What Is Garage Door Sideroom?

What sideroom means

DASMA’s terminology sheet defines sideroom as a horizontal measurement from each side of the door opening, outward to the nearest obstruction ¹. The same sheet lists “return” as another name for it ¹.

Clopay describes the measurement from the inside edge of the door opening to the nearest wall or obstruction, and says to take it at several heights, because pipes, storage or an uneven wall can get in the way partway up ².

It is one of the three clearances that decide what door hardware fits, alongside headroom above the opening and backroom into the garage ¹.

What uses the sideroom

The vertical track runs up each side of the opening, set just inside the jamb. It is fastened to the jamb either with separate jamb brackets or with a full-height continuous angle. DASMA calls these bracket-mounted and angle-mounted track ¹.

Track also sits at a slight angle. DASMA describes “inclined track”: tapered spacing of the vertical track away from the jamb so the door closes tight against the stop and releases easily when opening ¹. That taper adds a little width at the top.

Springs can use sideroom too. On an extension spring door the springs run along the horizontal tracks, and their pulleys and cables sit beside the track ¹. Some torsion designs put winders at the ends of the shaft, which need room past the track.

Sideroom by track setup (one maker’s published specs)

Measurement worksheet: a worked example

A sample single-car opening with a water heater near the right wall. Requirements from Clopay’s published track specs ².

The right side’s 5 inches decides the options. A standard or front-mount setup fits; a rear-mount low-headroom setup does not. Write down both sides and add the headroom reading before you ask for quotes.

How to measure sideroom

Safe to do with the door closed. Measure only; do not touch the track, springs or brackets ³.

1. Find the inside edge of the opening on the left: the face of the jamb.
2. Measure straight out to the side wall at floor level, at about 4 feet, and near the top of the opening.
3. Look for anything closer: pipes, a water heater, shelving, a support post, an electrical panel or a door frame.
4. Record the smallest number for the left side.
5. Repeat on the right side.
6. If two doors share a wall, measure the post between them; DASMA calls a structure between two single doors a center post ¹.

Sideroom on double openings and two-door garages

A two-car garage can have one wide door or two single doors. With one wide door, sideroom is measured at the two outer jambs only. With two single doors, each door needs its own track on both sides, so the post or wall between them must hold two vertical tracks back to back.

DASMA calls the structure between two single doors a center post ¹. Its width matters as much as the outer sideroom. A post that is too narrow for two tracks and their brackets forces a different mounting method or a narrower door.

Some commercial garages use a removable center post, which DASMA defines as a post and track assembly that substitutes for a jamb in a wide opening so two doors can share it, and that can be carried away when needed ¹. Homes rarely use one, but you may see it in a converted shop.

If you are replacing two single doors with one double door, the center post goes away and the sideroom question moves to the outer walls only. That swap also changes the header span, which is a framing question for a builder, not a door question.

Sideroom and opener choice

A trolley opener hangs from the ceiling in the middle of the door, so it uses no sideroom.

A wall-mount opener is different: it bolts to the wall beside the door at the end of the torsion shaft.

It frees the ceiling, but it needs clear wall space next to the track on one side, plus an outlet nearby.

DASMA notes that wall-mount (jackshaft) openers on standard-lift doors need the door maker’s provisions to keep the cables tight, because they move the door by turning the shaft rather than pulling the top section ⁸.

So the choice is not only about space. Ask the installer which openers the door maker approves for your track.

Good sideroom vs tight sideroom

What a sideroom number does not tell you

A sideroom figure does not tell you whether the jamb is solid. Track brackets fasten to the jamb, and DASMA publishes separate guidance on connecting jambs to building framing (TDS-161) and on back-jamb details ⁹. A wide space beside a weak jamb is still a problem.

It also does not account for the opener. A wall-mount opener sits beside the door at the end of the torsion shaft and needs its own clearance, which comes from the opener’s manual, not the track chart.

