Choosing Between Mortar and Mortarless Systems for Midwest Weather
Introduction
When it comes to glass block installation, one of the most common questions homeowners and contractors in the Midwest ask is: Should I use a mortared or mortarless system?
It’s a smart question — especially in regions like Ohio, where temperatures swing from humid summers to freezing winters. These weather shifts can cause expansion, contraction, and moisture buildup that directly affect the longevity of your installation.
Choosing the right system isn’t just about looks — it’s about performance, durability, and maintenance over time. This guide will help you understand the difference between mortar and mortarless glass block systems, how each performs in Midwest conditions, and which one is best suited for your home or project.
Understanding the Two Systems
Before diving into which is best for Ohio’s unpredictable climate, it’s important to understand how these systems differ in structure, installation, and performance.
Mortared Glass Block Systems
A mortared system uses traditional masonry mortar between glass blocks to hold them together. The result is a permanent, rigid installation that feels solid and timeless.
How it works:
Mortar is applied between blocks during assembly.
Joints are smoothed and sealed to create a seamless wall.
Once cured, the system becomes one unified structure.
Typical uses:
Basement windows
Exterior walls
Security-sensitive installations
Historic home renovations
Mortarless Glass Block Systems
A mortarless system replaces mortar with vinyl spacers and silicone sealant. This modern method creates flexibility, faster installation, and a cleaner aesthetic.
How it works:
Pre-cut vinyl spacers keep the blocks evenly aligned.
Silicone bonds the blocks and provides weather sealing.
Frames or channels hold the finished window or wall securely in place.
Typical uses:
DIY installations
Bathroom partitions
Interior walls
Smaller replacement projects
Both systems have their strengths — but in the Midwest, climate plays a major role in determining which one performs better in the long run.
Midwest Weather Challenges: What You’re Up Against
Ohio and neighboring states experience significant seasonal fluctuations, with humidity, heavy rains, and winter freeze-thaw cycles that can stress construction materials.
1. Temperature Extremes
In winter, mortar can freeze before curing if not installed correctly. During summer, high humidity can delay drying times and trap moisture inside joints.
2. Moisture and Condensation
Basement windows and exterior installations often face condensation buildup. If moisture seeps into joints or cracks, it can weaken seals and affect insulation over time.
3. Freeze-Thaw Cycles
Repeated freezing and thawing can cause expansion and contraction — leading to cracks in rigid materials like mortar if not properly sealed.
These conditions mean that choosing the right glass block system is about finding the balance between strength and flexibility.
Comparing Mortar vs. Mortarless Systems for Midwest Conditions
Durability
Mortared Systems: Extremely strong once set, forming a permanent wall. With proper sealing, it can last for decades. However, poorly mixed mortar or improper installation during cold weather can cause cracking.
Mortarless Systems: Highly flexible, allowing for slight movement during freeze-thaw cycles without cracking. Silicone remains elastic, making it a smart choice for shifting climates.
Weather Resistance
Mortared Systems: Performs well against heavy winds and impacts but can absorb moisture if not sealed properly.
Mortarless Systems: Offers superior moisture resistance due to silicone’s waterproof nature. Ideal for humid basements or bathrooms.
Aesthetic Finish
Mortared Systems: Traditional look with visible joints — complements brick or stone exteriors found in older Columbus homes.
Mortarless Systems: Sleek, clean lines with minimal seams — perfect for modern interiors or contemporary remodels.
Installation Time
Mortared Systems: Takes longer, requires curing time and masonry skills.
Mortarless Systems: Faster, cleaner, and easier for DIY homeowners or quick professional installations.
Maintenance
Mortared Systems: May need occasional repointing or resealing over decades.
Mortarless Systems: Low maintenance; silicone can be replaced or refreshed easily.
Decision Guide: Which System Should You Choose?
Both systems can perform exceptionally well in the Midwest — the right choice depends on your specific project and environment.
1. Choose Mortared Systems If:
You’re installing exterior or basement windows exposed to impact or high wind.
You want a traditional, historic look to match older Columbus architecture.
You prefer a solid, masonry feel that lasts for generations.
You’re working with a professional installer experienced in cold-weather masonry.
2. Choose Mortarless Systems If:
You’re completing a DIY installation or need a fast turnaround.
Your project involves interior walls, bathrooms, or modern remodels.
You want greater flexibility for shifting temperatures.
You’re installing during cold months when mortar curing could be affected.
3. Hybrid Approach (Best of Both Worlds)
Some Columbus contractors use a hybrid system, combining mortar on the perimeter for stability and silicone inside joints for flexibility. This approach can be ideal for exterior walls exposed to Midwest weather extremes.
Expert Tips for Midwest Installations
Temperature Control: Install during mild weather whenever possible. For winter projects, use insulated curing blankets to protect mortar.
Proper Sealing: Always use high-quality silicone around frames and edges to prevent water infiltration.
Vent Options: For basements, integrate vented glass block windows to allow airflow while maintaining security.
Local Materials: Work with a Columbus-based supplier that understands Ohio’s seasonal conditions and offers region-tested products.
Maintenance Check: Inspect seals annually — especially before winter — to ensure lasting performance.
FAQs
Which system lasts longer?
Both systems can last decades when installed properly. Mortared systems tend to have higher structural rigidity, while mortarless systems perform better under movement and temperature changes.
Can I install glass blocks myself?
Yes. Mortarless kits are designed for easy installation and are ideal for homeowners comfortable with DIY projects. Mortared systems are best handled by professionals.
Is one system more energy efficient?
Both systems provide excellent insulation. Mortarless installations may perform slightly better in humid climates due to silicone’s airtight properties.
Do mortarless systems look less durable?
Not at all. Modern mortarless designs use strong vinyl and silicone components that maintain a clean, professional finish comparable to traditional masonry.
Can I use mortarless glass block for basements?
Yes, but ensure proper waterproofing. Many Columbus homeowners use mortarless systems with vented frames for efficiency and convenience.
Conclusion
In the Midwest, where temperatures can drop below freezing one week and soar the next, choosing between mortar and mortarless glass block systems comes down to understanding your home’s environment and long-term goals.
If you value traditional craftsmanship and timeless strength, a mortared system is an excellent investment. But if flexibility, ease of installation, and moisture resistance are priorities — particularly for Ohio’s variable climate — a mortarless system might be your perfect fit.
Whichever you choose, working with a local Columbus glass block supplier ensures you get materials built for Midwest conditions — providing beauty, durability, and performance through every season.
