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July 31, 2008

Question: What is the U value of stainless steel?

Sridhar writes from somewhere in the world: "What is the U value of stainless steel 316 L 3 mm thick?"

Answer: In doing commercials for Owens Corning for more than 25 years I have learned a lot about R-value and fiberglass insulation. I also know enough about U-value to think you might want the C-, k- or R-value because U-value indicates the thermal conductivity of a system, such as a wall assembly, not the thermal conductivity or resistance of an individual material or component. Regardless, I recommend sending your question to a company that makes and knows steel.

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Question: Can I vapor barrier over the strapping?

Don writes from Thunder Bay, Ontario: "I have just discovered my 57 year old house has no vapor barrier in the attic. I am presently renovating the kitchen, which had a stippled ceiling, so want to cover over the ceiling with new gyproc. Have strapped the ceiling. Now can I vapor barrier over the strapping before adding the new gyproc??"

Answer: Typically, older homes are leaky; this means that air will find its way within wall and ceiling cavities and create drafts. Air/vapor retarders are a first line of defense to stop drafts. They also slow the movement of warm moist air toward cold surfaces where it could cause condensation.

As a rule, the vapor retarder should be installed on the warm side of the insulation and touching the insulation. For that reason, in a ceiling, the vapor retarder is often part of the attic insulation upgrade project. Are you planning to add insulation in the attic?

If you have no other choice, and want to add a vapor retarder from beneath, the difficulty will be to make it continuous, which means that the vapour barrier will need to connect in some ways to the wall vapor retarder.

If your attic has adequate ventilation a vapor retarder may not be needed. Check for moisture in the insulation first. If ventilation is not adequate you may want to improve attic venting. Generally vapor retarders are installed in contact with the insulation.

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Question: Can I put new insulation on top of the old insulation?

Michele writes from Saint Louis, Missouri: "I purchased an old 1920s brick bungalow. The attic has very old (and very dirty) batts of yellow insulation. The paper backing is all ripped up and facing up towards the roof (which I think is facing the wrong direction). Can I put new insulation over top (perpendicular) of the old insulation? Your recommendation is appreciated!"

Answer: You are correct; the vapor retarder should be on the warm-in-winter side of the insulation. One option is to turn it over before installing the new insulation. If there is adequate ventilation in the attic you may not need a vapor retarder, and in that case you could slash the existing vapor retarder in places where it is not already ripped. You don't say whether the current insulation fills the cavity between the floor joists but if it does not, you need to fill the cavity before placing additional insulation perpendicular to the direction of the joists. The U.S. Department of Energy recommends a total of at least R-49 for attics in most parts of the country and R-38 in your area.

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 03:52 PM | | TrackBacks (0)

July 30, 2008

Question: Why did it happen?

Debra writes from Bridgewater, New Jersey: "We are building an addition on our house. We have a cathedral ceiling that is built off 2 beams which form a T with a valley running down from each side of the intersection of the T. We installed, per our township official's direction, the foam raft-R- mates in every section between the rafters and then placed the R30C insulation below that. We then installed sheetrock and a faux wooden plank ceiling by Armstrong. We installed faux beams over the 2 valleys. Over the last few months, we have founds water dripping from the ends of both faux beams. When we removed the beams, wooden ceiling, and sheetrock next to the beams, we found the insulation and foam and wooden sheathing to be soaking wet. We are sure this moisture is from condensation but here's the problem - what do we do now? Why did it happen?

How can we correct the problem and still conform to our township's requirements? Our roof has a ridge vent. There are no soffits where these particular rafters end."

Answer: The cause of the condensation is likely due to the lack of soffit vents. Ridge vents and Raft-R-Mate® attic rafter vents work together with soffit vents to allow moisture to escape that could otherwise cause condensation.

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Question: Is there a thin board with a smooth surface?

Terry writes from Midlothian, Virginia: "My house is constructed using cinder block exterior walls. I want to give one bathroom exterior wall a "finished" smooth surface without framing in the wall. Is there a thin board with a smooth surface I can use, perhaps glue the board to the block? I want to be sure I use something that does not "wick" moisture or shrink/swell."

Answer: FOAMULAR® extruded foam insulation is not damaged by moisture. The product is closed-cell extruded polystyrene foam. However, the R-value is 5 per inch, generally not enough to be the only insulation in an exterior wall assembly since our retail products have a maximum thickness of 2 inches.

