How close should blinds be to the window frame?

Author: Mark Aufderhar  |  Last update: Wednesday, November 5, 2025

A good rule of thumb is to hang your blinds as close to the window as possible when hanging them inside of the recess, without getting so close to the window as to risk the blind catching on handles and/or sticking to a condensated window for fabric blinds.

How close should blinds be to the window?

Roller Blinds and Blackout Roller Blinds: To maximise their light-blocking capabilities, these blinds should be installed as close to the window as possible whilst still allowing movement. This close placement helps prevent light from leaking in around the edges, this is particularly important with blackout blinds.

How much space should be between blinds and window frames?

Add an overlap of 3” on each side of the window (6” total) to allow for more privacy and light blockage. Please note: Factory Deductions: Inside mounted products have a light gap between 1/8” and 1/4” on either side of the window – this gap is required in order for the product to operate properly.

Where should blinds sit in a window frame?

Inside mounts are the most popular choice. They offer a clean, finished look because the blinds or shades are recessed and contained inside the window casing. Inside-mounted window treatments are NOT the best choice for you if: Your window frame is not deep.

Should blinds touch windowsill?

Light Control: If you're installing Blackout Roller Blinds in a bedroom or media room, having them touch the sill can help prevent light from seeping through. Privacy: Blinds that touch the sill can improve privacy, especially in spaces like bathrooms or ground-floor rooms.

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Should blinds be flush with windows?

Inside mount blinds are typically flush with the window's opening and don't cover the window trim. On the other hand, outside mount blinds and shades get installed outside the window frame.

Should there be a gap between window and sill?

Gaps around windows and doors should be sized to allow for thermal movement and this will vary depending on the material of the frame. The maximum gap permitted for openings less than 3m should be 10mm. For openings more than 3m, the maximum gap permitted should be 15mm.

What is the gap between blinds and windows?

This aside, try to get your blinds within 25mm-50mm of the glass if at all possible to ensure a snug fit, and to minimise the amount of space for cold to linger!

How should you position blinds?

The brightest light and UV rays come in a downward angle directly from the sun. If your goal is controlling light but not closing your blinds completely, then the best option is to turn the slats up. Completely closing blinds in the upward position is also the preferred direction for the maximum room darkening effect.

How far off windowsill should vertical blinds be?

We recommend your blind overlaps the window recess by at least 5cm on each side (10cm overall). You will eliminate more light the more the blind overlaps the recess.

What is the rule of thumb for blinds?

Measure both the width of the window and the height of the window. Consider adding an extra 3 inches to the width and height for optimum light control and privacy. Extending the blinds outside the window will also provide the space needed for the mounts and help the window appear larger than it actually is.

How much space should be between window and frame?

Provide at least 3/8" (10mm) clearance between the backer rod and the exterior face of the window. Backer rods add shape and depth for the sealant line.

What size blinds do I need for a 35 inch window?

The actual width of the 35" blinds are 34.5" (half inch narrower) to comfortably fit inside a 35" opening. So if your frame is exactly 34.5 inches, I would go with the 35" blinds. But first check that the width is the same through the whole length of the frame.

How are blinds supposed to close?

Holding the cord at a 45-degree angle, release it to the desired length. Keep tension on the cord until the blinds reach your desired height. Lock the blinds. Move the cord in the opposite direction until the lock catches and the blind can remain at your chosen height.

Why you shouldn't close your blinds during the day?

Sunshine in your home can help kill bacteria that live in the air, and spending time outside can help reduce respiratory issues. Science Daily published an article that suggests closing blinds during the day can suppress melatonin production and increase respiratory diseases.

How much smaller should blinds be than the window inside mount per?

Width is typically the most important figure. Generally, inside-mounted blinds should be about 1/4- to 3/8-inch smaller than your narrowest width measurement. Length is a bit different. If you don't want your blinds to rest on your window sill, make sure they're ¼-inch smaller than the length of the window frame.

Should blinds be flush with the wall?

It should be flush with the wall's surface.

Where should blinds sit on a window?

In general, it's wise to position the blind as far back as possible, without it being obstructed by anything like trickle vents or window handles. This way you'll minimise light bleed around the edges if you've gone for a roller blind, and maintain as much windowsill space as you can!

How far off the window should blinds be?

For optimum light control, the blinds should extend 1-1/2 inches beyond the window opening on each side.

Should there be a gap between window and frame?

This gap is usually about 1/4 to 1/2 inch (that's around 6 to 12 mm). It might seem odd, but it's there for a good reason. This gives room for the materials to expand and shrink a bit when the temperature changes and also lets the building settle or shift slightly over time without messing up the window.

How do you fix the gap between blinds?

There are multiple effective ways to block or fill the gap between blinds, such as ensuring edge-to-edge fit, adding extra fabric, layering, and adding blackout liners or light-blocking strips. Among these options, layering offers an ultimate blackout effect.

How do you fix a gap between a window and a window frame?

So here's the step-by-step process of fixing a gap between the window sash and frame.
  1. First-hand Cleaning. ...
  2. Inserting Backing Rod. ...
  3. Apply a Masking Tape. ...
  4. Preparing Caulk and Placing Cartridge. ...
  5. Application of Sealant. ...
  6. Keep it Clean. ...
  7. Paint Your Frame.

Should window sills overhang?

It helps stabilise and absorb level changes on your openings, keeps water outside of your home and seals the wall cavity on the foot of your windows. Another key protective trait of sills is how their overhang keeps your glass from the risk of being shattered by, let's say, someone tripping in your living room.

What is the minimum gap required between the window frame and the window lintel or trimmer?

Min 15mm clearance between Lintel and window head.

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