Adrienne Ray
VTAdrienne
10/31/2011
Our local school is contemplating replacing our shingle roof next summer with a metal roof. It has been suggested that we use an exposed fastener metal roof with an ice and snow membrane adhered to the roof deck with wood strapping to create an air space and then the metal roof material. This all sounds great for the prevention of ice dams which have been a problem, but we are getting push back from our local roofers. What do the experts say?
Todd Miller
Isaiah Industries, Inc.
11/3/2011
There are many factors to consider. If you can call me at 1 800 543 8938 ext 201 , I will be happy to talk this through.
Guest User
11/20/2011
we are considering natural metal roofing and wonder what product choices fall into this category? We can't find a list anywhere. Obviously, copper is one. Thank you.
Todd Miller
Isaiah Industries, Inc.
11/20/2011
Copper and zinc would be the most common. Galvanized steel is another and there are some exotic products available like stainless steel and titanium. Another option would be something like copper or aluminum clad stainess steel.
Patrick Burton
2/14/2012
I am building a Bali style home in Panama, it will be around 10,000 Sq/ft of roofing, open inside i.e. cathedral, and I have several questions I would like to put forward to you: I will be using a white metal roof, with high solar reflectance and low emmisity characteristics, which seem hard to find. 1) What can I expect to pay for this option in materials only, prices look expensive to me at around $350 a square, is there an other cheaper option, other than say the ATAS product? I intend to use the foil coated sheathing with a sound barrier felt on top. The home will be passively cooled, maybe aircon in the bedrooms only. 1) Will I need any other insulation below it? (There is controversy regarding the requirement in tropical zones using passive cooling) 2) Will I need to ventilate the roof? (Assuming no aircon I dont expect any condensation and the cooling affect will be minimal based on what I have read. Your comments are much appreciated.
Todd Miller
Isaiah Industries, Inc.
2/14/2012
These are good questions. And thank you for considering metal roofing. Painted surfaces have high emissivity. It is a property of the coating. Most folks consider high emissivity to be good in terms of efficiency of a cool roof system. Here are some resources which address this: http://www.coolmetalroofing.org/content/faq/faqs.cfm?FAQCatId=1 http://www.mbma.com/display.cfm?p=34&pp=12&ppp=24 http://www.roofingcontractor.com/articles/cool-roofing-leed-and-metal-roofing Metal roofing is a higher investment than some temporary roofing materials. ATAS is a great and very proven manufacturer and one of the founders of this organization as well as a true industry leader. At the end of the day, because all manufacturers deal with similar costs for metals and coatings, as well as similar labor, you will not find any huge price differences. Will you need insulation? In my opinion, yes, it will be helpful. That said, I understand it is often not used in your area and, if you are not using it, the roof system you are assembling is giving you the best possible option when no insulation is used. I assume you will be installing the roof on solid decking and underlayment. That's right -- you mentioned that. Will the foil face the living space? Foil like that needs to face an airspace to be effective. As far as ventilation ... condensation occurs when warm moist air hits a cool surface. I like to see vapor barriers in any assembly to prevent moisture from inside the building from reaching anything, I also find that ventilation helps keep the building naturally cooler as well. In thinking it through, I think you could get by without ventilation but ideally I'd prefer to see some. Let;s see what others say -- others may be more familiar than I with roofing in tropical regions. I hope I have been able to help a little. All Best.
Dick Bus
2/14/2012
Patrick, thanks for using us as the standard. Todd, thanks for the kind words. I concur with Todd, that you need to design for ventilation in the roof assembly to minimize condensation. One method is to provide an airspace above the sheating using either wood battens, raised clips, Delta Sheet or Enkamat from Colbond. The latter two were designed in Europe to be used under zinc roof panels to prevent condensation. Make sure that the design includes an inlet as well as exhuast for the air to move. As far as the price is concerned we offer systems (note I said systems) that can be less as well as more. It all depends what is included and what is not. What guage and material type is being quoted. As Todd pointed out our input costs are not much different than other manufacturers. At the end of the day we have to be competitive to make the sale. I am not sure which part of Panama you are building but with the complex roof geometry that you are building I would recommend using aluminum as it is easier for the contractor to cut and handle. You will also have less problems with corrosion over the long term. If you are in high wind zone it should be an .040 aluminum panel. Also clip spacing is particularly important around the perimeter. If you do not use ATAS make sure that you select a manufacturing member of the Metal Roofing Alliance as we have all pledge to sell quality materials. Feel free to contact any of us. Thanks for contacting us.
Patrick Burton
2/14/2012
Thank you for the speedy response. The location of build is close to the Costa Rican border at an elevation of 350 Meters or so. The winds are generally around 7 mph - 10 mph max as location is surrounded by hills, although I have a great view of the Pacific in the distance. At that altitude the nominal temperature is 2.4 'C less than at sea level, so around 20 - 29' C (Night - day) As you say the roofing is quite complex and right now I only have conceptual drawings, I intend to use round section rafters, 6", planed on the top side and smaller diameter purlings across them. I will use the local Mangly (Mangrove) as its plentyful and cheap. The OSB with Radiant Foil will lay on the top facing into the roof space. As you said it may be benificial to use some form of insulation but as its a "hot" roof design I am not sure I will have room to install any considering that I need a 1" space between the foil and the insulation. I dont particularly want to cover over the wood. The drawing of the roof I posted does not show that only some 3,000 sq/ft is enclosed living space, the rest is breezeways and open bohios so insulation may not be required at these open locations. Having said that, the idea of venting the roof between tiles and sheathing might help the cooling somewhat. Although its not the norm to install guttering in Panama, I will incorporate them to prevent washout around the property. I guess I will need 7" for such a large roof. Once again than you for your input.

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