Repair and replacement · Rolling Shutter Guide
How do I replace the bottom bar (base slat) on a rolling shutter, including a locking one?
Raise the shutter, take off the box cover and remove any stops on the back of the bottom bar. Roll the curtain up slightly, lift the bar out past the entry guides, remove its end fastener, slide the old bar off the last slat's hinge and the new one on, then reassemble and test.
Key facts
- Roll-A-Shield's bottom-bar tutorial uses a #2 square bit for the cover (two screws each side), a Phillips driver for the two conical-stop screws and a 5/16 in driver for the bar's end fastener. Roll-A-Shield data
- Tighten the end fastener only until it is snug: the bushing under it has to stay free to turn so the bar can roll with the curtain. Roll-A-Shield data
- Put the conical stops back on snug; stops left loose work themselves off. Roll-A-Shield data
- Key, thumb-turn and slide locks on the bottom bar are a manual-shutter option; Roll-A-Shield does not offer them on motorized shutters. Roll-A-Shield data
- A key or thumb-turn lock on the bottom bar pushes two locking pins sideways into the guide rails rather than down into the sill. Roll-A-Shield data
- For a gap under a closed shutter, Roll-A-Shield's fix is a bottom slat with a thicker built-in seal, about 3/8 to 1/2 in. Roll-A-Shield data
Applies to: Manual rolling shutters whose bottom bar slides onto the last slat's hinge and is held by an end fastener. The steps follow Roll-A-Shield's tutorial on a 63 mm single-wall spring-loaded shutter with a key-lock bottom bar. Motorized shutters and bars without an end fastener differ: call before starting.
The bottom bar (also called the base slat or end slat) is the last slat at the foot of the curtain. It carries the lock on a manual shutter and the seal against the sill, and it is replaced on its own when it is damaged or when the lock or seal needs to change. Following this Roll-A-Shield guide does not void your warranty; mains wiring must be done by a licensed electrician.
The steps below follow Roll-A-Shield's service tutorial, filmed on a 63 mm single-wall spring-loaded shutter with a key-lock bottom bar. If your bottom bar has no fastener at its end, read the section on bars without an end fastener before you start.
When does a bottom bar need replacing?
Replace the bar when it is bent or dented, when its lock is damaged, or when you want a different lock or seal. If the curtain has come out of a rail or bunched up, check Shutter came out of its guide rail first: the bar may be fine.
| Problem | Likely cause | Fix |
|---|---|---|
| Bar bent, dented or cracked | Impact, or the shutter closed on something | Replace the bar (this page) |
| Lock will not turn, or every key is lost | Damaged lock, or no original key left to copy | New lock plate; see Lost keys and rekeying |
| Light or a gap under the closed shutter | Bottom seal too small for the gap, or rails cut short in the field | A bottom slat with a thicker seal (below) |
What tools and parts do I need?
- A drill or driver with a #2 square bit for the box cover
- A Phillips screwdriver for the two conical-stop screws
- A 5/16 in nut driver or socket for the bar's end fastener
- A ladder, and a helper to hold the roll on a heavier shutter
- A replacement bar made for your slat profile, color, width and lock
How do I replace the bottom bar?
- Raise the shutter so the bottom bar sits just below the box.
- Take out the front cover screws with a #2 square bit (two on each side on the tutorial unit) and set the cover and screws aside.
- On the back of the bottom bar, take out the two Phillips screws that hold the conical stops and remove the stops. They press on the roll and fill the box, and with them on the bar is hard to get out.
- Keep one hand on the roll at the top and one on the bottom bar. Roll the curtain up slightly while lifting the bar, until it clears the entry guides at the top of the rails, then pull it toward you.
Safety: On a heavier shutter, have a helper hold the tube from this step on so the roll cannot come down on you, and keep someone holding it while the bar is off.
- With a 5/16 in driver, remove the fastener at the end of the bar. The fastener and its bushing come out in one piece.
- Slide the bar off sideways, in the direction the fastener came out.
- Line up the hinge of the new bar with the hinge of the last slat and slide the bar all the way across, to the lock.
- Refit the fastener and bushing. Snug it until the bar cannot move, but stop while the bushing can still turn: the bushing is there to roll with the curtain.
