Frosted glass — also called milk glass — is glass with a cloudy, milky appearance that lets light through but prevents a clear view. The term covers both true opal glass, where the cloudiness lies in the body of the glass, and ordinary flat glass that has been obscured after manufacture.
How it is made
- Opal glass. Additives introduced during manufacture form fine crystals within the glass. It is milky right through its thickness and stays that way even if it is cut or damaged
- Acid-etched glass. The surface is chemically attacked, producing an even, velvety obscuration. It feels smooth and is relatively easy to keep clean
- Sandblasted glass. The surface is roughened with abrasive under pressure. The effect is stronger, but the open texture holds grease and fingerprints — for a bathroom door or a tabletop, etched glass is the more practical choice
- Film. Frosted window film gives a visually similar result and is a cheap fix for existing glazing, but it does not last as long
| Opal glass | Milky right through its thickness; stays that way even if cut or damaged. |
|---|---|
| Acid-etched glass | Even, velvety obscuration; feels smooth and is relatively easy to keep clean. |
| Sandblasted glass | Stronger effect, but the open texture holds grease and fingerprints. |
| Frosted window film | Visually similar and a cheap fix for existing glazing, but does not last as long. |
Uses and points to watch
- Privacy without losing light. The classic applications: bathroom and WC windows, internal doors, office partitions and stair landings
- How obscure is obscure? The further an object is from the glass, the more it blurs. Anything touching the glass stays clearly visible — worth remembering in a shower enclosure
- Safety glass. In doors, in glazing down to floor level and wherever there is a fall risk, safety glass (toughened or laminated) is required. Obscuring the glass does not satisfy that requirement; specify obscured safety glass instead
- No insulation benefit. Frosted glass insulates no better than clear glass. For a good U-value you need insulating glazing, in which the obscured surface can face into the cavity
- Cleaning. Use a neutral cleaner and a soft cloth. Abrasives polish the obscuration to a shine in patches, and that cannot be undone
Related terms
- Glass
- Patterned glass
- Building glass
- Wired glass
- Double glazing
- Glass door
- Etching
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.