I will tell you a fact.. when you go inside earth your weight decreases and when you go above earth's Surface , then also your weight decreases.It means your weight is the most when you are on the surface of the earth or else near to that. It means force acting on you above earths surface is less or else we can say that the gravity acting on us is less. So, definitely the conclusion is that the more further you go from earths surface the less will be the effect of gravity no matter you go up or down into the earths's surface drilling. But here there is very little difference in height as compared to radius of earth.So, it will affect the gravity acting on it or your weight very negligibly. Negligibly also your weight will be more at 1st floor rather than at 20th floor.YEAH THERE WILL BE DECREASE IN GRAVITY AND INCREASE IN HEIGHT.Hope it helps...!