CarolVentura
Registered Users
Posts:18
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| 03/14/2008 8:58 PM |
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Our 5,251 square foot sloped ICF roof is almost finished. You can see it at http://iweb.tntech.edu/cventura/roof.htm I want to cover it with a maintenance free roofing material that will last a LONG time and will be able to support solar panels. Our roof does not have enough slope for ceramic tile, and I can only get a 2 year warrantee for an insulated Sarnafil PVC membrane (that comes with a $40,000 price tag!!!). I was told that a standing seam metal roof would have to be installed on wooden strips that are screwed to the concrete because the metal would react with the concrete. I don’t like the idea of attaching the metal to wooden strips and if installed that way, it is not secure enough to support solar panels, so special penetrating clamps would have to be installed. I was wondering about another approach. Could roofing felt be put down and then could the metal panels be installed directly over the felt and onto the concrete? What if the concrete is first painted with waterproofing sealer? Would that work? |
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Amvic Texas
Registered Users
Posts:6
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| 03/15/2008 10:43 AM |
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| We did a project this year with a sloped concrete roof. We used a product made by BASF. It is a 1 part 2 step deck coating. First you roll on the primer, let it sit over night. Then you roll on the top coat. This must be done within 24 hours of placing the primer coat. The primer surface will still be tacky when you apply the top coat. The product is used to seal parking garage surfaces. It comes in 2 colors, grey and tan. The cost of material is about $ 1.50 per sq.ft. Coverage is about 35 sq.ft. per gallon. I can not remember the product number. We purchased it from a company called SSI in Dallas. They have offices in other parts of the country. We have been very satisfied with the finished product. |
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Amvic Texas
Registered Users
Posts:6
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| 03/17/2008 9:35 AM |
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| I went back and found the name of the product. It is Sono Gaurd. |
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keysgirl2
Registered Users
Posts:9
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| 03/21/2008 3:35 PM |
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Carol;
in my layman terms:
We just did a 4/12 pitch with decking, poured 47 1/2 yds of concrete. We have been researching the same thing, here is what we have found out:
1) seal the concrete after minimum of 30 days - check manufacturer specs
2) install a membrane (check local codes for your area), it is like a peel-stick, I have several different companies whom I spoke with at the International builders show, as well as the concrete manufacturer. This will form a moisture barrier, protection.
3) we will be using a 24 guage v crimp metal roof, this will be applied with tapcons-UV resistance nylon washers and furring strips. The membrane which was put down actually has a melting pigment like asphalt, this actually will help seal the "screws",
any questions, let me know, but speak to your roofers, they know alot about this. It has NOTHING to do with the decking product and everything about concrete.
(I also call sacrete, they were very helpful)
Kristie
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CarolVentura
Registered Users
Posts:18
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| 03/21/2008 3:48 PM |
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| Thanks so much for your information! We don't have any building codes where we are building. Yes, this is the United States, but things are different here! I spoke to several local metal roofers, but none of them knew how to install a metal roof over concrete. I don't understand why furring strips are needed though. Why can't the metal go down right over the membrane, the way it is installed on wooden roofs? |
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keysgirl2
Registered Users
Posts:9
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| 03/21/2008 4:54 PM |
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| I think??? it is the airspace which is necessary, I still would think condensation builds of if no venting how would it expel? I am far from an expert, maybe some of the builders out there could explain this. I too asked the same question. |
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CarolVentura
Registered Users
Posts:18
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| 03/21/2008 5:33 PM |
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| I recently saw (on a TV homebuilding show) roof felt being tacked to a wooden roof, then the raised seam metal was installed right on top with screws and clips. I don't understand why the same thing can't be done onto concrete. |
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wes
Registered Users
Posts:376
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| 03/21/2008 6:02 PM |
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Carol,
My biggest concern would be the fasteners. All the metal roofing fasteners I am familar with, are designed for attachment to either wood or metal (steel). Working with fasteners that are not designed to interact with the metal roofing and the concrete roof correctly could create a weak point in the process. By using the wood furring strips, you can avoid this problem. The furring strips are attached the concrete with Tapcons (designed for attachment to concrete), then the metal is attached to the furring with screws designed for that purpose. |
