Ekoplast50: the lightweight insulating plaster that replaces stucco, levels floors, and stops fire

Most building materials do one job. Stucco protects a wall. Insulation slows heat. Underlayment levels a floor. Acoustic board quiets a room. A weather barrier keeps water out. Each one gets specified separately, ordered separately, installed separately, and each one adds weight, cost, and another trade to the schedule.

Ekoplast50 collapses several of those jobs into a single material. It is a lightweight plaster for both exterior and interior use that insulates against heat, deadens sound, blocks liquid water while still letting the wall breathe, and does not burn.

What Ekoplast50 is

Ekoplast50 is an insulating plaster that applies much like conventional stucco or interior plaster, but weighs roughly one quarter of what standard stucco weighs. That single property changes almost everything downstream: less structural dead load, easier handling on the wall, fewer bags to move up a ladder, and lower shipping weight per square foot of coverage.

What makes it unusual is that the weight reduction does not come at the expense of performance. Ekoplast50 delivers R-1.2 per inch, a compressive strength of 2,562 psi, sound reduction of Rw 35 dB, a Class 1A fireproof rating as a non-combustible material, and a vapor permeability of 3.49 perms while remaining water resistant.

Part of the reason comes down to what is inside it. Ekoplast50 is formulated with glass beads rather than silica, a choice that improves both strength and insulating value, and that removes crystalline silica dust from the equation for the crews mixing and applying it.

Specifications at a glance

Where it gets used

As an exterior stucco replacement

Ekoplast50 goes on walls the way stucco does, but the finished assembly weighs a fraction as much and adds thermal resistance the stucco never provided. On retrofits, especially older buildings where added dead load is a real constraint, that weight difference can be the deciding factor. On new construction, it means the wall finish is contributing to the building's thermal envelope instead of being thermally neutral.

For interior plastering

The same product handles interior walls and ceilings. Because it insulates and absorbs sound, interior partitions finished in Ekoplast50 do double duty: a bedroom wall, a shared demising wall between units, or a home office all benefit from the Rw 35 dB reduction without adding a separate acoustic layer to the assembly.

For wall repairs

Patching, resurfacing, and repairing damaged plaster or stucco is a natural fit. Repairs blend into the existing surface, and the low weight means you can build up thickness over damaged areas without loading the substrate the way a heavy cementitious patch would.

For subfloor leveling

This is where the compressive strength matters. At 2,562 psi, Ekoplast50 is strong enough to level and top a subfloor while adding thermal and acoustic insulation to the floor assembly at the same time. In multi-story residential and mixed-use buildings, noise transmission between floors is a persistent complaint, and a leveling layer that also insulates addresses two problems in one pour. Because it is light, it does so without the dead load penalty of a conventional gypsum or cementitious floor topping.

Wind and transverse load performance

Compressive strength tells you what the material can carry underfoot. Transverse load tells you what a finished wall can take from the side: wind pressure pushing against it, and wind suction pulling away from it. For any exterior application, that second number is the one the engineer cares about.

Ekoplast50 was tested as part of a complete wall assembly rather than as a bare material sample. The test panels measured 4 ft by 4 ft and were built the way a real wall gets built: wood framing, plywood sheathing, stucco mesh, and Ekoplast50 applied 3/4 in thick. The results:

• Positive load (pressure): 369.9 psf (17.7 kPa)
• Negative load (suction): 382.2 psf (18.3 kPa)

Two things stand out. First, the magnitude. These figures sit far above the design wind pressures that typical wall assemblies are engineered to resist, leaving substantial margin even in high-wind regions. Second, the assembly performed slightly better under suction than under pressure. That matters because negative pressure is usually the governing case in wind design: it is the force that peels cladding off walls in a storm, and it is where lightweight finishes are most often suspected of being the weak link. Here it is not.

At 3/4 in thick over a conventional framed and sheathed wall, Ekoplast50 delivers this alongside its thermal, acoustic, moisture, and fire performance, without the weight of stucco.