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Question: Can I roll insulation over the old roof sheathing?

Sal writes from Avon, Ohio: "About 1 year ago - I purchased an older home (45 - 50 years old) that originally had a flat roof. At some point - an A frame roof was added over the old roof. I currently use the old roof flooring as the floor for my attic storage area. I have come to find out (after 2 $800 a month fuel oil bills) that there is no insulation in my ceilings. So I need to add some fiberglass or blown in insulation soon. Underneath the old flat roof sheathing is essentially dead air space / an empty cavity with no insulation between the inside house ceiling and the roof sheathing. Can I simply roll out fiberglass insulation right over the top of the old roof sheathing? If so - should it be faced or unfaced? If not - must I remove the old roof sheathing and then add the insulation between the ceiling joists? If so - must I use faced or unfaced insulation? If faced - should the vapor barrier be laid down first (touching the ceiling of the house)? Something tells me simply rolling out unfaced insulation right over the top of the old roof sheathing is not the best option - thereby leaving a dead air space between the ceiling and the roof sheathing - but this route will be a LOT cheaper to install as I will not have to remove the old roof sheathing. Are both options feasible?"

Answer: Both options are feasible. It would be more effective to insulate the original attic floor. In both examples, faced insulation should be used. The facing should be placed to the warm-in-winter side, or toward the house. Keep in mind that if you insulate on top of the first roof, you will still be heating the original attic.

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July 29, 2008

Question: What are the pros and cons of installing a poly vapor retarder over fiberglass insulation?

Mel writes from Monsey, New York: "I am renovating a very old home that has 2" x 4" framing at the exterior walls. I would like to know the most effective method of insulating these walls versus cost? Also, what are the pro's and con's of installing a poly vapor barrier over fiberglass insulation?"

Answer: The best way to insulate a 2x4 exterior wall is to use Kraft-faced R-13 Fiberglas™ insulation. The vapor retarder should be placed toward the warm-in-winter side of the wall. Owens Corning believes its Kraft facing is a sufficient vapor-retarder. The use of poly over Kraft or instead of the Kraft paper is, however, acceptable. Check with your local building code to be sure there are no special vapor retarder requirements in your area.

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Question: Should I put fiberglass batts over foam board?

James writes from Salisbury, North Carolina: "In my basement I have foam board insulation on concrete block walls with 2x4 studs over the foam. Should or can I put fiberglass batts over the foam board to increase the R value? If it is ok should it be faced or unfaced?"

Answer: My friends at Owens Corning do not recommend using Fiberglas directly over FOAMULAR® insulation in a basement due to potential moisture problems. If you decide to install insulation anyway because the stud cavities are already in place, we recommend faced insulation with the Kraft paper toward the inside (warm in winter side). The assembly will need to be covered with a 15 minute thermal barrier such as sheetrock.

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Question: Is InsulPINK® foam insulation the product to use?

Shawn writes from Saint Louis, Missouri: "I am planning on insulating my 90 year old concrete block basement. The basement is low ceiling, below code for finishing, so the insulation is for energy savings only. I am leaning toward the insulpink product, but my basement has some added issues. When we bought the house, the wall leaked badly, even with exterior landscape changes. The culprit is at some time in the past the basement was actually a cellar, and a previous owner wanted more head room, so near as we can tell, they dump out the basement floor and re-poured 6 inches lower, was is now 1 inch below the top of the footing. To fix the problem, we put in an interior french drain, but the gravel above the drain to the sump is exposed. I am interested in your opinions on viable solutions: will insulpink be the best course, or full stud walls erected inside the wall and french drain?"

Answer: Owens Corning manufactures InsulPink® insulation specifically for use on below-grade basement walls. It is channeled to be applied with furring strips. It is then meant to be covered with a proper finishing material such as sheetrock. Basement walls can also be studded out and insulated with Fiberglas™ insulation and, again, covered with sheetrock. Any existing moisture problems need to be resolved before insulating. FOAMULAR® InsulPink insulation is closed cell and hydrophobic so it is not damaged by moisture. Fiberglas insulation will need to be replaced if exposed to contaminated water. All that said, we don't recommend insulating the basement walls unless the basement is heated.

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July 28, 2008

Question: How can I go about insulating my crawl space?

