What criteria should be used to evaluate and select between a torch-applied bituminous membrane and a liquid-applied waterproofing system?

Choosing between a torch-applied and a liquid-applied membrane for a concrete roof based on the following specific requirements:

1. Roof Shape and Complexity
Torch-on membranes are ideal for large, flat, lesser obstructed surfaces.It can be difficult and risky to install around complex details like air conditioning units, vents, Service pipes and sharp angles.
Liquid-applied systems perform better on complex roofs with many pipes, drains, or corners. Liquid-applied systems such as polyurethane coating or acrylic coating can flows into tight spaces. It creates a seamless, monolithic coat that wraps perfectly around difficult shapes and penetrations.

2. Safety Considerations
Torch-on membrane demands the use of open-flame gas torches to melt the bitumen into place. It is dangerous—or even prohibited—if your roof is close to combustible materials.
Liquid-applied membrane are "cold-applied" coatings rolled, brushed, or sprayed onto the surface, requiring no open flames, making them safer for roof close to combustible materials.

3. Application Time and Curing
Torch-on membrane once torched and cooled, it provides an immediate waterproof seal.
Liquid-applied membrane takes longer to apply because you must wait for each of the multiple coats (usually 2 to 3) to dry and cure, which can take several hours depending on local humidity.