Can Poor Drainage Damage a Flat Roof?

I have a midcentury home with a flat roof that I just had replaced. Previous roof was a dura-last and it was attached to the facia boards with metal screws. Poor drainage and heavy rains made the facia rot away on almost all of the house. Around my fireplace they found a great deal of dry rot, and had to replace a beam and some of the ceiling.

Would this have been caused by the old roof and they way it was fastened? Or could this be an issue with my siding? Also, is there an easy way to match the stain of the finished groove to the unfinished repair work? Are adding solar panels out of the question for me?

👉🏻 Someone would need to do the calculations on for the weight of solar panels on your roof and if it can take the extra load. A good repair finish carpenter should be able to figure out the stain. You might try and grab some of the boards that were removed and do some tests with new boards to find the right stain and finish color if you want to do it yourself. Trial and error is sometimes the only way to find the exact color. The screws going thru the facia could have been the culprit on why all the facia had a problem. Oregon rain and these flat roofs aren’t the ideal. Especially the older types of roofs. When we bought our house the roof had probably been leaking for a good 15 years. We had to pull the entire thing and start over. We went with a TPO which has been great.

👉🏻 The rot arround the fireplace is most likely due to failing or improper flashing on the masonry/chimney. The rot on the fascia could be from a number of reasons. If you have downspouts built into the roof and they plugged or there was not proper drainage and water ran over the facial often than that is the likely culprit. The fasteners, if they don’t have little gaskets/sealant just provide a path for water that is flowing over the fascia. You don’t want water flowing over the fascia. Make sure the new roof had proper drainage to the downspouts and they are kept clean and flowing free.

👉🏻 I use western red cedar for fascia boards and other areas exposed to weather. Yes the fasteners on the old fascia could have contributed to rot. As too could failing flashings or roofing. Matching stain is a bit of an art. Get samples and strive to blend new and old. Sometimes dry brushing stain from the new into the existing helps blend it. You should be able to get really close and time and weather will take care of the rest.

👉🏻 We have a flat roof and solar panels, but we told the contractor that was our intention before we re-roofed. Not sure if that makes a difference. They are tilted/slanted up to catch the sun and face south.

👉🏻 We also have a flat roof, in Oregon, and just had it replaced last fall. We also had similar damage and repairs, and also need to re stain the new part of our ceiling. Our roofing contractors added slightly pitched insulation under our new membrane roof, which helps the water drain to the edges. We also want solar but have to wait until the rest of the siding is done.

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