There are a few different ways to waterproof your attic, depending on your needs and the condition of your attic. One way is to install a roofing membrane over the entire roof, which will prevent water from seeping in. You can also add insulation over the membrane to help keep your attic warm in the winter.

If you have a problem with water seeping in through the roof, you may also want to install roofing flashing along the edges of the roof. This will create a watertight seal and prevent water from seeping in.
If you have a problem with water seeping in through the walls, you can install waterproofing membrane on the inside of the walls. This will prevent water from seeping in and damaging your insulation.
If you have a problem with water seeping in through the floor, you can install a waterproofing membrane on the floor of your attic. This will prevent water from seeping in and damaging your insulation or flooring.
No matter what type of waterproofing solution you choose, it’s important to make sure that the attic is properly ventilated. Otherwise, the humidity levels could become too high and could damage your insulation or roofing membrane.