When we talk of resealing the shower walls, we need to understand that it is not the same as the regular DIY job of just sealing the shower head and the tiles. While the latter would just be sealing the edges of the tiles with a regular caulking and grout, the former needs a more specialized approach. There are two considerations which have to be kept in mind while carrying out this job of resealing the walls of your shower: the leaks that have been causing the leak, and the nature of the tile work which needs to be done. It is quite easy to find professionals who can undertake the job for you, but if the job seems too complicated for you, then you could always do the resealing on your own, using a few simple tools and techniques which will help you to succeed in your venture.
The first step towards shower resealing is to find out whether you have a single leak or a series of shower leaks that have caused the leakage in the first place. This will help you decide the extent of the resealing which you will need to do. You should also take into account the nature of the tiles that you have and the extent to which they have been damaged, whether by water or from cracks or other means. If you have very difficult or old tile work, you should not even consider rerouting the tilework, unless you are confident about doing so and the work involved is worth it.
If you have found one single leak, for example the one at the bottom of the tub below the water line, then you can easily reseal the entire shower, using just caulking and grout, without needing any assistance at all. However, if there are several leaks which are spreading over an area of about ten feet or more, then you will probably want to consider the services of a professional masonry contractor who will be able to assess the extent of the damage and help you decide what would be the best course of action for dealing with the problem. In fact, many masons will offer a complete turnkey service, whereby the entire shower is sealed and prepped for resealing, including the walls, floors, ceilings, caulk, and fixtures. They may also offer advice on how to keep the shower clean and well maintained, and will often recommend specific products which can help to make the whole process easier.