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BM Simply White Staircase Arched Wall Molding

BM Simply White Staircase Arched Wall Molding: wall elevation, color data (LRV 92.5), staircase layout for 8, 12, 16 ft walls, cut list, calculator and pre-cu

Catalog snapshot View 2 sources ↓

Project calculator

Wall molding linear-foot estimate

Estimate for rectangular molding frames.

Estimated quantity97.53 linear feet

Divide by 7.87 ft (240 cm stick) and round up for the number of sticks.

Formula & assumptionsframe_count * 2 * (frame_width_inches + frame_height_inches) / 12 * (1 + waste_percent / 100)

Assumes identical rectangular frames. The waste allowance is editable. The estimate does not optimize cuts or include separate rails, baseboards, or other trim.

Overview

BM Simply White (OC-117) is a white with a green undertone and a calculated LRV of 92.5. Against white trim the contrast ratio is 1.03:1, which gives almost no contrast, so the molding reads through shadow alone (a tone-on-tone look); painted tone-on-tone, the arched pattern shows only through its shadow lines.

Arched layout on a 12 ft staircase wall

Molding over the full wall height, upper and lower rows divided by a chair rail. On a 12 ft wall with an 8 ft ceiling this gives 4 frames per row, each 31 in wide, with 50 in upper and 21 in lower frames. The layout uses about 32.26 m of 2.5 cm molding, or 14 sticks of 240 cm, including 10% waste. Frames follow the stair angle: keep the bottom rail parallel to the stringer.

Building the arched pattern

Arched tops are pre-formed in MDF; the straight sides and the bottom rail are cut to the same width as the arch. Fix the arch first, then hang the sides from it.

Painting molding in BM Simply White

Whites show molding through shadow only, so side light (a window or wall sconce) brings the pattern out. Use satin on trim and eggshell on the wall to add a slight sheen difference.

Wall elevation

BM Simply White wall, tone-on-tone trim, arched layout on a 12 ft wall. Colors are screen approximations.

Color data

ColorBrandCodeHexCalculated LRVUndertoneDepthContrast vs white trimContrast vs black trim
BM Simply WhiteBenjamin MooreOC-117#F7F7EE92.5greenwhite1.03:115.3:1

Trim color pairings

PairingTrim colorHexContrastEffect
tone-on-toneBM Simply White#F7F7EE1:1Trim painted the same color as the wall
matching whiteBM White Dove#EFEEE51.08:1White with the closest undertone
contrastBlack#1F1F1F15.3:1Dark trim for a graphic outline

Staircase wall sizes: arched accent wall layout

Wall widthFrames per rowFrame widthFrame height (upper / lower)Molding incl. 10% waste240 cm sticksChair rail pieces (300 cm)
8 ft242 in50 / 21 in19 m81
12 ft431 in50 / 21 in32.26 m142
16 ft533.6 in50 / 21 in41.96 m182

Cut list for a 12 ft wall

Planning cut list
PieceQuantityLength
Frame top and bottom (lower row)831 in
Frame sides (lower row)821 in
Arch frame sides (upper row)834.5 in
Arch top + bottom rail (upper row)431 in span
Chair rail2300 cm lengths

Pre-cut kits for this wall

Pre-cut kits that fit this project. Open a kit for photos, options and pricing.

Double Arched Wall Molding Set | Pre-Cut MDF Decorative Wall Panels01 / KIT

Double Arched Wall Molding Set | Pre-Cut MDF Decorative Wall Panels

From $133.60

View kit
U Shaped Arch Wall Trim Molding Kit | Pre-Cut MDF Medium & Large02 / KIT

U Shaped Arch Wall Trim Molding Kit | Pre-Cut MDF Medium & Large

From $81.40

View kit
Arched Accent Wall Trim Molding Kit, 3 Widths | Pre-Cut MDF03 / KIT

Arched Accent Wall Trim Molding Kit, 3 Widths | Pre-Cut MDF

From $58.40

View kit
Flexible Arched Wall Molding, Paintable MDF Wall Trim, Pre-Cut Arch Decorative Wall Panels | Picture Frame Molding, Accent Wall Trim04 / KIT

Flexible Arched Wall Molding, Paintable MDF Wall Trim, Pre-Cut Arch Decorative Wall Panels | Picture Frame Molding, Accent Wall Trim

From $73.60

View kit
Modern Arched Wall Panel Kit: Pre-Cut MDF Wall Molding05 / KIT

Modern Arched Wall Panel Kit: Pre-Cut MDF Wall Molding

From $140.00

View kit
Arched Decorative Wall Molding Panels, 1 to 5 Arches | Pre-Cut MDF06 / KIT

Arched Decorative Wall Molding Panels, 1 to 5 Arches | Pre-Cut MDF

From $146.40

View kit

Questions

How much molding do I need for a 12 ft staircase wall with arched frames?

About 32.26 m (106 linear ft) including a chair rail and 10% waste, which is 14 sticks of 240 cm. That assumes 4 frames per row, 31 in wide, on an 8 ft ceiling.

Is BM Simply White warm or cool?

BM Simply White has a green undertone and reads as a white white. Its calculated LRV is 92.5, so it reflects a lot of light and keeps molding shadows soft.

Should trim be the same color as BM Simply White walls?

Painting the molding the same color gives a modern, tone-on-tone finish where only shadows show the pattern. White trim adds almost no contrast, so the molding reads through shadow alone (a tone-on-tone look) (1.03:1), and black trim gives 15.3:1.

How high should the chair rail be in a staircase?

About one third of the ceiling height: 32 in on an 8 ft ceiling, 36 in on 9 ft and 40 in on 10 ft. Frames follow the stair angle: keep the bottom rail parallel to the stringer.

Trace the details

Sources & dates

Prices, options and photos come from our product catalog on the date shown. Layout tables are planning estimates; measure your wall before ordering.

  1. Paint color dataset (screen approximations; LRV calculated)Recorded November 11, 2026
  2. DecoMoldings product catalogRecorded November 11, 2026