Side-by-side comparison
Sherwin-WilliamsA-100 Exterior Fast Dry Stain Blocking Alkyd Wood PrimerN/A · White—Not enough dataReplace
Sherwin-WilliamsExtreme Block Interior/Exterior Stain Blocking Waterbased PrimerN/A · White63GoodReplace
Sherwin-Williams A-100 Exterior Fast Dry Stain Blocking Alkyd Wood Primer N/A White vs Sherwin-Williams Extreme Block Interior/Exterior Stain Blocking Waterbased Primer N/A White
Sherwin-WilliamsA-100 Exterior Fast Dry Stain Blocking Alkyd Wood PrimerN/A · White—Not enough dataReplaceSherwin-WilliamsExtreme Block Interior/Exterior Stain Blocking Waterbased PrimerN/A · White63GoodReplaceSherwin-Williams A-100 Exterior Fast Dry Stain Blocking Alkyd Wood Primer has no score yet because the maker hasn't published every document we need. Missing data is not evidence of harm.
| Fact | A-100 Exterior Fast Dry Stain Blocking Alkyd Wood Primer | Extreme Block Interior/Exterior Stain Blocking Waterbased Primer |
|---|---|---|
| Use | Exterior primer | Exterior primer, Interior primer |
| Sheen · base | N/A · White | N/A · White |
| VOC (untinted) | 338 g/L | 24 g/L |
| VOC added by tint | Not stated | Not stated |
| Emissions testing | Not documented | Tested (LEED emissions) |
| Health certification | None found | None found |
| Safety Data Sheet warnings | None | 2 |
| Ingredient disclosure | Partial (environmental data sheet) | Partial (environmental data sheet) |
| Safety Data Sheet revised | Not dated | 8/25/2026 |
Highlighted rows are where the two products differ. Facts come from each maker's documents; "not disclosed" means the maker hasn't published it, not that the product failed a test.
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Scores summarize the evidence makers publish. They don't guarantee safety or predict individual health outcomes. How we score
Sources
Sherwin-Williams A-100 Exterior Fast Dry Stain Blocking Alkyd Wood Primer
Sherwin-Williams Extreme Block Interior/Exterior Stain Blocking Waterbased Primer