How to grout my tile floor without taking it up?

Hi - try this product called grout refresh. It's not too difficult to apply and makes your floors look brand new. Amazon sells it and I'm sure your local hardware stores too.

You can use a handheld grout remover tool to chisel out the old grout. You can probably rent a tool from a building supply store like Home Dept that would make the job easier. Then clean it up and re-grout.

Regrouping is a big chore. You have to carefully dig out all the old grout to regrout.

Grout Refresh is made by Maepi, It is a wonderful product, and Amazon has the best color selection. HD only sells in white in my area. It is a colorant with a sealer, if you have to truly replace your grout, you need a grout remover tool or a dremel to take out the old grout and replace.

Floor and Decor also sells Grout Refresh in several colors. I used this in my bathrooms several years ago, and it still looks like new. It is tedious, and just work in sections but worth it. Use an artist brush to paint the color on. Makes it easier than a tooth brush and much cleaner.