Inside Mount or Outside Mount, and Why It Matters

Where the Treatment Sits

Every window treatment has to be fixed somewhere, and there are only two broad places. It can sit inside the window opening, tucked within the frame, or it can sit outside it, on the trim or the wall, covering the opening. Whether to choose an inside mount or outside mount sounds like a technical detail, but it decides how the window looks, how much light gets around the edges and how much of the glass you see when the treatment is raised.

Neither is better in every room. Each gives you something and costs you something, and the house itself often settles the question.

Inside Mount: Clean and Tailored

An inside mount fits the blind or shade within the window frame, so the treatment lines up with the glass and the trim stays fully on show.

What you gain

• A clean, built-in look, with the window’s woodwork visible all round
• Nothing sticking out into the room, which suits windows behind a sofa or a desk
• A tidy finish when you plan to add drapes over the top

What it costs you

• Thin gaps at the sides, because the treatment needs room to move, so some light gets around the edges
• When raised, the stack of slats or fabric sits within the opening and covers the top of the glass
• It needs enough depth in the frame to hold the treatment

Outside Mount: Cover and Control

An outside mount fixes the treatment above the opening, on the trim or the wall, and makes it a little wider and taller than the window. It overlaps the opening on every side.

What you gain

• Better light control, because the overlap closes the edge gaps, which matters in a bedroom
• More glass on show when raised, since the stack can sit above the opening
• A way to make a small or oddly shaped window look larger and more even
• An answer for frames too shallow, too out of square or too fine to drill

What it costs you

• The trim is partly covered
• The treatment stands out from the wall, which shows from the side

Depth: The First Thing We Check

The single biggest factor in inside mount or outside mount is how deep the window frame is. A blind needs room for its slats to tilt without hitting the glass or the window latch. A shade needs room for its headrail and its fabric. Shutters need room for their louvres to turn.

If the frame is deep enough, an inside mount is often the first choice for the look. If it is shallow, an outside mount is usually the answer, or a slimmer treatment that fits the depth that is there. Handles, cranks and latches that stick out into the opening also count, because the treatment has to clear them. That is one reason we measure every window ourselves in your home rather than working from a rough size.

How the House Decides

The housing in this area shows how often the house itself answers inside mount or outside mount.

The historic sash on College Hill and Newport’s Point often has fine trim worth keeping on view, which argues for an inside mount. But old frames vary, some are shallow, and many are slightly out of square, so a treatment cut to fit tightly inside may show uneven gaps. Here the decision is made window by window, and sometimes an outside mount, or a drape on its own, protects the woodwork better than drilling into it.

The mill-era three-deckers and Victorians in Fall River and Pawtucket usually have tall windows with generous frames and deep, handsome trim. Inside mounts suit them well in living rooms and dining rooms. In bedrooms, where edge light matters more, an outside mount or a drape over an inside-mounted shade is often the better plan.

The 1950s capes and ranches across Somerset and Seekonk tend to have plainer trim and standard openings. Inside mounts give these houses a crisp, modern line, and outside mounts work neatly on picture windows where you want the glass clear when the shade is up.

The cottages and shingled capes near Mount Hope Bay and the Sakonnet often have small upstairs windows set into the roof slope. An outside mount above the opening can make these windows look bigger and let the shade clear the glass entirely, which matters when the view is the water.

Room by Room

A rough guide to inside mount or outside mount, room by room:

• Living and dining rooms: inside mount, to show the trim, with drapes alongside if you want softness
• Bedrooms: outside mount, or inside mount with a drape over it, to cut edge light
• Kitchens: inside mount, to keep the treatment clear of the counter and the sink
• Bathrooms: inside mount where the frame allows, for a tidy finish
• Sliding doors and wide openings: usually outside mount, so the treatment clears the door and the handle

Our guide to blackout and room-darkening fabrics goes further into darker bedrooms.

Shutters Are a Special Case

Plantation shutters are usually fitted inside the opening, with a frame made to the window. Where the opening is shallow or uneven, the frame can sit on the face of the trim instead. Either way, the shutter is built to the window’s real size, which is why measuring each opening matters so much.

Getting It Right on the Day

The choice between inside mount or outside mount is easier to make in front of the window than on paper. When we measure in your home, we check the depth, the squareness and the trim of each window, and look at how the room is used. Then we talk you through which mount suits each one and why.

Our team installs what we sell, so the mount we plan is the mount you get. You can also see inside and outside mounted samples in the Swansea showroom before you decide.

Treatments We Fit Both Ways

Custom blinds

Wood, faux wood, aluminium and vertical blinds, inside or outside mounted.

Custom blinds

Roller shades

A slim roll that sits neatly inside most frames.

Roller shades

Cellular shades

Honeycomb fabric with a shallow headrail for tighter frames.

Cellular shades

Plantation shutters

Panels built on a frame made to each window.

Plantation shutters

Book Your Free Quote

Use the call button to book a free quote, arrange measuring in your home or ask about installation. We will look at each frame and recommend the mount that suits it. If you would like to see both kinds first, visit the Swansea showroom.