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.


1,225 thoughts on “Ask Ted!

  1. hi i just had windows installed and im freaking out because at the bottom corners where a nice wood frame is , if i push on the part closest to the window i can draw moisture/water onto my finger !! i think it starting to rot my wood framing. just on the bottom corners??? what is going ??

    • It’s common during cold weather for windows to have condensation on them, especially over night when the curtains are drawn. Even with high quality windows and good installation, I have to go around with a towel to soak up excess moisture on some mornings. Especially in my BR where the humidity is higher than other rooms and I have thermal shades on the windows.
      If you’re experiencing too much moisture, and you have curtains or other window treatments, you should try leaving them open a bit at night to allow some of the warmer room air to warm the windows. This can help a little, but it won’t solve the problem.
      It’s possible that you have other problems, but condensation is the most common winter moisture issue, so I’d start there.
      One final suggestion, if you’re using humidifiers, use them less or not at all for a while to see if that reduces the problem. Humidifiers usually dump far too much moisture into the air, leading to mold growth, condensation, wood rot etc. If you must use a humidifier, keep the humidity level in the room below 50% during the winter. 40% is better.

  2. Ted
    I wrote earlier today about removing/replacing insulation that has rodent droppings.
    I’ve been re-reading your older articles about air-sealing, and it sounds like the right thing to do.

    But two more questions occurred to me:
    1) I do not have bathroom fans to vent moist air. Should I install them (2 upstairs full baths). Your article said to vent through the roof.
    2) My living room has a cathedral ceiling. In the attic, this is a sloped area. I emailed the rep I talked to, asking him if they air-seal and remove/replace the insulation in that sloped area.

    Once I understand these two questions, I think I am ready to get this job done.
    But as I said, I don’t want to solve one problem only to cause another!

    Your articles have been very valuable!


    • I don’t see my original posting, so here’s a brief summary:

      I had bats/squirrels in my attic a few years ago. I had a wildlife guy put an exclusion device to get the bats out, then he sealed around openings. I haven’t noticed any sound or activity since.

      The attic insulation has droppings, plus the squirrels messed it up a bit.
      I had a rep from a company to evaluate. He said they would remove the insulation/droppings (suited up, house area lined with plastic), vacuum up all droppings/debris, disinfect, air-seal gaps, install new R-30 insulation.
      My original question was whether the air sealing would affect air flow or moisture in the house.
      But then more questions occurred to me as I re-read some of your articles. I sounds like the air-sealing is a “go”. But I had further questions (post above) about the bath fans and I’m asking the rep about the cathedral ceiling area.

      Nancy M

      • Thanks for your questions and notes 🙂

        So, yes on air sealing the area under the insulation when you pull the insulation and clean out the attic.
        Your question on bath fans is timely because it’s easier to do when the insulation is pulled. Make sure the bath fans are air sealed to the ceiling as well – that’s a huge source of moisture damage that almost everyone ignores. A little canned foam from the attic side around the perimeter of the fan box works great.
        The duct from the fan should go straight up (or nearly so) to a vent hood mounted on the roof. This allows the fan to work efficiently (the less duct the less air resistance) and keeping it vertical reduces the chance of water building up inside the duct.
        I’m not sure I understand about the cathedral ceiling. Are you saying that the cathedral ceiling is visible in the attic, like protruding through the floor sloping up? I’ve seen this type of construction a couple of times. If that’s the case, then yes, air seal any gaps (there shouldn’t be any unless you have recessed lights poking through the ceiling) and ensure good insulation covering it, just like you would do the floor of the attic.
        Hope that covers it. My head is a little fuzzy today. Feel free to shoot over more questions.

      • The cathedral ceiling (or just a high ceiling) is above my living room, but below the attic, if that makes sense. About halfway across the living room, the ceiling slopes downward. So from the “normal” attic area, there is a section that slopes downward, which corresponds (as best I can tell) to the sloped area above my living room.
        I emailed the attic guy about whether they remove/seal/replace insulation in that area. I hope to get a response.
        I’ll also ask about the bath fan installation. I just re-read your article about it, and I was thinking just as you said, that it makes sense to do it when the insulation is removed. But I don’t know that I’ll be able to coordinate two jobs that way. I may be stuck doing it afterwards (I don’t want the installer to have to deal with the attic/rodent issues).
        Would have been easier if the original builder had installed bathroom fans!

        Thanks for your response!


