Ask Ted!

If you have any questions you want answered, feel free to drop me a note. If you’ve got a question, chances are, there are lots of others out there with the same question. So ask away!

Note: all comments are moderated unless I’ve approved one of your previous comments. Almost everybody gets thrown off by this, but I moderate comments to avoid spammers. The downside of this is that you won’t see your comments post until I’ve had a chance to review and approve them. Sometimes this can take days (sorry!) Thanks for your patience.



1,060 thoughts on “Ask Ted!

    • it depends on how bad the roof is. obviously if it’s so bad that it’s leaking, then it will adversely affect your home’s Energy Efficiency. on the other hand if the roof is still basically sound then the heat loss will almost entirely the due to how well are sealed and insulated the attic space is.

  1. Ted,
    Not sure if this is your area of expertise, but you haven’t let me down yet, so I thought I’d give it a shot. Just had an old concrete porch removed from the front of my house and it exposed some previously covered foundation. The crawlspace is entirely encapsulated with rigid foam and air-sealed, so the only exposed foundation is on the outside side. The basement will eventually get the same treatment (rigid foam on the walls and air-sealed). What is your opinion on painting exposed foundations? The previous owners had already painted mine. Foundations are mostly in the ground so they’re always damp and absorbing moisture. I had always thought that the portion that is above ground is the only opportunity for any moisture in the foundation to escape. If someone were to paint it would they be locking it in and doing potential damage to the concrete? Or potentially forcing that moisture up through the foundation plate and rim joist and maybe even into the wall assembly?
    Thanks in advance!!

    • well, that is a different question for me.
      you’re right, it is out of my realm of expertise, but maybe we can think this one through.
      I do know that’s often exteriors of foundations are coated with a waterproofing sealant, so painting it should be little different as far as the effect on moisture. since it is sitting in moist dirt, just like a normal foundation it will always be wet. The thing is now that it’s exposed it will be potentially subject to freeze thaw cycles which could lead to cracking. but I would imagine this would be the case regardless of whether it was water sealed or not.
      so I guess my real answer is “I don’t know” 🙂

  2. I recently purchased a 1-1/2 story Cape-style house that was built in 1959 and is in need of some updates. A previous owner updated the house in the mid-80’s and I’m currently in the process of undoing their work.

    When removing the interior wall coverings, I discovered there is no insulation in the exterior walls and I’m wondering if I should add insulation or leave well enough alone and button everything back up with new drywall.

    Prior to the original siding installation, the exterior of the house was horizontally “wrapped” in 6″-10″ boards and some of them have 1/4″-1/2″ gaps that have allowed pests to penetrate through the years. At a minimum, I would like to make the interior of the home less accessible to creepy crawlers.

    I have a game plan, but I do not want to DIY myself into a situation that will require a professional to fix down the road. I’m seeking advice before I make an expensive mistake.

    Is following method logical for this scenario?:

    1 – Seal the 1/4″-1/2″ gaps with a closed cell canned foam such as Great Stuff.
    2 – Install an encapsulated fiberglass insulation without a vapor retarder such as Johns Manville ComfortTherm R13.
    3 – Install a 4-6 mil barrier across the face of the studs.
    4 – Install and finish new drywall.

    Note: The house is located in a woody area in central West Virginia. The summers can be humid and the winters can be frigid. The house is located on the border of climate zones 4A and 5A. Climate zone 4A is the official classification, but the next county over is 5A.

    • If the walls are standard construction, framed out with drywall on the inside and the boards you mention working as exterior sheathing, then that looks like a sound approach. If you want it tighter and even better insulated, since it sounds like you’re ripping out the drywall anyway, you might consider adding a layer of faced polyiso sheet foam, maybe 1/2″ thick, to the interior studs, then put up the drywall. You wouldn’t need the interior barrier then as the polyiso would act as a moisture barrier,. I’m thinking 1/2″ because that might be thin enough that you wouldn’t have to extend widow jambs much. However, it may turn out to be too much of a hassle if it changes the way they’re framed out. In which case, you could go as you mention.

      • Ted, I greatly appreciate your insight.

        Over the last few days, I’ve read some nightmare scenarios regarding insulating the walls of an older home and effectively creating a wet environment.

        At some point, probably when the home was updated in the mid-80’s, a previous owner installed vinyl siding. I’ve not yet determined if all the original wood siding is present under the vinyl, but a rear full-width porch was converted to finished space and wood paneling was installed over the original wood siding in that area. That particular area is now an interior wall, so my insulation of exterior walls will not effect this area.

