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Trudy Mercurio Posted: Jan 26, 2008 11:11 PM	I need HELP! We have cathedral ceilings with an unvented airspace of only 3 1/2". The house was built in 1969 when insulation was obviously not a major concern. The roof decking is only 5/16". Although we had new architechtural shingles installed 9 years ago, we have several areas that are leaking and we're unable to locate where the leaks are coming from. So.......I began researching and discovered the benefits of closed cell insulation. Several sites said foam could be applied from the roof top. To do this, we would of course have to have the layer of shingles and the roof sheathing removed first. (Sounds expensive already.) Someone came today to give us our first bid. He said he'd never done this type of application and was a little leary of spraying from the top, due to possible condensation under the roof decking. Makes sense to me! So he suggested possibly having someone tear off the shingles, then he would apply 1" foam and coating (Conklin Cool Roof)directly to the plywood roof deck. This would probably be cheaper in the long run (no new plywood, because we were going to replace the 3/16" with 1/2" and we wouldn't have to buy new shingles). So what do you think of this type of roof on a residential home? I think if we did it, it should have the "gravel" finish or at least a bit of color. One thing that concerns me is that the foam will form the same contours of the roof. It is a bit wavey due to the thin plywood. So what do ya think? We're open to any and all advice! Thanks so much.
mason Posted: Jan 27, 2008 12:46 PM	SPF roofing is a good long term solution. The foam can be re-coated typically every 10 to 15 years and will be more effective as an insulation and an air barrier that if sprayed from the underside of the roof deck. As you can imagine, the foam roof will look different from other roofing systems. If the applicator is good, the foam will be uniformly installed over the wood deck. The finished roof will have the look of a snow covered roof. Coatings can be used to add the color that you would like. The foam will conform to what it is sprayed to so interesting designs could be incorporated into the roof by fastening patterns or shapes made of plywood or foam sheathing. I even had an razor back hog shaped into a residential roof in Arkansas for a rabid alumni in the 70s. I just got a local artist to cut out the design on a 1/4 sheet of plywood and then nailed that to the roof. We coated that section red. I would however use more than 1 inch of foam. If you have no insulation in the ceiling, you should install the amount required to meet codes. By the way, you don't have to remove the shingles to install the foam so long as there is only one layer of shingles and the wood deck is not deteriorated. You would have to install flashings on the edges. Check out AY 104 at sprayfoam.org for details on installing sprayfoam roofing systems.
Posted: Jan 27, 2008 01:55 PM	Paintfool, I use a lot of conklin coatings. I reccommend their Benchmark product over Rapid Roof III, and definately a Kolor Kote finish which is simply a decorative coat for color. you can choose from a 1,000 colors. I have used their coating directly over asphalt shingles and the white top coat looks dirty after 3-4 years. Our colored applications look better. Good Luck!
Trudy Mercurio Posted: Jan 27, 2008 05:29 PM	Thank you so much Mason and NDfoamer. OK, I REALLY like the idea of spraying directly to the shingles. Mason, you suggested having more than an inch of foam applied. We supposedly have "full fiberglass batt insulation" in that huge 3 1/2" space! I can only imagine what kind of shape it's in after 40 years and some leaks (yes, even some carpenter ants)! We live in Illinois, not far from St. Louis. Any thoughts on how much spray foam we should have applied? I read the document you referred me to. Thanks. It was great info. Now I know more what to ask the foam contractors when they come to bid. If I understand the info correctly, extra flashing should be applied around skylights before spraying? We have 4 of 'em. Also, the garage roof is about 3' lower than the house roof. Should special flashing be applied to the siding where the garage roof meets it? OK, 2 more things, then I'll quit picking your brains! What are your opinions on the lightly textured foam? And what are the pros and cons of the granule coating? Oops, just thought of one other thing. We have a ridge vent (which is probably doing absolutely nothing on this type of roof). Could the foam be applied right over it? Again, thanks so much. I'm so happy, thinking this might be the answer to our problem, without having to rip the roof off. ~Trudy
Posted: Jan 27, 2008 05:57 PM	im not a huge fan of the granules. Ive only used them on service areas of roofs and walk out deck roofs. Just for skid and abrasion resistance though, not for looks.
aaron koenig Posted: Jan 27, 2008 06:25 PM	what is the pitch of the roof? 4/12, 6/12, 8/12, 12/12? Sounds like a tough job. What type of equipment will the contractor need? How high up are the eves?
Trudy Mercurio Posted: Jan 27, 2008 08:58 PM	The pitch is 3/12 and the eaves are aprox. 12' from the ground. While I'm asking all these questions, what do you guys think about the dampness (and possible mold??) that might still be in the roof cavity? Once the foam is on and no more moisture can get in, will the area eventually "dry up" on it's own and be ok? THANK YOU!
