Troubleshooting by symptom · Rolling Shutter Guide
Do rolling shutters keep rain out, and why is water getting in around mine?
A fully closed rolling shutter keeps most rain off the window, but it is not watertight. The bottom seal and the closed slats keep out most wind-driven rain; water that gets in usually comes around the guide rails or box, where the wall joint was never caulked or the caulk has failed. Re-caulking the rails is the standard fix.
Key facts
- Roll-A-Shield's standard fix for water getting in around a shutter is thorough caulking of the guide rails. Roll-A-Shield data
- Every Roll-A-Shield self-install guide ends with the same step: seal the perimeter of the shutter with caulk. Roll-A-Shield data
- A U-channel under the shutter helps seal the bottom but is not watertight; in heavy rain it can fill with water. Roll-A-Shield data
- One fix Roll-A-Shield uses for a gap at the bottom of a closed shutter is a replacement base slat with a larger built-in seal, about 3/8 to 1/2 in thick. Roll-A-Shield data
- Clean shutters with mild soap and water twice a year; never use a pressure washer, and do not wash them in extreme heat. Roll-A-Shield data
Applies to: Exterior rolling shutters with insulated (foam-filled) or single-wall aluminum slats, any operator. Perforated slats have open holes and do not block rain.
A rolling shutter is a barrier, not a gasket. Closed, it keeps most rain, wind and dust off the window behind it, which is why owners notice the few places where water still gets past. Those places are predictable: the joint between the shutter and the wall, the bottom edge, and anything under the bottom edge.
What seals a closed shutter, and what doesn't?
The closed curtain and its bottom seal do the work; the edges depend on caulk.
| Part | What it does against rain | Limit |
|---|---|---|
| Closed slat curtain | When fully closed, the slats press together and block most rain. | Vented slats open their hinge slots while the shutter is partly open. |
| Bottom seal on the base slat | Presses on the sill or floor and seals the bottom edge against wind-driven rain, drafts and dust. | Only seals if the bottom slat reaches the sill evenly. |
| U-channel (if fitted) | Gives the shutter a flat surface to land on and helps seal the bottom. | Not watertight; it can fill with water in heavy rain. |
| Caulk around the box and rails | Seals the joint between the shutter and the wall. | Only as good as the bead; it has to be there and intact. |
| Perforated slats | None: the holes stay open when the shutter is closed. | Choose solid slats where rain matters. |
Where is the water getting in?
Find where it shows up, then match it to the source.
| Where water appears | Likely cause | Fix |
|---|---|---|
| Down the sides of the window, or behind a guide rail | Gap between the guide rail and the wall | Caulk the guide rails thoroughly. |
| Across the top of the window | Gap between the box and the wall | Caulk the box where it meets the wall, as part of the perimeter. |
| Under the bottom of the shutter | Bottom slat not reaching the sill, or a worn bottom seal | Check the shutter closes fully; a replacement base slat with a larger seal can close a remaining gap. |
| Standing in the U-channel after heavy rain | Expected: a U-channel is not watertight | Nothing is broken; keep the channel clear of debris. |
| Through the curtain itself | Shutter left partly open with vented slats, or perforated slats | Close it fully in a storm; perforated slats stay open and can let rain through. |
How do I seal around the guide rails?
Caulk the perimeter: where both guide rails and the box meet the wall. It is the last step in every Roll-A-Shield self-install guide, so on a shutter that was never caulked, or where old caulk has cracked or pulled away, this one job usually stops the leak.
- Roll-A-Shield's install checklist for spring-loaded shutters specifies paintable caulk, not silicone.
- Seal the outside joint between the shutter and the wall, and keep caulk out of the channel the curtain runs in.
- Do not pull out or disturb the felt (wool) pile that lines the rails.
- Cycle the shutter afterwards to check it still runs freely.
Why is there a gap at the bottom?
Either the curtain is not reaching the sill or the sill is uneven. A shutter whose bottom slat stops short leaves a gap the seal cannot close; see the stopping-point page if a motor stops early. Where a gap remains at the bottom, one fix Roll-A-Shield uses is a replacement base slat with a larger built-in seal, about 3/8 to 1/2 in thick. Current base slats also take a bulb seal along the bottom. A U-channel helps when the shutter has no flat surface to close onto, but it cannot be used as the bottom channel on a walk-through doorway, because it is a trip hazard.
Does washing the shutter count as "water getting in"?
No, but wash it the right way. Close the shutter fully and hose it off; use mild soap for stubborn dirt, then rinse. Do not use harsh cleaners or a pressure washer, and do not wash it in extreme heat. Clean the guide rails with a soft brush without pulling out the felt pile. The full routine is on cleaning and maintaining rolling shutters.
What next
Base slats, seals and U-channels for Roll-A-Shield shutters are ordered by phone on (480) 921-0200. In metro Phoenix, Roll-A-Shield services rolling shutters of any brand.
Frequently asked questions
Is a rolling shutter waterproof?
No. Closed, it keeps most rain and weather off the window, but it is a barrier, not a watertight seal. Expect some water at the edges and bottom in heavy, wind-driven rain.
Should I use silicone to caulk the rails?
Roll-A-Shield's install checklist for spring-loaded shutters says to use paintable caulk, not silicone.
Do vented slats let rain in?
Only while the shutter is partly open. The vent slots are in the slat hinges; when the shutter closes fully, the slats press together and the vents shut.
Can I hose my shutters down?
Yes, with a garden hose and mild soap, with the shutter fully closed. Do not use a pressure washer, and do not wash them in extreme heat.
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.