cracks due to volumetric change |
| Environmental impact:Materials Extraction: 27.39g of C02 emissions / SF wall areaNumber of truckloads to supply 25,000 SF of wall area: 1C02 emission at all stages of lifecycle:1686g C02 / SF wall area | Environmental impact:Materials Extraction: 46.29g of C02 emissions / SF wall area Number of truckloads to supply 25,000 SF of wall area: 6C02 emission at all stages of lifecycle:14906g C02 / SF wall area |
| Minimum insulation of R3 up to R20 | Does not qualify an R value |
| Water-Resistive Barrier (WRB):Seamless barrierUnaffected by exposure to weather Minimal punctures by fasteners (notched trowel insulation board) | Water-Resistive Barrier (WRB):Lapped barrierAffected by exposure to weather Punctured by fasteners (stables, disc, lath attachment) |
| Available in any color with high degree of uniformity & reproducibility | Limited color, color variability due to cement hydration |
| Equals stuccos’s puncture resistance with additional reinforcing mesh Good bunt impact resistance | Good puncture resistance Poor blunt impact resistance / brittle |