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Wes Shelby
Design Systems Group
Murray KY
wandr@ainweb.net |
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Amvic Texas
Registered Users
Posts:6
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| 03/22/2008 12:36 PM |
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| Carol, I looked at your link. The product I am suggesting would eliminate the need for the metal roofing. |
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CarolVentura
Registered Users
Posts:18
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| 03/23/2008 12:51 PM |
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Wouldn't it make sense to design a fastener for attaching the metal roofing directly onto the concrete (through a membrane like roof felt)? If the furring strip is only there for the sake of the fastener, then it doesn't make sense. Couldn’t Tapcons be adapted to work with the roof panel fasteners? Not only are the furring strips an additional expense, but it would make it more difficult to attach the solar panels. My solar guy said that the metal roofing would not be secure enough on furring strips, so solar panel brackets would have to be installed on the concrete, then the metal roof panels would have to be cut around them and the penetrations sealed. If the metal roofing is attached on the roof surface it would be secure enough that the solar panel brackets could be mounted onto the standing seams of the roofing. Having the roofing on furring strips also makes it problematic to walk on the roof when installing the panels. If the installer is not always stepping over the furring strips, the metal will buckle. |
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wes
Registered Users
Posts:376
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| 03/23/2008 2:05 PM |
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Maybe, in the ideal world, the fasteners would be available, and, if they are (or were) available, I would certainly use them. However, from a practical point of view, unless you can find such a fastener that is approved by your metal manufacturer, I don't think you have that option.
As to your solar panels, spot the location of all your mounting points of the panels, make sure that your furring strips are located at these points and secured to the concrete roof at those points. It would seem then that the panels would be as firmly mounted as they would be if the metal was screwed directly to the concrete, and so will the solar panels.
This is a problem that I see with many (most) new building technologies, the developers of each new idea cannot foresee every circumstance that will be faced in the real world use of their products, and cannot develop remedies for the problems that inevitably arrise.
As long as we continue to explore new options for construction, we will have such problems to deal with in the field, and we will have to develop our own solutions. If we wait for the designers and developers of these technologies to work out all the bugs before we use it. We would still be building houses the way my grandfather did.
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Wes Shelby
Design Systems Group
Murray KY
wandr@ainweb.net |
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CarolVentura
Registered Users
Posts:18
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| 03/23/2008 8:05 PM |
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| Thanks for all the input. I like options and it looks like I'll have several roofing / solar possibilities. I'm going to start a thread about ceramic tiles, then see which type of roof and solar panel will serve us best. Thanks again! |
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Opus
Registered Users
Posts:51
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| 03/23/2008 9:03 PM |
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| If you are screwing through the steel roofing remember that the steel is going to expand in the sun more than the concrete under it and pull on the screws. This can lead to leaking around the screw holes and other problems. I would screw directly to the concrete ( with a membrane on it) with tapcons but I would use a roofing product that used conceled clips that allowed for expansion and contraction. Stainless steel tapcons are available. I would consult the roofing manufacture but I can't see and problem with tapcons for this purpose and I would be very reluctant to put wood furring in a system that could otherwise last a very long time with no problems. |
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CFL-ICF
Registered Users
Posts:61
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xexpat
Registered Users
Posts:18
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| 03/25/2008 10:14 AM |
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I see no reason why standing seam metal roofing could not installed over felt and fastened with Tapcoms or other suitable fastener...but you will need find a manufacturer and installer who feel the same in order to get a warranty. Be sure they consider the thermal expansion issues.
Your solar panels should be attached directly to the roof structure using brackets or pads that can be sealed, flashed and roofed around. The roof should go on before the solar panels. I would not just fasten them to or through a metal roof.
