News from the Block, Innovate Building Solutions Blog
News from the Block, Innovate Building Solutions Blog
Bathroom, Kitchen, Basement Design & Remodeling Ideas for the Nicest Home or Business on the Block
Bathroom, Kitchen, Basement Design & Remodeling Ideas for the Nicest Home or Business on the Block

13 1/2 Frequently Asked Questions about Glass Block Basement and Bathroom Windows You Need to Know

Opening Image - glass block basement and bathroom windows | Innovate Building Solutions | #GlassBlockWindows #BathroomWindows #Basementwindows #FloodedBasement

The Fall cold snap has arrived. If you’ve stepped into your freezing-cold cast iron tub/shower this morning you know I speak the truth.

Conversely, if you’re not ‘enjoying’ your drafty, ‘spooky-spider-infested’ basement windows when you’re doing laundry, I bet you’d be glad to have new windows. You’ve dreamed about a first-floor laundry room, but in the meantime, you’d be happy to make this ‘dungeon’ of a basement a bit better.

It doesn’t take a rocket scientist to know your bathroom and basement windows have seen there better days. As a matter of fact, they saw their better days 20 years ago!

If you’ve ‘had it up to here’ (as Mom used to say) with rusted, rotten and drafty basement and bathroom windows I can feel your pain.

So, you’ve decided to ‘kick the digital tires’ and look into glass block bathroom and basement windows to replace your drafty, bug-infested, practically falling out ‘window gems’. You think glass block may be the answer. One problem is your contractor doesn’t seem to know squat about this product.

Like Colonel Nathan Jessup in my favorite movie A Few Good Men might say, you not only want the truth, you need the truth (in this case to determine if glass blocks windows are a sound solution for your basement and bathroom window replacements).

I’m a guy who has owned a glass block business since 1985 (I don’t want you to think I’m old so let’s say I started in the business at the age of 9). My company has put in over 750,000 glass block windows in the Cleveland and Columbus Ohio markets. Over the years I’ve learned a couple of things about these windows I’d like to share with you.

My goal in this article is simple. I’ll give you ‘the skinny’ on glass block windows by answering 13 ½ frequently asked questions. I want to make sure you’re not duped by a contractor or interior designer with misinformation I hear all the time about this product.

Let’s dig into the FAQ’s.

Frequently asked question #1– Will glass block windows get rid of drafts? Are they energy efficient?

When you want cold breezes OUT, you need a window which is not only energy-efficient, but also isn’t installed in a way you’ll get leaks through the perimeter surrounding the window.

Glass block windows are a sound solution.

Glass block basement window mortared finish basement Columbus | Innovate Building Solutions | #GlassBlockWindows #BasementWindows #BasementSecurity

With energy efficiency ratings like thermal pane windows, glass block is not only energy efficient, but the mortar around the edges (used in poured concrete and concrete block foundations), keeps bugs and drafts out.

If you want to ‘notch-up’ your energy efficiency (and increase security), check out the Protect All glass block window. It’s 21% more energy efficient than a ‘traditional’ mortared unit and ultra-tough to break out.

Frequently asked question #2– I’ve got a window in the middle of my bathtub and shower. Is there a high-privacy glass block pattern I can use to eliminate window shades?

Privacy is a must in a shower window – especially if you live where homes are close together. In fact, our company was recently asked to do a project where the owner heard about a ‘Peeping Tom’ lurking in the neighborhood. This is NOT something anyone should have to worry in a perfect world. However, we don’t live in a perfect world.

If you want privacy, yet don’t want blinds in a shower, check out the iceberg pattern glass block windows. They allow light, yet it’s not possible for someone to see in from the outside.

Multi pattern glass block bathroom window Columbus Iceberg | Innovate Building Solutions | #GlassBlockPattern #PrivacyGlassBlock #BathroomWindow

Frequently asked question #3– Do glass block windows reduce light transmission?

The short answer is no.

