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Guide to Glass Block Windows

Glass block windows are a little known but very appealing alternative to traditional windows and glazing. Glass block windows are a good option because of their versatility and valuable benefits. These windows can be used to fill a variety needs, are easy to install, durable and cost-effective. The following sections of this guide will outline more information about glass block windows, including uses and benefits, prefabricated glass block windows, installing glass block windows and pricing.

Glass Block Windows

There are a variety of places around the home that glass block windows are well suited for, including the basement, bathrooms and other areas that require privacy or do not require ventilation. Glass block windows are very functional in these roles because of their construction and properties. The windows allow in ample natural daylight to comfortable light a room, but can ensure complete privacy. A variety of attractive patterns can be designed into the glass to make it nearly impossible to see through the windows. Further, the thick glass block windows have an insulating R-value on par with double pane thermal windows. R-value measures the insulation quality and thermal resistance of building products. The higher the R-value, the better at insulating it is. Glass blocks are assembled by fusing two hollow glass halved together under heat, which creates a partial vacuum and increases the insulation capacity. This means that glass block windows are good at regulating temperature change within the room to help keep utility bills under control. In addition, glass block windows are durable and scratch resistant which is valuable during installation and with wear and tear over time. Some window products are made out of acrylic blocks, but these do not possess the same quality and durability as glass block. Glass blocks are 6.5 times stronger than acrylic blocks and therefore can remain looking good for many years. Lastly, installation of glass block windows is a simple and straightforward process that can be done at home.

Prefabricated Glass Block Windows

Prefabricated glass block windows are a valuable product for many homeowners. These are pre-assembled windows that can be found to match common window sizes around the home. The windows are completely assembled, including vertical and horizontal structural reinforcement between each glass block, siding, and all that is required is for the window to be installed. Prefabricated glass block windows often have nailing flanges around the perimeter of the window. This makes it easy to install the window and ensures quality weather proofing around the perimeter. Further, the prefabricated are very strong and durable, assuring a long life and added security to your home.

Basement Glass Block Windows

Basements are a common place to use glass block windows. Issues of quality lighting, security and ease of installation make them a good choice for basement applications. Glass block windows will allow in ample daylight to light these spaces of your home, but will also ensure privacy, durability and security. Quality constructed basement glass block windows will prevent moisture transfer between the outside and inside of your home. This is a particularly valuable asset in the basement, as moisture infiltration is more likely because of rain and snow runoff. Further, the durability of the basement glass block windows will ensure that the unit will continue to function well and look good for years to come. In addition, the strength and durability of the glass block windows will add security to your home by making forced entry difficult if not impossible.

Install Glass Block Basement Windows

Before purchasing and installing a basement glass block window it is important to determine the correct size. To do this, measure to each side of the foundation, including the width of the frame. Then measure from the top of the sill to the header of the existing window. Once these numbers are determined, subtract a 1/2 inch from each measurement to give room for mortar. Your final numbers should be in whole inches. Also, remember to check your local building codes, basement windows require a vent in some areas. If this is the case, prefabricated glass block windows can be found with vents built in.

A professional should be used to install large or custom windows, but most window replacements can be completed in a do-it-yourself fashion. Tools necessary for a typical window replacement include a hammer, tape measure, caulk gun, bucket, cold chisel, hand or circular saw, level, wrecking bar, trowel, mortar, stepladder, 3 wedges, hearing protection and eye protection.

Begin by removing the old window and the window jamb. The jamb may take some effort to remove and may be held in place by a mortar curb. A good strategy to try is to cut through the sill with a saw and then use a wrecking bar to pry it up. If there is a mortar curb holding the sill in place, simply chip it away with a cold chisel. Once the sill is free, continue to use the wrecking bar to remove the side jamb and head jamb. Use the chisel to remove the rest of the mortar curb so that there is a clean rough opening to install the glass block window.

Before setting in the new glass block window, screw in a temporary block below the sill plate to hold the window upright during installation. Next place the wedges bottom of the rough opening and set the glass block window in place with the bottom resting on the wedges. At this point it is a good idea to have a helper on the inside to prevent the bottom of the panel from sliding inward. Use the tape measure and level to assure that the window is centered and level. Tap the wedges in further to raise the glass block window about 1/8" to 1/4" above the sill. Once the panel is centered and level, the helper on the inside should place a third wedge near the center of window.

At this point it is time to mortar the window in place and caulk it. Begin by packing mortar under the panel and creating a smooth curb, but leaving room around the wedges. After the curb along the bottom begins to harden, move onto the sides and fill in all gaps. After the mortar has begun to stiffen, smooth out the joints with a striking tool. Allow the mortar to sit for at least two hours, longer on a cool day, and then remove the wedges and fill in the gaps. Lastly, use caulk to seal the gaps between the window and the sill plate. Remember to seal both the inside and outside.

Installing Glass Block Windows

To install a glass block window in other areas of the home, begin in a similar fashion by measuring the opening and removing the old window. If the home is brick, stone or a similar material, the process will be quite similar to the basement window described previously. For a wood frame home, begin by centering and leveling the window in the same fashion as for a basement window. Use a caulking gun to fill in the areas around the perimeter, remembering to caulk both the inside and outside. Allow the caulk to dry for 24 hours before removing the wedges and filling in the gaps. Some prefab windows will have nailing flanges or vinyl frames, which can be used to nail the unit to the existing framing of the window. Once again, be sure to caulk all around the window to ensure there is no moisture penetration.

Glass Block Window Prices

The pricing of glass block windows will vary with the manufacturer, the thickness of the glass block, the size of the prefabricated unit and other factors. For a ballpark estimate, expect to pay anywhere from $80 to $150 for a 9 1/2" by 9 1/2" opening. A 40" by 55" glass block window may cost anywhere from $450 to $950. The larger the unit and thicker the glass block the more costly the unit will be.

If you are considering new windows are replacement windows, glass block windows are a good option to consider. They allow for light, privacy, security, durability, good insulation and weather tightness and are an attractive solution for a variety of applications. Further, they are cost-effective and can be installed in do-it-yourself fashion.

Glass Block Windows Guide

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