Inside Mount vs Outside Mount: Which to Choose (2026)

The decision between inside and outside mount takes about two minutes once six words are in the vocabulary. Before that, it takes three trips to the tape measure and one re-order. This guide gives the six words, then crosses them against five real decisions: window depth, aesthetic, function, cost, and DIY difficulty.

The reference shade throughout is the Two Pages Isabella Cotton Roman Shade Cord Lift, because its headrail dimensions (1 5/8 inches high by 1 1/8 inches deep) and bracket dimensions (1 1/4 inches high by 1 3/4 inches deep) sit right in the middle of the market. If Isabella specs work in your window, roughly every other custom roman shade will too.

The rest of this guide crosses these six terms against the five decisions. Skip to the Decision Flowchart in section 4 if you already know your reveal depth and want the answer in 30 seconds.

Quick Verdict: Which Mount Wins for Most Windows

Short answer: inside mount when the reveal depth is at least 2 inches and the window trim is worth showing. Outside mount when the reveal is shallower, when blackout matters, or when the trim is damaged, uneven, or absent. About 60% of North American windows support inside mount cleanly. The rest need outside mount by physics, not by preference.

If you want to zoom out further, we mapped the full roman shade landscape in the hub guide. Otherwise, the five decision axes below give the shorter path.

By Window Depth: The Factor That Decides on Its Own

The depth of the reveal is the only factor that overrides every other consideration. Below a certain threshold, inside mount stops being an option regardless of what you want aesthetically. Two Pages roman shades sit on an aluminum alloy headrail that measures 1 5/8 inches high by 1 1/8 inches deep. On top of the headrail you need clearance for the cord to travel and for the shade to fold cleanly against the glass without brushing.

Hardware dimension (Two Pages roman shade)	Value	Impacts
Headrail height	1 5/8″	Inside mount stack height
Headrail depth	1 1/8″	Minimum reveal depth for flush inside mount
Bracket height	1 1/4″	Additional projection above headrail on outside mount
Bracket depth	1 3/4″	Wall standoff for outside mount clearance
Width range	18 to 71 inches	Both mount types
Length range	12 to 90 inches	Both mount types

Add 7/8 inch clearance to the headrail depth for cord travel and finger space, and you land on a 2 inch minimum reveal depth for a flush inside mount. Anything shallower forces a partial mount that projects out of the frame, which is the worst of both worlds visually. Under 2 inches, jump straight to outside mount.

Measuring the reveal correctly matters more than measuring the frame width. Use a rigid tape or a folding ruler, not a soft measuring tape. Take three points across the top of the window: left, center, right. Use the smallest of the three. Frames are almost never perfectly square, and the smallest depth is the one that decides whether the shade fits.

By Aesthetic: Frame Reveal or Full Coverage

Inside mount preserves the window trim. It reads as “the shade is part of the window”, not “the shade is furniture in front of the window”. On homes with original moldings, painted casings, or architectural trim worth showing, inside mount is almost always the right aesthetic call. It also layers cleanly: a linen drape hung on a rod above the frame will tuck alongside an inside-mounted shade without visual clash.

Outside mount reads as a design object on the wall. It hides everything behind it, which is exactly the point when the trim is damaged, when the frame is out of square by more than 1/4 inch, or when there is no trim at all (common in mid-century and contemporary builds). The Isabella variants read particularly well outside mount in Independence sand or Sand 7084-16, because the neutral tones blend into most trim colors without fighting them. Isabella in Sand 7084-16 is our current pick for outside mount on off-white or beige-trimmed rooms.

One aesthetic sub-decision that catches people off guard: outside mount forces the drape rod, if any, to sit higher. The rod has to clear the top of the shade plus its projection. For traditional drapes alongside the shade, the curtain rod height guide covers the vertical alignment cleanly. On inside mount, the rod placement stays independent, which is usually simpler.

By Function: Light, Safety, Blackout

Aesthetic is what the shade looks like off. Function is what happens when it is down. Three functional lenses actually change the mount decision: light gap tolerance, safety with children or pets in the room, and blackout requirements. The flowchart below runs the four questions in the order that resolves the decision fastest.

On safety: mount type does not change cord safety by itself. What matters is whether the shade uses cordless lift or corded lift, and how the cord is secured. The CPSC window covering safety guidance is the authoritative reference. In rooms with children under 8, cordless is the recommended default whichever mount you choose.

