Comparison Summary
For a sound, eligible surface where an existing-mold claim is the priority, Zinsser Mold Killing Primer 276049 is the most direct pick, followed by an appropriate topcoat. For a clean bathroom or laundry-room wall that needs its finished color and sheen, choose a PERMA-WHITE variant instead. Zinsser Mold Blocking Spray 287512 is a compact spot-priming alternative, but its blocking claim should not be confused with the gallon primer’s killing claim. WATERTITE-LX and KILZ Basement & Masonry Waterproofer address prepared masonry; neither replaces repair of an active leak. The WATERTITE-LX quart is particularly worth checking by model number: manufacturer documentation identifies 271098 as waterproofing paint, although its product listing calls it a mold-killing primer. (rustoleum.com)
Buying Guide
Sizing and Capacity
Size the purchase for coats and usable surface, not just the room’s floor area. PERMA-WHITE manufacturer data estimates approximately 300–400 square feet per gallon per coat depending on application and porosity, and calls for two coats for proper performance. Its eggshell 2774 and satin 02704 picks are quarts; the semi-gloss 2761 listing contains two 64-fl-oz containers. Check the package quantity before planning a whole room. (rustoleum.com)
Zinsser Mold Killing Primer 276049 lists 400–450 square feet per gallon, with smoothness affecting coverage. Spray 287512 is instead a spot-work format: its label estimates approximately 20 square feet per can. Masonry absorbs coating differently; KILZ 239041 specifies 75–125 square feet per gallon. Do not use an interior-wall paint’s coverage figure to buy masonry waterproofer. (rustoleum.com)
Feature Tradeoffs
Start with the claim you need. Zinsser 276049 is a primer labeled to kill existing mold on its eligible applications and can take any topcoat. KILZ Mold & Mildew primer instead describes protection of the primer film and adds stain-blocking utility; its name does not establish an existing-mold killing claim. PERMA-WHITE provides the finished eggshell, satin or semi-gloss surface and protects its paint film, not the material behind it. (rustoleum.com)
For masonry, WATERTITE-LX 270267 offers a film-protection claim alongside a specified waterproofing role. KILZ 239041 is an alternative when porous masonry waterproofing is the main task, but do not buy it on an assumed mold-killing claim. The compact WATERTITE-LX 271098 serves the same kind of small masonry project, despite the conflicting primer wording in its listing. (rustoleum.com)
Best For, Avoid If
| Profile |
Recommended Product |
Why It Fits |
Avoid If |
| Buyer priming a larger, sound non-porous area where an existing-mold claim matters |
Zinsser Mold Killing Primer 276049 |
Model 276049 is labeled as a mold-killing primer and accepts a topcoat. |
The material is damaged, remains wet or needs a finished sheen from this can alone. |
| Buyer finishing a smaller, cleaned bathroom or laundry-room wall |
Zinsser PERMA-WHITE 2774 Eggshell |
Model 2774 supplies a washable eggshell interior finish with mold protection on its paint film. |
You need an existing-mold treatment or protection against prolonged water contact. |
| Buyer spot-priming an eligible non-porous area |
Zinsser Mold Blocking Spray 287512 |
The 287512 aerosol targets small areas and can be topcoated after the label’s stated interval. |
You need to coat a broad wall or specifically want the gallon primer’s killing claim. |
| Buyer coating prepared basement masonry |
Zinsser WATERTITE-LX 270267 |
WATERTITE-LX 270267 combines a masonry waterproofing role with mold resistance on its paint film. |
You have not addressed an active moisture problem or are painting ordinary bathroom drywall. |
| Buyer priming several moisture-prone spaces before finish painting |
KILZ Mold & Mildew Primer L204614 |
The KILZ listing contains six quarts of a stain-blocking primer with primer-film protection. |
You need a finish coat or a product documented to kill existing mold. |
| Buyer waterproofing a properly prepared porous masonry wall |
KILZ Basement & Masonry Waterproofer 239041 |
KILZ 239041 is formulated for concrete and masonry above or below grade. |
The wall has an active leak, is a floor or requires an existing-mold killing claim. |
Key Specs to Compare
Check four items on the exact can: primer or finish, permitted substrate, sheen if it is a finish, and recoat interval. Model 276049’s label says touch-dry in 30 minutes and recoat in one hour; PERMA-WHITE technical data gives a two-hour recoat time under stated 70°F and 50% relative-humidity conditions. Those timings are not interchangeable. The Mold Blocking Spray label permits a topcoat after 30 minutes and estimates approximately 20 square feet per can—not the 8–10 square feet stated in the product listing. Use the exact product label when the two disagree. (rustoleum.com)
For finish choice, eggshell is the less reflective PERMA-WHITE pick, satin the middle option and semi-gloss the more reflective one. Match an adjacent painted surface by sheen as well as color. For masonry, check whether the wall is bare or previously painted before comparing waterproofing specifications.