Andrew writes from West Columbia, South Carolina: "The floors in my house are always cold. We have wood floors through most of the house, but even the carpeted rooms are chilly. Our attic is well insulated with a thick blanket of blown pink insulation. But our crawlspace is not insulated beyond the vapor barrier on the ground. The crawlspace is very tight - more of a wiggle on your belly space. So how can I go about insulating its ceiling (i.e., the underside of the floor)? What product should I use?"

Answer: Click here and you will see instructions for insulating a crawl space, including pictures. The U.S. Department of Energy recommends a minimum of R-19 be used under a floor.

Install the insulation with the vapor retarder up toward the warm-in-winter side. Once the insulation is in place between the floor joists, insulation hangers or nylon straps should be used to hold the product in place.

If the space is too tight to do the job yourself, consider hiring an insulation contractor.

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Question: What is the R-value for air film on a ceiling?

Fahim writes from Troy, New York: "What is the winter time R-value for inside air film on ceiling?"

Answer: For surface air film inside with still air and heat flowing up, the R-values are 0.61 for non-reflective film and 1.32 for reflective film.

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 11:12 AM | | TrackBacks (0)

Question: Why can't the additional insulation be installed with the plastic towards the roof?

Joe writes from Moreno Valley, California: "Our attic has insulation with a plastic barrier facing towards the roof (original construction). The plastic is deteriorating & of course the insulation is showing plus it has compacted over the years. I would like to add more insulation but your brochure states that when adding more insulation the plastic barrier should be down towards the ceiling of the house. I expect to go into the attic periodically, although it is not a living space, & am concerned about inhaling the fiberglass fibers. Why can't the additional insulation be installed with the plastic barrier facing towards the roof to prevent ingesting the fiberglass fibers?"

Answer: The plastic or paper retarder has a purpose and that is to keep moisture or condensation out of fiberglass insulation. Essentially, the vapor retarder slows the movement of humid air to a cold surface where it could cause condensation. In an attic floor, the bottom of the insulation will be the warm side and the top will be cooler. The vapor retarder needs to be on the warm-in-winter side to do its job.

If you have not had problems with condensation in your attic you may have enough ventilation that you don't need a vapor retarder. If that's the case, I recommend removing the existing plastic and installing unfaced insulation on top of the exiting insulation.

There is no long term health risk in the situation you describe but if you want to cover the insulation with plastic, I recommend slitting it liberally so it does not function as a vapor retarder.

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July 25, 2008

Question: Do I need a vapor retarder over the foam?

John writes from Columbia, Connecticut: "I am finishing off a basement and am installing rigid (Foamular) insulation against the concrete walls and then furring a stud wall (no batts in the stud wall) in front of that. Do I need a vapor barrier over the foam?"

Answer: We do not recommend the use of a vapor retarder over FOAMULAR® insulation in a below-grade application. However, I do suggest consulting your local building code to be sure there are no special vapor retarder requirements in your area.

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 11:02 AM | | TrackBacks (0)

Question: Any suggestions for curing a wet roof?

Susan writes from Newmarket, Ontario: "The north side of my roof, on the inside, is all wet. Some of the insulation is wet in the centre but we think that is causes by the poor job done by our contractor who didn't vent the bathroom right out of the roof. We stopped using that vent and the area around it dried but not the north section of roof - any suggestions??"

Answer: I agree that ventilation of the roof was a problem: vents should be venting to the outside. The north side of a roof is typically the side getting the least amount of sun heat and it will take time to dry out. Even if it will eventually dry out with warmer weather, I recommend removing the wet insulation and replacing it after the wood dries. The joists or studs adjacent to the insulation in your attic may be damaged by moisture over time so it is best to remove the insulation and ensure the wood dries out. Use this time to also inspect the roof in this area for leaks or blocked soffits.

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Question: How should I insulate the crawl space under an addition?

Curtis writes from North Babylon, New York: "I just found out one of the major reasons the extension on my house is always cold. There is no insulation in the crawl space under the extension! I have been told to use R-19, R-25 and even R-45 insulation and use a vapor barrier stapled over the insulation. Others have told me to put the vapor barrier on the ground of the crawlspace. I am confused as to who is right. I live in Long Island NY."

Answer: Click on the word Crawlspace and you will see complete instructions for the project you describe, including pictures.

Install the insulation with the vapor retarder toward the warm side of the structure in heating climates such as yours. In a vented crawlspace, the warm side is usually up, closest to the floor. Once the insulation is in place between the floor joists, insulation hangers or nylon straps should be used to hold the product in place. A 4- or 6-mil polyethylene vapor retarder should be laid down to completely cover the ground and keep moisture from coming up.

