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1920 home with standing seam roof how to insulate

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Caroline Donnelly
11/10/2017
We are in the process of purchasing a 1920 home with a replacement standing seam roof. When we inspected the home we went into the attic. It is very clean and dry and there is insulation under the plywood floor . The current homeowner uses the attic for storage and there is no sign of moisture anywhere. Access is a standard staircase with a door at the bottom . There is no sealant etc around the door. There are 5 original windows in the attic that need to be replaced. The standing seam roof is a replacement but at this moment I don't know what year it was done. It is laid directly on the roof rafters, we were told this is the way all ss roofs are done in this area. Two questions: 1) there are several very small holes in the metal roof. You can see light through them but they are covered by some kind of clear sealant/covering as there is no rain etc coming into the holes and you can feel a smooth surface covering the holes. Is this a problem and what should be done long term about these places to monitor or correct this repair. 2) we would like to add insulation to the attic as gas heat which supplies the cast iron radiators is expensive in VA. We were told by one person that we could have double sided reflective material put on the rafters leaving an airspace and that this would keep the house warmer in winter and cooler in summer. I have looked up this material but it isn't rated as insulation. Another person told us we could have closed cell foam sprayed directly on the underside of the metal roof and trimmed even with the rafters and then either add a ceiling to the space to finish the attic or leave the surface of the cc showing. I read that you can't use cc on standing seam roofing due to flex/warping that could occur. So what is the best suggestion for these two concerns. Thank you c
Eric Novotny
An informed customer is the Best Customer!
11/10/2017
Currently it sounds as if your attic is being unintentionally treated as "conditioned". Spray foam is the best prescriptive fix here but I would not spray to the back side of the metal. I would like to see some rigid foam installed installed between the rafters so that the foam doesn't adhere right to the back of the roof and create any issues there. Keep in mind, the foam will have to be covered with some sort of intumescent for code compliance. Once you spray the roof, it does not require any ventilation in that case.
Caroline Donnelly
11/10/2017
Thank you I too believe it is being treated as " conditioned" even though it isn't. By virtue of the wood floor with insulation under it to keep the downstairs warmer but then the door has nothing to prevent the heat from moving up under and around it. The windows that the we were told would be a good choice would be operable. Does that makes sense ? You say we wouldn't need any ventilation. Do you have any response to the issue of the very small holes through which we can see daylight in the metal roof ? If we put rigid foam and then spray how would we monitor those holes ? Thank you , as you can tell I know nothing about any of this and am relying on folks that may or may not be as well informed as the experts on this board . Thank you ! c
Eric Novotny
An informed customer is the Best Customer!
11/10/2017
If you insulated the roof deck via foam, you don't need any ventilation at that point. What you will need is to insulate the side walls (i.e. where the windows are) and provide for some active conditioned air circulation into the attic. You won't be able to monitor the holes so I suggest you get them looked at from the exterior prior to foaming the roof.
Caroline Donnelly
11/10/2017
Ok...thank you . We won't be letting conditioned air into the attic so that answers that question. So we won't be using foam. I will have the holes looked at as soon as we take residence. Thank you for your time ! c

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