Hello chaps, my first post and I'd like some advice.
Background: When we bought our house in 2000, the previous owners had the front entrance built out and bricked in under the small roof-cum-lean-to area above the porch. The small area involved had a couple of layers of roof felt installed. All was well until a couple of years ago when we had a so-called tradesman replace the gutters. He did about five houses in our terrace. To be sure he did a reasonably good job but I asked him to use a board if he was going to stand on the lean-to which of course the idiot did not. Hence, his clumsy size 12 boots pressed into the roofing felt and obviously did some damage to it. When we had the snow recently, it froze and the water expanded some of the fine cracks Mr. Bodgit's boots had caused. When the snow thawed, some water has come in and dripped onto the ceiling board above the front door. The damage itself is not serious but the problem is not going away.
Ideas: The idea I have is to put some new layers of roof felt down and use a good felt adhesive between the layers. What I would like to do is consider putting something rigid under them so that if anyone stands on it in future the weight will not damage the felt. The question is what material do you recommend? Our local timber yard has various board types in stock (I need about 8' x 2'6" which as you can see is small area. Some of the options that come to mind are a good ply-board or maybe an OSB-type board. To be honest, we don't get much rain on this area but obviously wind can drive rain onto it.
Although I have a 20Kg gas bottle I don't have the "soft-flame" burner they use when layering roofing felt. My only heat option is a blow-torch and that will likely burn holes in the felt hence my thoughts on using an adhesive.
I'd appreciate any advice you guys may have to offer.