Sherwin-Williams Waterloo SW 9141 on a house: LRV 12.97, undertones, siding, front doors, shutters and garage doors, with the trims and colors that go with it

Sherwin-Williams Waterloo (SW 9141) is a dusky, muted blue with a slight green-gray lean: darker than a slate blue, well short of a navy. Sherwin-Williams publishes an LRV of 12.972 (often rounded to 13), an RGB of 83, 104, 114 (hex #536872), files it in its Blue family, rates it for interior and exterior use and places it at 221-C6 on its color strips, with Mountain Air, Kestrel White and Coral Clay as coordinating colors. Outside, it works as a body color on wood and fiber cement siding, stucco and painted brick, and as an accent on a front door, shutters or a garage door against a white, gray or beige house. It reads darker and grayer facing north, clearly blue in southern sun. Two manufacturer rules set its limits: Sherwin-Williams keeps it off vinyl siding (LRV under 56), and it sits on the edge of one garage door maker's dark-color bands.

Color values come from the makers' pages and color data. Color differences, chroma, hue angles, LRV gaps and gallon counts are our calculations; advice on orientation and pairings is our color reasoning, not a manufacturer's rule.

Waterloo at a glance: the numbers Sherwin-Williams publishes

These values come from the color's page (Sherwin-Williams, SW 9141 Waterloo) and from Sherwin-Williams' public color data, which gives the same figures. Hex and RGB are an approximate digital rendering, not a tinting formula.

At Lowe's, Waterloo is sold in the HGTV Home by Sherwin-Williams line. Its Waterloo HGSW9141 page shows the same RGB and hex, the former code HGSW3322 Blue Mystery, a cool undertone tag and an LRV rounded to 14.0. Sherwin-Williams' own 12.972 is the precise figure.

Waterloo undertones: blue, gray or green?

The Lab values settle it. L 42.69 is below mid lightness. The a value of -5.31 leans to green, the b value of -8.18 leans to blue. By our calculation the chroma is about 9.8, low for a blue, and the hue angle is about 237 degrees: a blue pulled about a third of the way toward green. That is why Waterloo reads as a slate or denim blue with a gray-green undertone, never as a bright or royal blue. Against the blues it gets compared with:

Next to a true navy such as Naval, Waterloo looks lighter and greener; next to a gray such as Slate Tile, clearly blue. With so little chroma, the light changes it more than it would a saturated blue.

North, south, east or west: how Waterloo changes with orientation

An LRV of 12.97 means the wall reflects about 13 percent of the visible light that reaches it, on a scale from 0 (black) to 100 (a perfect white); our guide to reading LRV explains the scale. A dark, low-chroma blue follows the light. Color logic, not measurement:

Climate pushes the same way: a desert sun makes it look lighter and bluer than the chip, a Pacific Northwest overcast darker and grayer. Too gray facing north? Compare Distance SW 6243. Too blue facing south? Compare Slate Tile.

Siding, brick, stucco, doors, shutters: where Waterloo works

Lap siding and fiber cement

Sherwin-Williams' Duration Exterior data sheet (K32 series) lists wood, cement composition siding, stucco, concrete, block, aluminum and galvanized steel among its surfaces. New cement composition siding and stucco must be tested for pH and, above 9, primed with Loxon Concrete & Masonry Primer; new stucco cures at least 30 days first. The sheet calls for 2 coats on new, bare substrates and 1 coat for a repaint; going from a white or light body to a color this dark, plan on two coats anyway so the old color does not ghost through. Our Duration Exterior guide covers the product.

Vinyl siding and PVC: not within Sherwin-Williams' rule

Under the heading "vinyl or other PVC building products", the same sheet says not to paint vinyl with any color darker than the original or with an LRV under 56 unless VinylSafe colors are used, because the vinyl may warp. Waterloo, at 12.97, is about 43 points under that line. The VinylSafe palette, coded SWVS, offers 100 colors, including a limited selection of darker ones, but none is close to Waterloo: by our calculation from the screen colors on that page, the nearest is Gray Jacket SWVS 434, about ΔE 4.3 away and much grayer. On a vinyl house, keep Waterloo for a wood, steel or fiberglass front door; PVC trim and molded shutters fall under the same heading. Our VinylSafe guide walks through the palette.

Brick: left bare beside Waterloo siding, or painted

Waterloo siding next to unpainted red or orange brick tends to look intentional: by our calculation Coral Clay, the warm accent Sherwin-Williams lists with Waterloo, sits about 200 degrees away in hue, close to opposite, in the same warm range as most red brick. Painting the brick is a bigger step. The Brick Industry Association's Technical Note 6 (August 2024) warns that paint can be very difficult to remove from brick without damage and that acrylic latex is typically vapor semi-permeable, so heavy coats lower the wall's permeability further. Because mortar is alkaline, it recommends an alkaline-resistant primer or a paint designated for masonry, after at least 30 days of curing for new or repaired masonry. Our painted brick exterior guide covers the decision.

Front door

On a front door, Waterloo is softer than a navy and less severe than black, provided the body is light enough to frame it (see the body color table below). Behind a full-glass storm door in afternoon sun, read your door maker's warranty on dark colors first. For the paint itself, our SnapDry door and trim paint guide compares Sherwin-Williams' two door enamels, and the Sherwin-Williams front door colors page lists other candidates.

Shutters

Waterloo shutters on white, light gray or greige siding are a softer version of the classic black-shutter colonial. Check the material: vinyl or PVC shutters fall under the LRV 56 rule above unless their maker says otherwise. On a dark body they disappear.