  3. Hi Ted,
    I need your help. My exterior back wall is getting blister or bubbles in the paint but I dont have a leak. who do i need to hire to know if the house is having humidity problems? Thank you in advance.

    • Often, though not always, bubbles are indicative of moisture trying to force its way through from the other side. It can generate a lot of pressure which will literally blow the paint off the wall on the inside. It is possible that there is water or moisture behind that wall, which I guess means inside of the wall. Is this a sheetrock wall? One thing you can do very easily is take a sharp knife with a thin blade and carefully push it into the wall to see how much force it takes. If it goes in easily like butter then the drywall is probably saturated with moisture. If it resists and you can’t push the blade in without exerting a lot of force, then the drywall is not wet. This should be a minimally destructive test as it will just leave a small slice in the wall surface That could be easily repaired if it turns out to be nothing. If it does turn out to be wet, then that drywall will probably have to be cut out and replaced anyway.
      It can be hard to find somebody who is good that specializes in tracking down moisture problems. If you Google “building science” and “moisture troubleshooting” in your area, you may have luck finding someone. I would suggest looking at a person or company’s website to see if they have information like mine on there or if they are just trying to sell a product. That should be a start. Feel free to ask more questions if you learn more about your situation and need some more tips.

  4. Your blog has covered all of my questions. As an electrical contractor I see everyone doing just what you say and it sickens me that they get away with doing half the job wasting the clients money. I stand there looking like the a nit picker trying to make sure all of these items are done and I will stand by it to the end. You give my facts another point of meaning now as I will be able to show Clients I am not the only one who does it right. I will now be fixing up the air flow issues just in time for the winter your donation will come when my family sees how much you have helped!

  5. I live in the San Francisco Bay Area peninsula area in an older home with a dirt crawl space, CAN lights in a vaulted ceiling, and fiberglass insulation between the ceiling and the roof. You describe exactly what I have experienced in the Springtime during the past several years. Water drips from the CAN lights onto the floor below the vaulted ceiling (when it is not raining outside and has not rained for many days). There is visible water damage to the ceiling that has accumulated over several seasons. I’d like to have a qualified professional assess my situation before contemplating repairs, but I am struggling to find the right person using the search terms you suggested. Can you recommend some one in the Bay Area who I can work with to better assess my situation and propose solutions? Thanks.

    • I’m afraid I missed your message when you first sent it sorry for the long delay. In the Bay area, there should be many options. You can look for people experienced in building science and moisture troubleshooting. A BPI certification is a good thing to look for. If possible find an independent company, not one that provides services like insulation or HVAC installation. I generally have been more impressed with specialists who focus on building science issues. They don’t have a vested interest in selling you something usually.

    • Thank you! There are a lot of good analysts out in the Northwest. You can try searching for “BPI certified” or “building science” or “home thermal imaging” for your area. The trick is finding people with experience and the right motivations. I typically suggest looking for independent people, not associated with an HVAC or insulation company. If you don’t have luck, email me with your town and I’ll try searching for someone promising.

      • It is great to have the info you provided. I am having water dripping from the light features in the ceiling. I also have fiberglass ceiling. Is there a way to fix the light features without redoing the entire ceiling? Will removing the moisture from the house (for example, seal the crawl space) help?
        I live in San Mateo city, Bay area, California.

      • Water dripping from the ceiling light fixtures is definitely a big problem!

        As you suggested, the first approach would be to greatly reduce the moisture in the house. I’d suggest buying a few of these inexpensive moisture monitors and placing them in a few locations in the house including the rooms where the light fixtures are dripping and the crawl space. This will give you better idea of the current humidity levels in the house and confirm your thought that the moisture is coming from the crawl space. It might be that the crawl space isn’t the source of the problem, which would save you a lot of effort. However, if your crawl space is noticeably wet, then you want to take care of that immediately. I had a townhouse with puddles on the floor from water seepage up from the ground! The previous owners never dealt with the moisture and it rotted out the floor joists under the kitchen to such an extent that the refrigerator was at risk of falling through the floor!

        Given how much moisture is building up in your ceiling, it is very likely that damage has already been done inside the ceiling. The dripping water means that the wood is probably already saturated. Over time, this will lead to mold and rot. At the very least, I would consider replacing those light fixtures with sealed, flush mount LED fixtures. When installed tightly against the ceiling, these will greatly reduce additional moisture from entering the ceiling and will help to reduce additional damage. But ultimately, I think you’ll have to bite the bullet and cut out a section of the ceiling around the light to assess the extent of the moisture in the ceiling.

