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  1. #1
    Join Date
    Dec 2001
    Location
    Ocean Pines, MD
    Posts
    6,990

    Crawlspace problems?

    Since when have exterminators become the crawlspace experts?
    Obviously not their area of expertise. The ones I've seen they've made worse.
    Are you listening Teddy?

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,444
    Funny that you asked! Extermintors are in more crawlspaces than you can believe. They also are agressive and eager to solve problems. And to top it all off, they are getting very good at solving crawlspace problems. Actually, they have properly fixed more crawlspaces this last year than anyother trade. They get plastic on the earth, close the vents, and add a good dehumidifier.
    This could have been the a/c trades territory.
    Specifically, what was your comment? Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Nov 2009
    Location
    north georgia
    Posts
    19
    Teddy, here where I am located in Ga ,most if not all exterminators are telling people with problems they need more foundation vents ,in turn they ask me and I tell them to look at clean space and similar product's . How does the hvac industry need to educate the general public about crawlspaces, humidity and dewpoint's?

  4. #4
    Join Date
    May 2007
    Location
    Dry as a bone Tucson
    Posts
    4,344

    crawl space ventilation

    In a cold dry climate should crawl space ventilation air be heated in the winter?
    Should a vapor barrier be laid on the ground even in a dry climate?
    What is the ideal air exchange rate for a dry climate crawl space?
    Should it be forced air or are vent wells ok?
    Should water and drain lines be insulated?
    Should a vapor barrier be applied to the conditioned floor above the crawl space?
    Some Talk, Some Do
    "keeping condensing pressures low and evaporator pressures high"
    "Some customers are more interested in comfort than energy savings"
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  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,444
    Quote Originally Posted by Gaskeeter View Post
    Teddy, here where I am located in Ga ,most if not all exterminators are telling people with problems they need more foundation vents ,in turn they ask me and I tell them to look at clean space and similar product's . How does the hvac industry need to educate the general public about crawlspaces, humidity and dewpoint's?
    Recommendations on the ideal crawlspace are all over the place. Doing a search on the web leads to total confusion. Ventiltating, closed vents, or increase the amount of fresh air are recommended by all sorts of experts. Certianly the companys like Beasement Systems are giving guarentees on customer satisfaction. Eliminating the source of the soil moisture, stopping the infiltration of outside moisture laden air, and installing a durable dehumidifier is proving successful for many companies.
    I am attaching a pdf of from a research group showing how to achieve <70% RH levels without dehumidification. I suggest following these recommendations and providing enough dehumidification to maintain <60%RH. Confirm the moisture levels with remote moisture meters on a ongoing bases. Dehus like the Santa Fe Compact/Advance are designed for this application. Or try anything you may think works followed with ongoing monitoring %RH to confirm <60%RH. Regards TB
    Attached Images Attached Images
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,444
    Quote Originally Posted by ACFIXR View Post
    In a cold dry climate should crawl space ventilation air be heated in the winter?
    Should a vapor barrier be laid on the ground even in a dry climate?
    What is the ideal air exchange rate for a dry climate crawl space?
    Should it be forced air or are vent wells ok?
    Should water and drain lines be insulated?
    Should a vapor barrier be applied to the conditioned floor above the crawl space?
    Complicated question require complicated answers. This the best answer to your questions. Read the attached pdf. Pay close attention to the conclusions. Cover the earth in all climates. Closing vents is a little different. Also radon may be a issue in some areas. I am interested in your opinion in the massive amount of info. Keep us posted. Regards TB
    Attached Images Attached Images
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  7. #7
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,444
    Quote Originally Posted by Stamas View Post
    Since when have exterminators become the crawlspace experts?
    Obviously not their area of expertise. The ones I've seen they've made worse.
    Are you listening Teddy?
    I have been reminded that there are still several exterminators who recommend increasing fresh air ventilation of crawlspaces as a cure for rotting/stinking crawlspaces. There are also some code recommendations suggesting ventilation as a fix. The important point is that any fix must maintain <60%RH on a long tirm basis. Radio Shack/WalMart remote %RH monitoring is <$40 to confirm a real fix. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  8. #8
    Join Date
    May 2007
    Location
    Dry as a bone Tucson
    Posts
    4,344

