Parts, boxes, rails and mounting · Rolling Shutter Guide
What is the bottom bar (base slat) on a rolling shutter, and which type do I have?
The bottom bar, or base slat, is the extruded slat at the foot of a rolling shutter curtain. It carries the seal that meets the sill and, on manual shutters, the stops, grip and lock. It matches the curtain: a mini bar for 38 mm slats, a standard bar for 55 mm, a heavier end-retention bar for manual single-wall.
Key facts
- Roll-A-Shield matches the bottom bar to the curtain: mini for 38 mm insulated, standard for 55 mm insulated, a heavier end-retention bar for 63 mm single-wall manual and spring shutters, and normally the mini bar for 63 mm motorized shutters. Roll-A-Shield data
- Every Roll-A-Shield shutter leaves the shop with a branded sticker on the bottom bar. Roll-A-Shield data
- The heavier single-wall bottom bar has a built-in weather seal about 3/8 to 1/2 in thick, and fitting it is the documented fix for a small gap at the sill. Roll-A-Shield data
- Manual 38 mm shutters get two stops on the bottom bar, and 63 mm crank-wand shutters two conical stops on its back. Roll-A-Shield data
- On 38 mm curtains a weight bar is fitted inside the bottom bar when the curtain is assembled. Roll-A-Shield data
Applies to: Rolling shutter curtains of any make; Roll-A-Shield 38 mm and 55 mm insulated and 63 mm single-wall and perforated shutters, manual, spring and motorized.
The bottom bar is the part of a rolling shutter that does the most work for its size. It meets the sill, takes the knocks, carries the seal, and on a manual shutter holds the lock and the stops. When a bottom bar or its seal is damaged, getting the right replacement starts with knowing which type it is.
What does the bottom bar do?
It finishes the curtain. The bottom bar is a single extruded slat at the bottom of the curtain, with a weather seal along its underside that presses on the sill, floor or threshold when the shutter is closed. Depending on the shutter, it also carries:
- the stops that keep a manual curtain from being drawn up into the box;
- handles, or a T-bar with a finger-pull slat, for gripping the curtain;
- the lock on manual shutters;
- a weight bar inside, on 38 mm curtains;
- Roll-A-Shield's branded sticker.
Which bottom bar goes with which slat?
The curtain decides it, and on Roll-A-Shield shutters the order system picks it automatically.
| Curtain | Operator | Bottom bar |
|---|---|---|
| 38 mm insulated | Any | Mini bottom bar |
| 55 mm insulated | Motor | Standard bottom bar |
| 63 mm single-wall or perforated | Strap, crank or spring | Heavier end-retention bottom bar |
| 63 mm single-wall or perforated | Motor | Mini bottom bar as standard; the end-retention bar is an option |
You can often tell the two main styles apart by their hardware: the heavier bar carries a T-bar with a finger-pull, while the lighter bars have handles fitted instead. For a replacement, a photo of the end of the bar and the width of the shutter are the quickest way to identify it.
What is the weight bar?
On Roll-A-Shield's 38 mm curtains, a weight bar is fitted inside the bottom bar when the curtain is assembled, along with the end plugs for the bottom bar.
What seals are on the bottom bar?
A seal runs along the underside of every bottom bar and seals the bottom edge against light, dust, drafts and wind-driven rain when the shutter is closed.
- Current bottom seal. Roll-A-Shield's current bottom seal fits all of its current bottom bars. It sits in a slot along the bar and can be removed.
- Thicker built-in seal. The heavier single-wall bottom bar comes with a larger built-in seal, about 3/8 to 1/2 in (10 to 13 mm) thick, and replacing the bottom bar with that type is the documented fix for a small gap at the bottom of a closed single-wall shutter; ask whether it suits your curtain before ordering.
Fitting a different, aftermarket seal is something to check with Roll-A-Shield first. Sizes for the seals and the rail felt are on Weather seal and rail felt sizes.
What are the stops on the bottom bar?
Small stops on the bottom bar that keep a manual curtain from being pulled up into the box. Roll-A-Shield's manual 38 mm shutters (strap, crank, crank wand and spring) get two stops on the bottom bar, and 63 mm crank-wand shutters get two conical stops screwed to the back of the bar. For a missing or broken stop, call (480) 921-0200.
How is a bottom bar replaced?
By sliding the old bar off the end of the curtain and a new one on. On a 63 mm spring shutter with a key lock, for example, the steps are: take off the box cover; remove the two conical stops from the back of the bottom bar; roll the curtain up a little while lifting the bottom bar past the entry guides at the top of the rails; take out the fastener that holds the bar; slide the old bar off and the new one on; then refit the fastener, stops and cover and test the lock.
Safety: On a heavy curtain, have a helper hold the roll while the bottom bar is out of the rails.
The full procedure, including locking bars, is in How to replace the bottom bar (base slat).
Why is there a gap under my closed shutter?
Possible causes include a shutter that stops short, a seal that is worn or too thin for the sill, rails shortened when the shutter was installed, or a sloped sill.
| Symptom | Likely cause | Fix |
|---|---|---|
| Motorized shutter stops above the sill | Bottom limit set too high | Reset the bottom limit; see Shutter stops too high, too low, or leaves a gap |
| Small, even gap with the seal touching nothing | Seal worn, or too thin for the sill | New seal, or, where it suits the curtain, a bottom bar with the thicker built-in seal |
| Rails touch the sill but the gap "grew" after installation | Rails cut short in the field | Call (480) 921-0200; this is an install fix, not a part fault |
| Gap at one end only | Sloped or uneven sill | A custom bottom detail; send photos |
Frequently asked questions
Is the bottom bar the same color as the slats?
Usually, but not necessarily. Roll-A-Shield orders the bottom bar in its own color, so a curtain and bottom bar can be two-tone; not every bottom bar is made in every color, so the nearest standard color is used where needed.
How do I know my shutter was made by Roll-A-Shield?
Look for the branded sticker on the bottom bar; checking it is there is part of the shop's quality check. Some much older units sold under the Roll-A-Shield name were made by another manufacturer, so call if you are not sure.
What is the pull-down hook for?
Roll-A-Shield's shop checklist adds a pull-down hook, and a matching pull-down hole in the bottom bar, to shutters over 6 ft tall; the checklist lists it with the spring (push-up) shutters. The hook is for pulling the bottom bar down when it is out of reach.
Can I put a lock on my bottom bar?
On manual and spring 38 mm and 63 mm Roll-A-Shield shutters, yes: a slide lock on 38 mm, or a key or thumb-turn lock on 63 mm, is ordered with the shutter. See How rolling shutters lock.
Parts and next step
Need a part or a hand?
Need a replacement bottom bar or seal? Send a photo of the bottom bar's end and the shutter's width, and we will match it. Call (480) 921-0200; the factory answers technical questions for any rolling shutter, not only ours.