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April 30, 2007

Question: Will I lose much energy if the seams of the insulation board are not taped?

John writes from Islip, New York: "I hired a contractor to install vinyl siding. He insists on not taping the seams of the insulation board under the siding. How much energy is lost through these seams, and is it important."

Answer: We recommend taping the seams to help prevent water intrusion into the wall system. If you are installing new siding over existing siding it probably won't matter. If it is new construction, I would tape the seams when installing the foam insulation. Energy savings is only a small part of the benefit.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 05:09 PM | | TrackBacks (0)

April 27, 2007

Question: Can I use landscape fabric to hold up insulation in the crawlspace?

Edgar writes from Ladson, South Carolina: "Can I use landscape fabric or cloth instead of chicken wire to hold up the insulation in the crawlspace?"

Answer: Since we do not know the fire performance of landscape fabric we cannot recommend its use in a crawlspace in an exposed application. In order to leave a product exposed it must have a flame spread rating of 25 or less and a smoke-developed rating of 450 or less.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 06:59 PM | | TrackBacks (0)

April 26, 2007

Question: Can I add insulation over the inside drywall?

Arthur writes from Florissant, Missouri: "I have a house built in the 1950's. The outside walls have fiberglass insulation between the studs however the walls are quite cold. I would like to add insulation to these walls. The only feasible way to do so that I have come up with is to cover the existing inside drywall with 3/4" - 1" rigid foam board plus a 1/2" gypsum board for fire protection and to provide for a finished wall surface. Does this seem to be a practical method? Also if it does, would a vapor barrier be required?"

Answer: Yes, the system you describe is an acceptable method for insulating an existing wall. No, an additional vapor retarder will not be necessary and is not recommended.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 04:21 PM | | TrackBacks (0)

April 25, 2007

Question: Must the Kraft facing be stapled to the studs?

Paul writes from Saint Petersburg, Florida: "Is the insulation R-19 with the Kraft paper facing with what I think is a staple tab have to be stapled to the studs or can the installer just stuff it between the studs like he has in a lot of places. The walls in the addition are 2x6's."

Answer: No, the flanges do not need to be stapled when the insulation is installed into normal wall cavities that will be closed in on all sides and as long as the insulation fills the cavity completely in depth, width and height. In applications where stapling is needed, like knee walls or walls where the insulation will not fill the space completely, we recommend stapling the product every 8 to 12 inches. Owens Corning also produces a faced product without flanges called PROPINK FastBatt® insulation, which is available in some markets.

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April 24, 2007

Question: What causes icicles and ice dams?

Steve writes from Spencerport, New York: "I have a new house (6 months old) it has a high hip roof with a ridge vent and soffit vents every 2 feet or so, I have icicles and ice dams forming all around the house especially in valley areas, How do I know if this is due to not enough insulation or not enough venting?"

Answer: Depending on your location you should have anywhere from 12 to 16 inches of insulation in the attic. However, insulation alone won't prevent ice damning. Proper ventilation and a properly air sealed ceiling are also important. It sounds like you may have enough ventilation so the next thing to check is the insulation level and how well that attic is sealed. Adding insulation is relatively easy but many people miss the importance of sealing all the penetrations into the attic. You should check to see that all plumbing, electrical and heating penetrations, along with any lights and ceiling fan boxes, are sealed. Sealing these can typically be done with spray foam and/or caulk.

Even when everything is done right you can still end up with some ice depending on the weather conditions.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 08:05 PM | | TrackBacks (0)

April 23, 2007

Question: Can I link rafter baffles together?

Marty writes from Bethesda, Maryland: "I have a cottage-style (w dormers) house from 1948 that I'm adding additional attic insulation. I'm intending to add R30 unfaced perpendicular to the existing insulation. In doing this I'm adding rafter baffles. However, the rafter baffles don't reach the soffit vents since the distance from the intersection of the attic floor and roof line to the soffits is at least 12 ft. I plan to link the rafter vents together to get air from the soffit up to the attic. And then add faced insulation (it will have to be R-19 since the cavity is only 5 and 1/2 deep).