Dave Strnad Posted: Jan 27, 2008 09:08 PM	If you are looking for a long term solution you should rip the roof off and insulate it that way. I have done this before, and it is not that bad of a job. It may seem overwhelming but as longs as you have a decent roofer as far as schedualing etc it goes pretty good. If you have had leaking you probally have some rotten wood and moisture so you wouldn't want to seal that in. Also it would be difficult to get enough foam on to make a real difference. You could even buildup the top of the joists with 2x4's to get more depth for added insulation or ventilation. With this type ot application I suggest using ridge vent and leaving a gap for air. Typically I would recomend a ventless roof, however because the foam will not sprayed to the roof sheating there will be an air gap anyway.
mason Posted: Jan 28, 2008 08:11 AM	Carpenter ants are a sign of moisutre and wood rot. I would not spray over the existing shingles. SPF roofing is a specific type of foam application that requires experience and knowledge to install them correctly. Try to find a local SPF roofing contractor to assist if you decide to go this route. A SPF roof can be installed over both vented or unvented attics. If the sprayfoam is the only insulation, typically the attic is unvented, but if you are using fiberglass, it would typically need to be vented. As always perform a moisture calculation on your proposed designs in order to determine the most cost effective way to provide the insulation you need to prevent condensation and to provide the best energy efficiency.
Trudy Mercurio Posted: Jan 28, 2008 10:05 AM	Mason, our original plan was to have the roof torn off, pull out old insulation, make any necessary repairs, and have closed cell blown in. The foam installer was not thrilled with this idea. He was worried about condensation forming on the back side of the roof decking. He suggested removing the shingles and applying the Cool Roof to the roof decking. I realize there can be no moisture in the decking for the foam to adhere properly. As far as the carpenter ants, it's been years since we've seen any sign of them. We had an exterminator out and it hopefully took care of the problem. I am having a hard time understanding the vapor barrier theory. Our ceiling drywall is foil backed. The plans say "full insulation". We're not sure if it's paper backed or not. Our beams are supported by a steel I-beam running the length of the. Between these "beams", inside the roof cavity) are 4' long 2x4 joists on 16" centers. These would eliminate any possibility of airflow to the ridge vent we had put in 9 years ago with the last roof job (what were we thinking??). So, where would be the best place for the foam? Should it be in the roof cavity or on top of the roof deck? I'm so confused. This is going to be a MAJOR expense and we really want it done right. I would love to have the foam applied to the top of the shingles, as they are still in very good shape, but I don't want this to just be a band-aid hiding (and possibly causing) more problems down the road. What a mess, huh? One other thing.......I re-read my original post and I had a type. Our roof decking is 5/16" not 3/16". (Still not great, but a little better!)
mason Posted: Jan 28, 2008 09:02 PM	I don't like the idea of tearing off the roof and installing the foam from the top. I see too much potential for leaking water not being able to drain. This is getting fairly complicated for discussion on this forum. I suggest you get an expert there in person to determine what to do. ON this forum I try to use suggestions that have been field tested and are included in industry guidelines and standards. Unvented attic assemblies are part of the building code and are included in SPFA's technical document AY 112 and separate paper on cathedral ceilings. Building codes allow the use of less than code prescribed insulation thickness when you have a cathedral ceiling limitation. My first recommendation is to install 3-1/2 inches of closed cell SPF to the underside of the roof deck as part of an unvented assembly. Next when the roof is replaced, foam sheathing could be installed to the roof deck before the application of shingles. Again, there are guidelines for this type of application available from NRCA and from PIMA (Polyisocyanurate Insulation Manufacturer's Association. And you could install an SPF roofing system to the wood deck. There are many industry guidelines and ASTM standards (D 5469)for this practice. However, the solution that you have intitially proposed does not have a track record in the field that I am aware of and no industry guidelines or standards. When using a non-field verified approach or one that does not have the backup of industry acceptance, you are accepting a greater degree of liability. If something goes wrong, the best that you can say, is that someone on a forum said it would work. I doubt if a judge would accept that as justification for installing a non-traditional system. Hope this helps.
Trudy Mercurio Posted: Jan 29, 2008 10:17 AM	Mason, thank you so much for all the time you've taken to respond to my postings. We have definitely decided against our original thought of filling the area with foam. Besides your response, we've had several installers advise against it. Spraying from the inside is something I don't even want to think about!! Tearing off all the ceilings......... oh my! We had both a reputable foam contractor and a roofing/construction contractor come here together yesterday. They spent quite a bit of time on the roof, inspecting it. Their feeling was the roof was in good shape and if we decided to apply foam to either the top of the shingles or the wood deck, it would work fine. What we thought was a 3/12 pitch, turns out to be only a 2/12. They think our problem is due to lack of pitch, we're getting water backing up under shingles. We're leaning toward having the foam applied directly over the shingles, then going with the granule topping to make it look a little more "residential". My only concern is the skylights. We have 4 curbed, venting skylights. They are talking 1 1/2" of closed cell foam and I'm wondering if this would possibly allow rain to back up and get in under the skylight "door". They said they could bring the foam up the curbing of the skylights, but not have it quite as deep around it. Don't know......wouldn't that allow water to run towards them? They have been in this business for over 20 years and seem to really know what they're talking about. (Sure hope so!) What we don't have yet is the cost. With the garage, we have around 2200 sq. ft. of roof. I'm bracing myself!! Again, thanks so much. You have been a huge help. ~Trudy
Gerry Wagoner Posted: Jan 29, 2008 08:47 PM	Hi PF. We have sprayed onto knotty pine ceilings AND drywall ceilings after removing the exterior 3/12 roof material. It works very well, providing you have a good roof over it. Condensation? Not likely. oG (yes, this message is getting too lengthy).