- Roll the curtain up slightly while tucking the bar back past the entry guides, and let it down into the rails.
- Refit the conical stops: push the threaded bolt and its washer through from the back, start the stop on the thread, then run the bolt through. Make them snug, because loose stops work themselves off.
- Seat the top of the cover first, then refit the cover screws.
- Lower the shutter all the way and test the lock.
What if the new bar will not go back into the rails?
If there is not enough clearance above the rails to drop the bar straight in, hold the bar, push it over the top of the rail opening and guide it down into the rail. Run the shutter down and up to check it. The same move is used when a whole slat roll is replaced: the roll is wound up, the bottom slat is pushed back into the rails, and the shutter is lowered so the slats feed through the tracks.
How is a locking bottom bar different?
A locking bar carries the lock. Turning a key or a thumb-turn pushes two locking pins sideways into the guide rails, so the curtain locks to the rails rather than to the sill. Because the pins go into the rails, the rails have holes or notches cut for them, and Roll-A-Shield checks those cut-outs before a locking shutter ships. A replacement locking bar has to line up with the cut-outs your rails already have, so order it with the shutter's details rather than as a generic part.
What Roll-A-Shield offers, by slat:
| Slat | Bottom-bar lock options |
|---|---|
| 38 mm insulated (mini) | Slide lock |
| 55 mm insulated (standard) | No lock option |
| 63 mm single-wall | Key lock, or thumb-turn lock (not on black or metallic bottom bars) |
| Motorized shutters, any slat | None as standard |
Spring-loaded shutters are ordered with a lock whenever one is available for the slat, and the lock can sit on the box side or the back side of the bar. On a spring-loaded single-wall shutter the bar also carries a full-width aluminum angle that works as a continuous handle, and it stops against a lip on the bottom of the box when the shutter is raised.
What if my bottom bar has no end fastener?
Roll-A-Shield's tutorial shows the single-wall bar, which is held by an end fastener and bushing. Foam-filled (insulated) curtains use plastic plugs at the slat ends instead, and Roll-A-Shield frees a foam-slat joint by clipping that plug at the hinge with side cutters. On the 38 mm insulated curtain the bottom bar also has a weight bar fitted inside it. If yours has no end fastener, call (480) 921-0200 before cutting anything.
Can a new bottom bar close a gap under the shutter?
Often, yes. Roll-A-Shield's fix for a gap under a closed shutter is a bottom slat with a larger built-in seal, about 3/8 to 1/2 in thick. If the rails reach the sill and a gap of about 3/4 in remains, the rails may have been cut down in the field during installation, rather than the bar being faulty. For seals that slide into the bar, see Replacing weather seal, entry guides and end caps.
What next
Bottom bars are made to order: call (480) 921-0200 with the bar width, slat type, color and lock, or a photo. In metro Phoenix, Roll-A-Shield's service team can replace it for you.
Watch it done
Service tutorial: replace the base slat on a spring-loaded shutter
The written steps on this page are the reference; the video shows the same job.
Frequently asked questions
Can I buy a bottom bar in the parts store?
A bottom bar has to match your slat profile, color, width and lock, so it is made to order. Call (480) 921-0200 with the width of the bar, the slat type and the lock you have, or send a photo.
My shutter is motorized. Can I add a key lock to the bottom bar?
Not as a standard option: Roll-A-Shield builds bottom-bar locks for manual shutters only, so call (480) 921-0200 to ask about yours.
I lost every key to my bottom-bar lock. Do I need a whole new bottom bar?
Not always. A key can be copied from an original. If none is left, the standard bottom-bar lock cannot be rekeyed, so Roll-A-Shield supplies a new lock plate for the bottom slat rather than a whole new bar.
The new bar will not drop back into the rails. What now?
If there is not enough room above the rails to drop the bar straight in, hold the bar, push it over the top of the rail opening and guide it down into the rail, then run the shutter down and up to check it.
Parts and next step
Need a part or a hand?
Replacement motors, remotes, straps, slats and hardware ship from our Tempe, Arizona factory. Phoenix-area owners can book a service visit; everywhere else, our technicians help by phone. Call (480) 921-0200; the factory answers technical questions for any rolling shutter, not only ours.