Project Spotlight: The Main Interior Building, Washington, D.C.

Contractor: Grunley Construction


Consuming an entire city block in Washington D.C., the Main Interior Building is the headquarters of the Department of the Interior and houses twelve government offices and agencies including the Bureau of Land Management and the National Parks Service.  Construction of the building was completed in December of 1936 and it marked the first completed project designed and built under the Roosevelt administration as part of the New Deal.

The building is listed on the US National Register of Historic Places.

In the building’s nearly 80 years of service, it has been exposed to harsh weather conditions and periods of maintenance neglect that have left some extensive necessary repairs.  Grunley Construction has been executing these repairs and modernizing the building over the course of 6 phases since 2004.

The Main Interior Building houses over 4800 total window openings and each sill, sash and frame is being inspected and restored as part of the building’s restoration project.


Grunley is beginning work on the final wing of the building, which includes maintenance of around 900 windows.  ABATRON’S LiquidWood and WoodEpox have been used extensively to consolidate and harden weathered sills and rebuild missing sections of wood that have crumbled away.  Along with epoxy repairs, they are also executing lead paint abatement floor-by-floor.



“I use LiquidWood and WoodEpox simply because they outperform anything else I’ve tried over the past sixteen years.”

–          Todd Higdon, Assistant Superintendent

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These three pictures show typical sill damage, the application of LiquidWood and WoodEpox, and a sill that has been completely rebuilt with WoodEpox.

Another aspect of this restoration project included making repairs to broken cast iron grates. 

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“We used Aboweld 55-1.  It bonded them like we had put a weld on it.  It saved us time and money.” – Higdon


Grunley Construction has restored and modernized over sixty buildings in Washington D.C., and has been ranked as one of the top construction contractors in the nation by the Washington Business Journal and the Engineering News-Record.  For more information, please visit