The U.S. Department of Energy recommends a minimum of R-19 be used under a floor.

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July 24, 2008

Question: Any problem using unfaced insulation and covering it with plastic?

Roy writes from Beckley, West Virginia: "Are there any problems with using an unfaced insulation in a 2x6 wall and then sealing it with a sheet of plastic? All walls are above grade. I always thought it was easier to do this way. Any problems or concerns I should be aware of? What insulation would you recommend r-21?"

Answer: Our Kraft-faced insulation would be adequate as a residential vapor retarder. However, it is common to use unfaced insulation and a 4-6 mil poly over it in above-grade applications.

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Question: Can I spray the floor of the porch from an opening in the basement?

Art writes from Union, New Jersey: "I am purchasing a 1920's colonial style home. It has a raised front porch that has been enclosed and finished off with a drop ceiling. They installed thermal windows and an insulated door. At some point in the past someone bricked up the access underneath this porch and the only access is a 4" by 12" opening from the basement. I have shined a light inside this area and can see the floor of the porch isn't insulated. What are my options to do this insulating? BTW the floor of the porch has been rugged over recently and I would prefer not to have to rip it up to insulate. I was hoping that I might be able to bring in someone who could spray the floor from that opening in the basement. Any ideas on how to proceed?"

Answer: Blown-in insulation is likely the only way to go. But this area would only need to be insulated if the porch above it is heated. And if it is heated, there is still a question of a vapor retarder. A typical crawlspace application would have a vapor retarder up against the floor above, a poly sheet on the ground to keep moisture from coming up and ventilation to allow any that does to escape.

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Question: Is it OK to put a plastic vapor retarder over faced insulation?

Thomas writes from Wasilla, Alaska: "I am building a garage here in Alaska- south central area so weather isn't usually extreme. Is it ok to use faced insulation and put a plastic vapor barrier over the faced insulation?"

Answer: If you are installing Kraft-faced insulation, a poly vapor barrier is typically not necessary. The Kraft-facing is a sufficient vapor-retarder. The use of poly over Kraft is, however, acceptable. There should be no moisture problem as long as the poly and Kraft are adjacent. Check with your local building code to be sure there are no special vapor retarder requirements in your area.

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July 19, 2008

Question: Do you sell them or know who does?

Jim writes from Yorktown, Virginia: "My wife is a golfer and I've been looking all over for a PINK PANTHER head cover like Paula Creamer has for her driver. Do you sell them or do you know who does?"

Answer: Owens Corning doesn't sell the head covers but you can find some online. For example, click here and you will see one source on the Web. There may be others. I found this one by entering the following search words in Google: "golf club head cover pink panther."

P.S. Wasn't that fun seeing Paula win the Jamie Farr Owens Corning Classic? We posed for photos together after the event. I wish your wife all the best with her game.

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July 16, 2008

Question: Is it acceptable to "fluff-up" or redistribute the insulation to achieve the intended R-Value?

Gary writes from Smithfield, North Carolina: "In a 12yr old house in North Carolina, with blown-in attic insulation to a 12.5" depth to R-30 and where the insulation has been significantly disturbed and/or compressed, is it acceptable to "fluff-up" or redistribute the insulation to achieve the intended R-Value? Or does new insulation need to be added?"

Answer: Provided the insulation (fiberglass) has not been compressed to the point where the fibers are broken and the product has not been matted down due to exposure to dirty or contaminated water, what you propose doing is acceptable. However, the resulting R-value may not be the same since the product is made for installation with a special machine.

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July 15, 2008

Question: Do you offer any r value boosters to get an r 19 value in a 2x4 wall?

Lacy also writes from Montgomery, Pennsylvania: "How do you find the r values of spray in or blown in insulators? Do you offer any r value boosters to get an r 19 value in a 2x4 wall?"

Answer: The R-values for Owens Corning blown-in Fiberglas™ insulation can be obtained by calling 1-800-Get Pink™ (438-7465). The information is not online because it is primarily a professional product. We do have high density insulation for 2x4 studs but the highest you can achieve is R-15. Owens Corning does not manufacture spray-type insulations.

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July 14, 2008

Question: Is it possible to put foam board on the ceilings?

