M Streets Window Rules in Dallas: Conservation District

What are the M Streets window rules in Dallas?

The M Streets Conservation District ordinance sets window and door rules for the front facade and the wrap-around of each house. It allows only transparent, stained or leaded glass. Windows must be taller than wide. Muntins and mullions must show at least one-fourth inch. Metal frames must look like original wood.

The City of Dallas adopted these rules in ordinance 25116, which creates Conservation District No. 9, called the M Streets (Greenland Hills). The ordinance covers about 176 acres. This post reads the ordinance text as of November 2026. Rules change, so confirm with Dallas staff before you order.

Which part of the house do the rules cover?

The rules apply to the front facade and the wrap-around. The ordinance defines the wrap-around as the part of a side facade 25 feet behind the corner of the front facade. It also defines a street facade as any part of a building that faces a public street.

That wording matters on a corner lot. A side window that faces the street may count differently from a rear window. Do not guess. Mark each window on a plan and ask city staff which ones the rules cover.

What does the ordinance say about each window rule?

Here are the six rules that affect a window or door order, in the ordinance’s own words where we quote them.

Rule	What the ordinance says	What to plan for
Glass	“Only transparent, stained, or leaded glass is allowed in windows and doors.”	Choose clear, stained or leaded glass. Ask city staff before you pick a tint or film.
Proportions	“Window height must be greater than the window width.”	Favor tall, vertical openings. A wide picture window on the front facade needs review.
Fit	“All windows must fit the wall opening. Infill surrounding the window is not allowed.”	Measure the existing opening. Our post on rough opening vs frame size explains the gap.
Frames	“Metal window frames must have a finish that is indistinguishable from the finish on original wood windows.”	Ask for a finish sample and show it to staff.
Muntins	“Window muntins and mullions must be expressed by a minimum of one-fourth inch.”	Flat stick-on grids may not meet the standard. Ask staff.
Depth	“Window assemblies must have a profile depth of at least three inches.”	Check the frame depth on the product drawing.

The ordinance also says “Window air conditioner units are not allowed” on the front facade and wrap-around.

How do these rules shape the product you choose?

They favor vertical windows with real depth and visible dividers. A muntin is a bar that divides panes of glass. A mullion joins two window units. The ordinance asks that both show real depth.

The ordinance does not ban steel or aluminum. It sets a test: the finish on a metal frame must be indistinguishable from original wood. That is a finish question, so bring samples to the city, not just a color chip.

Some options to compare with staff:

• A tall casement or fixed unit with a deep frame. See our page on casement and awning windows.
• A window with the look of a classic sash. Bertrand describes one, and our post on simulated double hung windows explains how it works.
• A true double hung window line, if staff prefers a sash that slides.

We do not claim that any specific product meets the ordinance. City staff decides. Bring the drawing and the finish sample, and let them review it.

Do you need approval before you replace windows?

Yes, ask Dallas for a Work Review Form before work starts. The city’s conservation district packet says: “For alterations to a property, owners must obtain a Work Review Form (WRF).” It also says that if work is done without a WRF or city building permit, code inspectors will cite the owner and issue a stop work order.

The ordinance itself states a penalty not to exceed $2,000. Read the ordinance for the full text.

Whether a window swap also needs a building permit is a separate question. Ask Dallas Development Services. Do not assume “no permit.” The packet lists a WRF “or city building permit,” which means both can matter.

How is this different from a historic landmark district?

A conservation district is not a landmark district. Dallas landmark districts require a Certificate of Appropriateness before exterior work. The M Streets use the conservation process with a Work Review Form. The rules differ, and so do the forms.

Our guide on windows in Dallas historic districts covers the landmark process. If you are not sure which one your street falls under, ask Dallas staff for the district name and the governing ordinance.

What should you bring to the city?

Bring a window schedule, drawings, finish samples and photos of the existing front. A simple package makes review faster. We suggest this list:

1. A photo of each front and wrap-around window you plan to change.
2. A drawing with the opening size, the new unit size and the frame depth.
3. The muntin or mullion detail, with the depth shown.
4. A finish sample for any metal frame.
5. The glass type for each unit.

Honey Rock works with Jada, Bertrand and Sun Windows, and describes its approach as running “From the initial design process to the final installation.” We can help you assemble the drawing set. We do not decide what the city approves.

Next step

Planning window work in the M Streets? Tell us about the house at /contact-us or call (214) 484-9982. For the wider picture, see our pillar on window replacement in Dallas and the Dallas area page. This post is not legal advice. Confirm every rule with the City of Dallas.