The P4 door delivers STC ratings of 36-49 — significantly better sound control than hollow-core options that plague Montana’s multi-family projects. The drop-in core design allows contractors to trim up to 1” from both top and bottom rails, providing crucial jobsite flexibility when old frames don’t quite match new doors. At 1-3/4 inches thick with a solid particleboard core, it’s built for the commercial and multi-family applications driving Montana’s urban construction boom.
This door shines in apartment buildings, office tenant improvements, and anywhere sound transmission between spaces costs money in complaints and callbacks.
Sound Control That Actually Works
STC 36-49 range depends on installation and gasketing, but even the low end beats hollow-core doors by a wide margin. That 36 STC minimum blocks normal conversation from adjacent rooms. Hit the 49 STC upper range with proper gasketing and installation, and you’re approaching luxury hotel standards.
The particleboard core designated ‘P4’ provides the mass needed for acoustic performance. Sound waves can’t rattle through solid particleboard like they do through honeycomb cardboard cores. This improved sound control over hollow-core options makes the P4 worth every penny in multi-family housing where tenant satisfaction drives renewals.
| Specification | Value | Source |
|---|---|---|
| STC Rating | 36-49 | manufacturer |
| Core Type | Solid Core, Drop-in (loose-lay) | manufacturer |
| Core Material | Particleboard (designated ‘P4’) | manufacturer |
| Thickness | 1-3/4 inches (44.45 mm) | manufacturer |
Jobsite Flexibility Built In
Allows for site trimming of up to 1” on each end — that’s 2 inches total adjustment. Old building settling? Slightly out-of-square frames? The P4 handles it. Top and bottom rails measure 2” – 2-1/4” after trim, maintaining structural integrity even after maximum field modification.
The drop-in core design allows for on-site hardware preparation, glazing, and vision lite cutouts. Forgot to order the door with a window? Cut it on site. Need to relocate the lockset bore? No problem. This flexibility matters on remodel projects where surprises lurk behind every wall.
Environmental Compliance Without The Headaches
CARB Phase II compliant and TSCA Title VI compliant certifications mean these doors pass muster on government projects, schools, and healthcare facilities. FSC certification available upon request for LEED projects. Indoor Advantage Gold (2025) certification confirms low emissions for indoor air quality.
Montana’s growing institutional construction market demands these certifications. The P4 delivers them without special ordering or documentation hassles.
| Certification | Status |
|---|---|
| CARB Phase II | Compliant |
| TSCA Title VI | Compliant |
| FSC | Available upon request |
| Indoor Advantage Gold | 2025 |
| SCS EPD | Available |
Face Options and Applications
Face options include Prefinished Hardboard (Smooth, Textured/Rift-cut, Embossed), Molded Panel (raised or flat profiles), Wood Veneer, and Primed Hardboard. The range covers everything from basic apartment doors to upscale office suites.
Applications span interior residential passage doors, interior residential bifold doors, light-commercial interior applications (offices, tenant improvements), and multi-family housing projects. Suitable for interior use only — don’t try to use these as exterior doors.
Installation Requirements
Compatible with standard 1-3/4” interior door frames and standard hinges, locks, and surface-applied moldings. No special hardware required.
Gasketing must be properly installed per manufacturer’s instructions to achieve stated STC ratings. Skip the gasketing or install it wrong, and that 49 STC promise drops to 36 or worse. Proper installation separates professional results from amateur hour.
Warranty Coverage
1-Year Limited Warranty applies to Standard Construction interior doors for typical interior residential and light-commercial use. Standard warranty for this construction grade — nothing exceptional but adequate.
The Bottom Line
The P4 earns its place in multi-family and light commercial projects through genuine performance advantages. That STC rating range tackles real-world sound complaints. The trim allowance solves jobsite headaches. The drop-in core enables field modifications that would require door replacement with bonded-core alternatives.
Professional contractors praise particle board cores for their stability and insulating qualities, making them suitable for various residential and commercial settings. These doors provide enhanced soundproofing and insulation compared to hollow core doors, with versatility in use cases such as interior office doors, hotel rooms, or residential spaces.
Not the cheapest door on the rack. But for Montana’s booming multi-family market and tenant improvement projects, the P4’s combination of acoustic performance and jobsite flexibility makes it worth the upgrade from basic hollow-core options.
Frequently Asked Questions
What’s the actual difference between STC 36 and STC 49?
STC 36 blocks normal conversation but loud voices still penetrate. STC 49 approaches luxury hotel standards where even shouting becomes muffled. The range of 36-49 varies by installation and gasketing — proper perimeter seals make the difference.
Can I really trim a full inch off each end without problems?
Yes. The rails measure 2” – 2-1/4” after maximum trim, maintaining enough material for structural integrity and hardware mounting.
How does P4 compare to the P20 fire-rated version?
P4 is non-rated; P20 adds a 20-minute fire rating using a similar particleboard core. Use P4 where sound control matters most, P20 where code requires fire ratings.
Does the particleboard core handle Montana’s humidity swings?
The particleboard core provides improved rigidity compared to hollow-core doors. Particle board cores are praised for their stability, making them suitable for Montana’s variable humidity conditions when properly finished and sealed.
What face options work best for high-traffic commercial use?
Prefinished Hardboard and Primed Hardboard options are resistant to wear and easy to maintain — ideal for commercial applications where doors take daily abuse.
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