Since (in most cases) glass block windows will not have a frame around them, you’ll gain light vs. losing it. The ‘wave’ and ‘clear’ (see through) blocks let in more light than the high privacy ‘iceberg’ pattern mentioned above (although the difference is small).

Glass block basement windows home gym columbus ohio | Innovate Building Solutions | #GlassBlock #GlassBlockLight #GymWindows

Frequently asked question #4– How expensive are glass block windows? Can I DIY the job and save money?

Glass block basement windows range in cost from $70 up to $350 per opening depending on size of the window, whether it has air vents (see FAQ #11) and if you’re going to DIY or have it professionally installed.

For bathroom glass block windows you’ll pay between $150 (prefabricated and uninstalled) and up to $900 for completely installed unit with inside wood trim and exterior aluminum framing.

It is possible to DIY the job. However, it’s simpler to DIY the prefabricated glass block basement windows (which are simply mortared in), than the bathroom windows which require more skill due to trim work on the inside and outside.

Frequently asked question #5– How can I find a professional glass block window installer?

I’ll be honest. In many areas of the country this can be a pain in the rear. In some places it’ll be easier finding a glass block installer than getting your teenage daughter off her cell phone (anyone with teenage daughters knows iPhones are now surgically glued to their hands!).

Glass Block Window Ultimate Guide

So, if you’re looking for a professional glass block installation where do you start?

I recommend these steps:

  • Step 1) Let your ‘digital fingers’ do the walking. Type in your search engine ‘glass block installation contractors/the name of your town.’
  • Step 2) If you come up empty in step 1, look for a handyman or handywoman (is handywoman even a word yet?) or small to moderate sized vinyl replacement window company who will work with prefabricated glass block windows.
  • Step 3) Have your handy person/ window contractor contact your prefabricated glass block supply specialist to get tips and instructions to install your window(s).

professional glass block window installer in Cleveland Ohio | Innovate Building Solution | #GlassBlock #ColumbusGlassBlock #BasementWindows #GlassBlockInstall

Frequently asked question #6– How long is the warranty on glass block windows?

Warranties vary by supplier (and installer). Because this product is built like a tank, many specialty glass block installation companies (like ours) offer lifetime guarantees.

Frequently asked question #7– How do you measure glass block windows?

In most cases with glass block windows you’re going to remove those ‘lovely’ (sarcasm intended) metal and wood frames around your old single pane window. Then you’ll install a ‘frameless glass block assembly.’ Therefore, you want to measure the full size of the opening.

For basement windows measure the opening go from side to side and measure from the top of the sill to the header plate at the top.

Bathroom windows are trickier than basements to measure. If you’re looking to DIY, first take inside and outside pictures of your window. Second, email your pictures and then call your glass block specialty supplier to get feedback on how to measure your job to make sure you get the right sized prefabricated window.

Frequently asked question #8– How long does it take to install glass block windows?

Assuming you’re using a prefabricated glass block window (and IMHO you’re crazy if you don’t), most basement windows take 30 and 90 minutes to install. Bathroom windows – if they need interior and exterior trim – can take from 2 to 6 hours to put in.

Frequently asked question #9– My contractor and designer say glass block windows are behind-the-times. Are they correct?

I’m going to admit, I’m biased here. However, in my opinion this is crap!

The glass block window industry doesn’t have a style problem, the glass block industry, however, does have a marketing problem. While there are attractive styles and design possibilities, they have not been effectively shown to the market. That’s why some believe they’re out of style.

Here’s why I say this.

Name me another material with both the strength and privacy benefits of glass blocks where you can combine multiple sizes and colors in the same design?

Glass block bathroom window with colors and multi-sizes texas | Innovate Building Solutions | #GlassBlock #BathroomWindow #ColorGlassBlock #GlassBlockDesign

As I could imagine Stacy in our Columbus office saying, “Glass blocks (just like handbags) can be ‘super-cute!” And I’ll have to admit, as a guy I’m dying to say something is ‘super-cute’ just like Stacy to get people laughing!

Frequently asked question #10– Can a glass block window be used for egress in a basement?  

