Acrylic Dome vs Glass Skylight: A Burnaby Roofer’s Guide

For most Burnaby homes and small commercial roofs, the choice comes down to the roof and the room. A glass skylight suits living spaces where clarity, comfort and a long service life matter most. An acrylic dome suits flat and low-slope roofs, utility spaces, stairwells, warehouses and larger custom openings where cost and size flexibility count. Either one only performs if the curb, flashing and membrane around it are done properly, because on the Lower Mainland that is where leaks start.

Below, we walk through how the two compare, what Burnaby’s weather does to a dome, what the BC Building Code says about glass, and how to decide before you book a roofer.

TL;DR

• Glass skylights generally give clearer views, steadier insulation and a longer warranty. They are the usual pick for bedrooms, kitchens and living areas.
• Acrylic domes are a practical fit for flat roofs, big custom openings and commercial spaces. Over time they can yellow and craze, so plan for replacement.
• A major manufacturer’s 2022 Canadian warranty covers acrylic units for 5 years, glass units for 10 years, and sealed insulating glass against seal failure for 20 years.
• Burnaby gets about 1,840 mm of rain a year, so curb height, flashing and drainage matter as much as the glazing.
• If your dome is crazed, discoloured or leaking, a roof inspection tells you whether to repair or replace.

Table of Contents

• The short version of how they differ
• Clarity and light: what you see after a few winters
• Insulation and comfort in a wet, mild climate
• Lifespan, crazing and the Burnaby question
• What the BC Building Code says about skylight glass
• Which one fits which Burnaby building
• Where skylights actually leak
• A simple decision checklist
• Promo: skylight work from one roofing crew
• Our perspective
• FAQ
• Sources

The short version of how they differ

A dome skylight is a formed plastic bubble, usually acrylic or polycarbonate, mounted on a curb. Most are built with two layers (double dome) or three (triple dome) to trap some air between them. Manufacturers such as Canadian dome makers offer double or triple domes in clear, bronze and translucent white, on curbs from 6 inches up, and they are designed for flat roofs with a pitch as low as 0:12.

A glass skylight is a framed, sealed glazing unit. It usually has an insulating glass unit with a low-E coating and a gas fill, and often a laminated inner pane. It sits on a curb or is set into a frame, and it works on flat or pitched roofs.

Here is how they compare on what matters to the person who owns the roof:

The warranty figures come from VELUX Canada’s 2022 warranty, effective June 1, 2022. Warranty terms differ by brand and model, so read the one for the unit you are quoted.

Clarity and light: what you see after a few winters

The first thing most people notice is the view. A glass skylight stays clear, so the sky looks like the sky. A clear acrylic dome starts out bright too, but plastic reacts to sunlight over the years. The same 2022 warranty sets limits on yellowing: it specifies a yellowness index below 4.0 for 5 years and below 10.0 for 10 years on clear acrylic and polycarbonate domes, measured to ASTM D 1925. That tells you something useful: yellowing is expected enough that manufacturers put numbers on it.

What does that mean at home? In a hallway, a walk-in closet or a warehouse, a slightly warmer tint is rarely a concern. Over a dining table or a bedroom, where you look up at it daily, glass is the better match.

Tints matter for the sun side of the building. Domes come in clear, bronze and translucent white. Translucent white diffuses light and cuts glare, which suits offices, showrooms and shop floors. Bronze reduces brightness and heat on south-facing roofs.

Insulation and comfort in a wet, mild climate

Burnaby is not an extreme-cold city. The City of Burnaby’s climatic values guide, revised January 15, 2025 and based on 2024 BCBC data, lists a January design temperature of -7°C, a July design temperature of 25°C and 1,840 mm of annual rain. That means skylights here face a lot of moisture and a modest temperature swing, not deep freeze. The practical risk is condensation on a cold inner surface during damp winters, and drips where condensation runs down a curb.

