Ulnderlayment for standing seam roof

Guest User
5/15/2004
We know that we are going to install a standing seam metal roof. We have talked to two contractors and have estimates. I went on line last night to compare what they said vs other information that I could find. The 30# felt paper seems to be a good choice. However; one website suggested the installation of blanket fiberglass insulation over the felt paper. Question 1) should we do this? I am also thinking about having them install ridge vents along the entire length of the roof cap. We do not have continuous soffits - they are probably 5' apart plus we have louvers at each wall where the roof comes to a point. Question 2) should be have a continuous ridge cap or should we use turbines like we have now? We live in the San Antonio, Texas area and I do not know what to ask our contractor to do. Question 3) should we be be using red resin paper too in addition to the 30# felt paper? I can't find anything on the internet about it and yet our third contractor said that he would use that. I just want to make certain that we do this project right the first time. Also, we are leaning toward galvanized metal instead of the galvilume. I know it can be soldiered. Question 4) Is it a good choice? We still have many questions before we can start our project. We will be taking off the old composite shingle roof. Please help! We can't wait to get started, but we won't budge until we get more information.
Todd Miller
Isaiah Industries, Inc.
5/15/2004
Barbara -- I will try to help. Thanks for planning on metal. 1) I would not put insulation between the underlayment and the roofing panels. It will make it too difficult to get the panels to lay flat. 2) 30-pound felt has been used for years but it should have red rosin paper over it. Otherwise, the felt will stick to the back of the roofing and tear when the roofing expands. 3) There are some "high-temperature" asphaltic based underlayments available as well as numerous non-asphaltic polymer underlayments (such as SharkSkin and RoofTopGuard) which would not need red rosin paper. 4) I suggest continuous ridge vent and then making sure that your soffit vents are at least equal to the ridge vent in terms of free airflow. 5) Unless there is something odd about your roof, it should not need soldering. In your climate, there probably is pretty good indication that galvanized and galvalume will perfor similarly. 6) If you wish, send me photos or contact me direct for more details. Todd Miller [email protected] 1-800-543-8938 ext 201
Guest User
5/16/2004
Todd, thank you so much for the quick response. Would 30# felt and red rosin (I mispelled the word - that is why I could not find anything on the internet), sharkskin, or some of the other polymer papers have a longer life? Have they been tested for their performance and can any of them be guaranteed not to crumble, deteriorate,etc? How can we determine which one would be best? I love options, but my search is for the best. We want to do our roof right the first time.
Guest User
5/16/2004
Todd, since galvanized metal and galvilume would perform about the same for our climate, can you think of any reasons that we might choose galvilume instead of galvanzed or visa versa? Also, we are one the dry line, so weather conditions can shift easily from high humidity and lots of rain to very dry desert air.
Todd Miller
Isaiah Industries, Inc.
5/16/2004
Well, I definitely would not use 30-pound felt without the red rosin paper. (Hey -- I've never been sure how to spell that actually!). These ither polymer underlayments have better life when exposed to the elements but, once the roof is in place, the underlayment is fairly well protected, especially if you have the rosin paper on top of the 30-pound.
Todd Miller
Isaiah Industries, Inc.
5/16/2004
There is some evidence that galvalume has better life on standing seam type of products so you might keep that in mind. The real key as far as I am concerned aould be to look for the best possible paint finish you can find. That generally is considered to be a Kynar/Hylar finish. You might also inquire whenther the product meets Metal Construction Association certification standards for Premium or Standard grade metal roofing. This is a fairly new program but it does help to identify quality products.
Don Swingler
5/19/2004
Good info regarding 30# felt as well as usage of red rosin paper. Never was informed about that and will now take that step. History: I put 30# felt on roof 6 months ago and roof has endured every type weather that could occur. Pitch of roof 12/12. Uppermost run of felt stripped off in spots, I totally replaced that felt. Sheathing is 3/4 inch toung/groove OSB and in one area has 3/4 inch "Advantech". I am one-man-show who built the outbuilding; thus a long time between various steps. Question 1: Can I still use the existing felt paper or must I rip all off and replace? History: I purchased Velux skylight but not installed in roof, yet. Quedstion 2: After reading horror stories about leaks, do I need to forego installation and go another route? I purchased metal flashing, and was informed that it will fit the type metal roofing I purchased.
Guest User
5/20/2004
I would recover the old felt with a new layer of underlayment for safety. Velux makes good roof windows which typically are up on a curb. It should work fine for you. Check with your metal roofing manufacturer for flashing details.
Guest User
5/28/2004
I am in the process of building a home and getting quotes on a steel roof. The one builder puts a l" x 4" or 6" board on top of the felt. The steel is installed on top of the boards. This gives a free air space for the hot air to release up and out. This is a more energy efficient way to install the standing seam panels. I have been investigating and learning a lot about this subject. I also wanted a colored panel. Talking to one contractor it does not reflect the heat as much as galvalume. In today's high cost of energy, I am tryin to build it so that the electric bills won't be too high. I am going to check into the rosin also. This is the first I have heard of it.
Guest User
5/28/2004
Do you use a glue or tacks for installing the red rosin paper? Can you explain. Thanks,
Todd Miller
Isaiah Industries, Inc.
5/29/2004
Red rosin paper would be installed on top of the underlayment (moisture barrier). Typically, with standing seam roofing, the installers put it down vertically as they apply the panels. It may need to be tacked down some to help hold it in place during installation but, generally, it is held in place by the roofing panels which are installed on top of it.
Guest User
5/30/2004
I live in St.Petersburg Fl. and installing 24 guage 18" galvalum 1 1/2" standing seam, white Krynar paint, 7200sq ft. 3/12 pitch. 1) Is ($55 per 200sq ft roll)Tampco Moisture Barrier peel-n-stick ok? Or is the ($65 per 200sq ft roll )Tampko Tile and Metal peel-n-stick better? 2) Is it ok to use the galvalun panels with aluminum fascia? Will this cause electrolysis? 3) Can the panels be laid right on top of the Tampco product or should there be battens? 4) I am building a flat 9'x14' sundeck on the (3/12 pitch roof). What would be the best shape of roof penatration for sealing around? IE: 1/2"x4" steel flat bar, 4" steel box channel, 4x4 wood post, 2" angle iron...? Thank You, Dan in Tierra Verde
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