is it ok "safe" to use roof felt on my guinea pig ramp to give them grip ? awnsers on this need to be within the next couple of hours as I'm making the ramp in a mo?/ thankyou 
I think its perfectly safe, we have a two storey hutch with one on and its been no problem from the previous pair of piggies that were in it for over 4 years. In my inside 3 storey house ive used sand paper to wear their little claws down and get some grip.
x.
I have no idea who made my hutch but it's deffo not handmade, I'm sorry I can't be more helpful on that bit because I brought it second hand, we've had it for about 6 months and not had any problems with it and the girls find it easy to run up and down xx