Under what conditions can liquid asphalt be applied over cured asphalt emulsion roof patches?

It can be considered only when the emulsion patch is fully cured and dry through its thickness, not just skinned over. Trapped moisture under hot asphalt can cause blistering, foaming, or loss of adhesion. The emulsion residue must also be heat-tolerant enough not to re-soften excessively or bleed. Surface preparation matters: remove dust, ensure the patch is sound, and confirm compatibility via the roofing system manufacturer. In practice, many specs prefer compatible asphaltic mastics or membrane systems over hot liquid asphalt unless the supplier explicitly approves the build-up sequence.