Your Original Window

Understanding Your Traditional Double-Hung Window

Common Construction and Dimensions

Your existing traditional double-hung wooden window units probably looks very similar to the illustration on the right, if you slice it horizontally and look down. Standard residential units manufactured between 1865 and 1940 or so will all be similar with 1 3/8" sash, a 1/2" parting stop and a jamb width of 3 1/4" Some of the more elegant residential and most all commercial applications used 1 3/4" sash, a 1/2" parting stop and a 4" jamb width.

Because all traditional windows are so similar in construction they are also similar in the way they fail over time...
  • Drafts at the meeting rails
  • Drafts around the edges of the sash and sills
  • Sash painted shut and windows inoperable
  • Improper balance due to bad cords, stuck pulleys or obstructions in balance cavity
  • Deteriorated sills, jamb bottoms, upper meeting rails and bottom rails

Traditional Residential Double-Hung Window Horizontal Cross Section

Weatherstripping Kit Origins

The Weatherstripping Kit is an outgrowth of our Magnum Line of High-Performance Replica Window System. The kit is comprised of the same state-of the-art, contemporary materials we use in our $800 high-performance series replacement sash, MAGNUM REPLICA SASH SYSTEM, only slightly modified to work with the reduced dimensions of a traditional residential window.
The Weatherstripping Kit is a complete system that allows you or your contractor (or Heirloom Windows under the right circumstances), to upgrade your existing windows so that they perform "better than new" in terms of operating to ventilate and eliminating drafts. The Weatherstripping Kit will... 

  • Completely eliminate air-infiltration around the sash sides, head, meeting rails and sill 
  • Create a maintenance free surface on the sills and jamb sides
  • Make your windows "silky smooth" to operate 
  • Not change the appearance of the windows
  • Allow you to paint the jambs to your specific color

Horizontal Cross Section
Weather-Stripping Retainers (WSR)
and Jamb Liners

Same Plane Weather-Stripping - Critical to Obtaining a Proper Seal 

Please note that throughout the web-site, colors are used for highlight and emphases. All components are either hidden or extremely inconspicuous. 

"Same Plane Weather-stripping" is a very simple yet critical concept in sealing the multiple moving parts that form the window unit.

The drawing on the left is an attempt to illustrate the "Same Plane Weather-stripping" concept. It shows the same window as above, except sliced vertically rather than horizontally. The blind stop shown in yellow is the primary sealing surface in the system. The components that look pink and red are cutaways of the upper and lower sash. The solid red and translucent red represent the Fin Pile and Fin Pile Carrier, respectively with an actual photograph to the left of the drawing.

As with all graphics on this web site, except the headers, you can enlarge them to their full size with just a mouse click.  

The key issue is the fact that the exterior weather-stripping (right) of the lower sash and the interior weather-stripping (left) of the upper sash, as well as the head and sill seals, all mate against the same element - the parting stop. THEY ARE ALL IN THE SAME PLANE and together they make one solid sealing unit when the window is closed. There is only a small fraction of an inch of non-unified sealing surface between the meeting rail seals and the vertical weather-stripping, which will be unnoticeable. 

In addition to the primary sealing surface at the parting stop, a secondary seal is made at the interior stop, the blind stop, the head and sill. This system, properly applied to your existing windows, effectively eliminates all possibilities of air-infiltration!