Installation of Glazing Systems

Chapter Introduction

The installation of glazing systems is the core of the glazier trade. This chapter covers all the techniques, standards, and procedures required for the safe and code-compliant installation of glazing systems in commercial, institutional, and residential buildings. You will be evaluated on your ability to interpret drawings, select appropriate materials, execute installations according to best practices, and apply Canadian regulatory requirements.

Types of Glazing Systems

Fixed Glazing (Storefront and Fenestration)

Fixed glazing refers to any glass panel permanently installed in a frame without an operable opening. Storefront systems are typically used for commercial storefronts and consist of extruded aluminum mullions and transoms. The standard depth of storefront frames ranges from 38 mm to 114 mm, depending on the calculated wind load and panel dimensions.

Residential fixed windows typically use vinyl, thermally broken aluminum, or wood frames. Thermal breaking (thermal barrier) is mandatory in Canadian climates to prevent condensation and heat loss. It consists of an insulating barrier made of polyamide or polyurethane inserted between the interior and exterior profiles.

Operable Glazing (Venting)

Operable systems include casement, double-hung, hopper, and sliding windows. Each type has specific requirements for hardware, weatherstripping, and adjustment. Window hardware must be adjusted to ensure uniform compression of the weatherstripping, typically between 3 and 5 mm of compression.

Curtain Walls

A curtain wall is a non-load-bearing façade system attached to the building structure. It supports only its own weight and wind loads, which are transferred to the structure via anchors. Common systems include:

Stick system: assembled on site, piece by piece (mullions, transoms, panels)

Unitized system: factory-preassembled panels, installed by crane

Semi-unitized: a combination of both methods

Curtain walls must accommodate differential movement between the structure and the façade. Expansion joints are typically provided every 6 to 9 meters in aluminum systems.

Structural Glazing

Structural glazing uses a structural silicone adhesive to attach the glass to the frame without visible mechanical pressure. The structural silicone must be certified to CAN/CGSB-19.13 and applied under controlled conditions (temperature between 5°C and 40°C, relative humidity below 80%). The minimum structural joint width is 6 mm, but engineering calculations determine the exact dimensions.

Materials and Components

Types of Glass

Glass Type	Common Thicknesses	Typical Use
Annealed (float)	3 mm – 25 mm	Interior, single glazing
Tempered (thermally strengthened)	4 mm – 19 mm	Doors, skylights, safety zones
Laminated	5 mm – 25 mm (total)	Safety, guardrails, roofs
Insulating (double/triple glazing)	20 mm – 50 mm (total)	Windows, curtain walls
Low-Emissivity (Low-E)	Variable	Solar control, insulation

Tempered glass is four to five times stronger than annealed glass of the same thickness. It breaks into small, non-cutting granular fragments. Laminated glass holds its fragments in place thanks to the PVB (polyvinyl butyral) or SGP (SentryGlas Plus) interlayer, typically 0.38 mm to 1.52 mm thick.

Profiles and Frames

Extruded aluminum profiles are the most common in commercial systems. The alloys commonly used are 6063-T5 and 6063-T6, with an anodized finish (architectural class AA-M10C22A41) or a powder-coated finish. Dimensional tolerances for profiles are governed by CSA A440 for windows and AAMA standards for curtain walls.

Joints and Shims

Setting blocks are neoprene or EPDM blocks placed at the quarter points of the panel width, never at the center. They support the weight of the glass and prevent glass-to-metal contact. Side blocks keep the panel centered and control thermal movement.

Weather seals are classified into two categories:

Gaskets (preformed seals): EPDM, silicone, neoprene — installed dry

Sealants: silicone, polyurethane, polysulfide — applied wet

Structural silicone is the only sealant recommended for structural glazing. Polyurethane is used for expansion joints between panels. Polysulfide is used in the manufacturing of insulating glass units.

Installation Procedures

Site Preparation

Before any installation, you must:

34.Verify that the openings conform to the drawings (dimensions, squareness, level)

35.Inspect bearing surfaces (concrete, steel, wood) for flatness — maximum tolerance of 3 mm over 3 m

36.Check environmental conditions: temperature, humidity, wind

37.Confirm material availability and proper storage (glass stored vertically, tilted at 5°-10°)

Storefront System Installation

Step 1: Layout and Anchoring

Lay out the mullion locations according to the drawings. Anchors must be spaced no more than 600 mm apart on mullions and 450 mm on transoms. Use galvanized steel or aluminum anchors, fastened with mechanical or chemical anchors. Tightening torque must comply with manufacturer specifications (typically 10-15 N·m for 8 mm screws).

Step 2: Frame Assembly

Assemble mullions and transoms with aluminum brackets or screw-in connectors. Joints must be sealed with neutral-cure silicone sealant. Check squareness with a laser level — the diagonal must not vary by more than 2 mm over 2 m.

Step 3: Setting Blocks and Glass Installation

Place neoprene setting blocks (durometer 80-90 Shore A) at the marked points. Insert the glass panel using suction cups, guiding it without forcing. Side blocks must be installed after the panel is centered.

