Martin SI36 Fireplace Doors — Custom Exact-Fit Replacement
Replacement Doors for the Martin SI36 Fireplace
The Martin SI36 is a 36-inch wood-burning zero-clearance fireplace from Martin Industries of Alabama, produced in the 1980s and 1990s alongside the better-known SF36 and SA36. From the hearth, the SI36 presents the same nominal 36-inch radiant opening as its siblings, which is why aftermarket door fit lists bundle the SA36, SI36, SF36, and SF36I together as one door family. If any of those numbers is on your rating plate, the path to a proper set of doors is the same.
Find that plate before you order anything. It's a metal tag inside the firebox — look along the interior side walls near the top of the opening, or reach up behind the top edge of the front. Decades of fires often leave it smoked over or half-detached; if you can't read it, don't guess. A photo of the fireplace front is enough for a confident identification.
Sizing: Trust the Tape, Not the Model Number
Size charts place the SI36 opening around 36 inches wide by 19 3/8 inches tall — the same nominal figure as the SA36 and SF36. Your installed opening will not be exactly that. Refractory panels, hearth height, and the way tile or brick veneer was cut to the opening all move the real dimensions, sometimes by more than a door can forgive. Take the width at the top, middle, and bottom of the opening and keep the smallest; do the same for height at left, center, and right; then check the depth to the nearest obstruction inside the opening, like an old screen track. Our photo-illustrated measuring guide covers each step. If two of your numbers disagree, send both — raw measurements beat rounded ones every time.
Why There's No Factory Door to Buy
Martin Industries filed for bankruptcy in 2002, and its hearth assets were sold off in the aftermath. The factory glass door kits that matched these fireboxes never went back into production, and what's left in circulation is aging secondhand stock with no guarantees on glass, gaskets, or squareness.
That vacuum pulls people toward universal doors, and it's the wrong pull:
- Zero-clearance means inside-fit, full stop. The SI36 has a sheet-metal face with wood framing close behind the finished surround. An overlap-fit masonry door clamps to flat brick outside the opening — on a prefab there's nothing sound to clamp to, and the overlapping frame can trap heat against the face.
- Fixed sizes meet variable openings. An inside-fit door seats within the opening against the firebox flange. Stock doors come in steps; real openings don't. The gap between the two is either a door that won't seat or one that leaks air around its whole perimeter.
- The firebox was listed as a system. A door made for prefab fireboxes — tempered safety glass, correct shallow frame depth, no restriction of the unit's airflow — keeps the installation consistent with how the fireplace was designed and tested. An improvised door doesn't.
Rule These Out Before You Spend a Dollar
- No fires with the glass shut. Tempered glass isn't made for sustained direct flame heat. Doors stay fully open during the burn and close after the fire is out, when they block draft loss up the flue.
- No overlap-fit masonry doors. Nothing on a prefab face will anchor one safely, and the frame can hold heat against the sheet-metal front.
- No ordering "a 36-inch door" without measuring. 36 x 19 3/8 is nominal. Installed openings on this family vary house to house.
- No sizing from a sibling's numbers. A chart figure for an SF36 across town isn't your installed opening — even identical models measure differently once the surround goes on.
- No drilling into the firebox liner or refractory. Doors fasten at the front flange only; penetrating the box damages it.
The ExceptionalFire Route: Measured, Built, Installed
We build doors for orphaned prefab fireplaces every day, and Martin's 36-inch family is one of the most common fireboxes we fit. The workflow is deliberately short:
- Photo identification. Upload a shot of your fireplace to the AI Fireplace Expert and get the model confirmed from the face and frame style — no rating plate required.
- Instant pricing. Enter your measurements in the configurator on our prefab fireplace door collection, choose finish, glass, mesh, and handles, and watch the price update live as you build.
- Exact fabrication. Your door is made to the measurements you supply, to the 1/8 inch, with tempered safety glass and an inside-fit frame designed for zero-clearance fireboxes. It installs with basic hand tools — no welding, no masonry work, no contractor required.
Frequently Asked Questions
What size fireplace doors fit a Martin SI36?
An inside-fit prefab door sized to your measured opening. The SI36 is nominally 36 inches wide with an opening height around 19 3/8 inches, but we build to your actual numbers, not the chart — that's what makes the fit exact.
Does the SI36 use the same door as the SF36 and SA36?
Yes — aftermarket fit lists group the SA36, SI36, SF36, and SF36I together because the front opening design is shared. Measure your unit anyway; installed openings differ even between identical models.
Is it safe to burn with the glass doors closed?
Not with standard tempered glass on a prefab fireplace. Burn with the doors open; close them once the fire has died to stop the flue from drawing heated room air out of the house overnight.
What if my opening isn't square?
Common on this family, and exactly why we ask for width and height in three places each. Send every number — our specialists review measurements seven days a week and will flag anything that needs a second look before the door is built.
Put Doors Back on Your SI36
Grab a tape and our measuring guide, then configure your door with live pricing on the prefab fireplace door collection. Prefer to start with certainty? A photo in the AI Fireplace Expert confirms the model first, and our specialists are a message away, seven days a week.
Tracking down doors for another Martin? See the Martin SF36, Martin SA36, Martin SC36, Martin GD36B, Martin SF42, Martin SC42, Martin SA42, Martin BE42, and Martin SB4800.