A crack across a skylight does not automatically mean the roof opening, frame and interior shaft all need rebuilding. Some units accept replacement glazing or a replacement glazed sash. The answer depends on the exact model, available parts and condition of the surrounding assembly.
A cracked overhead pane also changes the immediate priority. Keep people clear of the area beneath damaged glass and arrange qualified assessment. Do not press it, open the unit to test it or put tape on it from a ladder. The purchasing comparison can wait until the situation is made safe.
Pat lays out the two proposals: one says glass, the other says skylight. "Before we compare prices, we need to know how much window each of them means." That turns out to be the useful question.
Find out what the replacement part actually includes
The VELUX Canadian replacement page says replacement glass is available for most of its skylight models, with the operating sash included for specified venting generations. That is a useful example of why "glass only" can mean different things. It is not a promise that a pane can be supplied for every old brand or discontinued unit.
Use the model-identification guide before requesting prices. Ask the supplier to name the service item: sealed glazing assembly, complete operating sash, lens assembly or whole skylight. Those descriptions tell the installer which parts remain and which connections must be opened.
Replacing one sheet within a sealed insulating-glass unit is not the same job as exchanging a manufacturer-supplied assembly. Do not compare a general pane-cutting price with a complete, fitted service kit and assume the difference is markup.
Look at what the new glass would be attached to
A sound frame, working mechanism and serviceable roof connection make a limited repair more attractive. Frame deterioration, repeated operating faults or unsuitable flashing can change that calculation. New glass does not correct those defects. On the sketch, Pat draws a line around the glazing, then another around the frame. Keeping those two circles separate prevents the most expensive misunderstanding in the conversation.
Suppose the glass is damaged but the frame is recent and dry, with an identified replacement assembly available. Retaining the rest may avoid unnecessary work to the room. Now suppose the same enquiry reveals a deteriorated frame and staining around a poorly connected curb. Pricing only the glass postpones questions that are already visible.
Have the inspection separate those findings. A crack is not evidence that every flashing has failed; an old roof is not evidence that the skylight frame is sound. Ask for photographs of the condition used to recommend each part of the scope.
Compare the complete visit
Both proposals should include safe access, removal and disposal of damaged glazing, the correct replacement components and completion checks. Ask whether ceiling protection, internal trim or redecorating is included. If a sash changes, confirm compatibility with the operating mechanism, screen and shade.
For full replacement, add any curb, flashing, opening and interior-finishing work. For a limited repair, ask what warranties apply to the replacement part and installation. A low parts price can still involve substantial access work above a staircase. The access platform is conspicuously absent from the photograph of the replacement pane. It is less absent from the installer's working day.
VELUX Canada's warranty summary treats glass seal failure, parts defects and hail breakage as separate coverage categories.
How much of the skylight changes?
A service part can replace more than the visible pane without requiring a whole new opening.
Glazing assembly
Retains the suitable frame and compatible surrounding components.
Glazed sash or lens
Replaces a larger product-specific assembly; check mechanisms and accessories.
Complete unit
Addresses a wider condition or compatibility problem, with roof and interior scope included.
Keep cause, coverage and repair separate
A supplier may need the model, purchase history, photos and cause information to assess a warranty enquiry. Do not describe a crack as hail damage merely because a storm occurred nearby. Nor should a warranty enquiry delay urgent protection where glass is unstable or water enters.
Check the actual manufacturer's current terms and the age of your product. Coverage for seal failure, component defects and hail breakage can differ. A repairable unit is not necessarily a covered repair, and a covered part does not establish that every access or finishing cost is included.
When ordering, confirm the required glazing construction. Similar appearance is not permission to substitute a different overhead-glazing specification. If a roof replacement is already planned, compare the timing before paying for access twice. The useful choice preserves serviceable parts while resolving the defects actually found.