How do I replace countertops?

Home Depot have premade laminate tops. Unscrew old one from underneath and put on new one. View on you tube step by step instructions on how to.

You could also order quartz or granite countertops from Home Depot and have them installed, but this would be more. I’d check for sales.

First. I'd decide what kind of material you want for a countertop. Then, find a local store you can meet with to discuss details. Home Depot and Lowes are great, too.

If your existing countertops are wood or laminate, you can unscrew them from inside the cabinets. Remove drawers and look up and you should see flat boards with screws that attach the countertops. If your countertops are some solid surface (Corian, stone, concrete) you will need to consult a professional because those types of countertops attach differently and are extremely heavy.

To replace countertops with something with a wood base (laminate, butcher block, etc.), you would cut the new countertops to fit based on the size of the old ones and screw them in just as the old ones were done.

If you are adding an overhang for a breakfast bar type seating area, you will need to add some sort of support from underneath to keep the overhang part from sagging.

If you are replacing countertops with a solid surface, you will need a professional to make sure the existing cabinets can structurally support the weight and probably will need them professionally installed unless you are one of those amazing people who can pour your own concrete countertops.

Here is another suggestion: https://www.alifeunfolding.com/blog-1/2019/5/28/how-to-diy-a-concrete-bar-top-in-a-weekend?rq=Countertop