My question is, can I link the rafter baffles together to form a continuous channel for air to the attic or do I have to leave a 2" gap between each baffle?

I have a roof-ridge vent and two side vents in the attic. Is this alone sufficient?

Also, for some reason the former owner has the original fiberglass insulation with the Kraft paper facing down. I'm thinking about just flipping it over before I put in the R30 layer."

Answer: You need to leave 2" spaces between adjacent baffles or moisture could build up and run down causing a possible leak. There should be no need to extend the length of the baffles since their purpose is to provide a clear path past the insulation. Without the baffles, insulation could get blown or pushed too close to the roof deck and block the flow of ventilation. There is information on the Owens Corning website about installing raft-R-mate® attic rafter vents.

There is also information on the website that will help you determine the amount of ventilation you need. You should leave the insulation as it was installed. The vapor retarder should be on the warm side of the insulation in winter, which means in your case it should be facing down.

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April 21, 2007

Question: Am I using the right vapor retarder and placing it in the proper way?

Rich writes from Independence, Ohio: "I am in the process of finishing my basement into a recreation room. A few yrs. ago I used Dry-lok (2 coats) on the walls of the basement and I recently studded the walls and had all the electrical done, After much research on insulating and vapor barriers I am still very confused on this issue. My decision was to put up Owens-Corning R-13 3-1/2 " fiberglass insulation with the Kraft vapor barrier, I have the Kraft paper toward the inside of the room, it's going up great, can you reassure me that I'm putting up the insulation in the correct way? I live near Cleveland where the winters get very cold."

Answer: You are installing the insulation in the correct way. In your part of the country the Kraft paper will go toward the warm-air-in-winter side.

You are also using the correct vapor retarder. Kraft paper is the recommendation over poly in a basement application.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 11:41 AM | | TrackBacks (0)

April 19, 2007

Question: Is it OK to compress insulation when installing flooring in an attic?

Asa writes from Clover, South Carolina: "I have a new home and I am considering how best to floor a ventilated attic for storage, which currently has 13" blown insulation over 2x8 floor joists. Can I compress the insulation by placing flooring directly over the existing insulation and reducing the current height 5 inches without a significant reduction of R value, or do I need to remove the blown insulation and replace with rolled. Also, just wondering if OSB offers any significant insulation properties, and if so is it possible to remove blown insulation to the top of the rafters and then floor, or will this not offer enough insulation (R value)."

Answer: Compressing the insulation will reduce the R-value and oriented strand board (OSB) does not have a significant R-value.

You should consider insulating the attic rafters and walls if there is significant storage in your attic. There is information on the Owens Corning website about insulating for a finished attic.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 01:48 PM | | TrackBacks (0)

April 18, 2007

Question: Do I need a 6 mil vapor retarder when insulating exterior walls?

Sal writes from Holmdel, New Jersey: "I am renovating a 15 x 15 room with two exterior walls. Of course I am going to insulate but do I need a 6 mil vapor barrier also?"

Answer: What is the building code in New Jersey calling for? Personally, I think a 4 mil or Kraft vapor retarder will do. A 6 mil vapor retarder is very strong but would not cause a problem.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 05:19 PM | | TrackBacks (0)

April 17, 2007

Question: Does insulated siding qualify for the federal income tax energy credit?

Ron writes from Osseo, Minnesota: "Does the 'Polar Wall Plus!' insulated vinyl siding qualify for the federal income tax energy credit (2006)?"

Answer: Unfortunately, the IRS has determined that the "primary purpose" of insulated siding is appearance, and so it has determined that NO insulated siding qualifies for the tax credit. You still get the benefit of the extra R value, however, and that's something to feel good about.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 11:34 AM | | TrackBacks (0)

April 16, 2007

Question: How do I insulate under the stairs?

