Just the opposite of what you might think, doing a metal over metal recover may actually add strength to your existing structure especially when using the roof hugger system. The roof huggers are structurally attached to the existing purling and designed in a way that stiffens the purling. That being said reputable metal roofing contractors will take advantage of the engineering services offered by roof hugger or the metal roofing manufactures and will have a recover system designed to your specific building’s needs.
2. Do I have to use a standing seam metal?
You do not have to use a standing seam metal roofing panel with roof hugger and the metal directly over metal type of recovers but the high clip system only works with standing seam. That being said most building owners and facility managers are looking to avoid the problems and maintenance associated with screw down metal roofing and choose to re roof with standing seam.
3. How Much does a metal over metal recover cost?
There are far to many variables in metal roofing, types of steel buildings, and geographical snow load consideration to throw out unit prices figures or even ball park numbers. But I can tell you that doing a metal over metal recover is far less expensive than trying to tear off your existing metal roof and insulation and replace it but it is more expensive doing a PVC metal roof lay over or a metal roof Coating. For the folk who just need a dry building the PVC metal roof lay over is a great option but many people prefer the look and performance of metal and are willing to pay more to get what they want.
4. Do you have to add insulation to fill the space between the old metal roof and the new?
You do not have to add insulation to fill the cavity created by laying metal over metal but it is recommended. Not only will you be adding R - Value to your building the added insulation can greatly reduce the chance of having condensation between the two pieces of metal. Another benefit of the insulation is that wind blowing hard over standing seam and cause “panel chatter” and the insulation stops this from happening. Panel chatter is when the metal roofing panel vibrates against the purling and makes noise that can be heard inside the building.
5. What if I want to spend the extra money to Remove the old metal and insulation and go back with new insulation and standing seam metal roofing?
This can be done and some folks may prefer to pay more and remove old metal and insulation however a structural engineer must be hired especially if the old metal that is to be removed is screwed down. The screwed down metal provides the Structure with Diaphragm strength. Standing seam metal because it moves along the clips do not provide diaphragm strength so bracing must be added to properly support the purling before the standing seam metal roof can be installed. Again, Reputable metal roofing contractors will assist you will engineering calculation and specs if this is the route you would like to take.