Our roof is 200 years old. The house is 45 ft long and 20 ft wide. The roof pitch is about 8.5 in 12. The rafters vary from 3.5 to 4 inches high and are about 3 inches wide. Most of them are on 28 inch center but 3 of them are on 40 inch centers. the roof is not sheeted. The perlins are a full 1 inch thick by about 2.5 inches wide. They average about 4 inch centers....nothing consistent about this roof. The roof now has a very old standing seam steel on the back of the house and a 12inch by 12 inch embossed steel shingle on the front. There was a paper of some sort under the steel roofing but it has all deteriorated badly and is flaking off. We have some leaks.
The house is on the national historic register.
We found some metal shingles we like here. http://www.classicmetalroofingsystems.com/styles/rustic-shingle/
The questions is, what are our options. One roofer said that we could probably not sheet this roof as it would not take the weight. I am also concerned about having too many people on the roof at one time for weight reasons. It is leaking so we have to do something. Thanks for any help you can give. Fred
Guest User
2012-02-05 11:20:27.000000
You are right about the mositure. It is a problem. I have put almost all new windows in the house and sealed the doors better. I have also added unbacked insulation to the attic. That has made the attic colder in winter. I am now seeing mold on the perlins. Once in a while I see moisture on the underside of the galvanized metal. I never saw that before. When we moved here the upstairs bathroom had a fan that vented right into the attic. I piped that so it vents out through the window in the end wall of the attic, but I still see mold. I also installed a 12 inch fan in a window in the end wall. There are no vents in the roof and no vents in the end walls of the attic (except for the fan I added). I run that fan winter and summer. When we do the roof I am going to make sure we have proper venting.
My main worry is the size and spacing of the rafters. They are only 3.5 to 4 inches high and about 3 inches wide, and their spacing is about 28 inches on center. The fact that the roof has a rather steep pitch probably helps with the weight load.
Which would you use to sheet it, plywood or OSB board?
I really appreciate your help on this.... great to hear you are co-owner of the product I am looking at.
Guest User
2012-02-20 17:21:25.000000
This sounds like a wonderful old home. I'd love to see photos!
I would caution you against not decking the roof. Let me explain why. We tend to do things that make old homes tighter. Things like new windows and doors and even sidewall treatments. When we do these things our homes breathe less. When they breathe less, moisture we generate inside of them tends to migrate to the attic. If you do not have a great vapor barrier behind your ceilings as well ad great attic ventilation, that moisture will want to collect and condense. The bottom side of metal roofing can be very attractive for that scenario. Having decking will help avoid this though I still encourage a vapor barrier and ventilation.
Plywood decking will weigh about 1.5 pounds per square foot. Your current steel roof probably weighs about 1.25 pounds per square foot.
The product you are looking at is very low weight because it is aluminum. It weighs about .4 pounds pet square foot. Adding decking and this product will still keep your roof very low weight.
As exta safeguard though having a structural engineer review things would not be a bad idea.
You may know this but Rustic Shingle is manufactured by the company my father started over 30 years ago which I co-own today. I'd love the opportunity to work more with you on this project and see if our product really makes sense. You can email direct to me at tmiller@Isaiahindustries.com or Todd@asktoddmiller.com
Todd Miller
2012-02-05 12:13:41.000000
Thanks Fred. There is the weight of the decking but on the other hand it also will increase structural integrity to some degree. I would suggest CDX plywood over OSB just because it is more consistent and generally offers a better substrate. I would suggest nominal 1/2" thick decking.
I hope that we will have the opportunity to work together on this project.
Todd Miller
2012-02-20 20:27:22.000000
+1
Todd is absolutely correct in this application. Plywood adds very little to the overall roof weight and helps from a structural standpoint to disperse the load more evenly when walking the roof.
I would be surprised if the older structure could not handle the weight. Most older homes were overbuilt by comparison to today's lumber.
Where is the home located?
The Classic Rustic Shingle is a great looking product and has a very solid company behind it as well. You won't find a better company to deal with in that regard without question.
Eric Novotny
2012-02-05 14:28:31.000000
3 words Fred...air-seal, air-seal, air-seal!!!
Ventilation is critical but getting the attic space isolated from the living space is just as critical.
+1 on CDX vs. OSB and get all those fans vented directly through the roof deck.
Feel free to call/email me about the approach to the attic and get some pictures of it when you can. That will help with my recommendations.
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