Glass units with low-E coatings and a gas fill are built to slow heat loss, and that usually helps keep the interior surface warmer. A dome’s performance depends on how many layers it has and how well it is sealed. Triple domes improve on double domes, and an insulated curb makes a real difference to comfort either way. An uninsulated curb is a cold bridge that sweats, regardless of the glazing above it. If you want a deeper look at how roof windows manage light and heat, this explainer on skylight light and efficiency covers the principles.

For a room you heat and cool every day, glass is the steadier choice. For a stairwell, mechanical room or open-plan commercial space, a triple dome on an insulated curb is a sensible, economical answer.

Lifespan, crazing and the Burnaby question

Crazing is a network of fine hairline cracks that spreads across the surface of the plastic. It starts as a haze or spiderweb pattern, often on the sun-facing side of a dome. In acrylic it comes from long exposure to UV, temperature cycling and moisture, and it makes the dome more brittle. Once it begins, a wind gust, a falling branch or a hard hailstone can crack the dome through, and a cracked dome leaks.

The same Canadian warranty expressly excludes dome breakage and crazing from coverage when they result from accidents, and also excludes damage from corrosive environmental factors such as acid rain. So a crazed dome is usually a replacement matter, not a warranty claim.

In Burnaby, three things combine:

1. Constant moisture. Months of rain and damp mean water sits on the dome and around the curb. Moss and debris on a low-slope roof hold that moisture against the dome’s base.
2. Sun in the dry months. The summer sun still bakes a horizontal dome, which sees more direct UV than a window on a wall.
3. Roof movement and age. The membrane around a curb ages at its own pace. A new dome on an old, cracked curb flashing just moves the leak.

How to read the condition of your dome

From inside, look for a milky or yellow cast, fine crack lines, and brown water stains on the ceiling or light well. From the roof, a trained inspector looks at the dome edge, the gasket or seal, the curb, the flashing, and the membrane or shingle courses around it. We would rather you call us for that than climb up. Wet flat roofs are slippery, and a brittle dome can fail under a boot.

If the dome is clear, crack-free and dry, with sound flashing, maintenance is often enough: clearing debris, checking sealants and the surrounding roof surface. If you see crazing across the surface, or if the dome has been patched before, replacement is generally the safer path. Replacing the dome at the same time as the flashing and curb details is usually more reliable than doing the pieces separately.

What the BC Building Code says about skylight glass

This is the part many comparison pages skip. BC Building Code Section 9.6 on glass applies to skylights as defined in Sentence 9.7.1.1.(2). It requires glass to conform to standards including CAN/CGSB-12.1-M for tempered or laminated safety glass, CAN/CGSB-12.8 for insulating glass units, and ASTM E 2190 for insulating glass unit performance and evaluation.

A few practical points follow:

• Safety glass is either tempered or laminated, and Fenestration Canada’s compliance advisory notes it must be tested to CAN/CGSB-12.1 and permanently marked so building officials can see the class and category.
• The safety glazing standard exists to reduce the likelihood of cutting and piercing injuries when glazing in an area of human impact breaks.
• An older BC Building Code Appeal Board decision from 1988 states that safety glass in a skylight is not mandatory under the National Building Code, though the Code requires it where glass could be subject to human impact. Code editions change, so your municipality’s building department and the installer should confirm what applies to your project.
• The same advisory notes that glass in skylights must have strength suited to Canadian wind loads, which is a reason to avoid unmarked imported units.

If the skylight sits over a walkway, a stair, a pool deck or any place someone could fall onto it, tell your roofer at the quote stage. Laminated glass holds fragments in place if one pane breaks, which is the sensible specification over a space people use.

Which one fits which Burnaby building

Detached homes and townhouses

Over a kitchen, bedroom or living room, glass is the better fit for clarity and comfort. If the roof is sloped, our guide to roof types for Burnaby’s sloped homes helps frame what the skylight has to tie into. For a flat-roof addition or a garage, a double or triple dome on a proper curb is a common, economical choice.

Strata corporations

Strata roofs often carry many domes of different ages. The practical approach is to inspect all of them in one visit, record their condition, and fold replacements into the next roof maintenance cycle or reroofing project, so curb and flashing work happens once. That also gives the council one clear scope for a contractor quote. Strata and multifamily work is something we handle on our strata and multifamily roofing page.

