Composite Siding — ACRE
ACRE Siding — What It Actually Is
A tree-free, stainable rice-hull composite — with a real fire-rating trade-off worth understanding before you choose it.
What It Actually Is
A Rice-Hull Composite, Not Pure Rice Hull
ACRE by Modern Mill is roughly half upcycled rice hulls — the shells discarded during rice processing — and half proprietary PVC-based resin and stabilizers. It's tree-free, formaldehyde-free, phthalate-free, and made in the USA. It cuts, routs, and stains like real wood, but resists rot and pests the way a composite does.
Worth knowing plainly: it's a newer product from a smaller manufacturer — the siding line launched in 2022. That's not disqualifying, but it's a shorter track record than more established siding categories.
Real Positives
- Only stainable composite siding in its category
- No silica dust when cut, unlike fiber cement
- No wood fiber for pests or moisture to attack
- Closed-loop manufacturing process
Worth Knowing Before You Choose ACRE
The Real Trade-Offs
Class B, Not Noncombustible
Combustible, unlike James Hardie's Class A rating. Only the Shiplap profile holds a CAL FIRE WUI listing — other profiles don't, and we verify per SKU before any fire-zone job.
Thermal Movement
The most consistently reported real issue — boards expand and contract more than fiber cement, and correct install-temperature gapping matters more here than with most materials.
Color Affects the Warranty
Coatings need a Light Reflectance Value of 55+ to stay under warranty — dark colors need Modern Mill's pre-approval, an easy detail to miss.
Profiles
Every ACRE Profile We Install
Shiplap Siding
WUI-ListedThe profile with a real CAL FIRE OSFM wildfire-zone listing — the only ACRE profile currently approved for WUI use.
Nickel Gap T&G
ModernTongue-and-groove boards with a consistent nickel-width reveal. No current WUI listing — verify separately if fire zoning applies.
Board & Batten
VerticalVertical boards with batten strips. Same material, no current WUI listing of its own.
Sheets & Millwork
CustomFull sheets for custom facades and architectural millwork, cut to spec.
Material Properties
What Actually Sets It Apart
Resists Rot, Pests & Moisture
Behaves like a composite, not raw wood — no wood fiber for insects or moisture to attack the way they attack cedar or LP.
Stains Like Real Wood
The only stainable composite siding in its category — takes color directly, no primer required. A real differentiator from most composites.
Works With Standard Tools
Cuts, routs, mills, and sands with ordinary woodworking tools — good screw retention, low dust.
Tree-Free Material Story
Roughly half upcycled rice hulls, half proprietary resin — made in the USA, formaldehyde-free, no added adhesives.
FAQ
ACRE Siding — Common Questions
ACRE by Modern Mill is roughly half upcycled rice hulls and half proprietary PVC-based resin and stabilizers — a rice-hull composite, not pure rice hull. It's tree-free, formaldehyde-free, and phthalate-free, made in the USA. Worth knowing if sustainability is your main reason for choosing it: some green-building commentary has pushed back on the PVC content specifically, arguing it complicates the eco pitch. We think that's a fair thing for a customer to weigh, not something to gloss over.
Only in one specific form. ACRE carries a Class B fire rating overall — combustible, not noncombustible like James Hardie. ACRE's Shiplap profile specifically holds a CAL FIRE OSFM listing for use in wildfire hazard zones, including Very High severity zones — a real and meaningful listing. That listing does not automatically extend to ACRE's other profiles (Nickel Gap, V-Groove, Board & Batten, trim). If you're in a fire hazard zone and considering ACRE, we confirm the current listing status for the exact profile before recommending it — never assume.
Yes, and it's an easy detail to miss. ACRE's warranty requires water-based coatings from Modern Mill's approved list with a Light Reflectance Value of 55 or higher — darker colors need pre-approval. Choosing a dark, low-LRV color without checking this first can put your warranty coverage at risk.
It's worth knowing going in: thermal movement is the most consistently reported issue with this product. ACRE expands and contracts with temperature more than fiber cement, and it requires install-temperature-specific gapping to account for it — darker colors make this more pronounced. Correct installation discipline matters more here than with most materials we work with.
ACRE is lighter, generates no silica dust when cut, and is the only siding in this category you can stain directly. Hardie is noncombustible where ACRE is combustible (Class B, Shiplap-only WUI listing), and has a longer track record in the broader market. If sustainability and stainability matter most to you and you're outside a fire hazard zone, ACRE is a legitimate option. If fire-zone eligibility matters most, Hardie is the safer choice on that specific point.
It's a premium-tier material — roughly $10-12 per square foot for material cost alone, similar to cellular PVC and generally at or above pre-finished James Hardie. We'll walk you through how it compares to your other options with a free on-site estimate.
Curious if ACRE is the right fit for your property?
Free, no-pressure estimates across Sacramento, the SF Bay Area, Sonoma County, and Lake Tahoe.