        Here’s a link to a bunch of these humidity/temperature gauges at Amazon:

  6. I’m having a problem with condensation on my ceilings and bricks of my chimney. I have vaulted ceilings and there isn’t anywhere for venting. I’m at my wits end with this problem and I don’t know where to go next. Is there a way I can talk directly to you or send pictures? Please help!

    • Sure -send me anything you’ve got to
      The more details, the better. What the conditions are when it happens – outdoor temperature and weather conditions. Time of day. What was the day before like? And clear photos showing the area where the condensation occurs and the relative position in the room. It’s also useful to know where you live (city and state) so I can look up weather/temperature history.

  7. I have a 1980’s atrium. Fully HVAC with humidistat and exhaust fan. If I dont manually adjust humidity exhaust almost daily and sometimes hourly, condensation forms in the house.

    • That probably means there’s missing insulation in the areas of condensation. Moisture rises and collects at the ceiling so that’s usually where the problems are worst.

      • Thanks for quick response. The atrium roof is glass and the house surrounds the atrium. It is a t & g, cathedral ceiling on house. Is there way to insulate around atrium from the inside? Its a one story house with asphalt shingles and a 3″ roof deck which in the 1980’s was good enough for insulation.

      • Is the condensation forming on the glass or somewhere else?
        If it’s the glass, there’s nothing you can do other than reduce the humidity in the house or get more warm air movement up near the glass to try to keep it warmer.
        If it’s on other surfaces, like the T&G ceiling, that can be more problematic. Again, any time you get condensation, the first thing is to review your home’s humidity. This can vary greatly from room to room depending on usage. For example, the humidity in my bedroom at night increases considerably because it’s sealed up and we’re breathing all night! Other examples are near showers, if the bathroom isn’t being vented adequately and in areas with lots of house plants that release a lot of moisture into the air.
        If you’re using a humidifier, try not using it for a while and see how that changes things.
        You can get little humidity meters from Amazon for cheap. If possible, put them close to the places where condensation is forming so you can see what the level is right there. Since the moist air rises, the humidity at the ceiling can be significantly higher than a few feet off the ground.
        Here’s one example of the gauges I’m referring to

  8. I have a 2-story property in Huntington Beach, California that was built in 1964. It was renovated in 2017. Starting last December, two sections of the property is showing excessive condensation and moisture accumulation. This condensation problem is mainly on the north facing areas. One area is on the first floor, and the other area is on the second floor, and these areas are not on top of each other. I am using a 50 pint dehumidifier and DampRid closet hangers to absorb the excess moisture continuously, but I want to know what is the cause of this so I can fix it. I greatly appreciate any feedback. Thank you.

    • Huntington Beach has a very mild climate, so it’s surprising that you’re having condensation problems.
      What surfaces is the condensation forming on?
      It’s common for people to develop condensation issues after a renovation due to the improved construction which makes a home “tighter.” The tightness is good, but that also means one has to be careful about uniform insulation and reducing interior humidity sources.
      Condensation will form on the colder surfaces in a house. Often, that’s windows, which is almost unavoidable if there’s excess moisture in colder climates. In your climate, it’s less common.
      I’d do a couple of things
      1 – check for interior moisture sources. Most common is showers that aren’t properly vented. I always recommend checking the bath fan for good suction at the intake. Then, make sure the fan runs during the shower and for at least 15-30 minutes after you finish showering in order to remove the excess moisture.
      2 – monitor the humidity in those rooms where condensation is occurring. You can get these on Amazon so cheaply –
      If you find the humidity in those rooms rises up past 60%, you know there’s too much moisture in the air under most circumstances. During the summer, it can be hard to keep it down.

      I checked the daily humidity numbers for your area in December and they were very high – 60%-80% for many days. If you open the windows, especially at night or early morning when the humidity is very high, the house will fill with moisture which will condense easily. Unfortunately, that’s unavoidable. The humidity drops quickly as the day warms so you can flush out the extra humidity by opening up the house on non-humid days in the afternoon. But it can be a tough battle in your climate.

      I’d start with those little humidity gauges placed throughout the house. See what the indoor humidity is like and if it is associated with any particular usage patterns, like opening windows or showering or cooking. Keep using dehumidifiers when the house is closed up, that might be your only solution during the colder months. During the summer, running the air conditioner will suck the moisture out of the air quickly.

      Hope that helps.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s