Historic Steel Windows Repair, Restoration, and Weatherization

Why would you repair a metal window? Let's ask the experts:

"The repair and thermal upgrading of historic steel windows is more practicable than most people realize. Repaired and properly maintained metal windows have greatly extended service lives. They can be made energy efficient while maintaining their contribution to the historic character of the building."
Secretary of the Interior National Park Service Preservation Brief 13

Steel window

Any window that can be repaired should be repaired.
Secretary of the Interior Standards for Rehabilitation Guidelines for Windows

"The big issue... with classic steel casement windows is energy efficiency. While steel is not a good insulator of heat or cold, glass is far worse. [Heat loss from windows is about the same] regardless of what material the window sash is made of or the type of glass. Air infiltration is the primary culprit...."
Bob Yapp, About Your House

Repair and Restoration

If the principal problem with the windows is draftiness and cold, then repair may not be needed. In this case, just go to methods of weatherization. BUT NOTE: weatherization may be better with a certain amount of repair or maintenance work to provide clean surfaces to work with, so inspect your windows first.

What to Do?

There is not a single and simple answer, because the repair depends on:

Repair goals can range from minimal to extensive. In fact, the less, the better!

Have a plan

The How to Do It section shows what things can be done, from minimal to full restoration. Know what the goal is, then plan just the repair needed to get there.
Don't overdo it.

What do you need to know?

You need to know only how to do the repairs the windows need. Nothing more. What you need depends on the goal and the plan.

How to Do It?

Steel window

What needs to be done for steel windows falls into three categories.

The main thing is knowing what to do and how to do it.

The two courses of action...

DIY Steel Window Repair and Restoration

[W]ith some work, you can often turn even the sorriest-looking steel windows into reasonably efficient, draft-free units that, because they are original, also fit your home's architectural style...
Kendall Holmes, Steel Casement Windows, Old House Web

Repairs to steel windows usually are not complicated.

Many repairs require only simple skills and common tools. A Do-It-Yourself owner can save money doing some or all of the repairs. Many historic homeowners are more familiar with working with wood than with metal. Nonetheless, with knowledge about steel windows, the DIY owner can do many repairs.

Major repairs, however, are more likely to require a window repair professional with more metalworking capacity than owners have.

The first step is to figure out the condition of the windows. Remove surface dirt and grease and scrape away loose and flaking paint. Only then can any metal deterioration be assessed.

Surface imperfections do not necessarily indicate actual deterioration of the window material. Even if there is paint build up, cracked or broken glass, missing hardware, and some evidence of rust, the steel windows still are not likely to be seriously deteriorated. What looks like a badly deteriorated window may just be a window that needs some deferred maintenance.

DIY Information in Three Parts

  1. Guidebooks. Comprehensive information about repairing steel windows. They are a guide to complete restoration of windows. But, one can use only the portions that provide information about the particular work that is needed.
       Restoration. Most problems that owners have with window weatherization and deterioration can be solved without the total restoration of the windows that is explained in the Guidebooks. Most owners will not want to do such extensive work on their windows, and usually it is not necessary. Nonetheless, complete restoration is the ultimate historic preservation, if that is a goal.
  2. Specific Repairs. Information and demonstrations on how to repair specific problems. The solutions to specific problems are the same as in complete restoration.
  3. Weatherization. Weatherization is the solution to the usual problems with steel windows.


A good overview of preservation of historic steel casement windows is City of Phoenix, Steel Casement Window Repairs.

The guiding reference on historic steel windows is U. S. Secretary of the Interior, National Park Service, Preservation Brief 13, "The Repair and Thermal Upgrading of Historic Steel Windows" (Sharon C. Park, AIA).

Specific Window Repairs

Routine Maintenance and Minor Repairs

Wood Windows

For repair and weatherization of historic wood windows, see the article on Historic Window Repair and Rehabilitation

Steel windows, like anything else, require maintenance and occasional repair to remain in top working condition. Routine maintenance includes

Specific Repairs

Repair of steel windows differs in important ways from the repair of wood windows. Materials made specifically for steel windows are needed, as noted below.



Unsticking Windows


Replacing Glass






Sills and Casings




Major Repairs

Steel window

When corrosion is extensive, or when metal window sections are misaligned, then major repair is required. Sometimes major repairs can be done with the windows in place. Other times, windows may have to be removed to a shop.

Fortunately, major repairs rarely are needed for steel windows in houses. And severe deterioration is unlikely to happen for more than a few windows.

The scope of major repairs is presented in Preservation Brief 13 Steel Windows.

Generally a contractor with specialized knowledge and skills will be necessary for major repairs.

Weatherization of Steel Windows

"The big issue... with classic steel casement windows is energy efficiency. While steel is not a good insulator of heat or cold, glass is far worse. [Heat loss from windows is about the same] regardless of what material the window sash is made of or the type of glass. Air infiltration is the primary culprit..."
Bob Yapp, About Your House

Steel Casement Windows is a good overview of the issues in weatherizing steel windows. Also, see Preservation Brief 13, which has a section on weatherization.

What to Do for Weatherization



There are reliable contractors who specialize in the window repair and restoration. They know how to do it correctly. Several well-known ones are listed below.

Since many of the repair and weatherization tasks are simple, general contractors, handymen, or house painters may be able to do them. However, employing non-specialized contractors for window repair can be risky.

Information About Working with Contractors