The answer is no.

Since glass blocks are fixed into the opening, the entire window is not operable – which is what’s needed for egress.

With this being said, there is a ‘block-like’ window you can use. With an operable acrylic block window, you’ll get the look of glass blocks, but the entire window sash can open. If you’re looking for an egress window, research your local building codes. Most window openings must be 2’ x 3’ or larger to be approved for egress.

Operable casement acrylic block window for egress | Innovate Building Solutions | #AcrylicGlassBlock #OperableWindow #CasementAcrylic

Frequently asked question #11– Can I get air through a glass block window?

Not through the glass (unless it’s broke – ha! ha!), but absolutely through the window if it has an air vent.

Vinyl glass block air vents have screens on the outside and open like a hopper style window on the inside.

Glass block air vents for air flow in a basement window | Innovate Building Solutions | #GlassBlockBasement #BasementWindows #VentedGlassBlock

Frequently asked question #12– What’s the best glass block prefabrication system? Which system can be shipped across the country since I don’t know anywhere to get these windows in my town?

If I had a bunch of ‘grizzled’ glass block industry veterans in a room (and I do call a many of these people my friends) this question, we might have a knock-down drag-out fight over the answer.

The ‘old-timers’ would argue the mortared window is best. It’s tried and true. The mortar joints are 100% filled on the inside and out.

Glass Block Window Ultimate Guide

The people who want to maximize profits while minimizing costs will argue the system where the blocks are ‘butted’ together with industrial grade silicone is best. After all, it’s the cheapest method.

Me, on the other hand, would argue for the prefabrication system behind ‘door number 3.’ This system would be the Protect All Glass Block window. It has vinyl spacers running vertically and horizontally through the blocks.

Protect All Glass block window for nationwide supply | Innovate Building Solutions | #GlassBlockSupply #LocalGlassBlock #WindowsforBasement

The Protect-All system is not only the strongest and most durable, it’s also safe to ship and 21% more energy efficient. While it’s not the cheapest, it is the best.

Frequently asked question #13– Are glass block window simple to maintain?

Oh yah. After all they’re made of glass. Wipe them down. Hose them off. Hit them (not literally) with Windex (or an organic glass cleaner) and you’re good to go.

Frequently asked question #13 1/2– Are glass block windows secure?

In addition to getting rid of drafts, another HUGE reason people choose glass blocks are for security. Since they’re mortared to a foundation, are 3 1/8” thick and difficult to break, security (and keeping the ‘bad guys out – sorry I’m being sexist here) is a big benefit.


IMHO glass block windows are not only smart because of their functional benefits (they’ll keep you warm in the Fall and Winter, keep intruders out and provide privacy), but are also fashionable (combining multiple patterns, textures and colors offer fun design possibilities for styles ranging from Bohemian to Modern Minimalist).

Is this product misunderstood? You betcha!

So, have these 13 ½ FAQ’s helped dispel the ‘half-truths’ and ‘total crap’ you’ve heard from contractors and designers before?

If you’d like assistance with design, installation or nationwide factory direct supply call us at 877-668-5888. For local installation contact Columbus Glass Block at 614-252-5888 or Cleveland Glass Block at 216-531-6363.

Mike Foti

President of Innovate Building Solutions a nationwide supplier and regional (Cleveland and Columbus) remodeling contractors. Some of our product lines include glass counters, floors, backsplashes, glass blocks and grout free shower and tub wall panels

Comments (14)

  • Joelle – yes you usually put mortar (or grout) between the glass block window joints. To repair a cracked grout joint, you’ll usually ‘rake out’ what’s cracked and ‘tuck point’ in new mortar. Feel free to call our company at 877-668-5888 for more input – Mike

  • Hello Mike, my husband & I purchased a home that was built in 1958. The bathroom tub/shower has block glass windows. Is it mortar that goes between the blocks, if so how do you clean that? It looks like there is a small chip about 2 1/2 inches long in the “mortar”, how does that get fixed? I can send you a photo. Any help would greatly be appreciated. By the way we live in Fairbanks Alaska where our temperatures in winter are usually around -15 to -45. Thank you, Joelle

