Dos and Donts of roofing Dec, 2016. Call Portland Roof and Deck for all your roofing and decking needs. 503.465.4940.Portland Roofing, Do’s and Dont’s.Hire a Professional.I got a call to look at a roof that the friends from the neighborhood had installed the prior year. When I first arrived at the house they took me inside to show me the attic. Well I thought they were going to let me crawl up into the attic, but I did not need to as the ceiling was open because of the leak. During the inspection of the leak I noticed that there was black mold all around in the attic.When I went around to the back of the house to look at the roof I noticed it was really flat maybe 1/12 pitch. Here is what I found on the roof itself. They had put 3 tab roofing on the flat part of the roof instead of torch down, 3 tab roofing is not to be used on any pitch less then 5/12. They ran the end of the 3 tab rows into the valley and then applied some sealer. At the top of the flat roof there was a little dip in the framing of the roof. So that made a puddle of water all the way across the top of the 3 tab roofing. That aloud the water to seep down through the keys of the roofing and onto the plywood sheeting and into the attic causing the black mold in the attic.The main leak was from the valley area, but the whole flat roof was leaking. There is no easy fix to repair this. The roof on the back side of the house will now need to be removed and the plywood replaced because of the black mold that is on it, There is no way to treat the mold as you can not access the attic area, it is only 8 inches of space.Staples.One of the main reasons for a leaky roof is the use of staples during the shingle installation. As the roof ages and flexes with the weather (snow load and wind) the top of the staple rubs the back of the shingle and eventually works its way up through the shingle. A roofing nail has a flat head of about 3/8 of and inch, while a staple is about 1/32 of an inch.This photo shows a staple placed in the face of the roof ( in a new roof you should not see any fasteners in the roofing body).This roof that we replaced had the keys of the old roofing (ends of the shingles) stacked about 2″ apart.These keys should be 8 ~ 10″ apart.Pipe Jacks.Many of the repairs that we go out on are caused by improper or worn out pipe Jacks.This pipe jack is not even nailed in and when we got on the roof it was about 1″ up the pipe and bottom of the jack was not making contact with the roof.These pipe jack installations will last as long as the rubber gasket around the pipe will hold up. Wall step shingles.When it comes to a total roof replacement we replace the wall step shingles with new metal step shingles. As we remove the multiple layers of the old roofing the level of the roofing material drops (If you remove 1 layer of comp roofing and 1 layer of cedar shake the roof height will drop about 11/2″) this means the metal step shingles that are behind the siding of the house is no longer flush with the top of the roof.Roofing Dos and Donts, Right and Wrong Roofing.Valley Metal.We have seen many different Technics when it comes to a valley in a roof.We have found that here in Portland the best method for the valley is a open metal valley. As all roof valleys catches leaves and fir needles, a open metal valley will not catch as many as a valley that is covered with the shingles.The other trouble that we have found with valleys of a roof is most people when they walk up a roof they tend to walk up the valley, nothing wrong with that but we have repaired many shingled valleys do to someone stepping through a high spot in the valley.You can see this open metal valley is not loaded full of pine needles like a closed shingled valley would be.A open metal valley will add cost to your new roof (about $50 every 10′ of valley) but closed valleys are one of the main roof repairs from holes in the valley to a improperly installed closed valleys.The next best would be a weaved valley. The one side cut valley is not the best valley for our rainy and windy Oregon weather. As you can see in the photo below rain water runs down one side and can go under the top layer of the other side. After time this will happen.