What Is ACRE by Modern Mill? A Builder’s Perspective on an Innovative Wood Alternative

At Kasay Construction, we’re constantly evaluating building materials that offer a better combination of performance, durability, and design flexibility.

One product we’ve found particularly interesting is ACRE by Modern Mill, a wood-alternative building material manufactured from recycled rice hulls and PVC.

ACRE offers some of the workability and appearance of traditional wood, with added resistance to moisture, rot, and insects. But like any building material, understanding its properties and installation requirements is essential to getting the best results.

Here’s what we’ve learned about ACRE, where we see value in using it, and what builders and homeowners should know before incorporating it into a project.

What Is ACRE Made Of?

ACRE is a composite building material manufactured by Modern Mill in Mississippi.

Its primary ingredients are upcycled rice hulls—the protective outer husks removed during rice processing—and a PVC resin that binds the material together.

Rice hulls are an agricultural byproduct, so using them in building materials creates another purpose for a resource that might otherwise be discarded.

The finished material has a wood-like texture and can be cut, shaped, and machined using conventional woodworking equipment.

ACRE is available in several forms, including:

• Trim boards and millwork

• Sheet goods

• Siding and exterior cladding

• Decking and porch flooring

• Decorative architectural components

Although ACRE contains a significant amount of recycled agricultural material, it’s important to understand that it is still a PVC-based composite, not natural wood or a completely plant-based material.

That distinction matters when considering how the product moves, fastens, and accepts finishes.

Why We Use ACRE

There isn’t a single material that’s ideal for every application. We believe good construction comes from understanding the strengths and limitations of different products and selecting them accordingly.

ACRE offers several characteristics that make it worth considering.

1. Moisture and Rot Resistance

One of ACRE’s most compelling properties is its resistance to moisture-related deterioration.

In coastal environments like the South Carolina Lowcountry, high humidity, wind-driven rain, and prolonged exposure to moisture can create significant challenges for traditional wood products.

Unlike natural wood, ACRE is engineered to resist rot and moisture damage.

That makes it an interesting option for properly detailed exterior trim, siding, and other applications where moisture exposure is a concern.

Of course, moisture-resistant trim doesn’t eliminate the need for good water management. Proper flashing, drainage, and detailing remain essential regardless of the finish material.

2. Workability and Design Flexibility

ACRE can be worked using many of the same tools used for conventional carpentry.

It can be cut, routed, shaped, and fabricated into custom architectural details without requiring highly specialized equipment.

That’s particularly useful in renovations and custom construction, where matching existing conditions often requires creativity rather than relying on off-the-shelf products alone.

3. Architectural Appearance

Many synthetic building materials perform well but don’t offer the texture or appearance desired for certain architectural styles.

ACRE has a wood-like grain that can be painted or stained, providing flexibility for different design applications.

For traditional homes, that flexibility matters. Modern materials still need to complement the architecture rather than detract from it.

4. Using an Existing Resource Differently

We also appreciate the concept behind ACRE’s manufacturing process.

By incorporating rice hulls into a useful building product, Modern Mill has found a way to utilize an agricultural byproduct while reducing reliance on harvested wood for certain applications.

Sustainability is more complicated than any single product claim, and material selection should account for durability, manufacturing, maintenance, and eventual disposal.

Still, finding productive uses for recycled materials is something we believe deserves consideration.

A Recent Application: Matching Existing Custom Doors

We recently encountered a situation where four new doors needed to match an existing custom architectural design.

Having four new doors fabricated would have cost approximately $3,000–$4,000 per door.

Instead, we started with standard single-panel doors and recreated the existing decorative pattern using ACRE.

Its workability allowed us to fabricate the applied detailing and achieve the architectural appearance we needed without commissioning entirely custom doors.

The finished solution cost approximately $4,000 for all four doors.

While the cost difference was substantial, the more important takeaway was the ability to preserve the existing architectural design through thoughtful material selection and fabrication.

It’s a good example of why we enjoy exploring alternative building materials: sometimes they open up solutions that wouldn’t otherwise be obvious.

How Do You Paint or Stain ACRE?

This is where understanding the material becomes especially important.

Although ACRE can be painted or stained, it does not absorb finishes the same way natural wood does.

The manufacturer has specific requirements for compatible coatings, and those requirements are especially important for exterior applications.

Does ACRE Need Primer?

According to Modern Mill, ACRE can be painted or stained without primer when an appropriate, approved finishing system is used. That’s a useful feature, but it doesn’t mean every paint or stain will perform correctly.

The coating itself still needs to be compatible with the composite material.