Garage door: Waterloo sits on Clopay's line

Clopay's painting instructions (effective May 11, 2020) call for a 100% acrylic latex exterior paint, strongly recommend a bonding primer and recommend solar reflective paint on all doors when available. On its Coachman doors, colors with an LRV of 12 or less are not permitted and a tested and approved solar reflective paint is required between 13 and 38. Waterloo's 12.972 falls between those two bands, so on a Coachman door ask Clopay before you buy. On its other doors, solar reflective paint is recommended, not required. Other makers set their own limits; our garage door paint color ideas compare more options.

Trim and accent colors with a Waterloo body

Coordinating colors first; the gap is the LRV difference from Waterloo (Sherwin-Williams' color data).

As we read these gaps, every white stands out; the choice is about temperature. Mountain Air and Extra White keep the house cool and coastal, Kestrel White and Alabaster warm it up. The darks sit only 8 to 10 points below, so they read through depth and sheen; Coral Clay, only 13 points lighter, stands out through hue. Our Pure White exterior guide covers the default trim white, and the Sherwin-Williams exterior color combinations show full schemes.

What colors go with Waterloo as a door or shutter color

When Waterloo is the accent, the body color does the framing. The gap is the LRV difference between the body and Waterloo:

In our reading, below a gap of about 30 points the door merges with the walls. On a greige house, see the Agreeable Gray SW 7029 exterior guide; on a cooler gray one, the Repose Gray SW 7015 exterior guide.

Strip 221: from Lullaby down to Moscow Midnight

Waterloo is the sixth of seven steps on Sherwin-Williams strip 221. The colors share the same gray-green blue base, so two or three of them can sit on one house without an undertone clash. Values from Sherwin-Williams' color data, all rated for exterior use:

A one-strip scheme: Stardew on the upper story or gables and Waterloo below (a 30-point gap), tied by one white trim. Only Lullaby clears the LRV 56 line, so on vinyl the rest of the strip is out under Sherwin-Williams' rule.

Waterloo vs Smoky Blue, Naval and other deep Sherwin-Williams blues

The first seven are in Sherwin-Williams' similar colors for Waterloo; the last three are deeper blues. The color difference (ΔE2000) is our calculation from Sherwin-Williams' Lab values: under about 2 is hard to tell apart on a wall, above 5 is clearly another color.

So Waterloo is not a navy: Naval reflects about a third as much light (LRV 4.46 against 12.97). If Waterloo looks too dark on your board, Smoky Blue is the same hue one step up; our Smoky Blue SW 7604 exterior guide covers it on siding and doors. If it looks too blue, the Slate Tile SW 7624 exterior guide covers the grayer option. For a real navy body, compare dark blue siding colors in our navy and dark blue siding guide.

Benjamin Moore colors near Waterloo

No official equivalent exists. These are the closest by our calculation from each page's screen color, with Benjamin Moore's LRVs; each page's color data marks the color as available for exterior.

Treat all three as starting points for a painted sample, not as matches.

Painting conditions and how much Waterloo you need

The Duration data sheet sets the conditions: air, surface and material above 35°F and at least 5° above the dew point, no application if temperatures may drop below 35°F within 48 hours, no rain or snow expected within 2 to 3 hours, and no painting in direct sun, which matters more on a dark color. Recoat takes 4 hours above 45°F, 24 to 48 hours between 35 and 45°F. Coverage is 250 to 300 sq ft per gallon. Standard latex primers cannot be used below 50°F.

Our arithmetic at that coverage: for 2,000 sq ft of siding after windows and doors, two coats over a light color take 13.3 to 16 gallons, about three 5-gallon buckets plus a spare gallon. A 36 by 80 inch front door is 20 sq ft per face, so two coats on the outside face (40 sq ft) fit in a quart, which covers about 62 to 75 sq ft. Eight pairs of 15 by 55 inch flat shutters take about 183 sq ft for two coats, under a gallon.

If the house was built before 1978, assume the old paint may contain lead. Under the EPA's Renovation, Repair and Painting Program, anyone paid to disturb paint in that housing must be certified; homeowners working on their own home are exempt unless, for example, they rent part of it. Under a homeowners association, check the HOA color rules guide before you order.

How to test Waterloo before you commit

1. Paint two coats on a 2 by 2 ft board, with a strip of your trim white along one edge.
2. View it on the front and back walls, at noon and late in the day, from the street.
3. Put Smoky Blue beside it if it looks too dark, Distance if it looks too gray, and Naval if you were really after a navy.
4. Try the whole scheme on a photo of your own house before buying the first gallon.

For the wider Sherwin-Williams exterior range, start with our Sherwin-Williams exterior paint guide.

Sources and references

• Sherwin-Williams, SW 9141 Waterloo: LRV, RGB, hex, family, use, strip, coordinating colors.
• Sherwin-Williams, color pages for Smoky Blue, Slate Tile, Naval, Moscow Midnight, Mountain Air, Kestrel White and Coral Clay: comparison and coordinating values.
• Sherwin-Williams, Duration Exterior product data sheet (K32 series): substrates, vinyl and PVC rule, primers, application conditions, coverage.
• Sherwin-Williams, VinylSafe colors for vinyl siding: palette and swatches.
• HGTV Home by Sherwin-Williams, Waterloo HGSW9141: retail code, former code, LRV as rounded on that page, undertone tag.
• Benjamin Moore, color pages for Spellbound 1659, Vermont Slate 1673 and Nocturnal Gray 2135-30: LRV, collection, screen color, exterior availability.
• Brick Industry Association, Technical Note 6, Changing the Appearance of Brick Masonry (August 2024): permanence, vapor permeance, primer, curing.
• Clopay, Painting your garage door (effective May 11, 2020): paint type, primer, LRV bands, solar reflective paint.
• U.S. Environmental Protection Agency, Lead Renovation, Repair and Painting Program: pre-1978 homes, certification and homeowner exceptions.