Peter writes from Manchester, United Kingdom: "How do I insulate under the stairs. The area under the stairs has an external door, which gives access to the utility meters etc under the stairs. The only access to the understairs area is from outside the property. So I'm looking to insulate the under side of the stair boards and probably the triangular solid bit of wall facing the door. What should I use, and should I worry about moisture (damp rather than a leak) getting behind the insulation?"

Answer: We recommend fiberglass insulation. Use the largest R-Value that will fit in the cavity. Most likely, that will be R-19 insulation.

If you have moisture issues now, you need to take care of that problem before installing fiberglass insulation. You may need more ventilation in the area.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 12:24 PM | | TrackBacks (0)

April 13, 2007

Question: How much insulation do I need?

Gene writes from Camden, New York: "How many batts of insulation r38 for attic floor 24x24 with 2x10 joists? Also, how many bats per package and how many packages will I need, or how many loose insulation bags for the attic as opposed to batts for the same r rating and how deep? Also, how many rolls r19 for walls 2x6 studs for 4 walls 8ft high x 24 ft long Kraft faced 16 inch centers."

Answer: The Owens Corning website has a page titled "How Much Insulation Do You Need?" that will help answer your questions. The page includes a calculator that will determine the number of packages needed for your project.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 06:41 PM | | TrackBacks (0)

April 12, 2007

Question: How should I insulate the floors of an above-ground home?

Trey writes from Plaquemine, Louisiana: "I have and an above ground home that sits approximately 10" or so off the ground. I find the floors to be quite cold during the winter months. I was wondering what would be the best solution to insulating underneath my house?"

Answer: We recommend insulating under the floor in the same way just as a crawlspace application. The Owens Corning website has a page with instructions and photos to show how a crawlspace can be insulated.

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

April 11, 2007

Question: How should I insulate a shallow wall cavity?

M. C. writes from Albany, New York: "I'm un-doing a bad 1960s reno of the kitchen in our 1890s brownstone in upstate NY. I want to insulate the back exterior wall, but it's shallow and I'm wondering how best to proceed. The depth I have to work with is only about one inch, as I plan to sheetrock directly to the original furring strips that are attached to the brick. I don't want to build the wall out for reasons of space, and because I want to stay at the original depth of the door and window frames. Questions: Would roll insulation work, or would it lose its value from being too compressed? I'm thinking of rigid foam board, but I'm wondering if it has enough insulating value to make a difference. And, finally, what about a vapor barrier before I close the wall back up? (As an aside, I'm retaining the original wooden wainscoting over plaster along the bottom of the wall and won't be able to insulate that portion. I want to make some difference but realize my situation in working with an old house is not ideal.)"

Answer: Since you don't want to build out, foam is about the only option we can think of for your situation. One inch of extruded PINK foam insulation (R-5) is certainly better than nothing. I would use foam if I were in the same situation.

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April 10, 2007

Question: Do I need to obtain an itemized bill?

Ian writes from Wakefield, Massachusetts: "I had an Owens Corning Basement Finishing System™ installed in 2006 and I would like to take the Federal energy tax credit. My reading of the tax law leads me to believe that I can take a credit of 10% of the 'cost of the insulation material,' and specifically not the cost of the entire project. However, my installer did not provide an itemized bill, and so I am unable to determine the cost basis on which to compute the tax credit. Am I misunderstanding something, or do I need to fight with my installer to obtain an itemized bill?"

Answer: You will need to get the material cost from the contractor. Ask the contractor for a line item for the insulation panels.

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April 09, 2007

Question: How should I insulate a knee wall that is exposed to a cold attic?

Terry M. writes from Gaylord, Michigan: "I would like to know how to properly insulate a knee wall that is exposed to a cold attic. The big question is should the knee wall be backed with foam board? And, if the wall is not backed, what percent of the r factor would I lose?"

Answer: Some building codes do not allow foam board to be exposed on the back side of a knee wall. If your local code allows it, I would suggest using it as a backer. It will also give you an additional R-5 per inch.

Losing R-Value will only happen if the physical characteristics of the insulation are changed. For example, if the insulation is compressed it would lose R-Value. I recommend getting a good seal with the vapor retarded and caulking all seams for air infiltration.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 12:09 PM | | TrackBacks (0)

April 06, 2007

Question: How do I insulation a garage in a humid climate?

