A. Normally, an adhesive caulk wouldn’t be as strong as glue, but they are really intended for different purposes. Glue should be used in cases where two surfaces can be brought into intimate contact and held there under pressure for an extended amount of time. Often, this just isn’t possible on the job site. Thus, the reason for adhesive caulks and mastic adhesives: They have a gap-filling ability not available with traditional yellow or white glue.
Adhesive caulk should certainly be strong enough to adhere a backsplash to drywall. The limiting factor is really the strength of the drywall.
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