U.S. DEPARTMENT OF AGRICULTURE 

FOREST PRODUCTS LABORATORY 

In Cooperation with the University of Wisconsin 

U.S.D.A. FOREST SERVICE 

RESEARCH NOTE 

FPL-0221 

1973 

FOREST SERVICE 

MADISON, WIS. 

A LOW-COST WINDOW -- WITHOUT JAMBS 
Abstract 

Experimental low-cost windows were designed and 

prototypes built. The windows, fixed and ventilating,

differ from conventional ones because jambs have been 

eliminated. The cost of fabricating, packaging,

shipping, installing, and maintaining this window 

should be less than that of conventional windows. The 

experimental window is designed to fit into 24-inch 

on-center stud spacing, but can also be used with 

other stud spacings. 
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A LOW-COST WINDOW--WITHOUT JAMBS 

By 

JOSEPH CHERN, Technologist 

Forest Products Laboratory, 1 Forest Service 

U.S. Department of Agriculture 

 Introduction 

Walls constructed with studs spaced 24 inches on center and combination sheathing-siding 

are likely to be extensively used in housing. Windows, illustrated in figures 1 to 5 and 

described here, have been designed for this type of spacing. The design eliminates the 

labor involved in framing. The thick (1-3/8 in.) members for constructing the outside 

frame can be used with combination sheathing-siding or with conventional separate sheathing

and siding. The unit may be fixed, opening (ventilating), or a combination of the two. 

Quality has not been sacrificed for low cost. 

Maintenance is reduced by exposing less wood to weathering by positioning the glass as 

close as possible to the exterior surface 2 (figs. 1 and 2). All exposed joints are vertical 

to minimize trapping water (figs. 3 and 4). Storm panels (fig. 2) or screens (fig. 4) are 

easily removed for cleaning, repairing, or replacing. The yearly maintenance tasks of 

removing storm sash and installing screens or removing screens and installing storm sash 

are eliminated because the storm sash and screen are fixed. Thus, space for storage of 

storm sash or screens is not needed. 

Compared to conventional double-hung windows, heat loss should be less with the experi- mental windows. In these windows, the glass panes are a sufficient distance apart to 

reduce conduction heat transfer, but sufficiently close to minimize convection currents. 

Fabrication Details 

The design permits machining with relatively simple woodworking equipment. Either 

mortise and tenon or dowel joints may be used to join vertical to horizontal members. 

Kiln-dried shop-grade lumber, preferably ponderosa pine (Pinus ponderosa Laws.), Sitka 

spruce (Picea sitchensis (Bong.) Carr.), basswood (Tilia L.), yellow-poplar

(Liriodendron L.), or any white pine (Pinus sp.) is recommended. Almost any other spruce 

or aspen or cottonwood (both Populus sp.)--without tension wood--would also be satisfactory.

After the wood components have been machined to size, they may be dipped in a 

pentachlorophenol and mineral spirits solution to minimize staining and decay. 

1 Maintained at Madison, Wis., in cooperation with the University of Wisconsin. 

2 Heebink, B. G. Proposed Low-Cost Window Unit. USDA Forest Serv. Res. Note FPL-0212. 

Forest Prod. Lab., Madison, Wis. Jan. 1972. 

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The glass is 20 inches wide (figs. 3 and 4), a commercially standard size. Because 

the edges of the storm panes are not covered with a strip of wood or metal, the edges should 

be rounded for safety in handling. When installing the inner glass pane, glazing com- pound can be used alone or under wood moldings to fasten the glass in position and to 

seal against outward water vapor movement. The outer panes are set in a flexible plastic

gasket to prevent water leaking between the outer and inner glass panes and to allow for 

easy removal of the outer pane for cleaning. To provide for the escape of any water vapor

that may accumulate between the inner and the outer panes, the gasket on the lower edge

is noncontinuous. Three 1/16-inch-wide openings in the gasket should suffice. A 

suitable plastic gasket is not available, but could be produced if demand were 

sufficient.

3 

The hardware (fig. 5) is simple, and could be produced by almost any small machine 

shop, but, like the plastic gaskets, is not now available. 

Installation Details 

The windows may be installed without special framing members, such as headers or 

supporting members, but nailing members above and beneath each unit are required. The 

fixed or the ventilating units may be used independently or they can be grouped. When 

placing window units one above the other, a spline should be inserted into the grooves

of each unit. A bead of calking should be spread on both sides of the spline, and the 

units compressed until there is "squeezeout" of the calking material. Thewindows 

are installed using a level to plumb them and by nailing them to the sheathing and 

studs with tenpenny casing nails. A drip cap is required (figs. 1 and 3). 

When finishing the interior surface, the studs may be covered with gypsum board or 

plywood. This results in a clean, trim appearance. 

Cost Considerations 

The design, production, and installation of the proposed windows should reduce costs 

by the following: 

1. Eliminate jambs, which, in turn, will reduce machining, packaging, and shipping 

costs, and the quantity of lumber required. 

2. Eliminate cost of framing window openings in the wall. 

3. Eliminate insulation between studs and casing, thus eliminating the need for

narrow pieces of insulation blankets. 

4. Reduce maintenance. 

3Bordner, J. Extruded Window Components. Woodworking and Furniture Digest. Pp. 41-43. 

April 1971. 

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PESTICIDE PRECAUTIONARY STATEMENT 

This publication reports research involving pesticides. It does not contain recommendations for their use, nor does it imply that the uses discussed here have been registered.

All uses of pesticides must be registered by appropriate State and/or Federal agencies

before they can be recommended. 

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and 

fish or other wildlife--ifthey are not handled or applied properly. Use all pesticides

selectively and carefully. Follow recommended practices for the disposal of surplus

pesticides and pesticide containers. 

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Figure 1. Installed -- unit shows both fixed window with 

drip cap and ventilating window. M 140 761 

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Figure 2.---Window unit from exterior showing screened 

opening and interior finishing of plywood with 

corner trim. Positioning of glass is shown at left

midsection. M 140 763 

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Figure 4. --Front (outside) of ventilating unit (left), 

cross section (center), and detailed cross section,

(right). M 141 358 
U.S. Government Printing Office: 1973 754-550/40 

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