        Given the above information, would the earlier method I mentioned still apply if I discover original wood siding remains under the vinyl?

        What if the wood siding was removed and the house was wrapped prior to the vinyl installation (unlikely, I know)? I assume my plans will need to change if this is the scenario, but I’m not sure of the extent of the change. Would I simply omit the 4-6mil barrier across the face of the studs if an exterior barrier was installed?

        …maybe I’m in over my head.

        I apologize for supplying so many scenarios.

        Guidance would be most appreciated!


      • The vinyl siding itself should cause any problems. It’s not air-tight so moisture should be able to drain out. I’d probably want a Tyvek or other barrier like that between the sheathing and the siding, but otherwise, that should be no problem.
        The interior moisture barrier should be fine also. These days, in most places, building scientists don’t see a need for this for the reasons you mention. This would allow any moisture that might get into the walls to dry to either the inside or outside, so you could save yourself the effort. Painted sheetrock is actually minimally moisture permeable. So just do your best to seal around outlets and other holes you make in the wall. Those types of things let hundreds of times more water into the wall than can pass through the sheetrock.

      • Ted,

        I’ve given this considerable thought and I’m positive new siding will be part of the plan a couple years out. I’m leaning heavily toward a Hardie product.

        For now, I think I’m going to modify the wall insulation plan (from the inside out) as follows:

        1 – Finished sheetrock
        2 – Omit the 4-5mil barrier
        3 – Encapsulated fiberglass without vapor retarder between the studs
        4 – Canned closed-cell spray foam in the cracks between the plank sheathing.

        When the time comes to install the new siding, I will specify everything should be removed down to the plank sheathing and the house should be wrapped prior to the installation of the Hardie product.

        Thanks again for your insight. This place is a wealth of information.

        Kind regards,

      • We did a Hardie siding for a while on our house. Durable and good looking.
        Good luck with your project! And thank you for your feedback. All the best.

  3. Hi Ted, I have two houses. One was built in 1967 and the other one 1972. Both have a gable roof, brick veneer with weep holes and are on a slab. #1 has gable end vents, soffit vents and 2 whirlybirds near the roof peak. #2 has soffit vents and a ridge vent but no gable vents. Both also have gas furnaces that draw combustion air from the attic. Both also have apx 12″ of blown in insulation in the attics.
    A foam contractor wants to completely seal the gable ends and roof decking with closed cell foam. I asked about the source for combustion air and he had a blank look then said no one ever asked that question before. I assume that a properly sized duct would need to be installed. I am also concerned that the wall space will not be vented any longer.
    Both houses are located 60 miles northwest of Houston,Texas. Thanks Rick

    • That doesn’t give you a lot of confidence in him, I’m sure! You definitely need combustion air but adding a vent defeats the purpose of the insulation. If the furnace is old, you might consider replacing it with a direct vent unit that draws combustion air through a duct to the outside.
      A sealed attic of this type is usually ok. Ventilation is usually used for either cooling or moisture control. The foam, if properly done,solves both problems.

      • Thanks Ted, that makes me feel more comfortable about the foam on the roof decking. I was hoping that I could retrofit the old furnace with a dampened duct if it was properly sized for the furnace and distance to the gable end. House #1 has a 29 year old Trane so it will be replaced next spring. I will be sure to get a ducted heater for that house. Rick

      • you can rig something up. Sometimes they do this for furnaces in homes. They run an appropriate sized duct to allow fresh air in. Then they put the outlet, facing down, into a container, like a trash can. This allows cool air to pool without just flowing into the living space. It’s supposed to be quite effective.

      • Thanks again from the quick response! I have searched all over for information and your site is top notch. I am learning a lot and will keep on reading.
        I will get with someone to size the duct for the furnace. House #2 has a fairly new system. A/C is the biggest deal in our area, I think I used my furnace about 2 weeks last winter. Thanks again, Rick.

  4. Hi Ted, Thank you for your article about mold. We just received a mold report on a house we are selling… would you be willing to look at it and let me know if it seems normal. Our relator said she has never seen one, but it looks very discouraging and extremely high levels. (?) Appreciate your time.

    • hi there, thanks for asking. I’m afraid I can’t do this type of work and your best bet is to stick with your mold specialist. you might be able to find a second company around there perhaps look for a company that specializes in indoor air quality rather than just mold in order to get a second opinion. this is especially important when buying and selling homes because mold has become such a big legal nightmare.
      just be wary of extreme reports from companies that do mold remediation because they charged thousands of dollars and operate on scare tactics. that’s why I like to use a company that doesn’t do the actual remediation work. since they have no vested interest in selling Youth Services they’re more likely to give you an honest answer.

