Stage 3 glass corrosion will not wipe off, and a magic sponge makes it

Singapore shower glass fails in three stages. Stage 1 is calcium carbonate that an acid can lift. Stage 2 is silica bonding. Stage 3 is alkali-silicate corrosion of the glass itself. A melamine sponge or a cream cleanser scratches tempered glass and speeds Stage 3. Cerium-oxide polishing and a silica hydrophobic coat are S$180 to S$450 a screen. Marble, terrazzo and matte-black taps have to be masked first.

Stage 1 is calcium carbonate from hard water, sitting on the glass. A suitable acid dissolves it. Stage 2 is silica and mineral that have bonded. Acid slows down. The haze stays. Stage 3 is the glass surface itself reacting. Alkali-silicate corrosion roughens tempered glass at a microscopic level, and the rough surface holds the next deposit. At that point a wipe cannot make it clear because the smoothness is gone. SS 341 is the local tempered-glass context people mean when they say the screen is safety glass. Scratching it with a household abrasive is how a screen that was only dirty becomes a screen that is permanently matte.

Melamine sponges and cream cleansers such as CIF feel soft and cut like a fine grit. On tempered shower glass they leave a field of micro-scratches that show up in sunlight a week later. A razor does the same, faster. The restoration, when the corrosion is early, is cerium oxide on a rotary pad, which polishes glass rather than scratching it at random, followed by a silica hydrophobic coat so water sheets off. Deep Stage 3 orange-peel cannot be polished back to new without thinning the temper. The honest line is a new screen. Say that with the lights on, before the pad starts.

The bathroom around the glass is often the constraint. Acid on marble or on some terrazzo etches a dull patch you cannot buff out with the same pad. Matte-black taps spot if the acid sits on them. The sequence is mask the stone and the tap, treat the glass, rinse, then polish if the haze remains. A squeegee after every shower is the maintenance that makes the coat last. A coat without a squeegee is a delay, not a cure. Homey Furnishing prices the screen on the bathroom deep-clean page and in the room calculator when the rest of the bathroom is in the same visit.

Homey Furnishing Pte. Ltd. (ACRA UEN 202018148K), 27 Mandai Estate, #06-10 Innovation Place, Singapore 729931, carries the permit-exempt portion of this work. V On Construction Pte. Ltd. (ACRA UEN 201611708H), listed on the HDB Directory of Renovation Contractors, carries any scope that needs an HDB renovation permit. Those two invoices are not interchangeable. Tempered safety glass should not be aggressively abraded. Acids are used as labelled, with the stone masked. No hacking permit is involved. A new screen, if the glass is finished, is a glazing line and still not a renovation permit if the opening is unchanged.

Spend ten minutes with a torch, your phone camera, and a tape before you buy a product or book a hack. Write down what you see. The safe checks below do not ask you to open a live wire, cut a pressurised pipe, or lean out of a window. Look along the glass in sunlight. If acid clears it, it is Stage 1. If a rainbow haze remains, it is Stage 2 or 3. Note marble, terrazzo or matte-black fittings before anyone mixes a bottle.

Stop at the red-flag column. Stop if the only tool you have is a magic sponge, if the floor is marble and unmasked, or if a quote promises new glass clarity on orange-peel corrosion. The reason DIY fails is almost never a lack of effort. It is that the tool or chemical makes the next professional repair harder, or it hides a leak, a live conductor, or a deposit line until the damage is larger than S$80 to S$180 for a carbonate clean. S$180 to S$450 if the glass needs cerium polishing..

This is the sequence a careful technician uses so you can tell a shortcut from a finished job. Tools stay in the van. Readings and photos go on the same worksheet as the price. Labelled acid for carbonate, masking for stone and taps, cerium-oxide pad for polishable haze, silica hydrophobic coat, and a squeegee demonstration. No melamine. No razor. No CIF.

1. Step 1. Make the area safe and confirm the symptom still matches the photos. For Stage 3 glass corrosion will not wipe off, and a magic sponge makes it, that means Stop if the only tool you have is a magic sponge, if the floor is marble and unmasked, or if a quote promises new glass clarity on orange-peel corrosion.
2. Step 2. Measure before touching the finished surface. Look along the glass in sunlight. If acid clears it, it is Stage 1. If a rainbow haze remains, it is Stage 2 or 3. Note marble, terrazzo or matte-black fittings before anyone mixes a bottle.
3. Step 3. Set protection and lay out the tools that belong to this material. Labelled acid for carbonate, masking for stone and taps, cerium-oxide pad for polishable haze, silica hydrophobic coat, and a squeegee demonstration. No melamine. No razor. No CIF.
4. Step 4. Carry out the repair in the order the material allows. abrasives scratch the temper, acid etches the stone, or a hydrophobic coat is sold as a repair for Stage 3 damage is the failure this order is written to avoid.
5. Step 5. Test in place. Stage 1 film is gone, polishable haze is improved or a replacement is recommended, stone and taps are unmarked, and you have used the squeegee once before the crew leaves.
6. Step 6. Clean, label the photographs against the invoice lines, and leave the statutory openings, weep holes, access panels and labels visible.

The order matters because abrasives scratch the temper, acid etches the stone, or a hydrophobic coat is sold as a repair for Stage 3 damage is what happens when a step is rushed. Handover is a measurement, not a handshake. Stage 1 film is gone, polishable haze is improved or a replacement is recommended, stone and taps are unmarked, and you have used the squeegee once before the crew leaves. If the reading or the water test fails, the visit is not closed and a second line is priced before anyone leaves. Permit work, if the diagnosis has moved into hacking, waterproofing, or a new layout, stops here and is repriced through V On Construction Pte. Ltd. UEN 201611708H.

A carbonate wash is the small band. Polishing is the band when acid is not enough. A new screen is outside both and should be said clearly. Prices below are 2026 Singapore bands for the described scope. They are not a coupon and they are not a guess after an unopened door. A second trade, such as a PUB licensed plumber or an EMA licensed electrician, is named when the law requires it rather than buried inside the labour line. Compare rows by what they include. The planning-life column belongs to that row only.

2026 SGD scope bands

Brand, material and lifespan

Book the bathroom deep clean and add the screen on the kitchen and bathroom calculator if the whole room is in scope.

Three worked jobs show how the same symptom is priced differently in a new BTO, an older resale flat, and a private condo or landed house. The totals are the lines a household actually paid, not a national average. Permit-exempt invoices are issued by Homey Furnishing Pte. Ltd. UEN 202018148K.

Case 1: 4-room BTO in Tengah

Stage 1 chalk on a frameless screen, tiled floor, no marble. Acid clean and a coat, S$160. One hour. They were given a squeegee and a ban on magic sponges. The glass stayed clear at the one-month photo they sent.

Case 2: resale flat in Kallang

Acid did not clear the haze. Cerium polish and coat, S$320. The marble nosing was masked. A test patch was done before the full screen. The haze improved. It was not sold as new glass.

Case 3: condo in Sentosa Cove

Orange-peel corrosion and a matte-black tap already spotted by a cream cleanser. Polish was declined. The tap was left alone. A new screen was quoted as glazing. The visit charge for the honest inspection was S$80. That was cheaper than a polish that could not work.

Book the bathroom deep clean. Say whether acid already failed, and whether the floor is marble. Send the photos and the measurements from the ten-minute check. The reply prices the band on this page against what the photos actually show.

• Book the bathroom descale
• Deep-clean calculator
• Other glass in the flat