Storm window guide

Storm Window Weep Holes: What They Do and Why You Never Caulk Them

Exterior storm windows have weep holes so trapped moisture can drain. Learn what they are, where they are and how to keep them clear.

Weep holes are small openings at the bottom of an exterior storm window frame. They let moisture drain out instead of collecting between the windows, and they are one of the most important details to protect when you install, caulk or paint. This guide explains what weep holes do and how to keep them working.

Key takeaways

Exterior-mounted storm windows have weep holes at the bottom of the frame
They let moisture between your existing window and the storm window drain out
Never caulk over weep holes
Check and clear them when you clean your windows
Mask the bottom of the frame before painting or sealing the trim

What weep holes are

Exterior-mounted storm windows have small weep holes at the bottom of the frame. They let moisture that collects between your existing window and the storm window drain out instead of sitting against the original frame.

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Never caulk over them

Do not caulk over the weep holes. Sealing them traps moisture between the windows, which can fog the glass and damage the original frame over time. Follow the installation guide for your window for where sealant belongs, and leave every weep hole open.

Read the installation guide

Keep them clear

Dust, pollen, paint and insects can block a weep hole. When you clean the windows, check the bottom of the frame and clear each opening with a soft tool. Never push anything into the frame that could damage the weatherstripping.

How to clean storm windows

Before you paint or seal

If you paint around the window or seal the trim, mask the bottom of the storm window frame first so the weep holes stay open. Fixing a blocked weep hole later is much easier than repairing moisture damage.

Installation help

Why moisture gets between the windows

Rain driven by wind, condensation from indoor humidity and cold glass can all leave moisture in the space between your original window and the storm window. Without a way out, that moisture sits against the original frame. Weep holes give it a path to drain.

How to clean storm windows

Signs a weep hole is blocked

Look for standing water or staining along the bottom of the storm window, fog or water spots between the panes, or peeling paint on the original sill. Any of these can mean a weep hole is blocked by dust, paint or sealant.

Read the installation guide

Weep holes during installation

Follow the installation guide for where to seal, and leave every weep hole open. If you hire an installer, tell them to keep the weep holes clear and check them before they finish.

Installation help

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Vertical storm windows

An operating exterior option for tall, double-hung openings.

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Horizontal storm windows

A side-sliding exterior option for wide openings.

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Fixed picture windows

A fixed panel for glass that does not need to open.

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FAQs

Do all storm windows have weep holes?

Exterior-mounted storm windows with a sealed perimeter have weep holes at the bottom of the frame so moisture can drain. Our exterior-mounted windows have them, and our interior-mounted windows do not. Check your product page and installation guide for the details of your style.

What happens if I caulk over a weep hole?

Moisture can stay trapped between the storm window and your original window, which can cloud the glass and damage the original frame over time. Keep the weep holes open.

How do I know where the weep holes are?

Look along the bottom of the frame on the outside face. They are small openings that let water out.

Is a little condensation between the windows normal?

Some moisture can collect, which is why the weep holes are there. If moisture keeps building up, make sure the weep holes are open and your original window is sealed on the inside.

Can I add more weep holes?

Do not alter the frame. If you think a window needs better drainage, contact us and we will help.

Do interior storm windows have weep holes?

Weep holes are a feature of exterior-mounted storm windows. Check the product page and installation guide for the style you are buying.

How do I clean a weep hole?

Use a soft tool, such as a small brush or a plastic pick, to clear dust and debris. Do not push anything into the frame that could damage the weatherstripping.

Will bugs get in through weep holes?

Weep holes are small and are designed to drain water. If insects are a concern, contact us before making any changes, and do not seal the holes.

Next steps

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