Introduction

We'll show you how to install a preassembled glass block panel for a basement window. This is much easier than installing a traditional window. In fact, it's nearly foolproof. All you need are a few tools and a few hours and you'll be done!

Cutaway of the glass block windows panel

The glass block window panel sits on the block or concrete wall and is held in place with mortar and caulk.

When it comes to basement windows, there’s nothing more practical than glass block windows. Glass block windows are weather-tight and maintenance-free. They let in the sun but keeps burglars out.

And installing glass block windows (or glass block window replacement) is nearly foolproof—if you use preassembled glass block panels. Glass block window panels come ready to install, with the blocks mortared together and secured with a metal band. All you have to do is set the panel in place and pack mortar in around it.

This isn’t exactly easy—large glass block window panels might weigh 100 lbs. or more, and filling in alongside the panels is tedious business—but it is simple. Aside from ordering a panel that won’t fit into its opening or dropping the panel, there’s not much that can go wrong. Installing glass block window panels is fast, too: You shouldn’t have any trouble installing two panels in one day.

This article will walk you through the process of ripping out old windows and installing glass block window panels in a basement made from poured concrete or concrete block. Installing glass block window panels in a wood-framed wall or basement is a bit different and not covered here.

The only specialized tools you’ll need are the masonry tools shown in our photos: a masonry or cold chisel, a pointing trowel, a margin trowel and a striking tool.

Measuring and Ordering

Some home centers carry glass block window panels in standard sizes like 14 x 32 in. and 18 x 32 in. You can also have panels custom-made by a fabricator (search online). With custom-made panels, you can choose from a variety of glass block sizes, colors and surface textures. You might also want glass block window panels with small operable windows built in to allow ventilation.

NOTE: Some building codes require that basement windows allow for ventilation. Call your local building inspector.

Fabricators can make glass block window panels any size in 1-in. increments. Panels usually can’t be returned, so it’s vital that you give the fabricators correct measurements. Most fabricators simply ask for the rough opening measurements, then figure the size of the panel.

To determine the size of the glass block window panel yourself, just subtract 1/2 in. from both the length and the width of the rough opening. This will allow space to build up a curb under the panel and provide gaps at the sides, which will be packed with mortar. Remember, your measurements must be in whole inches, not fractions of an inch.