Paint cratering on renovation jobs? Learn causes, field fixes, and prevention contractors use to eliminate fisheyes and avoid rework.
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Nothing kills the finish on a fresh coat like those tiny craters that refuse to level out. Fisheyes happen when contamination beats your paint’s surface tension — silicone, oils, waxes, even polishing sprays. Why it matters? Rework, delays, and awkward callbacks. In this guide, you’ll nail the why, learn quick on‑site diagnostics, and use proven fixes that stop craters in their tracks. We’ll also cover prevention so your next room doesn’t bite back.
A fisheye is a small, circular crater that forms as wet paint pulls away from a contaminated spot. You’ll see perfect little rings, often reappearing even after a second coat. Common culprits: aerosol silicone (furniture polish, bathroom sealant residue), cooking oils, hand creams, old waxes, and glossy alkyds not keyed in.
Fisheyes don’t just look bad — they signal low surface energy. If you don’t change the surface (clean, abrade, bond, or block), the next coat will usually crater in the same spots.
Mist or wipe clean water across a small area. If the water beads or forms “islands” rather than sheeting within a couple of seconds, you’re likely dealing with silicone, oil, or wax.
Use isopropyl alcohol (70–90%) or a dedicated deglosser on a small patch. Let flash off for 5–10 minutes.
Scuff a 150 mm square to dull the sheen. Spot prime with a shellac‑based or high‑adhesion bonding primer. When dry to touch, apply a small test topcoat.
On a busy hallway, a solvent wipe plus bonding primer typically stops cratering. As a rule of thumb, whole‑wall priming adds around 1–2 hours per 12–15 m² for a two‑person crew.
Many contractors find one coat of shellac stops fisheyes on small patches; widespread aerosol overspray may require priming the entire wall or room. Plan for an extra litre of shellac per small room and ventilation time due to odour.
On old doors, time spent on deglossing is recovered in finish quality. A solvent wipe on the handle area is smart insurance.
It’s common for fisheyes to radiate around light switches. A 200 mm perimeter of shellac primer in these zones often prevents re‑occurrence.
State clear assumptions and care notes in your proposal:
With Donizo, you can speak these assumptions on site using voice‑to‑proposal, attach quick photos of suspect surfaces, and send a branded PDF for e‑signature. Contractors often report this reduces back‑and‑forth and cuts admin by a couple of hours a week because clients accept the conditions up front. Accepted proposals convert to invoices in one click, so you’re not retyping line items.
| Risk | Common Source | Prevention That Works |
|---|---|---|
| Silicone film | Furniture polish, sealant handling | No silicone on paint days; shellac spot‑prime hotspots |
| Light oils | Cooking vapours, hand transfer | Degrease, abrade, bonding primer |
| Glossy alkyd | Old trim/doors | Thorough degloss + bonding primer |
| Wax residues | Old furniture wax | Aggressive clean, mechanical key, shellac block |
In general, building a small contingency into room redecoration pricing avoids unpaid rework. Many contractors find adding a clear “Decontamination and Priming (if required)” line reduces disputes.
Using Donizo templates, you can keep these clauses consistent. Speak site notes, generate the proposal, get a legally binding e‑signature, then convert to an invoice when the client accepts — all without re‑entering data.
Usually not. If the surface energy is wrong, extra coats simply replicate the crater. Fix the surface first (clean, abrade, and prime with shellac or a bonding primer) and then topcoat.
Shellac‑based primers are the go‑to when silicone is present. They block, bond, and raise surface energy. For light oils or glossy but clean surfaces, a high‑adhesion bonding primer can be enough.
Not reliably. Degrease thoroughly until water sheets, abrade, then prime. If in doubt, spot prime with shellac around switches, handles, and high‑touch zones.
As a practical rule, avoid silicone products in the space for at least 48 hours before painting and keep fresh sealant work protected from overspray or roller mist. If sealant has been applied recently, mask it and plan to shellac prime adjacent surfaces.
Additives can improve levelling but won’t cure contamination. You still need to remove or block the contaminant and raise surface energy with the right primer.
Fisheyes are a surface‑energy problem, not a paint quality problem. Diagnose fast with a water‑break, solvent wipe, and adhesion patch. Fix with targeted cleaning, abrasion, and the right primer — often shellac where silicone is involved. Prevent issues by controlling site products and locking clear assumptions into your paperwork. If you want to capture those assumptions and photos on the spot, build a branded PDF, get a legal e‑signature, and turn the accepted proposal into an invoice without retyping, try Donizo’s voice‑to‑proposal workflow. Less admin, fewer callbacks, better finishes.
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