Setup and Handling Considerations
First resolve the moisture source and assess whether the material is sound. EPA guidance advises cleaning and drying moldy surfaces before painting and notes that moldy porous material may need removal; a coating does not restore damaged drywall. The 276049 label’s existing-mold claim is limited by its non-porous-use directions and calls for pre-cleaning when a surface is wet, slimy, heavily soiled or covered with loose material. Its label also prohibits application below 50°F or in poor drying conditions. (epa.gov)
Choose application equipment to match the area. A brush or roller suits the gallon primer and wall paints. Spray 287512 suits a contained spot, but its manufacturer label calls for a well-ventilated area; contrary to the listing’s water-based cleanup description, that aerosol label specifies mineral spirits or xylol for wet-paint cleanup. Read its aerosol safety directions rather than borrowing instructions from the water-based gallon. (rustoleum.com)
Maintenance and Longevity
A washable coating still needs the moisture conditions that let it last. For PERMA-WHITE near a shower, the manufacturer says to wait 24 hours before shower use and seven days before scrubbing; regular cleaning and ventilation remain relevant after that. Its paint-film protection is not protection against an active leak, immersion or prolonged water contact. (rustoleum.com)
Watch masonry for renewed seepage, peeling or persistent dampness rather than treating a freshly coated wall as proof that its water source is solved. Before maintaining or recoating a waterproofed wall, check for cracks or unsound coating and follow that exact product’s preparation directions. A bathroom finish, a blocking primer and a masonry waterproofer have different service conditions.
Reliability Signals
The strongest evidence for a particular job is a product number paired with its label or technical data—not the word “mold” in a storefront title. Rust-Oleum identifies 02704 as satin PERMA-WHITE, even though that listing’s model field says something else. It identifies WATERTITE-LX 271098 as waterproofing paint, not the mold-killing primer named in its listing. These differences make checking the received can especially important. (rustoleum.com)
Treat a film-protection guarantee as a claim about the coating under its application conditions, not a promise to remediate a room. Compare stated substrate exclusions and required coats along with any duration claim. Likewise, an EPA-registered ingredient protecting KILZ primer film is not evidence that the primer kills existing mold.
How to Compare Reviews
Check that an account describes the same model, package and surface you intend to use. An experience with Zinsser 276049 on a sound non-porous surface is more relevant to that primer than one involving aerosol 287512; both use mold-related names but carry different claims and application directions. For PERMA-WHITE, separate 2774 eggshell, 02704 satin and 2761 semi-gloss experiences so sheen or package differences are not mistaken for coating performance.
Give particular weight to descriptions of preparation and moisture exposure. A comment about a dry bathroom wall says little about a leaking masonry basement. For WATERTITE-LX 271098, confirm that the writer received the waterproofing paint identified by the manufacturer rather than assuming the listing’s primer title was accurate.
Common Mistakes
Do not substitute film resistance for treatment of an existing problem: PERMA-WHITE and KILZ Mold & Mildew primer serve different roles from Zinsser Mold Killing Primer 276049. Do not assume the similarly named 287512 aerosol makes the same killing claim as 276049. And do not use any of these coatings to conceal wet, damaged material or avoid fixing the moisture source.
A second mistake is buying by nominal container size alone. A quart may not cover two full coats of a room, while six aerosol cans remain a spot-application format. Finally, distinguish bathroom walls from masonry: KILZ 239041 and WATERTITE-LX are specialist waterproofing choices with substrate and preparation requirements, not general substitutes for interior finish paint.
Frequently Asked Questions
Which pick is actually labeled to kill existing mold?
Zinsser Mold Killing Primer 276049 has that label claim for eligible non-porous applications. Follow its preparation and use directions; do not treat the claim as permission to coat wet or damaged material.
Can I use PERMA-WHITE instead of primer?
On a suitable, clean interior surface, PERMA-WHITE is a self-priming finish paint. It provides the final sheen and mold protection on its paint film. It is not a substitute for an existing-mold treatment or for a separate stain-blocking primer when staining calls for one.
Is the Zinsser 287512 spray the same as the gallon mold-killing primer?
No. Model 287512 is Mold Blocking Spray for spot priming; model 276049 is the gallon Mold Killing Primer. Match the claim and surface directions to the model on the can.
Will masonry waterproofing paint stop an active basement leak?
Do not use a coating as a shortcut around diagnosing and fixing the water source. In particular, KILZ 239041 technical data excludes walls with active leaks. Check the selected waterproofer’s substrate and preparation directions before coating.
Why is WATERTITE-LX 271098 listed as a primer?
That product listing conflicts with manufacturer documentation, which identifies 271098 as a one-quart WATERTITE-LX waterproofing paint. Confirm the can’s model and label if you want the masonry coating; choose 276049 if you need Zinsser’s mold-killing primer.
Final Recommendation
Choose Zinsser Mold Killing Primer 276049 when a sound, eligible non-porous surface calls for a primer with an existing-mold claim and you plan to add a finish coat. If the surface is already clean and dry and your main job is finishing a smaller bathroom wall, Zinsser PERMA-WHITE 2774 Eggshell is the better fit: it supplies the final washable sheen and protects its paint film.
