My boyfriend and I have lived in our house for six months. When we first bought it we did a housing inspection and nothing was mentioned or noticed with the roof. Now, when we had our cable company out the other day fixing our TV signal, they told us that they noticed some cracks in our concrete tiles and that we should get them checked out. What I'm wondering is how long are these concrete tiles meant to last in the first place? Should we be concerned that cracks are appearing now, especially if they weren't before?