KILLZ is a primer, but there are special concrete paints which are formulated to bond with the cement; KILLZ isn't one of them. If you place KILLZ out for a primer, it will set and you will be able to coat it with your regular paint, but it will begin to chip in a few years and become almost unsightly in about 5 depending on the wear and traffic over the painted surface.Can you use Kilz to prime a concrete porch before painting?
Yes you can but should you? No cement paint adheres best to bare cement or other cement paint. It is formulated not to require a primer. You should be able to coat the porch with one coat. Make sure the porch is clean and dry before you start to paint. If you have a pressure washer I would use it first. Don't forget to make sure you are aware of the drying time. Temperature and humidity have an effect on the drying time.