Installing Window Openings

Our typical window openning is created by building a buck for each window.  We build the bucks out of 2" x 10" treated lumber.  The windows may then be installed as per manufacturer specifications.   Wire mesh and flashing are installed prior to the application of stucco.  The buck construction lets the homeowner decide how far they want their windows recessed from the outside, and correspondingly, how much windowsill they want on the inside. Once our walls are stuccoed and drywalled they are about a foot thick, and windows that are centered in the opening have a substantial recess from the outside (which gets the window out of the sun and away from weather somewhat), but they still have a decent sill left over on the inside.

The Look of a Tech Block Wall. In the Southwestern United States, a deeply recessed window results in the "adobe" look, and gives the home a completely different visual impact from the outside than what would result from a stud or CMU block wall. Even in areas of the country that don't have adobe, the thickness of the wall that becomes apparent when the windows are recessed gives the home a more solid and substantial look and feel that differentiates it from the average home.

Our method for forming window openings is to make a box form and hang it from the framework, then install our blocks around it. We make our forms from 2x10s, from which we cut pieces of the appropriate size, which are attached together at the corners using Simpson TA9 angle brackets and #10 X-head screws. It is important to leave about an 1/8" gap between the top and bottom pieces of the form and the sides to aid removal. After grouting, the screws that attach the TA9 to the sides can be removed, and this will collapse the form a little bit within the opening, which facilitates removal. (The 1/8" gap is too small for grout to escape).

The attachment of the window forms to the framework is accomplished simply by screwing through the 2x4 frame into the edges of the 2x10 box. Depending on the size of the opening and the amount of wall above, the box form may need to be braced inside in order to resist the pressure of the grout, which is immense. When in doubt, use a brace.

More About Windows

The Tech Block Wall System can accommodate just about any size window opening, but some sizes lend themselves to our system better than others. Obviously, when a wall is made out of blocks that have vertical seams every 24", and horizontal seams every 16", working with window rough openings that are multiples of those dimensions is going to involve the least waste in material and effort. Also, sill heights and the tops of windows that are planned to happen along horizontal seams will reduce labor and waste. Happily, our blocks are well sized for conventional window dimensions and locations. For instance, living and family rooms normally have sill heights around 32" from the floor, which is two of our blocks in height. Bedroom windows are normally 48" off the floor, which is three rows of our blocks (they are this high so that a headboard can fit under them and so that the view from the outside is restricted, although some egress stipulations will require lower sill heights). Our blocks also have horizontal seams at 6'8" and 8', which are common header heights.

There are window manufacturers that require window rough opening dimensions that are so illogical that their disregard for common sense should have an impact on whether or not you use their windows. They will want you to, for instance, add 1/2" to the horizontal and to subtract 3/4" from the vertical nominal dimensions, and then this changes if the window is a single hung rather than a slider, and changes again if the window is awning. Make it easy on yourself, and chose a window company that has standard masonry set dimensions that are meant to fit inside nominal rough openings, or at least will make "call out" sizes without a big increase in cost.

Finally, any discussion of window size should also take into account that there are environmental and energy efficiency factors to consider. If you're living in a cold climate, a house with a profusion of large windows is basically designed to lose heat. If you live in a hot climate, a house with a lot of windows will gain heat. At some point the question that begs asking becomes, "Why have an R-47.5 wall when all the advantages of the wall are defeated by all the holes in it?" We know that our blocks have great resistance to sound, water, fire, air infiltration, and termites, but the characteristic of our wall system that we are most proud of is its energy efficiency. We believe in responsible design, and that begins with reducing or eliminating excessively large windows. This will save you money both during initial construction and then on every monthly bill thereafter. In the typical home, most windows are hidden behind curtains or drapes and are rarely opened, and are designed into buildings more from habit than need. We ask that you please examine your design to see if you can't reduce the size and/or number of windows -- it will save you money, and you can congratulate yourself on being earth friendly besides.