kari mercer
6/13/2011
We are replacing the roof, soffit & fascia on our home that was built in 1966. We have lived there 13 years and our roof has 1 layer of shingles. The house was purchased at an auction and needed a new roof at the time of purchase but it wasn't something we could afford at that time. We have found a contractor with good references and are considering a metal roof. Currently we have no attic ventilation and very little soffit ventilation (it's wood soffit). With the new roof, a ridge vent will be installed as well as a few gable vents (whatever those are : ) The outside of the some of the boards that should've been covered with some form of flashing are rotting. We have spoken to our roofing guy and he is going to replace and repair all the issues before laying a underlayment and then the metal. Is this the proper way to handle the situation? We are hoping to sell in the next couple of years. We want to make sure it's cost effective for us but at the same time done properly so it doesn't cause an issue down the road. I'm the worrier of the family (my hubby takes it all in stride). My questions are: Is it ok to lay metal over existing roofing (our current roof is set on 1 bi's not sheets of plywood)? Will the ridge vent & soffit ventilation help with the moisture problem we see now? Will the ventilation also help keep the metal from sweating and causing an issue to the underlaying materials? Sorry so long. I've been worried about this for far too long : )
Todd Miller
Classic Products, Inc.
6/13/2011
Kari, all good questions. Due to its low weight and rigidity, many metal products can be installed over existing shingles. I always suggest a layer of underlayment between the two though. I would encourage you to choose a metal product and then send the manufacturer photos and info on your roof to get their input as to whether you install over the old shingles or not. Ridge vent is a good idea but rather than add gable vents I would increase your soffit vents. You want air coming in the soffits, bathing the underwise of the roof deck with fresh air, and exhausting out the ridge vent. Gable vents will disrupt that airflow pattern. www.airvent.com has much good information on venting. If installed with good ventilation and also a layer of underlayment, you should not have any condensation issues.

If you would like to reply to this thread, please log in. If you do not have an Ask the Experts forum user account, create one here.

Find a Contractor

Get Started Today

Take the first step to increasing the value of your home with a great looking, durable, fire resistant and energy efficient metal roof. Browse our list of qualified MRA Member Roofing Contractors in your area for a free consultation and estimate.