Step 4: Fixing and Sealing

Install gaskets or apply sealant. For silicone sealant, the joint width must be at least half of its depth (2:1 width-to-depth ratio). Tool the sealant within 10 minutes of application.

Curtain Wall Installation

Step 1: Topographical Survey

Perform a precise survey of the structure. Deviations from the drawings must be documented and corrected before installation. The anchor positioning tolerance is ± 6 mm.

Step 2: Mullion Installation

Mullions are installed from bottom to top, with an expansion gap of 12 to 20 mm between sections. Mullion connectors must allow vertical movement while transmitting lateral loads.

Step 3: Transom Installation

Transoms are clipped or screwed to the mullions. Joints between transoms and mullions must be sealed with silicone. Weep holes must be provided at the base of mullions, typically 6 mm in diameter, spaced no more than 600 mm apart.

Step 4: Panel Installation

Glass panels are installed from the interior or exterior depending on the system. Use vacuum suction cups with a load capacity greater than the panel weight. Verify that gaskets are properly positioned before final fixing.

Insulating Glass Unit Installation

Insulating glass units (double or triple) require special handling:

Never lay the panel flat on a hard surface without protection

Use neoprene setting blocks, never wood

Respect the maximum panel deflection: L/180 where L is the smallest dimension

Check the perimeter seal (butyl, polysulfide, silicone)

The barometric pressure inside the insulating glass unit is sealed at the factory. Installation at high altitude can cause glass deformation. Panels with an elevation difference of more than 600 m from the manufacturing location must be reported to the manufacturer.

Calculations and Sizing

Wind Load Calculation

The design wind pressure is determined according to the National Building Code of Canada (NBC) , Part 4 and Commentary I (wind loads). The simplified formula:

p = q × Ce × Cg × Cp

Where:

p = design pressure (kPa)

q = reference velocity pressure (kPa)

Ce = exposure factor (height, terrain)

Cg = gust factor

Cp = external pressure coefficient

For a 10 m building in urban terrain, the typical design pressure ranges from 0.8 to 1.5 kPa. The glazing must resist this pressure with a safety factor of 2.5 for annealed glass and 4 for tempered glass.

Allowable Deflection Calculation

The maximum deflection of profiles under wind load is limited to:

L/175 for storefront mullions

L/240 for curtain wall mullions

L/360 for transoms supporting glass

Where L is the clear span of the profile. For example, a curtain wall mullion with a 3.6 m span will have a maximum deflection of 3600/240 = 15 mm.

Setting Block Calculation

The minimum width of setting blocks is calculated using the formula:

Width = (Panel weight × 1.5) / (Block length × Material strength)

For a 2.4 m × 1.5 m panel of 24 mm insulating glass (weight ≈ 60 kg/m²), the total weight is 216 kg. With 100 mm long neoprene blocks (strength of 7 MPa), the required width is:

(216 × 9.81 × 1.5) / (0.1 × 7 × 10⁶) = 0.0045 m = 4.5 mm

Therefore, blocks with a minimum width of 6 mm are used.

Applicable Standards and Codes

National Building Code of Canada (NBC)

The NBC is the primary reference for safety requirements. Relevant sections include:

Part 3: Fire protection — requirements for fire-rated glazing

Part 4: Structural design — wind loads, snow loads

Part 5: Environmental separation — moisture control, condensation

Part 9: Residential buildings — window requirements

Safety glazing is required in the following areas (Article 3.3.1.19 of the NBC):

Doors and adjacent panels (within 900 mm of doors)

Showers and bathtubs (within 1500 mm of the floor)

Stairs and landings

Partition walls (within 900 mm of the floor)

CSA A440 — Windows

CSA A440 (Windows) specifies test methods and performance requirements for windows. Classifications include:

A440.1: Window selection for residential use

A440.2: Air tightness, water tightness, and wind resistance

A440.3: Window performance evaluation

The performance classification is expressed in three digits: for example, A3/B7/C5 means:

A3: air leakage ≤ 0.5 L/s·m²

B7: water tightness at 700 Pa

C5: wind resistance at 2500 Pa

CSA A500 — Curtain Walls

CSA A500 (Curtain Walls) covers the design, installation, and testing of curtain walls. It requires performance testing for:

Air infiltration (max 0.75 L/s·m²)

Water penetration (no leakage at the specified pressure)

Wind resistance (permanent deformation ≤ 0.2% of the span)

Inter-story movement (accommodation of ± 12 mm)

Canadian Electrical Code, Part I

Although the Canadian Electrical Code, Part I (CE Code) (C22.1) primarily concerns electrical work, it is relevant to the glazier when installing electrochromic glazing or defrosting systems. Rule 8-200 requires that all circuits be protected against overcurrent. Electrical connections in window frames must comply with the requirements of Rule 12-100 regarding wiring methods.

