How do i stop my puppy peeing in the kitchen?

My 8week old lurcher puppy is doing really well with his house training, he has not yet pooped in the house!! but will ask to go out for the toilet and sometimes come in and wee on the floor in the kitchen, I've been taking him out when he makes the mistake and positively reinforcing it when he goes in the right place but he's still making mistakes. Can anyone help???