Inspired by my brother’s success story of how well his basement was improved by glass-block windows, I decided to have glass block installed in my basement. Also, my wife had been mentioning that it would be a good thing to do. I called a local glass-block window installer, and he quoted $360 ($120 for the 3 windows). In case you’re comparing your own basement windows, mine were 33 inches wide by 17 inches tall, so the glass block windows use 8 inch by 8 inch blocks, 4 wide and 2 high.
I felt like not spending that much money, so I declined his quote and decided to do it myself. My wife, knowing how I like to start projects but not finish them, gave me a deadline of one month. It was the beginning of October when I bought the materials, and she said if they were not installed by November 1st, I had to return the stuff to the store. Two of the three windows were done on October 18th, and the third one was installed on the 25th, so I beat the deadline. I just need to grout the joints of the last window, and it’s done.
Was it worth it? I spent $98.45 per window, saving $21.55 per window or $64.65 overall. But I spent 11 hours on the project, making my hourly rate about $5.88. Maybe it would have been better to hire the guy. But now I have experience installing glass block windows, and I got to spend quality time with my sons as they helped me with the project, and it’s not like I would have earned $60 more dollars if I had those 11 hours to do something else.
The main improvement is that there is now natural light in the basement. Before, because they were so old and in bad shape, the windows were boarded over, so that room in the basement had only a single light bulb. Now, during the day, I don’t need to turn on the light bulb because there is so much light. The old windows were wood-framed and single-pane. So they let in water and outside air, and let out the inside air (which, with winter starting and the furnace running, is not good). The only thing the glass blocks let in is light.
Details:
Cost:
- glass blocks: 8 for $37.63 = $37.63 per window
- railings: 6 for $49.74 = $16.58 per window
- horizontal spacers: 3 for $13.05 = $4.35 per window
- vertical spacers: 20 for $25.18 = $1.26 per spacer or $7.56 per window (plus $2.50 in waste)
- sealant: 3 tubes for $17.64 = $5.88 per window
- grout: $26.40 or $8.80 per window
- lumber for spacers: $49 = $16.33 per window
- caulk for spacers: $3.97 or $1.32 per window
Extra items that I’ll use again so they don’t count against this project:
- grout float: about $5
- grout sponge: about $2
Time:
- 2 hours (over 3 different occasions) of trips to the store to buy the materials
- 1 hour for setup
- 1 hour for tearing out the old windows
- 2 hours for installing the first window
- 1 hour for installing the second window
- 2 hours for installing the third window
- 2 hours for grouting
Setup consisted of opening the boxes, explaining each item to my two little helpers, taking price stickers off the windows, reading the instructions to figure out how to proceed, etc. The glass blocks came in boxes of 8, so that was perfect for my situation. The store sold assembled windows (a 4 by 2 block window), but they all came with the fresh-air vent, which I did not want.
The first window took a while, because of the learning curve, both of the glass-block installation procedure and also how to work with my basement window openings. My window openings were about an inch or inch-and-a-half too big in each direction, so I had to install a board on each side to act as a spacer, making the window opening just a bit smaller so the glass blocks fit snugly. My main problem was that the saw was upstairs in the garage, so I would measure a board, take it up to cut it, come back and install it, etc. If I had the saw in the basement, where the work was occurring, that would have saved a lot of time.
The third window should have taken less than an hour to install, as I was getting faster with each window. But that window had dirt piled around it outside, so I had to dig that away. Then I discovered that the existing wood frame was rotten, from the wet dirt, so I had to cut out the rotten parts and replace them. For the other windows I just left the existing wood and built onto it.
Here’s how much time it should take to install a window, if the opening is the right size.
- Cut railings and horizontal spacer to length: 10 minutes
- Install railings and glass blocks dry fit (assemble them in the window put don’t attach anything): 5 minutes
- Attach railings with screws and then place glass blocks with sealant: 10 minutes
So really, each window takes less than a half hour to install. It’s just the preparation work that slows it down. The grout doesn’t count in this time because the sealant has to cure for at least 24 hours before you can grout. So wait for all the windows to be installed and cured, then grout them all at once.
Tips:
Cutting:
The railings and spacers are plastic. My tip for cutting them is to start with a hacksaw and switch to a utility knife. maybe my hacksaw was just getting dull, but it seemed like it was taking forever to cut each piece. By the end, the method that worked best was to start the cut with the hacksaw, to get a straight line in the plastic – a groove for the utility knife to follow. Once the groove was there, I ran the utility knife down the groove several times, attempting to bend the plastic after each run. I guess the knife is more for scoring the piece than cutting it. Once I could bend the plastic at the cut (the snap after the score – hey wait, this isn’t about football), the piece broke apart quite nicely and one more run of the knife finished the job.
Spacers:
If you have even more time than money, don’t buy the vertical spacers. They are $1.26 per 8-inch spacer. But they are the same as the horizontal spacers, just cut to size. If you buy an extra 4-foot horizontal spacer and cut it yourself, it would be 40 inches / 8 inch spacers = 5 spacers for $4.35 or $0.87 per spacer. On this project, that would have saved me (25.18 – 17.40 = 7.78). But it would have taken at least an hour to cut the 18 pieces that I needed. I think it’s not worth it.
Sealant:
The sealant gives some recommendation for how many blocks you can seal per tube, but I’ll give my experience here. If you apply it sparingly, you could get one tube to last for 12 blocks (1.5 windows). But I don’t recommend using it sparingly, so I suggest getting one tube for every 8 or so blocks.
Lumber:
For the lumber to fill the extra window space, I used 1x6s and 1/2x6s, about 27′ of length of clear pine. That was the $49. I could have saved some money by going for the lower grade of pine, and right now I don’t know why I didn’t. Most of it is hidden, so it doesn’t need to be pretty. I think I just didn’t want to be working around knots.
Grout:
The grout came in a medium-size bucket. I mixed only half the powder, and that would have been enough for at least 10 windows. So if you buy the 15-lb bucket of grout (and that’s the only size they carry), don’t use much of it. I estimate a full bag would be good for 160 blocks. I expect that an open bag of grout won’t keep indefinitely (it is plastic-lined to keep out moisture), so I don’t know what the point would be of using only a quarter of the grout and saving the rest. That’s what helps the profit margin of the construction-products companies: people buy more than what they need and throw away the excess. In this case, I would like to have bought a smaller container of grout mix, but I couldn’t. And I could store the extra in an airtight container and save it for the next project, but I don’t know when that will be and storage space is at a premium. So I’m just going to dispose of the extra grout mix when I’m done with the last window.
Hammering:
Even if you tell yourself you’re going to be careful, do not use a standard hammer around glass block. I was trying to adjust something next to the first window, just after I had installed the last block in that window. Unfortunately, the hammer missed its target slightly and broke a newly-installed glass block. Since the sealant was only a few minutes old, I could remove the block and install another one. But, as it was broken, that set me back about a half hour – removing the pieces, cleaning out the sealant from that opening, putting in new sealant, and putting in the new block. Little pieces of broken glass and sealant are not a good combination. So use a rubber mallet, not a hammer, around glass blocks.
The light is pleasant, and {it is} good for the eyes to see the sun.
Ecclesiastes 11:7