Some home inspectors, not IOC inspectors, completely ignore the roof and exterior for condos and town houses, because the HOA is responsible for them.
Couple of problems with that: Outdoor problems can quickly become indoor problems and you become your percentage of the HOA once you take ownership. In the real world, if you were buying a condo or a townhouse, you are typically responsible for the interior walls in, and the HOA is typically responsible for the exterior and the roof. Because of those reasons, if possible, we will ensure there are no glaring defects on the exterior and the roof, because those things can be detrimental to your purchase.
It is important that you understand that the seller can do nothing about any defects found on the exterior and the roof, and the HOA will not address your concerns until you were an actual owner.
Once you purchase a condo or a townhouse you are now a small portion of the HOA, so if a new roof is needed in a year, and they have not saved money for it, you may receive a special assessment, which requires you to pay for your portion of the roof.