How can I keep squirrels, raccoons, etc. from ruining my roof?

That's not good. Why weren't any points of entry screen or closed off?

If you have had companies come out to your house , I guess you have already been told to make sure you have no tree branches hanging over or coming close to your house !!!! Another thing you can do is go around the house and stuff steel wool in any openings around the eves. Also check into any repellents...keep lights on in your attic...They make boxes that you plug in that make high pitched noises that humans can't hear , but animals can...Also you can buy predictor scents that will deter them from staying in there. Good luck !!!

you could try a Wildlife Trapping service -- such as https://www.crittercontrol.com/, or contact your local/State Wildlife Management for recommendations ... you can purchase kill or trap/release traps from various sources .... but bear in mind that any removal will only be temporary --- Nature abhors a vacuum, and eventually, if feed supply, shelter, is available something will take advantage of it.

My local hardware store has bags of animal repellant that you can throw onto your roof, and they won't want to be there anymore! Also, I have had great results with a company that uses "Hav-a Heart" cages/traps. They trap & remove the critters. Sometimes it takes awhile--there might be many raccoons or squirrels in your yard, so they have to keep trapping until no more show up. Good luck!

If you have trees nearby, squirrels will use them to gain roof access. If trees are oak or walnut, your attic provides a warm, secure storage space for the acorns/nuts, as well as a birthing habitat. Consider trimming tree limbs or tall, heavy shrub branches, to limit access.

Unfortunately, squirrels must constantly keep their teeth filed down, and once in your attic, they will use your roof trusses/ attic wood framing for this purpose...

If you have textured brick, squirrels will easily climb it.

If you have 1950's styles louvers on gable ends of your house, squirrels will "bench press" them apart to gain access to attic. You'll have to attach "hardware cloth" with multiple, closely mounted screws into the perimeter, to refuse them access.

Some styles of roof vents have permitted access to determined squirrels, so insure yours do not.

Your chimney will need securely screened with squirrel proof material, or otherwise covered to prohibit entry.

If you or your neighbors are feeding birds, consider stopping the practice, as it only encourages more squirrels.

Keep your yard well trimmed, and monitor for squirrels attempting to hide items in your yard or mulch. You may try spraying putrescent egg and garlic mixture nearby to dissuade squirrels.