DIY Network

Glass-Block Basement Windows Glass Block Window From "Ask DIY Home Improvement" episode DADH-213

Q: I have drafty basement windows, and I'd like to install something more energy-efficient and secure. Do you have any suggestions?

A: In most cases, old or damaged windows are the top source of a home's energy loss. Escaped heat around windows can actually account for as much as 25 percent of a monthly utility bill. But here's a money-saving option: glass-block windows. These attractive windows not only elminate drafts, but also provide privacy and keep out prowlers. Read on for measuring and ordering tips from DIY Home Improvement expert Brad Staggs ....

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	Basement window, BEFORE.
	Basement window, AFTER -- with glass blocks.
	Figure A
	Figure B
	Figure C

At the DIY Project House for Habitat for Humanity, the basement windows are a mess -- and Brad Staggs is on hand to head up their replacement. While changing out beat-up windows is often a low priority on most homeowners' to-do lists, that's a shame, says Staggs. Old, drafty windows waste lots of energy -- open sections can drive utility bills through the roof -- and worse, the glass is easy to kick in or break, making them all too appealing for burglars.

As we learn from the Habitat project featured in this segment, the installation of glass-block windows is fairly simple. Just follow these easy guidelines:

• Measure the window openings from outside, not inside. A common mistake people make is to measure the windows inside for the replacements, but for glass block, you'll need to be outside. Since the windows featured here are built right into the foundation, Staggs measures the full width (figure A) of the masonry opening (as if the frame were already removed).

• Next, he measures the height of the opening from the top of the foundation wall up to the wood or steel support (figure B) , making sure the height includes the sill thickness, since the sill will be removed.

  Tip: To see if a sill is removable, tap it. If it sounds hollow, it should come off easily. If a sill is permanent, just measure the height from the top of the sill.

• The next step is to measure each remaining window, since the dimensions of many basement windows are different. Once all measurements are verified and recorded, they're ready to take to a glass-block vendor. The retailer will help make sure you order the proper size (figure C) -- and remember to let them know if the windows in question will require any kind of vent openings.

• Once the shipment has been received, follow the manufacturer's instructions for installation, and consult the vendor / retailer with any specific questions regarding the process.