Terry L. writes from Brookshire, Texas: "I live in a hot humid climate (Houston area). I am going to insulate my garage, and want to know: 1) what direction should the facing be (from what I have read it should be facing the outside in a humid climate). Since I already have Hardy Plank on the outside, will it not be difficult to put the insulation on with the fiber facing the inside and the facing the Hardy Plank. 2) I have some left over radiant barrier and was wondering if it will do any harm or good to put the radiant barrier foil over the studs after the insulation is installed (assuming I put the facing on the outside). The radiant barrier is permeable and does allow some air flow."

Answer: 1) Building codes in high humidity climates may require the insulation to be placed so the facing is toward the outside, and in some cases they do not recommend a faced insulation. This varies from region to region. The requirement for your area can be found at you local building department.

2) I do not recommend two facings within one cavity. I am not familiar with the specifications of the product you currently have.

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April 05, 2007

Question: What is the best way to insulate a garage that has been finished?

Dwight writes from Fuquay Varnia, Virginia: "What is the best way to insulate a garage that has been finished, (sheetrocked) already? I want to do this myself, but I think the blow-in would cause bulging if it gets damp and settles. How would you put the vapor barrier on a wall that has already been sheetrocked? Or, do I just get rid of all the sheetrock and insulate then re-sheetrock the walls? The floors of the bonus room just above the garage are very cold in the winter and warm in the summer, should I remove the ceiling sheetrock and add more insulation? I will be removing the large double garage doors and studding it out to accommodate an exterior door and windows to match the rest of the house."

Answer: Well, the quick way would be to drill holes and blow in the insulation. You can then paint on a vapor retarder. For the best result, tear off the drywall and start from scratch. Install insulation with a vapor retarder facing the inside. In the ceiling, install an R-30 with the paper facing up toward the living area in the home. Before putting up the wall board, caulk all the seams between studs and plates to prevent air infiltration.

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April 04, 2007

Question: Why do I have to cover the insulation?

Kevin writes from Troy, Michigan: "I have a detached garage I would like to insulate. I would like to start with the ceiling. I am thinking of using the Kraft R-13 between the 16" centers. If I staple them and they are on the ceiling why do I have to cover the insulation with drywall or plywood?"

Answer: You need to cover the insulation because the paper facing is combustible and cannot be left exposed. It is a code violation to leave the Kraft paper vapor retarder exposed.

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April 03, 2007

Question: Should I enclose and condition my home’s crawlspace to eliminate moisture?

Joan writes from Portland, Oregon: "I have a two story house built in 1989. I have an issue with water in the crawlspace. I am trying to decide whether to just replace the existing 6 mil vapor barrier with 20 mil and air seal or go with a closed conditioned crawlspace. Is it worth the extra money to go with the second option?"

Answer: Yes. It should help eliminate your moisture problem and save energy dollars in the long run.

Posted by Pink Panther Ask the Pink Panther , Frequently Asked Energy Questions at 11:40 AM | | TrackBacks (0)

April 02, 2007

Question: Is R-80 over-insulating and is that a problem?

Julie writes from Rochester, New York: "One contractor tells me I need R 49 as a minimum in my attic and his project will give me R 56. Another tell me when he is done I will have R 80. If I need R49 why would I go with either of them if I need R49? Is going to R80 over-insulating and is that a problem?"

Answer: To maximize the energy efficiency of both new and existing homes, the U.S. Department of Energy (DOE) has published R-value recommendations based on specific heating and cooling needs and the cost of energy across the country -- Zip Code by Zip Code. The Owens Corning website has a calculator to help you determine the R-Value Recommendations for your area. The DOE recommendations are substantial so I don't see a need to exceed them. The only drawback in going beyond the recommendations is the long time it may take to save enough additional energy to pay for the extra insulation. Once you reach the recommended R-values there may be other opportunities in your home that will deliver a better energy efficiency payback.

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