Roof cleaning companies in Portland should check the roof for good seals, check vents, nails, flashing etc. Pipe vent boots wear out about every 10 years or so and a lot of times you would not know it unless you are on your roof and know what to look for. Most the time people do not notice leaks because the water is a small amount and leaking onto the insulation causing mold and dry rot. We are able inspect, advise and repair. Pipe vents are the number one cause of roof leaks.  We check them when doing your roof cleaning job.