Jeff writes from Pahrump, Nevada: "I live in a 1980 manufactured double wide home. We just had the roof re-shingled in in OC Shasta white shingles. We put in a bath fan and discovered after it was to late that our roofs R-value is an R-13. There is very little space left in between the insulation and roof sheeting. The ceilings are flat in the kitchen and bedrooms, with cathedral in the rest of the house. Is it possible to put rigid foam board on the inside ceilings and cover it with some type of paneling to bring up the R-value?"

Answer: There are times when this can be done but there are several things to consider before we can recommend this - ventilation, vapor retarders, etc. Please call the Owens Corning customer service department to discuss your situation. The number is 1-800-Get Pink™ (438-7465).

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July 11, 2008

Question: Is there a product we can use instead of building out the walls?

Josh writes from Montgomery, Pennsylvania: "I had an addition built recently they used 2x4 walls. I need to have an insulation of at least a r19 codes says to pass inspection is there any product out there we can use instead of trying to build the walls to a 2x6 since all electrical and plumbing is already installed?"

Answer: Owens Corning does have high-density Fiberglas™ batt insulation for 2x4 stud walls that yields R-15. To get additional R-value you can apply FOAMULAR® extruded polystyrene insulation either to the interior or exterior face of the studs. FOAMULAR insulation has an R-value of 5 per inch. Confirm with the inspector that this will be an acceptable solution. Also speak to them about proper use of vapor retarders in your area. We generally recommend using Kraft-paper-faced Fiberglas insulation in the stud wall with the paper installed toward the warm-in-winter side and the FOAMULAR insulation on exterior.

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Question: By 'condensation' we are referring to water dripping between the boards

Jim writes from Outing, Minnesota: "By 'condensation' we are referring to water dripping between the T & G Boards. So it is somewhat substantial amount - enough to wet the carpet. This only occurs with a warm up first thing in spring while still cold. There was about 8" snow on the roof with no sign of melting, so the insulation vent chutes were doing their job. There was no "ice damn" at the theoretical cold edge. Construction is vent chutes stapled direct to sheathing with full layer of Ice Shield followed by shingles above the sheathing. There is full fill of fiberglass insulation, and then the 2" of foam. The leakage appears to come through the butt seams in the foam, i.e. condensing between the foam and fiberglass. There is 1 x 4 stripping perpendicular to the foam holding up the foam and giving us a solid surface to attach the T & G. We had a few days in the 20'S warmed up to 30's, dripping started, cooled down drastically and has quit again. Has done each spring since we built the house. No other issues. No issues with rest of house standard truss construction and fiberglass."

Answer: Sounds like the moisture is coming from the living space and through the foam. Is it then hitting a vapor retarder? This is a tough one. Can you give us a call to discuss at 1-800-438-7465?

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 11:26 AM | | TrackBacks (0)

Question: What will stop the wetness?

Barb writes from Croswell, Michigan: "Our house was built in 1938. It has an attic with a wood floor. I started to re-insulate today and upon pulling up some of the flooring I found wetness. The original insulation is all there is in the ceilings and it is shiny particle stuff. My question is do I remove this completely or can I put my pink stuff over it. And what will stop the wetness? I have roof vents and a new roof. I live in MI where the temperatures change sometimes by the hour."

Answer: Attic condensation is common in winter months in cold climates. Thicker insulation and the proper use of vapor retarders can help. Please call the Owens Corning customer service department to discuss your situation in detail. The number is 1-800-Get Pink™ (438-7465).

If your current insulation is wet it may have been contaminated with dirt in the water. If that is the case there could be mold issues and you will want to remove it. If the insulation is dry, leave it in place to save yourself a messy job, keep the material out of the landfill and let you benefit from whatever R-value it has.

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 11:24 AM | | TrackBacks (0)

July 10, 2008

Question: What is the best way to get to R-49?

Al writes from Muskegon, Michigan: "I am looking to re-insulate the attic of a home built in the 1930s. There is some insulation in the attic but it is very old and needs to be replaced. The studs are 22 inches apart and look like 2x4s the R rating is 49 in Michigan. What would be the best way of getting close to the rating?"

Answer: The best thing to do is add unfaced Fiberglas™ insulation to what is presently there. If the cavities between the floor joists are filled, run the new insulation perpendicular to the joist. If they are not filled, run the new insulation in the same direction of the joists. R-49 is about 15-1/2 inches of Fiberglas insulation.

