FYI: If you're not looking for a full-home resealing, you can try using mastic duct sealant — basically, a paintable sealant that will close leaks and holes — for a quick DIY way to plug one ...

Keep in mind, it doesn’t have the elasticity of crack sealant rubber. What is it Used for? Ryan explains in the interview, that mastic has many uses. Great for patching over “spider-cracks ...