Wood Windows Issues Checklist: Questions and Answers on Historic Window Restoration

To discuss the benefits of restoring historic wood windows, we consulted with Paul Marlowe, of Marlowe Restorations, a Northford, Connecticut company specializing in wood conservation issues. According to Paul Marlowe, new wood replacement windows cannot equal the durability of a fully restored historic window.

How durable are restored historic wood windows?

The technology of wood conservation and protection (specialty epoxies, embedded preservative borate rods, sacrificial weather seals) can guarantee a well restored window a life expectancy near that when it was new.

How durable are well made custom reproduction replacement wood windows?

If the joinery, craftsmanship and wood grade are equal, begin to inspect for rot after about fifteen years, assuming that the lumber used was second growth.  Protective strategies and custom lumber selection will extend the life of this material, but it is as yet unclear how long.

How durable are mass produced wood, vinyl and aluminum replacements?

When the sealed glazing units fail, typically after about fifteen years, they admit air and the water vapor that causes fogging.  Maintenance is often not cost effective because of the overall window quality and the difficulty in finding parts for discontinued models.

What is the present and future value of historic wood windows?

The market value of any building is diminished by the permanent loss of parts of historic significance, but is uncertain by how much.  The durability of properly restored wood windows, however, is a more tangible asset.  The maintenance and replacement costs of properly restored historic windows is equivalent to that of replacements over the long term.

What are the long-term costs of maintaining replacements versus those of maintaining restored historic wood windows?

Restored historic windows require paint and caulk operations every ten years or so.  These costs are less than that of the periodic replacement required by lower quality replacement windows.

Can historic wood windows be made energy efficient?

Historic windows can meet modern standards for energy efficiency once restored to their original fit and equipped with modern air infiltration seals.  Interior or exterior storms are also required.   



  1. Marlowe Restorations, Northford, CT.

Wood window conservation and consultation.

2. John Leeke, Preservation Consultant, Portland ME.

Window conservator and author of The Save Your Wood Windows Report, available from John Leeke.



  1. Hull Historical Millwork, Fort Worth, TX.

Custom fabrication of wood windows.

2. Weston Millwork, Weston, MO.

Custom duplicate windows produced on 19th century sash machinery.



  1. Duluth Timber Co., Duluth, MN.

Graded and resawn old growth lumber.


List of Wood Window Restoration Specialists.

By John M. Corbett

This entry was posted in Reproduction, Window Restoration and tagged . Bookmark the permalink.

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