  5. Ted, first off thank you for the post on l.e.d. inserts, I will opt for this solution.

    Are gaskets needed? None came with the Phillips airtight inserts I purchased. If so, I assume a window seal would do the trick?

    New question – the home energy audit also recommended more attic insulation. We are currently at R30 and would like to get to R50+.

    We currently have batting topped off with cellulose. Do you recommend more cellulose, or is it ok to add fiberglass on top of the existing insulation?

    Thank you again!

    • It’s definitely best to get circular cutout gaskets, though many are really cheap foam and don’t do much. What you could do that would provide an excellent seal, would be to use that gasket material that’s like clay rope. I’d take a couple strands, roll it together into one larger strand and make yourself a gasket. Then compress the LED insert to the ceiling. I’ve not done this myself since I had already sealed my fixtures from above, but in your situation, I think that could work quite well.
      As for insulation – blown in cellulose is a double edge sword. It’s great because it goes in quick, is pretty inexpensive, and fills in gaps. Batt insulation is much more labor intensive and prone to installation errors which can leave gaps.
      The flip side is that blown in insulation is not good if you need to use the attic for other things because it hides everything then clings to your pants, making a big mess when you come down from the attic. But if you never access the attic, it’s a great way to go.

  6. Ted, we recently had a home energy audit and found that we need to seal some recessed lights to prevent air flow into the attic.

    We have a contractor quote to seal from the top down, i.e. using a fireproof box installed from the attic. Option 2 is more d.i.y., to replace the recessed lights with an l.e.d. insert and gasket.

    I would prefer the l.e.d. insert option given it is much cheaper and prevents the contractor from crawling around in a tight space.

    Are there any pros or cons I should keep in mind for both options? Is the l.e.d. insert option going to be as air tight as the fireproof box?

    • Adam, thanks for asking – that’s a great question, I should write a feature article about this because it affects so many homes!

      I’ll start by saying that I have upgrades all of the recessed lights in my home with LED retrofits. This has numerous benefits over attic sealing. Prior to good LED retrofits being available, I had constructed airtight/fireproof boxes installed from the attic, so I can comment on both from first-hand experience.

      The retrofits were easy to do, taking maybe 10 minutes each, at most. These days, high quality retrofits are inexpensive, typically less than $30.

      – Totally air-tight when installed with a good gasket
      – Energy efficient – depending on your electric cost, the light will pay for itself, especially if it’s in a high-use location, like the kitchen. Usually less than a year.
      – Energy efficient part 2 – you can insulate the attic properly above the fixtures. LEDs generate much less heat than incandescents. Plus, you won’t lose the heat from air escaping through the housing.
      – Long lasting – quality LEDs are rated to last about 2-4 years running continuously. Compare this with an incandescent which has a life only one-tenth as long. This is much more convenient (less time on the ladder is safer too!). For most uses, that means you’ll never have to replace a bulb.
      – The light quality of “good” LEDs is very natural if you buy high CRI (color rendering index) fixtures. This is very personal, so compare the light from different fixtures to find one you really like. I brought home several, installed them and then my wife and I could see how they looked in our own homes which is much different than the display case in the store. You can usually return the ones you don’t like, so it’s worth trying a few.
      – The retrofit itself is quite simple usually. Most wire into your existing fixture using a screw in connector that replaces the existing bulb.

      Challenges with retrofitting from the attic:
      – Working in attics is not fun. It’s hot, dusty and access is often difficult. This makes contractors less likely to do a good job because they’ll be anxious to work quickly and get out of there.
      – It can be difficult to mount the air-tight enclosure in the attic given the construction of a typical recessed light fixture. This often leads to compromises that leave gaps, defeating the purpose of an air-tight enclosure.
      – Incandescent lights generate a lot of heat. Some older fixtures aren’t rated for enclosure. Usually this isn’t a problem however.
      – Covering the fixture with a housing can make insulation challenging. Most contractors are afraid of insulating around fixtures, leading to compromised insulation.

      Other considerations:
      – Some are dimmable – so make sure to buy the right type if you need them to dim.
      – The convenience factor of not having to replace bulbs in high ceilings is worth a lot.
      – Make sure the chosen fixture is the right size (4″, 5″ or 6″) for your retrofit. There are also different mounting styles that can affect compatibility.
      – Avoid off brands or those without a good warranty. The only trouble I’ve had with LED bulbs/retrofits are with cheap “knock-off” type. My favorites have been manufactured by CREE, which were the pioneers in LED lighting. Phillips also makes quality products.


