Rats can cause considerable damage in the attic. But not always. It depends on many factors, such as the length of time the rats have been in the attic, the number of rats, the presence of electric wires or water pipes or lack thereof, they type of insulation, and so on. This is why a thorough attic inspection is important. You can get an understanding of what the rats have done, and see specifically what damage they may have caused. Look for areas of trampled down insulation, and paths and tunnels in the insulation. Look for rat feces and urine stains. You should notice hundreds or thousands of fecal pellets. Often, but not always, rats bring nesting material into the attic. It's usually leaves and other plant matter. This is a good place to find a nest of baby rats. Look for chewed wood, and play close attention to electric wires, to see if they have been chewed and constitute a fire risk. Rats are rodents, and they love to chew, and for some reason are drawn to wires. Also, sometimes rats in the attic will die, and keep in mind that a dead rat in the attic is another form of "damage", in that it causes a terrible odor and flies! The feces and urine that the rats leave behind may cause slight odor problems, but more importantly are a potential source of pathogens or illness. Read more about specific diseases from rats. Don't touch them! Waste left behind can also encourage the growth of mold, attract bugs like cockroaches, and contains a pheromone scent that will encourage new rats to enter the attic in the future.
Here is a photo of typical rat damage - you can see brown fur grease, some chewing on wires, and lots and lots of rat turds scattered everywhere.
In this attic, rats had chewed holes in a pex water system that went into the walls and attic, causing a large water leak and damage in the house.
If exposed copper rests against any flammable material, such as wood, the heat can ignite the material and cause a house fire.
Here are rat feces, along with some acorns that they have brought into the attic. Rat feces can contain some diseases like leptospirosis or hantavirus.
Having rats in your attic is much more than just a nuisance. These rodents can cause a considerable amount of damage, particularly because they tend to be social animals that live in groups. There is always a chance of the rats in your attic putting your family at risk of contracting a disease and these animals will also cause physical damage to your attic.
The most basic damage that rats will cause in an attic is leaving behind their waste products, particularly feces and urine. Depending on the number of rats in the attic and how long they were there, there can be a significant amount of these waste products, requiring a serious clean-up effort. In some cases, the urine may even soak into floorboards or other wood structures and compromise their integrity. At the very least, the urine and feces will contaminate your attic, transmitting disease and creating a foul odor. If you don’t take care of this smell, it may attract more wildlife to the attic.
Chewing Wires, Pipes, Insulation, And More
Rats, just like mice, will chew on nearly anything you have in your attic, whether it is a wire, pipe, or something else. Rats are notorious for their chewing behavior and will chew on nearly anything in your attic. In the case of chewed wires, this can be a serious fire hazard, particularly if you aren’t aware that the wire has been compromised. Rats may also cause damage to your pipes from chewing and do the same to insulation. Without the insulation in good shape, your home won’t regulate temperature as easily, leading you to spend more money to run your air conditioning in the summer and heating in the winter. Of course, if you have any items stored in your attic, such as books or old furniture, you can expect these to be damaged by rats as well. They will likely be chewed and may even end up covered in waste products.
What To Do About The Damage
Because rats can cause a great deal of damage to your attic, you will need to thoroughly inspect the space after removing the rodents. You should work with a wildlife removal expert to make sure all rats are out of the attic. Then, you can clean and carefully inspect the entire space. Ideally, you will have a professional of some sort help with the inspection as they will know exactly what to look for. The sooner you clean the attic and repair any damage, the better since you don’t want to attract more rodents or put your home at risk.