I am taking "2 metres, then 113 metres, and so on" to mean "2 metres, then 1\dfrac{1}{3} m, and so on."
The height of the bounces is a GP, with the first term (let's call it h) being the height of the roof. The GP is thus:
h,\ h\left(\cfrac{2}{3}\right),\ h\left(\cfrac{2}{3}\right)^2,\...