mason Posted: Jan 30, 2008 07:31 AM	Skylights can be a big problem. You need to raise the curbs higher and reflash them. Do not spray foam over the curbs, it will make them leak. Check out the details in AY 104 for specific instructions. SPF roofing is a specialized type of application. The substrate must be prepared properly, flashings done correctly and the foam and and 1st layer of coating installed the same day. Be sure to use a higher density foam, (nominimal 3 lb density). The foam will yield approximately 2.5 to 3 board ft per lb. Overspray can be a big problem as well. Protect everything in sight that might get overspray on it. Use shields when on the roof, and fall protection.
richard sucher II Posted: Jan 30, 2008 02:50 PM	I just found this site and this is my first post. Have been in the spray foam business since 1979. Regarding question of how to re-insulate 3.5" batt filled ceiling area, I cannot believe anyone would want to spray over shingles. The appearance has the potential to look hideous and really out of place with other properties near you. If you live in the back woods and do not care, go ahead but buyer beware - beauty is in the eye of the beholder. I would suggest two options: tear off shingles, repair anydamage to sheeting, frame out deck with 2x, spray cavity with closed cell foam, redeck, shingle. Other option would be to tear off shingles, repair decking, install urethane foam composite board and install new felt paper and shingles. No way do I spray over shingles - also know that when you spray there is risk of overspray and damage to property. Keep this in mind when foamer sprays in too high of winds and gets foam over personal property. If there are others that live near-by, this can add up to hefty insurance claims. Make sure foamer has adequate insurance for liabilities such as these. good luck with your project.
Trudy Mercurio Posted: Jan 31, 2008 09:49 AM	OK, I hesitate to post again due to the complaints of the lengthy thread. But, I'll give it a shot. Now I'm getting nervous about spraying over the shingles. I would want to see a house where this had been done, but there doesn't seem to be any! So what would you experts suggest? Can shingles be applied over a foam application (possibly foam sheets)? I have probably spent close to 3 hours a night researching this and can't find quite what I'm looking for or I find conflicting opinions. I'm open to ANY ideas on how this roof could be repaired and insulated from the top (with the least amount of expense). Thank you all for your patience.
Tim O'Keefe Posted: Jan 31, 2008 03:54 PM	I have no first hand experience with this, but to eliminate the shingle look in the foam, why couldn't a smooth substrate be installed first (poly iso board/plywood/luan) If there are waves in the roof this will not help but if the roof is straight this would give a nice smooth substrate the lay the spray foam on top of! Apply a coating and be done with it! There is a contractor here who did install directly to the shingles of a building, perhaps he will add some suggestions! Tim Granite State Spray Foam Co.
mason Posted: Jan 31, 2008 04:47 PM	I actually have sprayed many SPF roofs over shingles in South Texas. It is very common in coastal areas. The foam keeps the roofs on during hurricanes and high winds. If you install 1-2 inches of foam it will look exactly like a snow fall on your roof,(assuming you can spray smoothly. You can tint the coating to a color the homeowner would like. It is in the eye of the beholder. As for overspray, any exterior applications require that the applicator protect against overspray. Be careful use wind screens, protect property with covers and don't spray when the wind is blowing Again, in South Padre Island Texas where the wind blows constantly, I had two overspray claims in 7 years of business.
Tim O'Keefe Posted: Jan 31, 2008 08:11 PM	In addition to the tinted color to the foam, wouldn't the finished layer of foam require a coating over to protect from UV's? Tim Granite State Spray Foam Co.
Trudy Mercurio Posted: Jan 31, 2008 09:33 PM	Mason, is there anywhere I could access some photos of shingled roofs covered with the spray foam? Thanks!
SprayFoamSupply.com Posted: Feb 01, 2008 04:40 AM	I have sprayed some foam on a couple of shingle covered roofs. They are going through their first winter. I have a few pic if you want to email me. George info@freedomfoam.com
mason Posted: Feb 01, 2008 01:30 PM	email me at Masonknowles@aol.com and I can send some photos from the Hurricane Katrina and Charley research and a wood frame building I insulated 30 years ago and a photo of it last year.