In Spain, they use cast in place concerete for shallow sloped roofs and use mortar to attach the clay roofing tiles directly to the structure. Clay tile will not take the loads of the solar panels directly without cracking.
xexpat |
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J.Schmidt
Registered Users
Posts:1
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| 03/25/2008 2:03 PM |
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Hi Carol,
My name is Justin Schmidt and I am a Direct Sales Representative for Sika Sarnafil. I just wanted to make a few comments on your post/project. I am not sure who quoted you for a 2 year warranty but that is grossly off. Our shortest warranty is 10 year and our longest warranty is 30 years. Our warranties are No Dollar Limit and Full System, also there is no exclusion for ponding water. Due to the smaller size of your roof the difference in price would be minimal from a 48 mill to a 80 mil. The above price you were quoted (depending upon the application) sounds a little steep. I would say depending upon the application( Wind warranty you are seeking, FM Rating etc, adheared, mechanical or engineered) the price range should be $25-$35,000.
I sent you a e-mail.
Thanks,
Justin Schmidt
Strategic Account Specialist (MS)
Sika Sarnafil, Corp
schmidt.justin@us.sika.com |
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CarolVentura
Registered Users
Posts:18
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| 03/25/2008 6:24 PM |
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| The $40,000 price tag included 2" of insulation between the concrete and the membrane, overhang flashing, and a gutter along one side. Here is part of the message I recieved, "...the Sarnafil representative for this area (Nashville, TN) said we could offer a 10 membrane only warranty along with our 2 year warranty. To answer your question about other products with better warrantees to my knowledge there is not. The big commercial product companies like GAF, Firestone, Johns Manville do not offer long term warrantees on low slope residential projects..." |
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CarolVentura
Registered Users
Posts:18
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| 03/30/2008 1:13 PM |
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I looked at their page at http://www.cadeco.com/productfiles/Sonneborn-Sonoguard.pdf but I couldn't see how long the coating lasts before it needs another coat . Do you know how many years it's good for?
Also, do you know how the flashing of the overhang would work with it? Roofing materials usually extend over te flashing to keep water from penetrating between it and the eave. How would this product seal around the edges where the flashing begins?
Thanks so much! |
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ICFHomeOwner
Registered Users
Posts:2
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| 08/04/2008 12:44 AM |
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We painted our roof with a water based concrete paint that has a 20 year warranty. The biggest problem was getting the seams where the wall meets the roof to seal properly. The roof penetrations for plumbing where not as much of a problem. The cost for about 2000 sq ft was still about $2,000 and took several coats.
I am curious about experience with concrete slap roofs. Our insurance company loves it but we are in southern Coloardo and I'm concerned with our 2 summers of experience with the heat. It seems that the concrete absorbs the heat during the day and then continues to radiate it over night. That's through our R50 ICF ceiling. |
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CarolVentura
Registered Users
Posts:18
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| 08/08/2008 1:42 PM |
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After considering several options, we decided to cover the slab with 1.5" thick foam panels and .060 ml. fire resistant Firestone rubber. We found a solar laminate product that will glue to the roof. You can see the installation of the rubber roof at http://iweb.tntech.edu/cventura/RubberRoof.htm Our installer guarantees it for 10 years but said it should last much longer. We chose black Firestone because the solar laminate doesn't stick to their white laminate and the other white laminates available did not come with a guarantee. So now the concrete is completely covered with insulating foam panels - top, sides, and bottom. With the foam on the bottom and top of the slab, we should not have any problem with heat or cold passing through.
As far as the cost of the slab roof - since it was poured onto thick, expensive foam panels, it cost more or less the same as the combined cost of the footer, slab, and first floor (poured onto steel beams). I think it's worth it though - no matter what the cost - because it ties everything together and will withstand severe weather and even a tree falling on it! Fire could hurt it, but only a very strong one. |
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