Typically, old insulation does not stop working. In fact, Owens Corning recently tested some Fiberglas insulation that had been in a home more than 50 years and found that it still meets today’s performance specifications for the product. Leaving the old insulation in place will save you a messy job, keep the material out of the landfill and let you benefit from whatever insulating ability it has.

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Question: Will you confirm that my understanding is correct?

Earnie writes yet again from Salisbury, North Carolina: "So I understand you correctly, here is what I could do:
  • On top of T&G boards, install thinnest Foamular board, and caulk or silicone seal the foam boards edges at the rafters.
  • On top of Foamular boards, install "kraft" faced OC fiberglass insulation.
  • On top of OC kraft faced fiberglass insulation install, if necessary for additional insulating value, OC "unfaced" fiberglass insulation.

If this appears to be correct, no need to reply. I will take a no reply that I have it correct."

Answer: The answer is "yes." Your understanding of my response is correct.

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 12:07 PM | | TrackBacks (0)

Question: What is causing the dripping condensation?

Jim writes from Outing, Minnesota: "I have a 2x12 rafter ceiling, vent chutes, full insulation and 2" foam. Every spring with a rapid thaw, I have gotten dripping from condensation through the T & G Ceiling. It is a 3 year old 4/12 roof fully covered with ice shield and asphalt/fiber shingles, Heat source primarily wood/ electric baseboard so not high humidity. I shoveled 8" snow off the roof, no melting, no ice damn, and no shingle damage. I think we may have vapor barrier (poly) between the fiberglass and foam. Foam was taped and caulked. Not sure if it was double vapor barriered or not. May not be poly as foam would have been a barrier? Leakage seems to be at seams of the foam."

Answer: It is common to see some condensation during the winter months, especially in cold climates like Minnesota. Poly is not generally used as a vapor retarder in ceilings. Owens Corning FOAMULAR® extruded foam insulation is not a vapor retarder. It is closed cell but does allow water vapor to pass through it. Question we have is how is the ventilation set up? Also, how are the air chutes (Raft-R-Mate® attic vents) installed? Both of these are very important in reducing condensation.

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July 09, 2008

Question: Will there is a moisture issue?

Earnie writes again from Salisbury, North Carolina: "If I use the 1" Foamular, and since the existing batts are kraft faced, will there is a moisture issue? I seem to recall that it's not good to have more than one moisture barrier. Actually, the insulation batts in my ceiling were probably not installed correctly either. I have noticed that there is a second kraft faced batt on top of the kraft batt that is next to the T&G ceiling boards. Is that a problem? I'm not wanting to spend money unnecessarily, but if the original insulation was done incorrectly, now would be the time to correct it. So, if an OC batt is applied on top of the Foamular board, with board edges caulked/siliconed, would it be best to use unfaced?"

Answer: Since FOAMULAR® insulation is not a vapor retarder, it will not create a double retarder. The top layer of Fiberglas™ insulation should be unfaced.

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Question: If we buy Kraft-faced insulation will we need to install a plastic vapor retarder over it?

Tammy writes from Salem, Oregon: "We live in Oregon where it is often wet and cool, but somewhat humid in the summer too. We are installing either r-13 or r-19 in exterior walls in a small bathroom. If we buy the type with the Kraft facing, do we need to install a plastic vapor barrier over it?"

Answer: No, the Kraft facing is your vapor retarder. Just be sure to use bathroom exhaust fans and vent them to the outside of the home.

Posted by The Pink Panther™ Ask the Pink Panther™ , Frequently Asked Energy Questions at 10:07 PM | | TrackBacks (0)

Question: How can I stop air flow through the ceiling boards?

Earnie writes from Salisbury, North Carolina: "I have pine tongue and groove board ceilings. The boards have separated at the tongue and groove, I suspect, due to improper installation. How can I stop air flow up through the boards? In the vented attic above the T&G boards is OC kraft faced fiberglass insulation between the rafters. Could the batts be removed, install a 1" XPS rigid insulation board between the rafters, then re-install the kraft faced batts? Any other possibilities to stop the air movement between the boards?"

Answer: Your idea of using XPS should work but it will need to be caulked to provide a good tight air seal. I recommend using PINK FOAMULAR® insulation in the thinnest sheet available since the Fiberglas™ batt insulation is faced.

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July 08, 2008

Question: How much will I save if I insulate the crawl space?