  7. Hi Ted,
    It’s July in the Laurel Mountains in western PA. It’s been unseasonably warm and humid, high 80’s and up. My kitchen/dining room cathedral ceiling is a combination of tongue and groove and sheetrock. We have central air conditioning, most of the time we don’t need to use it. When the temperature is the highest around noon and the air has been on, I’ve noticed condensation and dripping from the area where the sheetrock joins the wood. Our roof is closed – no ridge or soffit vents, air conditioning vents are on the floor. From construction pictures that came with the house, it looks like the insulation is solid. The leak seems to be from the ridge and dripping down the slope. We had ceiling fan put in this past winter, it hangs from the boxed ridge. We’ve had a roofer check and there are no noticeable issues with the roof. After reading the comments above, I’m wondering if we need to open the boxed ridge and check if the electricians removed the solid insulation in the area of the fan? Other suggestions?
    Thanks, Deb

    • It is strange that the issue occurs under those circumstances. Normally, mid-day, the roof would be hot, leading to the least likely conditions for condensation.
      The location, where the sheetrock joins the wood is expected, since that seam is where the water could drip out. It’s also where the moisture from inside the house could rise up into the cavity.
      One possibility is that the wooden beam is cool enough (because of the air conditioning) that when the hot, humid air from outdoors comes in contact with it, it condenses, then drips down the beam and into your house.
      Did the dripping only start after the electrician added the fan?

      Another possibility – do you open the house up at night to get fresh air? Nighttime air is cooler and often saturated with moisture. That moisture could float up to the peak and condense on the cooler wood. I couldnt’ say for sure that is the cause, but it’s a possibility.
      If you do open the house up, I would discourage doing so on anything but low-humidity days. I’m always tempted to get fresh air too but usually regret it because of the amount of moisture that this lets in the house. Then I spend all day running the AC to remove the moisture.

      If the dripping continues in spite of being diligent to prevent excess moisture from entering the house, I would have someone carefully remove the ceiling along the wood beam so that the inside of the ceiling cavity can be inspected. If the wetting has occurred for a long time, it could lead to wood rot. You’d want to examine this and see exactly what is happening in there. Then formulate a strategy for “fixing” the problem. Without knowing the cause, I wouldn’t try to fix it by speculating about causes. That can lead to more problems and cost you $$$ and time.

      • It only occurs when we have the air conditioner running AND only during the hottest part of the day. We’ve only noticed it since the ceiling fan was installed. Thanks for your suggestions, I’ll have a contractor look at it.

      • That is truly odd! Based on your description, this is a longshot, but is there any chance that there’s an AC duct running up there? Often cold ductwork will lead to condensation. Highly unlikely given what you’ve described, but I wanted to rule out all known possibilities.

  8. Hi Ted,
    I recently purchased a home and have undertaken some substantial renovations. My home has a metal roof with a low pitch. It has soffits around the perimeter but no ridge or upper vents in the attic or anywhere else on the roofs. There has been a history of ice damming and there were some leaks which I have fixed.
    I am now thinking to spray foam insulate the attic area, but want to know if I should seal the soffits? The ice dams occurred at the lower portion of the eaves in a seam between 2 sections of 2 different roofs with ceiling heights being significantly different. One vaulted and one a more traditional height.
    If I close cell insulate the attic, but keep the same batts insulation in the other areas, will the other areas require vents to be installed? And do the soffits in the attic need to be sealed?
    I’m sorry if this is a little confusing- I have been researching a lot of different information and have also received a couple of different opinions.
    I’m thinking a combination of spray foam and venting may be required.
    Clarity and any help is greatly appreciated.

    • The ice dam issue is typically going to be due to heat leakage from the house around the perimeter. Due to the usually poor accessibility where the roof meets the wall, this area is often hard to seal. With proper blocking and vent chutes, they could spray in foam while protecting the soffit vents from being covered and allowing air to flow up the soffit and under the roof.
      For example, here’s a video showing how you could do this:

      Granted, since you’ll have the ceiling/attic floor in place, it won’t be this easy, but you get the concept. Once the baffles are in place, the foam will seal the air leaks and provide excellent R-value. If you choose, you could then use loose fill or batts elsewhere. But I’d recommend at least foaming a thin layer over the rest of the attic floor (i.e. ceiling of room below) to seal all air leaks, then add less expensive insulation elsewhere. But use a thick layer of foam out near the soffits, against the baffle, to avoid ice dams.

      Again, with the low pitch, access will be a bugger. But it’s worth a try.

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