James Hardie Iron Gray Siding: See Dark Gray on Your House

Iron Gray is a deep gray in James Hardie's palette and was named its 2026 Color of the Year. Upload a photo of your house below to see a very dark gray on your own home, then read what sources say about trim and undertones.

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Before and after examples

Example images are AI-generated: both the sample houses and their redesigns. Results change from render to render, so treat them as concepts, not exact product matches.

AI-drawn generic stand-in of a two-story house with white lap siding, white trim, a gray roof and a black front door — Example 1 (prompt 1 below; the before is an AI-drawn generic stand-in house, not a real photo): white siding became a very dark charcoal. The shutters also darkened, which we did not ask for. The white trim, the roof and the black door look the same.

The same house with very dark charcoal lap siding; the white trim, gray roof and black door kept, shutters also darkened — Example 1 (prompt 1 below; the before is an AI-drawn generic stand-in house, not a real photo): white siding became a very dark charcoal. The shutters also darkened, which we did not ask for. The white trim, the roof and the black door look the same.

AI-drawn generic stand-in of a one-story ranch house with tan lap siding and tan trim, black windows and a gray roof — Example 2 (prompt 2 below; the before is an AI-drawn generic stand-in house, not a real photo): tan siding and tan trim both became charcoal, as asked. The window trim is dark too. The black windows and the gray roof look the same, so the whole front reads as one dark mass.

The same ranch house with charcoal siding and charcoal trim; the black windows and gray roof kept — Example 2 (prompt 2 below; the before is an AI-drawn generic stand-in house, not a real photo): tan siding and tan trim both became charcoal, as asked. The window trim is dark too. The black windows and the gray roof look the same, so the whole front reads as one dark mass.

AI-drawn generic stand-in of a two-story colonial house with light blue lap siding, white trim, a gray roof and a white front door — Example 3 (prompt 3 below; the before is an AI-drawn generic stand-in house, not a real photo): light blue siding became charcoal. The white trim, the white front door and the railing look the same.

The same colonial house with charcoal lap siding; the white trim, white door and railing kept — Example 3 (prompt 3 below; the before is an AI-drawn generic stand-in house, not a real photo): light blue siding became charcoal. The white trim, the white front door and the railing look the same.

What the AI can and cannot do

It can recolor the siding in your photo while usually keeping the shape of the house, so you can compare colors before you order samples.

It cannot reproduce the real Iron Gray ColorPlus color. We asked for "very dark neutral gray" in our examples and the model chose its own shade. Check the whole image and name what must stay the same.

AiExterior is not affiliated with James Hardie; brand names only describe the products.

How to think about Iron Gray

The points below come from James Hardie (the maker; its Color of the Year announcement and product pages), Kylie M Interiors (a design blog) and a color-data site (unofficial). The maker sells the product. Sources were read on 24 October 2026. Some of them sell siding or lead homeowners to local pros, so treat the color advice as sales-adjacent.

Question	What the sources say
What is it?	Named James Hardie's 2026 Color of the Year on 10 November 2025, described as a deep, dramatic neutral. It is in the Statement Collection with the ColorPlus finish.
Official trim ideas	James Hardie shows Arctic White trim for contrast, or matching Iron Gray trim for a monochrome look.
Where it suits	The maker's copy says it suits strong architectural lines and highlighted trim.
Undertone	James Hardie gives no undertone. Third-party readings call it very dark with a slight green lean and an LRV around 10. Those are unofficial.
Paint look-alikes	Kylie M Interiors suggests Sherwin-Williams Roycroft Pewter (a bit lighter) and Benjamin Moore Rocky Coast or Gunmetal as near matches. Treat these as starting points only.
Pairings seen	With white trim and windows, or black windows with matching trim; it also appears on a mid-century home with red-orange brick (Kylie M Interiors).

Three Iron Gray-style looks to try

Very dark neutral gray. Example 1 turns white lap siding charcoal. The shutters darkened too, which we did not ask for.
Siding and trim both charcoal. Example 2 turns tan siding and trim dark gray for a monochrome look.
Charcoal on light blue. Example 3 turns light blue siding charcoal and keeps the white door and railing.

How to try a siding color on your house

The examples were run directly on an image model, not through the tool above, so your results will look different.

Photograph the front in daylight, straight on, with the whole house in the frame.
Upload it in the tool at the top of this page, or open the exterior designer, and choose a style.
Name the color and what must stay the same, like the prompts below.
Compare two or three colors and note which parts moved.

The exact prompts behind the examples

These are the edit prompts used for the three examples, word for word. Swap in the color and the list of what stays.

Prompt 1: very dark neutral gray

Change ONLY the color of the lap siding: repaint it a very dark neutral gray, close to charcoal. Keep the white trim, the gray roof, the black front door, the driveway and the lawn exactly the same, and keep the camera angle.

Prompt 2: siding and trim both charcoal

Change ONLY the color of the siding and the trim: repaint both a very dark neutral gray, close to charcoal. Keep the black windows, the gray roof, the driveway and the lawn exactly the same, and keep the camera angle.

Prompt 3: charcoal

Change ONLY the color of the lap siding: repaint it a very dark neutral gray, close to charcoal. Keep the white trim, the gray roof, the white front door, the walkway and the lawn exactly the same, and keep the camera angle.

Before you order siding

Order a real Iron Gray sample and look at it outdoors next to your roof and trim.
Ask about heat and fade limits for dark colors before you commit.
Check how dark shutters, doors and railings read against a dark wall.
Check your HOA or town for color rules.

Who this is for

Homeowners considering a very dark gray on fiber cement siding who want to see how heavy or crisp it looks on their own house.

More siding and color ideas

Frequently asked questions

What color is Iron Gray, blue or green undertone?

James Hardie gives no undertone. A third-party reading calls it very dark with a slight green lean, but that is unofficial. Look at a sample next to your roof and trim.

What trim goes with Iron Gray?

James Hardie shows Arctic White trim for contrast, or Iron Gray trim for a monochrome look.

Is Iron Gray too dark for my home?

We cannot say for your climate or house. A render shows how dark it looks on your house; ask your dealer about heat limits for dark colors.

What paint matches Iron Gray?

Kylie M Interiors suggests Sherwin-Williams Roycroft Pewter (a bit lighter) or Benjamin Moore Rocky Coast or Gunmetal. These are not official matches.

Can I see a dark gray siding color on my own house first?

Yes. Upload a photo of your house in the tool at the top of this page and name the color to try. A render is a guide only; test real samples outdoors on all sides of the house.

Will the render match a real dark gray siding color?

No, not exactly. In our examples the model drew its own idea of each color. Use the render to narrow your choices, then compare real color samples.

Is this tool free?

Signing up is free and gives you 5 credits, which is enough for 2 renders in most countries. Free renders carry an AiExterior watermark. If you want more renders or clean images, paid plans are available on the pricing page.

Do I need an account?

Yes. You need to sign in before a render starts, with an email code or your Google account.

Try it on your own house

Upload your house photo

Free sign-up with email or Google. You get 2 free renders in most countries; free renders are watermarked.