CSA B149.1 — Natural Gas and Propane

CSA B149.1 (Natural Gas and Propane Installation Code) applies when glazing is installed near gas appliances. Rule 8.4 specifies minimum distances between gas appliance vents and ventilation openings or operable windows. These distances range from 300 mm to 1200 mm depending on the appliance type and rating.

Safety and Glass Handling

Personal Protective Equipment (PPE)

The glazier must wear:

Cut-resistant gloves (ANSI A4 rating or higher)

Safety glasses with side protection

Safety footwear with steel toe caps

Hearing protection when using power tools

Safety harness for work at height (fall arrest line mandatory above 3 m)

Lifting Techniques

Manual lifting of glass is limited to 25 kg per person. Beyond that, use mechanical suction cups or a crane. Suction cups must have a load capacity of 4 times the panel weight. The glass surface must be clean and dry to ensure proper adhesion.

For large panels, use an A-frame glass cart with retaining straps. Vertical transport of glass must be done at an inclination of 5° to 10° from vertical to distribute the weight.

Specific Hazards

Tempered glass can spontaneously break due to nickel sulfide inclusions. This phenomenon is rare (1 in 10,000 panels) but unpredictable. Heat soaking reduces this risk by causing defective panels to break at the factory.

Glass edges must be protected during handling. Raw edges (sharp edges) must be ground or polished before installation. Polished edges are required for exposed laminated glass.

Quality Control and Inspection

Pre-Installation Checks

Panel dimensions: ± 2 mm from the drawing

Insulating glass unit thickness: ± 1 mm

Integrity of the perimeter seal (no bubbles, no delamination)

Certification marking (manufacturer's label, applicable standard)

Post-Installation Checks

Squareness: diagonals equal within ± 3 mm

Level: maximum deviation of 1.5 mm over 3 m

Alignment: adjacent panels must not vary by more than 1.5 mm

Water tightness: water test (spray for 15 minutes, check for no leaks)

Operation: for operable windows, opening and closing must be smooth

Water Tightness Testing

The water tightness test is performed according to ASTM E1105 or AAMA 501. The test pressure is typically 15% higher than the design pressure. Water is sprayed at a rate of 3.4 L/m²·min for 15 minutes. No water penetration into the interior space is acceptable.

Summary

Fixed glazing (storefront) and curtain walls are the two main commercial systems, with distinct installation tolerances.

Setting blocks must be placed at the quarter points of the panel width, never at the center, and made of neoprene or EPDM.

Structural silicone is the only acceptable adhesive for structural glazing, with a 2:1 width-to-depth ratio.

Installation tolerances: squareness ± 3 mm, level 1.5 mm over 3 m, alignment ± 1.5 mm.

The NBC requires safety glazing in hazard areas (doors, showers, stairs).

CSA A440 classifies windows according to three criteria: air infiltration, water tightness, wind resistance.

CSA A500 governs curtain walls with mandatory performance testing.

Wind loads are calculated according to NBC Part 4, with safety factors of 2.5 to 4 depending on the glass type.

Maximum deflection of profiles is limited to L/175 for storefront and L/240 for curtain wall.

Manual lifting is limited to 25 kg; beyond that, use mechanical equipment.

Water tightness tests must be performed at 15% above the design pressure.

Common Pitfalls to Avoid

158.Placing setting blocks at the center of the panel: blocks must be at the quarter points (150 mm from the edges for a 600 mm panel). The center is the area of maximum deflection.

159.Confusing tempered and laminated glass: tempered breaks into small fragments; laminated stays in place. NBC requirements specify the type required for each application.

160.Forgetting weep holes: frames must have weep holes to drain condensation and infiltrated water. A frame without drainage will accumulate water and cause damage.

161.Using acetic silicone sealant on metal: acetic (vinegar-cure) silicone corrodes aluminum and zinc. Always use neutral-cure silicone (oxime or alkoxy) for metal applications.

162.Ignoring thermal movement: aluminum expands at 23 × 10⁻⁶ m/m·°C. A 3 m mullion undergoes a 2 mm variation for a ΔT of 30°C. Expansion joints are mandatory.

163.Over-tightening fasteners: excessive tightening torque crushes gaskets and causes local stress on the glass. Respect manufacturer values.

164.Installing annealed glass in a safety zone: always check NBC Article 3.3.1.19 requirements before selecting the glass type.

165.Neglecting dimensional verification: an opening that is 5 mm too small can make installation impossible; an opening that is 5 mm too large can cause leaks. Always measure before ordering.

166.Forgetting the certification marking: safety glass must bear a permanent label indicating the manufacturer and the standard. Missing markings can result in rejection during inspection.

167.Working at height without protection: falls are the leading cause of fatal accidents in the trade. The harness is mandatory above 3 m, with a certified fall arrest line.

168.Confusing CSA A440 classifications: the sequence is always A (air), B (water), C (wind). A B7 classification means water resistance at 700 Pa, not 7 kPa.

169.Applying sealant in cold weather: most silicone sealants must not be applied below 5°C. Adhesion will be compromised and the joint will need to be redone.

Installation of Glazing Systems