Commercial and industrial buildings

Offices, showrooms, warehouses and recreation facilities often use domes because large custom sizes are available, and acrylic can be made in openings of up to 98¼ inches square according to one Canadian manufacturer’s custom size page. Integrated insulated curbs, available from 12 to 24 inches on certain commercial models, simplify the roof tie-in. If you manage a commercial roof, our Burnaby commercial skylight leak prevention guide and leak locations checklist show where problems tend to start.

Where skylights actually leak

People blame the dome or the glass. In our experience on Lower Mainland roofs, the more common culprits are around it:

• Curb height. A low curb on a low-slope roof lets ponding water reach the seam. A taller curb keeps the glazing clear of standing water.
• Flashing and counterflashing. Corners, step flashing and the membrane turn-up at the curb are the weak points.
• Seals and gaskets. Domes are held with gaskets or butyl tape. These age and shrink.
• Condensation. Often mistaken for a leak. An insulated curb and good ventilation reduce it, which is why our piece on roof ventilation in Burnaby’s wet climate is worth a read.
• Debris and moss. Leaves and moss hold water against the curb.

This is why swapping a dome for glass, or glass for a dome, is only half the job. The new skylight has to tie into your actual roof system, whether that is asphalt shingles, torch-on membrane, EPDM or another low-slope membrane.

A simple decision checklist

Answer these before you ask for quotes:

1. Is the room lived in daily? If yes, lean to glass.
2. Is the roof flat or low-slope? If yes, a curbed dome or a curb-mounted glass unit both work, and the curb detail matters most.
3. How big is the opening? Very large custom openings often point to acrylic domes.
4. Will anyone walk or fall near it? Specify laminated or tempered safety glass.
5. Do you need a long warranty horizon? Compare the glass and acrylic terms on the exact model.
6. What is around it? Ask for the flashing, curb and membrane to be assessed in the same visit.

If your existing dome is already crazing, the decision is mostly made for you: replace it, and use the opportunity to choose the right glazing for the room.

Promo: skylight work from one roofing crew

We install, repair and maintain skylights as part of residential, commercial and strata roofing in Burnaby and across Metro Vancouver. Because we work on the roof itself, we look at the curb, flashing and surrounding roof surface with the glazing, not as separate problems. You can see how we handle it on our Burnaby skylight installation page, or book an inspection through our residential roofing services.

For commercial roofs, start with our commercial roofing services.

Our perspective

FAQ

Is glass or acrylic better for a skylight?

For living spaces, glass is usually the better choice because it stays clear and has a longer warranty. For flat roofs, large openings and commercial buildings, acrylic domes are a practical fit. The best answer depends on the room, the roof and the budget.

How long do acrylic skylights last?

It depends on the product, exposure and maintenance. One major Canadian manufacturer’s 2022 warranty covers acrylic units for 5 years against defects, and it sets yellowing limits for 5 and 10 years. Many domes serve longer than their warranty, but crazing and yellowing signal that replacement is approaching.

What does crazing on a skylight dome mean?

Crazing is a web of fine surface cracks in the plastic. It means the dome is ageing and becoming brittle, so a knock or a wind gust can crack it. If you see it, have the dome and its flashing inspected before the next heavy rain.

Does a skylight need safety glass in BC?

The BC Building Code requires skylight glass to meet standards for tempered or laminated safety glass and insulating glass units. Rules vary with location and use, so confirm with your building department and installer. Over any area where people could fall against the glass, laminated glass is the sensible specification.

Sources

• VELUX Canada 2022 warranty
• City of Burnaby climatic and seismic values guide
• BC Building Code Section 9.6 Glass
• Fenestration Canada Code Compliance Advisory
• CAN/CGSB-12.1 safety glazing standard
• Canadian dome skylight product page
• Ordering custom skylight sizes

Recommended

• Burnaby commercial skylight leak prevention guide
• Commercial skylight leak locations checklist for BC facilities
• Skylight Installation