And it does not tell you about wind hardware. Doors in high-wind zones can carry vertical reinforcement and different track; DASMA TDS-153 covers vertical reinforcement for wind load ⁷.

How sideroom affects cost

No prices here; see the cost guide. Sideroom-related drivers:

• Moving an obstruction such as a pipe or water heater vent is separate trade work.
• Special mounting such as reverse-angle mounts for restricted sideroom ¹.
• Jamb repair or new framing if the existing jamb cannot hold the track.
• Spring system choice driven by available room.

How an installer works with limited sideroom

1. Measures both sides at several heights.
2. Checks the door maker’s chart for which track mounts fit.
3. Considers a reverse-angle mount, which DASMA says is used in sideroom-restricted garages ¹.
4. Confirms jamb strength and fastening.
5. Installs and runs the door through full cycles to check that nothing rubs.

Keeping sideroom clear

• Keep shelving, bikes and tools a hand-width away from the vertical tracks.
• Do not hang anything on the track or its brackets.
• If something hits the track, watch for a bent section. DASMA TDS-174 lists track misalignment and loose fasteners as things to check ³.

Risks when sideroom is too tight

Crowded track can get knocked out of line by storage, a bike or a car door. A bent or loose vertical track can let rollers bind or jump. Signs include scraping, a door that shudders on one side, or a gap at one jamb when closed.

If the track looks bent or loose, stop using the door. DASMA advises that any deformation of tracks or hardware makes a door questionable and calls for a trained technician ³.

Rules that touch sideroom

Building codes do not set a sideroom number; the door maker’s instructions do. Sideroom does matter for opener controls. DASMA’s checklist says wall controls should be in clear view of the door, at least 5 feet up, and safely away from moving parts, so they should not end up crammed beside the track ⁵.

For wind-rated doors, the certified installation drawing controls the track and jamb fastening. Substituting parts that are not identical can void the certification ⁶.

Sideroom vs related terms

Myths about sideroom

Myth Only one side matters.

Reality Both sides need room; the tighter side decides ¹.

Myth Measure at the floor and you are done.

Reality Pipes and shelves can intrude higher up; measure at several heights ².

Myth Every setup needs the same space.

Reality Rear-mount low headroom needs more than standard track ².

Regional differences

What to do with your sideroom number

If both sides have more than about 5 inches clear the full height, most residential setups fit. If one side is under about 4.5 inches, ask about reverse-angle mounting or moving the obstruction.

If you also have tight headroom, check that the rear-mount option still fits your sideroom. Then compare quotes that name the track setup; see track lift types.

Related terms

Headroom

Garage door headroom is the clear vertical space between the top of the door opening and the lowest obstruction above it, such as a ceiling, beam, pipe or light.

Backroom

Garage door backroom is the horizontal depth measured from the door’s mounting surface back into the garage to the first obstruction, which the open door, tracks and opener must fit inside.

Vertical Track

The vertical track is the upright section of garage door track fastened beside each side of the opening, which guides the door’s rollers from the floor up to the curved radius section.

Garage Door Jamb

A garage door jamb is the upright framing member on each side of the door opening, to which the vertical tracks, brackets and side weatherstrip are fastened.

Track Lift Type

Track lift type is the shape of the track a sectional garage door rides in, which sets the path the door takes as it opens: turning back under the ceiling early, late, or not at all.

Garage Door Rough Opening

A garage door rough opening is the framed hole in the wall that the door closes, measured as opening width between the jambs and opening height from the floor to the bottom of the header.

Extension Spring System

An extension spring system is a way of lifting a garage door with two long springs that stretch along the horizontal tracks when the door closes and pull back as it opens, through cables and pulleys.

Track Misalignment

Track misalignment is a fault in which a garage door’s vertical or horizontal tracks are bent, loose, out of plumb or not parallel, so the rollers bind, grind or leave the track instead of running freely.

Also referenced from: Garage Door Jamb, Garage Door Rough Opening, Vertical Track, Headroom, Backroom, Track Lift Type