Gail writes from Virginia Beach, Virginia: "If I put insulation in the crawl area what is the percentage of savings will there be on my electric bill?"

Answer: It is difficult to provide an accurate percentage because there are so many variables that come into play that impact energy savings. That said, I recall a study done several years ago showed that going from no insulation in a basement to just R-11 can save several hundred dollars a season in cold climates like Chicago. Your biggest benefit may be more comfortable floors. With insulation under the first floor and above the crawl space, the floors of your home should feel warmer in the winter. And in a more energy-efficient home, rooms stay closer to the set point on the furnace thermostat and therefore feel more comfortable.

Another point to consider is whether the attic has adequate insulation. Since heat tends to move up, most of a home's energy loss typically occurs through the ceiling. We know from experience that increasing attic insulation from R-19 to R 38 can typically pay for itself in about 5 years.

Sealing the envelope of the home is also an important step in enhancing energy efficiency. It is important to caulk and weather-strip around all seams, cracks and openings. Pay special attention to windows and electrical outlets. Unwanted air leakage alone can raise energy bills up to 10 percent.

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Question: Are we nuts to attempt this project on our own?

Chris writes from Carmel, New York: "I have a weekend house with a cathedral ceiling w/ visible beams. We have discovered that the ceiling in not insulated. (A recent reroofing has left us with nails poking through the ceiling between beams.) I would like very much to retain the open beam work and so would prefer not to sheetrock over the full ceiling. We are considering installing Foamular between the beams and so that we have apprx. an inch of beam visible on the surface. We realize this is much more work. Is Foamular a good solution, and if so, what light weight material should be used to cover the Foamular between the beams. Are we nuts to attempt this project on our own?"

Answer: Wow. No insulation. That's a tough situation. FOAMULAR® insulation is not typically used in cathedral ceiling applications. The R-value for FOAMULAR insulation is 5 per inch of thickness. The product is commonly covered with drywall because it requires a 15 minute thermal barrier for fire protection. As you mention, there would be addition labor involved in using rigid foam insulation. Owens Corning does not have a product that will allow for exposed beams. If you choose to insulate, remember to maintain a minimum one inch of space under the roof deck for ventilation.

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Question: How do I hold the insulation in place for the inspector before putting up the sheet rock?

Jeff writes from Stillwater, Minnesota: "I'm finishing a new bonus room (above a 3 stall garage). Regarding insulation in the top, flat ceiling, should I put faced batt insulation? If yes, how do I put this in place and hold it for the inspector before putting up the sheet rock? I'm not sure stapling it up will hold."

Answer: Yes, we recommend using Kraft-faced insulation. The paper should be installed facing the heated room (warm-in-winter side). If stapling is not suitable, insulation supports can be used. You should be able to find them at your local retailer alongside the insulation products.

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July 07, 2008

Question: Do you have insulation with a radiant barrier?

Rich writes from Live Oak, California: "I AM RESEARCHING RADIANT BARRIERS FOR THE UNDERSIDE OF MY ROOF (AT THE RAFTERS AND PLYWOOD SHEETING), DO YOU HAVE AN ISULATION PRODUCT WITH RADIANT BARRIER ATTACHED TO IT? DO YOU HAVE ANY RECOMMENDATIONS ON INSULATING THE UNDERSIDE OF MY ROOF? GOOD IDEA? BAD IDEA? WHAT DOES IT DO TO THE COMPOSITION ROOF SHINGLES? WHAT ARE THE RECOMMENDATIONS REGARDING VENTILATION AND CONDENSATION? I AM CURRENTLY VENTILATING WITH EAVE AND DORMER VENTS (PROPERLY SIZED) AND I HAVE ADDED A POWERED ATTIC FAN. ANY INFORMATION OR DIRECTION IS APPRECIATED."

Answer: Owens Corning manufactures Fiberglas™ and FOAMULAR® insulation products. Radiant heat harriers are not part of the product line. The undersides of roof decks used with asphalt (composition) shingles are commonly insulated with Fiberglas insulation. A minimum one inch gap is recommended between the top of the insulation and the bottom of the roof deck. Vent openings should conform to or exceed current construction standards, which usually call for a minimum of 1 sq. ft. of net free vent opening for every 150 sq. ft. of attic surface where there is no vapor retarder; or, 1 sq ft. of net free vent opening for every 300 sq. ft. of attic surface where there is a vapor retarder.