On blackout: outside mount with a 3 inch side overlap and a 6 inch drop above the top of the frame eliminates roughly 95% of the residual light that leaks around an inside-mounted shade. Inside mount plus blackout lining still leaves a 1/4 to 1/2 inch light gap on each side, plus a top-edge gap. For bedrooms, that gap is livable. For nurseries and shift-worker bedrooms, it usually is not.

By Cost: Fabric, Hardware, Install Time

The cost model is simple. Outside mount uses more fabric because the shade extends past the frame on both sides and above. On Isabella at $79.99/panel base, going from a 34-inch inside mount to a 42-inch outside mount pushes the fabric cost up by roughly $40 to $50. Blackout lining adds another $60 to $100 depending on lining grade. Hardware cost is identical between the two mounts, since the bracket set is the same.

Install time is comparable if the wall is stud-solid: about 15 to 20 minutes per shade for either mount. Inside mount trips people up when the reveal is out of square, because the headrail has to sit level with the sill, not the trim. Outside mount trips people up when the wall is drywall alone, because bracket screws need toggle anchors rated for 10 lbs minimum per bracket. Same install time, different failure modes.

When to Skip DIY Entirely

Four window types make the mount decision hard enough that a professional measurement pays for itself: bay windows with converging angles, plaster or lath walls in pre-1950 homes, casements with hand cranks that project into the reveal, and any window paired with plantation shutters where the shade has to layer inside the shutter cavity. On these, the wrong mount call means a shade that binds, catches, or leaves a visible gap that no amount of styling hides.

Even if you keep the install DIY, a paid measurement visit resolves the inside-versus-outside question with hardware-accurate numbers. The measurement fee is typically credited toward the order, so the net cost is near zero for anyone ordering multiple shades. For a single window, DIY measurement is fine, provided the three traps below are avoided.

Quick Summary: The Scorecard

Five axes, verdict per axis. Inside mount wins clean aesthetic, cost efficiency, and drape layering. Outside mount wins light gap control and DIY ease on square-averse frames. Nothing here is opinion, just how the numbers fall.

FAQ

What is the minimum reveal depth for an inside-mounted roman shade?

Two Pages roman shades ship with a 1 1/8″ deep headrail. Add 7/8″ clearance for smooth operation and cord travel and you land at a 2″ minimum reveal depth for a flush inside mount. Anything shallower forces a partial mount that sticks out, or an outside mount decision.

Can I mount an outside roman shade if my window has no trim?

Yes. Outside mount attaches brackets directly to the wall or drywall anchors, not to trim. The main constraint becomes wall material. Solid stud or plaster holds bracket screws cleanly. On drywall alone, use toggle anchors rated for at least 10 lbs per bracket.

With kids or pets in the room, is one mount safer than the other?

Mount type does not change cord safety by itself. What matters is whether the shade uses cordless lift or corded lift and how the cord is secured. See the Window Covering Safety Council standard and the CPSC window covering safety guidance. For rooms with children under 8, cordless lift is the recommended default whichever mount you choose.

Can I mount a roman shade over an existing blind or shutter?

Outside mount, yes, if the projection budget allows. Two Pages brackets stick out 1 3/4″ past the mounting surface. Add any existing hardware depth to that. Combined stack over 3″ starts to visually crowd most windows. Inside mount over an existing blind is almost never viable.

Does inside mount work with blackout linings?

It works, but expect a 1/4″ to 1/2″ side light gap per side. For rooms that need true blackout (nurseries, bedrooms of shift workers), outside mount with 3″ side overlap and a 6″ top-of-window drop above the trim kills 95% of the residual light. Inside mount plus blackout is a good bedroom compromise, not a nursery solution.

If I order inside mount and change my mind, can I switch to outside mount?

Only if you did not shave the width for the reveal fit. Roman shades cut to a 32″ reveal width cannot re-cover a 34″ trim outside. Order the width you plan to use on the mount surface, plus overlap if outside mount. If in doubt, order slightly wider and rely on the mount projection to hide extra fabric.

What to Do Next

The decision breaks down into three steps that take 25 minutes total between them. Do them in order, and the mount question resolves without a re-order.

Step 1, measure the reveal (5 min). Rigid tape, three points across the top, take the smallest. If it reads under 2 inches, skip to Step 3 and configure outside mount. If it reads 2 inches or more, both mounts are on the table and Step 2 helps you pick.

Step 2, order swatches ($8.99, refundable, 3 to 5 day ship). Drape one swatch against the trim on the inside surface of the reveal, and drape another over the trim on the wall. The one that reads better in your room lighting wins the mount decision. Skipping this step is the single most common source of post-install regret.