Some agents and buyers ask me why I am spending so much time on the exterior of a town home when it is the responsibility of the home owner's association. The answer is really quite simple. Defects with the exterior often effect the interior. And although the association may repair a bad roof, they may not be so interested in replacing the moldy insulation and dry wall in your walls and ceilings.
In addition, I have found that many town home associations tend to use the lowest bidder, not necessarily the best craftsmen. Consequently, the work done can be rather poor quality. Often times no one goes up and actually checks out the work that has been done. Most associations do not have staff technically trained in these areas nor do they have someone that is actually willing or able to get on the roof.
Roofs are just one are of the exterior items that require attention. Issues such as poor grade can cause moisture and mold issues. Missing or deteriorating caulking can can cause damage to walls and windows. The damage caused by these defects are seldom covered by the association.
Bottom line, make sure you have your town home inspected and be insistent that your inspector cover the exterior as thoroughly as he/she would a single family detached dwelling.