The short answer
Restore when the damage is on the surface, removable without distorting the glass, and the glass is structurally sound. Replace when the damage is inside the unit, has destroyed an exposed coating, goes too deep, affects safety, or when restoration costs approach replacement.
Six questions to ask
| Question | Points to restoration | Points to replacement |
|---|---|---|
| What kind of damage? | Staining, etching, scratches, oxidation, graffiti, weather pitting | Failed insulated-glass seals, damaged exposed coatings, cracks that affect strength |
| How deep? | Removable without distortion | Too deep to remove without distortion |
| How much? | Localized, or across otherwise sound panes | Widespread, with replacement already planned |
| Is it safe? | Structurally sound | Strength or safety affected |
| Time and disruption? | Typically faster and less disruptive | Lead times, permits, scaffolding acceptable |
| Cost? | A fraction of replacement | Approaching replacement |
What replacement really costs
Replacement runs into the thousands per opening and can mean permits, scaffolding and tenant disruption. It is a capital event. Restoration brings scratched, stained and oxidized surfaces back at a fraction of replacement cost and downtime. See how exterior restoration work gets classified.
How to decide fast, under pressure
- Photograph the damage before anyone touches it. See how to document existing facade damage.
- Identify the damage type with the damage taxonomy.
- Identify the glass: heat-treated, coated, tinted or spandrel.
- Get a restoration assessment with a test area on the actual glass.
- Compare the written restoration scope with replacement quotes.
When the answer is replace
- Fogging or moisture between the panes of an insulated unit
- A scratched or damaged exposed reflective or low-E coating
- Scratches or etching too deep to remove without distortion
- Cracks or damage that affect strength or safety
Get an honest answer
S&K will assess the glass, tell you honestly whether it needs cleaning, restoration or replacement, and scope the work in writing. See glass and metal restoration.