Use Approved Water-Based Coatings

Modern Mill specifies water-based paint and stain systems from its approved coatings list.

Before choosing a finish, we recommend reviewing the manufacturer’s current coating recommendations rather than assuming a product that works well on wood or conventional PVC trim will also work on ACRE.

For stained applications, the same principle applies. ACRE’s surface behaves differently from porous wood, so conventional penetrating wood stains shouldn’t automatically be considered compatible.

We also recommend producing a finish sample before proceeding with a larger installation.

Pay Attention to Paint Color and Solar Heat

One of the most important considerations for exterior ACRE is the color of the finish.

Modern Mill generally requires approved coating colors with a Light Reflective Value (LRV) of 55 or greater. Darker colors require additional manufacturer approval.

LRV measures how much visible light a color reflects, on a scale of 0 to 100.

Lighter colors typically reflect more light, while darker colors absorb more solar energy.

Why does that matter?

ACRE contains PVC and responds to temperature changes through expansion and contraction.

A dark finish exposed to direct sunlight can increase the temperature of the material, potentially contributing to dimensional movement, distortion, or other performance issues if the proper coating system and installation details aren’t used.

This becomes particularly important in warm climates and highly exposed locations.

Specially formulated darker coatings may be possible, but they should be evaluated and approved for the application rather than selected based on appearance alone.

Should ACRE Be Finished Before Installation?

Modern Mill recommends applying finishes while boards are laid flat whenever practical.

This helps maintain consistent coating thickness and appearance, particularly with stains and clear finishes.

Finishing after installation is possible, but greater care may be needed to avoid uneven application.

Regardless of when the finish is applied, following the coating manufacturer’s surface preparation, application, and curing requirements is essential.

Can ACRE Be Left Unfinished?

ACRE doesn’t require a coating simply to prevent the type of rot associated with untreated wood.

However, that doesn’t necessarily mean leaving it unfinished is the best choice for every project.

Exterior UV exposure can change the appearance of the material over time, including fading.

An approved UV-resistant finish can help preserve its appearance and simplify cleaning.

For a project where color consistency and long-term appearance are important, we’d generally prefer to establish a finishing strategy before installation.

Installation Considerations Beyond the Finish

Finishing isn’t the only area where ACRE differs from wood.

Thermal movement: ACRE expands and contracts in response to temperature. Proper spacing and fastening must account for installation temperature and the selected finish.

Adhesives: Modern Mill identifies compatible PVC cements, polyurethane adhesives, and construction adhesives for appropriate applications. Conventional wood glue is not recommended.

Fasteners: The manufacturer’s installation guides specify acceptable fastening methods and prohibit certain fasteners, including brads and finish nails, for standard product installations. Custom architectural applications should be reviewed for suitable attachment details.

Surface preparation: Light surface imperfections may be addressed by sanding with 120-grit abrasive in the direction of the grain. Modern Mill cautions against aggressive sanding and orbital sanders because they can alter the surface texture.

The details matter. ACRE may resemble wood and work with familiar tools, but it shouldn’t automatically be installed using every method associated with traditional lumber.

Is ACRE Better Than Wood?

That depends on the application.

Natural wood remains an excellent building material. It offers unique character, established fabrication methods, and a long history of successful use when properly selected, protected, and maintained.

ACRE provides an alternative where moisture resistance, dimensional consistency, or specific fabrication opportunities may justify using a composite.

There are trade-offs, too.

It has different thermal movement characteristics, requires attention to compatible finishes, and may not be the most economical choice for every application.

For us, the question isn’t whether ACRE should replace wood altogether.

It’s whether ACRE offers meaningful benefits for the specific architectural detail, exposure conditions, and performance requirements of a project.

Our Approach to Building Materials

At Kasay Construction, we’re interested in materials that solve real problems.

Sometimes that’s a high-performance insulation system, an improved water-management detail, or a more durable exterior finish.

Other times, it’s something as straightforward as using an alternative material to replicate an existing architectural feature.

We don’t believe innovation means selecting the newest product simply because it’s new.

It means understanding how a material performs, where it makes sense, and how to install it correctly.

ACRE by Modern Mill is one of several materials we’re continuing to explore as we look for better ways to combine architectural craftsmanship with durable, thoughtful construction.

Because better building often begins with asking whether there’s a better way to approach the details.

Considering a custom home or renovation in Bluffton, Hilton Head Island, or the surrounding Lowcountry? Kasay Construction brings a thoughtful, performance-focused approach to residential construction, from material selection to the smallest architectural details.