    Thanks TB

    Quote Originally Posted by teddy bear View Post
    Complicated question require complicated answers. This the best answer to your questions. Read the attached pdf. Pay close attention to the conclusions. Cover the earth in all climates. Closing vents is a little different. Also radon may be a issue in some areas. I am interested in your opinion in the massive amount of info. Keep us posted. Regards TB

    Thanks for the study. I was excited to see that the study included crawl spaces in Flagstaff Az. The building that I am preparing for is in Tuba city which is just north of Flag but not as high in elevation. It is a three story clinic built on piers and is going to have a crawl space. I want to know exactly what needs to be done before the project starts. The project just broke ground and is a modular building. It is going to take 9-12 months before we are completed. I will definently keep you updated with what the engineers have designed, what was actually installed, what problems arise and what solutions were developed. Thanks for the timely info!
    Some Talk, Some Do
    "keeping condensing pressures low and evaporator pressures high"
    "Some customers are more interested in comfort than energy savings"
    Blog
    Web
    Facebook


  9. #9
    Join Date
    Nov 2009
    Location
    north georgia
    Posts
    19
    Thank's for the reference Teddy, it is a good read for a typical homeowner.

  10. #10
    Join Date
    Dec 2001
    Location
    Ocean Pines, MD
    Posts
    6,990

    Right Teddy.....

    The unit is pitched wrong and leaking. Sump pump, well, I should have taken side pic's too, maybe get them and post, but the jammed the flex hose in till it cracked, so 25% out the pipe, (1-1/2" PVC behind the pump)-75% re-circulated in the sump, why they didn't hard pipe I don't know. The pump torques and jams, they tried weaving some scrap wire in and suspending it. So pumped jammed off. Then added a condensate pump to the dehumidifier and I'll have to go open a box to check but I believe a trap is required-but the cond. pump? The unit is uphill from the sump.
    Just a mess and not the only one.
    If I find one they do that is even near acceptable I'll post pic's out of fairness.
    Attached Images Attached Images     

  11. #11
    Join Date
    Dec 2009
    Location
    Baltimore, MD
    Posts
    2
    I'm planning to install the thick, "swimming pool" vapor barrier in my crawl space and have foam sprayed on the block walls to insulate the space. The spray insulation guy said I needed to have my forced air hvac system condition the entire space, so I guess I need to cut some vents from the heating ducts, but am concerned about returning the air from crawl space back into the house. If the barrier is installed well and everything else is sealed and insulated well, do I have anything to worry about? The concept of thinking about a heated crawl space as "a small basement" makes a lot of sense to me, but I'm still just a little worried about returning air back into the house.

    Thoughts? Advice?

  12. #12
    Join Date
    Nov 2009
    Location
    north georgia
    Posts
    19
    mheitt
    Sound's like you are on the right track,but you most likely have crawl space air returning to your house now! through leaky return duct's.If you don't think so have your ductwork tested by a duct blaster,you will be surprised at the amount they leak! It is very hard to seal up 100%. I like to add a little fresh air to a home to put it under a positive pressure and keep infiltration to a minimum, in my opinion the better your crawl space air quality the better your home's air quality!

  13. #13
    Join Date
    Dec 2009
    Location
    Baltimore, MD
    Posts
    2
    The more I read (and the more people I talk to who want to sell me something), the more I'm confused. I know I want to lay down a good barrier on the dirt floor, but I'm still confused about insulating the block walls and conditioning the air in the space.

    The guy who specializes in spray-on foam insulation wants to insulate the exterior walls of the crawlspace and said I need to condition the air by cutting into the existing HVAC duct work.

    The crawlspace/basement guy said I only need to spray insulation above the block (between the block and the floor above), and said there'd be enough natural air flow that cutting into the HVAC duct work was not necessary.

    Some articles I've read (referenced on this site) have talked about creating a positive pressure but cutting two vents into the space and only one out of the space as this would "force out" moisture that otherwise would seep in.

    My head is spinning. Can anyone provide more guidance (with explanation)? I'm in Baltimore, where we have 90+ degree humid summers and sub-20 degree winters. There's no standing water (despite a couple inches of rain over the weekend on top of 20 inches of snow melting) in the crawlspace. The crawlspace is about 3-4 feet tall (nice storage space, but also significant block exposure) and measures about 20x30.

    Thanks!

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