Typically, insulated roof assemblies do not allow for adequate ventilation of a roof system due to the lack of free-flow ventilation space that is necessary between the top of any insulation and the underside of a nailable roof deck. The insulation in these types of assemblies is normally in direct contact with the roof deck.

Radiant barriers are sheets of aluminum foil which are applied above or to the underside of the roof deck. As solar energy is absorbed by the roof, heat radiates down to the radiant barrier which is reflected back toward the roof. We recognize that there are several ways in which radiant barriers are installed. The application method to which Owens Corning is concerned with is where the radiant barrier is applied in direct contact with, or laminated to the roof deck. This type of system does not allow for free flow ventilation between the decking and the radiant barrier.

Due to the lack of free-flow ventilation in either of the above systems, heat build-up, which is typically a result of inadequate ventilation, may accelerate weathering and compromise the long term performance of the shingles. Because of this, Owens Corning does not recommend installing shingles over insulated roof assemblies or radiant barriers without proper ventilation.

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Question: Do I have to install a vapor barrier?

Jennifer writes from Midland, Texas: "I have just completed an addition to my existing home. To apply blown in insulation technique do I have to install a vapor barrier? Or can i just blow in insulation right over the ceiling drywall?"

Answer: A vapor retarder is not always used with blown-in insulation if ventilation is adequate. Vent openings should conform to or exceed current construction standards, which usually call for a minimum of 1 sq. ft. of net free vent opening for every 150 sq. ft. of attic surface where there is no vapor retarder; or, 1 sq ft. of net free vent opening for every 300 sq. ft. of attic surface where there is a vapor retarder.

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Question: Will I have a double vapor retarder?

Dennis writes from Allen, Texas: "I want to retro-fit existing exterior walls. Currently they are using R-13 Kraft faced OwensCorning - the pink stuff.

Is this okay:
1) take off trim
2) remove drywall
3) add foam sheating that is considered a vapor barrier
4) put dry wall back up
5) put trim back on

The kraft face (facing interior room) is a vapor barrier. The 3/4" R-5 sheating is also a vapor barrier. So essentially, I would be putting a 3/4 vapor barrier over the thing kraft faced paper vapor barrier.

In this case, since both are vapor barriers and are together, I don't see why the kraft faced backing needs to be slashed? The air gaps in between the kraft faced paper and the sheating will provide some additional small R-value.

Please confirm."

Answer: First, I applaud you for doing all this work to make your home more energy efficient. I can see where you could think that foam insulation is a vapor retarder but it is not. That is one reason why FOAMULAR® extruded foam is suitable for use as an exterior insulation. In your example above you would be placing insulation on the warm side of a vapor retarder. If I was doing the job I would slash the Kraft paper and install a poly sheet over the whole wall before reinstalling the drywall. Then I would have one vapor retarder and it would be on the warm-in-winter side of the system. Walls are important but I hope you already have adequate insulation in the attic because most of a home's energy loss goes out through the top of the structure. The attic is the place to start making a home more energy efficient and I trust you have done so.

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July 04, 2008

Question: Would it help if I removed all the Kraft paper?

Dave writes from Summerhill, Pennsylvania: "I recently built a house. My basement has 8" poured concrete walls. I framed up the walls with 2x4's in order to hold the fiberglass batts, however I do not plan on hanging any wallboard for a few more years. Since no wall board was hung for my final inspection, my inspector made me turn the kraft paper to face the concrete walls (instead of being exposed in the basement) (the other option was to tear off the paper). The other day I noticed a few small puddles on my basement floor and upon further inspection found that ice was actually formed on the top 3 feet of the concrete wall behind the insulation - which is above grade (from condensation). Should I install any kind of vapor barrier to prevent condensation/icing/mold etc? Would it help if I removed all the kraft paper?"

Answer: The inspector (my friend Jacques Clouseau by any chance?) had you turn the insulation around because the Kraft paper facing is flammable. However, you now have a vapor retarder facing the cold side of the wall. Removing the paper may help. Before you go through the trouble of removing all of the paper, I recommend that you try removing it from a piece or two and checking to see if the condensation problem goes away.

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Question: How should I insulate my apartment building?

Charles writes from Chicago, Illinois: "HELP! I own a brick 9-unit 3-story apt building in Chicago. I want to make the 1st floor apartments warmer, and hopefully save on my heating bills ($1900. this past month!!) by insulating the basement ceiling which is plaster-on-lathe. The basement