  • Stephanie – you could call our company and ask for Rob or Jeff and they could give you the process to install the windows – but it would be good to send us pictures (inside and out) so we can see what your foundation looks like and how we would recommend you install them. I’ll send you a direct email and you can then send your pictures and I’ll ask one of our team to follow up with you regarding the process – Mike

  • I ordered 2 Redi2set basement windows but the mason I was working with dropped off the planet. I was going to try installing myself but chickened out and started looking for Handyman services to install. The only response I got was from a guy who told me he was going to install with caulk and trim. Good thing I read up on the windows because you’re right — they’re not well advertised or understood. I was at my niece’s in Cleveland and saw 3 in her basement. You probably installed. I’m in Southeastern CT and can’t find anyone I trust to properly install so I’d appreciate more info on where to get a clearer understanding of how regular basement windows are designed/engineered to know how to remove them. I don’t want my education to be a learn as I go. I don’t understand how they’re attached to the foundation and hesitant to open up the basement to learn.

  • Jason – this is a great question. Since the concrete will provide ‘pressure’ on the glass I would replace the glass with a concrete block – but I’d also recommend to put a ‘control joint’ (this would be a soft barrier) between the poured concrete driveway and the new concrete block inside the opening which used to be the window. You want to allow for expansion and contraction so nothing breaks. Hope this helps – Mike

  • Hello Mike,

    We are extending a concrete patio, and it will cover over an existing glass block basement window. Can we pour right over the window, 9r does it need to be replaced with masonry?

  • Liz – it is possible to install a glass block window from the outside only. Your contractor will need to put ‘stops’ up to slide the window up to. Mike

  • Elizabeth Pawlowski

    Dear Mike can a glass block window be installed solely from the outside?there is one window that a whole built in closet was built around. There is no access from the inside.

  • Lori – the answer to this is ‘yes and no.’ What I mean is the blocks come in 2″ increments (for example the most common sizes are 4 x 8, 6 x 6, 6 x 8, 8 x 8 and 12 x 12). So we can generally work in 2″ size increments. Now you can use grout to (somewhat) make up the difference in the 2″ sizes – but you also don’t want grout joints to get too big. Some of the specialty blocks (finished end blocks, curved blocks etc.) only come in 8″ high increments – so you need to be thoughtful in designing with them. If you want to make sure you can fit your window or wall opening, I’d recommend you contact one of our glass block designers who can help you to figure this out. You can reach us at 877-668-5888 – Mike

  • Tom – you have what we call a ‘pan framed’ window where it wraps around the concrete block or poured wall. We generally prefer to remove this frame before installing glass blocks since this metal frame can (and often will) rust over time. You to either burn the frames out or pull them up and over the foundation. These frames (unfortunately for you) are harder to remove than standard metal framed windows. Let us know if you need help. We also have prefab glass blocks we sell which make the actual glass block portion of the job simpler. If you need us call 877-668-5888. Mike

  • Hi Mike,

    I’m in a new build with the typical (horrible) basement windows. The metal frame was placed when the concrete was poured, and all four sides are flared and wrap around the basement wall. Everything I read says that the metal frame comes out, but I’m thinking this is a case where the frame stays, and the glass block window gets mortared inside (?) The dimensions on the frame interior leave room for a 12×30″ window to fit comfortably.

  • Sue – I am guessing from your comment you have a window system made by a company called IBP with a metal interior framework. While I’m not familiar with the specific type of metal they use – I can put you in touch with the guy who leads the division of this business and he can give you feedback on the best type of paint to use for their system. Feel free to call 877-668-5888 and ask for Mike

  • Our 2 block glass windows are 23 years old and we still like them. They are in a bathroom over a corner tub. We are updating and want to change the color of the 1 inch brass strips around each block. What type of paint can we use? We are wanting to change to a silver color. Wood trim around the windows is white

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