Fire performance: the torch test

Ekoplast50 is Class 1A fireproof and non-combustible. It does not burn, and it does not feed a fire or contribute fuel to one.

The clearest demonstration of what that means in practice is a direct torch test. A sample panel measuring 12 in by 12 in by 1 in thick was subjected to a torch flame on one face, bringing that surface to 1,200°C (roughly 2,190°F). On the opposite face of that same one-inch panel, the measured temperature rose to only 5°C above ambient room temperature.

One inch of material. A 1,200-degree difference across it.

That combination, non-combustible and profoundly insulating against heat transfer, is what allows Ekoplast50 to hold back a fire for hours, buying the thing that matters most in a building fire: time for occupants to get out and for responders to arrive. For multifamily buildings, commercial interiors, and any project where fire performance is part of the code path, a finish material that is itself non-combustible is a meaningful advantage.

Thermal performance

R-1.2 per inch in a plaster layer is meaningful for a simple reason: this is surface area that was already going to be covered. Every wall in the building gets a finish coat regardless. Choosing a finish that contributes thermal resistance means the envelope improves without adding a layer, a cavity, or a thickness that was not already in the plan. Because the value is per inch, thicker applications scale the benefit accordingly. Over a full building exterior, that is a lot of square footage doing work it was not doing before.

Water resistance and breathability

This is the pairing that separates Ekoplast50 from a lot of exterior coatings. Ekoplast50 prevents liquid water from passing through. Rain, splash, and wind-driven moisture stay on the outside of the wall. But it is also vapor permeable at 3.49 perms, which means water vapor generated inside the building can still move out through the assembly.

For anyone working from the code side, 3.49 perms places Ekoplast50 in the Class III vapor retarder range of 1 to 10 perms, the semi-permeable category. That is the range specified precisely when an assembly needs to shed bulk water while still drying outward, and it is the behavior most exterior wall assemblies are designed around.

Coatings that block water in both directions trap moisture inside the wall, and trapped moisture is how mold and mildew get started. By stopping liquid water while letting vapor escape, Ekoplast50 lets the building breathe, keeps the wall assembly dry from the inside out, and removes the conditions that mold and mildew need to take hold. Over the life of the building, that is a durability and indoor air quality benefit, not just a moisture one.

Glass beads, not silica

Most conventional plasters and stuccos use silica sand as aggregate. Cutting, mixing, and sanding silica-bearing materials generates respirable crystalline silica dust, a well-documented occupational hazard that OSHA regulates closely and that puts real compliance burdens on contractors.

Ekoplast50 uses glass beads instead. The benefit runs in two directions:

• Worker safety. No crystalline silica means the health risk and the associated exposure-control burden simply are not part of the job.
• Performance. The bead structure delivers better strength and better insulating value than sand aggregate, which is a large part of how the material achieves 2,562 psi at a quarter of stucco's weight.

It is rare that the safer option is also the better-performing one. Here it is.

Why the weight matters

It is worth returning to the weight, because it is the property that makes everything else practical.

• Structural: A quarter of the weight of stucco means dramatically less dead load on walls, floors, and framing, often the difference between a retrofit being feasible and not.
• Labor: Lighter material is faster to mix, carry, and apply. Crews move more square footage in a day and finish it with less fatigue.
• Logistics: Less weight per square foot of coverage means lower freight costs and fewer pallets to stage on a tight jobsite.
• Design flexibility: Where load budgets are tight, on upper floors, older structures, cantilevers, and additions over existing framing, light weight opens up options that heavy finishes close off.

Availability

Ekoplast50 is distributed in the United States by KemsetUSA, with stock available in California and Texas and shipping to the continental USA.

Whether you are specifying an exterior finish for new construction, re-skinning an existing building, leveling a subfloor in a multi-story project, or looking for a plaster that brings insulation, moisture control, and fire resistance along with it, Ekoplast50 is worth putting on the shortlist.

Contact KemsetUSA for pricing, technical data sheets, and availability in your area.