Historic Slate Dormer Window Restoration

In the historic Forest Hill section of Newark, this magnificent early 20th-century Colonial mansion—a three-story, 20-room estate crowned with an authentic slate roof—presented a preservation challenge that demanded both technical expertise and unwavering dedication to historic accuracy. Several slate-clad shed dormers on the third floor housed original double-hung windows that had suffered decades of water infiltration and neglect, resulting in severely compromised structural integrity.

The scope of deterioration was extensive: window sills had rotted through completely, side jambs were failing, and the surrounding trim and dormer cladding showed advanced decay. Working three stories above ground on a steeply pitched slate roof added significant complexity to an already demanding restoration. But the real challenge lay in restoring these windows to their original historic appearance and function—not simply replacing them, but bringing them back to life.

Our approach began with careful documentation and selective demolition, removing all compromised wood while preserving every salvageable historic element. We fabricated custom millwork to match the original profiles exactly, using old-growth lumber with similar density and grain characteristics to ensure longevity. Each sill, jamb, and trim piece was fitted with the precision joinery that characterized the home’s original construction.

Equally critical was addressing the root cause of the failure: improper flashing. We installed correctly detailed pan flashing beneath each window sill and meticulously integrated step flashing with the surrounding slate roof—a technical detail that requires understanding both traditional slate roofing methods and modern waterproofing principles. This flashing system, largely invisible in the finished work, is what will protect these windows for the next century.

The patience required for this restoration cannot be overstated. Every measurement, every cut, every flashing detail was executed with care, working from scaffolding in all weather conditions to honor the craftsmanship of the original builders. The final result preserves the mansion’s architectural character while ensuring these third-floor dormers will continue to function beautifully and remain watertight for generations to come.

Call or text us at (201) 248-2861 to discuss what we can do for your beautiful old home.

Close-up documentation of the extensive decay found at the lower corner of the window jamb and sill. Black rot and complete structural failure show decades of water infiltration—the inevitable result of failed flashing and deferred maintenance on these high-elevation dormers.

Close-up of the dormer’s exterior corner trim and slate integration, showing peeling paint, exposed bare wood, and rot at critical junctions. The failed paint and flashing allowed water to penetrate behind the slate cladding, accelerating the decay of all wood components.

Exterior view of the window sill in advanced stages of decay, with deep cracks, splitting, and complete loss of structural integrity. The dark staining and separation show years of water damage that penetrated through failed flashing systems.

View from inside looking out through the dormer window opening during the selective demolition phase. The completely failed sill is visible at the bottom, with rotted wood debris scattered—evidence of the structural compromise that threatened the entire dormer assembly.

Mid-process view showing new solid wood sill installed with fresh side jamb work. The contrast between the new blonde lumber and original dark-stained elements illustrates the extent of replacement required while maintaining the window’s historic configuration.

Fresh lumber replacement in progress, showing new sill and jamb components being fitted into the dormer opening. The yellow protective membrane and exposed framing reveal the extent of structural repair required after removing decades of rotted material.

Beautifully restored double-hung window sill viewed from inside the third-floor room. The clean, smooth finish of the new wood trim blends seamlessly with the historic window, showcasing the precision millwork that matches the original profiles.

Interior perspective looking down through the restored window opening toward the slate roof below, showing the dramatic height and challenging working conditions of this third-floor dormer restoration. The dark wood jambs frame the view, emphasizing the precision required when working at this elevation on a historic slate-roofed mansion.

The finished slate-clad shed dormer showcasing the completed restoration work. Revealing completely restored window sills, side jambs, trim, and properly integrated flashing systems. The dormer now sits cleanly within the third-floor slate roofline, with all wood components rebuilt to match original profiles and the critical pan flashing and step flashing correctly installed to prevent future water infiltration. The restoration preserves the historic character of this early 20th-century Colonial mansion while ensuring structural integrity for generations to come.