Masonite Flush Series Interior Doors

The Masonite Flush Series delivers smooth-surface interior doors in both hollow and solid core configurations, with primed hardboard ready for paint or real wood veneer finishes. These doors serve everything from budget apartments to custom homes, with widths from 18” to 36” and multiple height options that fit Montana’s diverse housing stock.

Core Construction and Sound Control

The choice between hollow and solid core defines what these doors can do. Solid core provides Privacy Level 10/10 sound reduction — the difference between hearing every word of a conversation and blessed silence. That solid core construction packs 70% more material than hollow core doors, delivering the heft and sound dampening that matters in multi-generational homes where grandkids share walls with home offices.

Hollow core is lighter weight, more affordable, suitable for areas where sound transmission isn’t a priority like closets. These work fine for pantries and linen closets where privacy doesn’t matter and budget does. But stick them on bedrooms or bathrooms and homeowners will complain about hearing everything through the door.

The warp-resistant construction applies to both core types. Even Montana’s dramatic humidity swings from winter heating to summer air won’t twist these doors out of true.

Surface Options and Installation Reality

Primed (smooth white), ready for paint defines the base model that moves by the truckload. That pre-primed surface saves painters a full coat compared to raw doors. Some contractors grumble about priming quality can be inconsistent, but it beats starting from bare hardboard.

The wood veneer options — birch, oak, and mahogany veneer options — target higher-end installations where stain-grade finish matters. These cost more but deliver the natural wood look that paint can’t match.

Specification	Details
Width Range	18 x 80 in, 24 x 80 in, 28 x 80 in, 30 x 80 in, 32 x 80 in, 34 x 80 in, 36 x 80 in
Standard Height	80”
Additional Heights	84” and 96” options
Thickness	1.375 in (standard interior)
Trimming Limit	Maximum 1/2 inch from the bottom; excessive trimming voids warranty
Hinge Prep	Slab only (requires manual hinge routing); standard placement 5-7 inches from top, 10-11 inches from bottom

That half-inch trimming limit catches contractors who need to clear thick carpets or uneven subfloors. Go beyond it and Masonite won’t honor the warranty — period. Plan your rough openings accordingly.

Certifications That Matter

CARB Phase 2 compliant (on most models) keeps these doors legal for California projects and anywhere else that follows CARB standards. The SCS Global Indoor Air Quality (Low VOC) certified rating matters for health-conscious homeowners and green building programs.

For commercial work, Available with 20-minute fire-rating (Solid Core variations) opens up corridor and stairwell applications where code demands rated assemblies. That’s solid core only — hollow core won’t pass fire ratings.

Warranty Coverage

1-year limited (Hollow Core), up to 5-7 years limited (Solid Core depending on retailer/region) on the door slab itself. 1-year limited for Masonite applied finishes covers the priming or veneer. Covers manufacturing defects and workmanship under normal use.

The warranty length difference between hollow and solid core reflects the durability gap. Solid core doors last longer and Masonite knows it.

Frequently Asked Questions

What’s included with a Masonite Flush door slab?

Door slab only, No hinges included, No doorknob or bore (unless specified by retailer as ‘bored’), Requires paint or topcoat to finish. These arrive as blank slabs ready for hardware installation and finishing.

Can these doors work in bathrooms?

Yes. Bathrooms appears on the official application list. The primed hardboard surface handles normal bathroom humidity when properly painted. For heavy-moisture situations, solid core provides better long-term stability.

How much sound reduction do solid core doors actually provide?

Privacy Level 10/10 according to Masonite’s rating system. 70% more material than hollow core doors translates to meaningful sound dampening — enough to muffle conversations and TV noise between rooms.

What’s the real difference in feel between hollow and solid core?

Night and day. Hollow core version feels light/flimsy to some according to reviews. Solid core provides superior sound reduction and durability plus that satisfying weight when the door swings. The solid version closes with authority.

Do these doors require special installation considerations?

Fits standard finished door openings; compatible with standard 1-3/8 inch interior hardware. No special framing needed. Standard hinge mortising and bore prep apply. Circular saw (for trimming), Chisel/Router (for hinges), Paint/Stain tools covers the tool requirements.