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Crawl Space

SW Sink
SW Sink
Discussion
mydreamhome
47

(X-Post) Crawl Space Condensation & Humidity Solutions

Q

Comment
pelkeytm

Rich, first let me apologize for thinking your post was an add. Now about the job itself, can you tell us what you used? On the site I am seeing 20mm reinforced vapor barrier for $495, not sure how big your crawlspace is but the pic looks like you would need 3 rolls of it. That itself is as much as you claim to have spent on the entire project. Add to the the cost for a Dedicated GFCI outlet that would need to be installed, the dehumidifier (do you have one?), the HVAC contractor (for most Crawlspaces) that would need to come out and inspect your unit then all the little items like seam tape that costs $32 for 50 feet and the list goes on. All the little things that DIY homeowners don’t take into account. Now then you say that your humidity is at 30% in the summer. As someone who has spent all of his adult life in a crawlspace I can tell you that if that number is accurate then you need more. Encapsulations are (should be) advertised as moisture reduction treatments not elimination. To little moisture in your crawlspace is bad for your wood memebers just like to much is harmful. Now wood/moisture content is what is important, not necessary the humidity. A 30% humidity will take your wood moisture content down to around 6%, this number is way to low, healthy wood need to be 10-14%. Drying wood out to much will make it become brittle over time and with all the weight above it dry rott can do serious damage to your home. You are absolutely correct on one account, for DIY people, encapsulations are not hard work. Very time consuming and attention to details are key for them. As a professional, I will say that the first step in an encapsulation (after inspections) is completely removing all debris, rock and leveling out the ground. That sir is a lot of hard work, there is a difference between what you shown and what a professional does but it does cost more unfortunately.

Q

Reply to: Rich, first let me apologize for thinking your post was an add. Now about the job itself, can you tell us what you used? On the site I am seeing 20mm reinforced vapor barrier for $495, not sure how big your crawlspace is but the pic looks like you would need 3 rolls of it. That itself is as much as you claim to have spent on the entire project. Add to the the cost for a Dedicated GFCI outlet that would need to be installed, the dehumidifier (do you have one?), the HVAC contractor (for most Crawlspaces) that would need to come out and inspect your unit then all the little items like seam tape that costs $32 for 50 feet and the list goes on. All the little things that DIY homeowners don’t take into account. Now then you say that your humidity is at 30% in the summer. As someone who has spent all of his adult life in a crawlspace I can tell you that if that number is accurate then you need more. Encapsulations are (should be) advertised as moisture reduction treatments not elimination. To little moisture in your crawlspace is bad for your wood memebers just like to much is harmful. Now wood/moisture content is what is important, not necessary the humidity. A 30% humidity will take your wood moisture content down to around 6%, this number is way to low, healthy wood need to be 10-14%. Drying wood out to much will make it become brittle over time and with all the weight above it dry rott can do serious damage to your home. You are absolutely correct on one account, for DIY people, encapsulations are not hard work. Very time consuming and attention to details are key for them. As a professional, I will say that the first step in an encapsulation (after inspections) is completely removing all debris, rock and leveling out the ground. That sir is a lot of hard work, there is a difference between what you shown and what a professional does but it does cost more unfortunately.

Q

Comment
Rich

You assess a companies products by simply reading a URL? Good for you. I went to the companies warehouse to pick up the vapor barrier and their products are USA made and far superior to what the "pro's" and contractors are installing in my neighborhood (Crawlspace medic etc). I have no relationship to this company other than being a very satisfied customer (and lucky they were within an hours drive from me). As for the math... The OP got an $11,000 quote. I did my own for $1500 (including spray foam). It's labor intensive but if you have the skill to do it you can save a lot of $. It wasn't even really that hard to do compared to the other remodeling I've done. Here's a picture of mine before I spray foamed the walls. Previously this was all just dirt.

Q

Reply to: You assess a companies products by simply reading a URL? Good for you. I went to the companies warehouse to pick up the vapor barrier and their products are USA made and far superior to what the "pro's" and contractors are installing in my neighborhood (Crawlspace medic etc). I have no relationship to this company other than being a very satisfied customer (and lucky they were within an hours drive from me). As for the math... The OP got an $11,000 quote. I did my own for $1500 (including spray foam). It's labor intensive but if you have the skill to do it you can save a lot of $. It wasn't even really that hard to do compared to the other remodeling I've done. Here's a picture of mine before I spray foamed the walls. Previously this was all just dirt.

Q

Comment
Rich

I'm in SC and I encapsulated and totally sealed my crawlspace and then spray foamed the brick walls. My humidity stays around 30% in winter, 40% in summer. It's made a huge difference, esp with the smells and dust. Depending on how much of a diy'er you are and how accessible the crawl space is you can do all of this for $1500 (I bought spray foam off of ebay...was skeptical but it was the lowest price and worked great). I bought all of the encapsulation stuff from a company in SC. See link....crawl space company

Q

Reply to: I'm in SC and I encapsulated and totally sealed my crawlspace and then spray foamed the brick walls. My humidity stays around 30% in winter, 40% in summer. It's made a huge difference, esp with the smells and dust. Depending on how much of a diy'er you are and how accessible the crawl space is you can do all of this for $1500 (I bought spray foam off of ebay...was skeptical but it was the lowest price and worked great). I bought all of the encapsulation stuff from a company in SC. See link....crawl space company

Q

Comment
energy_rater_la

Have to agree with Ionized...but based on La. climate.. great LSU link..loaded with info, although climate specific. how close to the ground is your house? how close to the ground are ducts & plenums? hard pipe ducting, not flex? there is lots of conflicting information..even among trades people. open crawl vented crawl semi vented crawl non-vented crawl. the only thing that is the same in all of these scenarios is that the vapor barrier has to be complete, and sealed to pilars, or walls of crawl. here where I live in La. we have open crawlspaces...and houses with ducts in floors that are low to the ground... like 2'..have wet ducts, plenums, equipment. just not enough air flow in and around ductwork & equipment. when you get to 3' crawlspaces the problems lessen... again because of increased air flow. 4' and higher..usually no problems..some of our houses were raised 8' due to flooding from hurricanes. on another forum, I know a guy who's company does enclosed crawlspaces in NC. great work from the pics he posts & a very intelligent guy. if you'd like drop me an email & I'll send you his user name & the website where we are pro members. while I don't have issue with posting website here, I don't want to post his user name. so ...email. best of luck.

Q

Reply to: Have to agree with Ionized...but based on La. climate.. great LSU link..loaded with info, although climate specific. how close to the ground is your house? how close to the ground are ducts & plenums? hard pipe ducting, not flex? there is lots of conflicting information..even among trades people. open crawl vented crawl semi vented crawl non-vented crawl. the only thing that is the same in all of these scenarios is that the vapor barrier has to be complete, and sealed to pilars, or walls of crawl. here where I live in La. we have open crawlspaces...and houses with ducts in floors that are low to the ground... like 2'..have wet ducts, plenums, equipment. just not enough air flow in and around ductwork & equipment. when you get to 3' crawlspaces the problems lessen... again because of increased air flow. 4' and higher..usually no problems..some of our houses were raised 8' due to flooding from hurricanes. on another forum, I know a guy who's company does enclosed crawlspaces in NC. great work from the pics he posts & a very intelligent guy. if you'd like drop me an email & I'll send you his user name & the website where we are pro members. while I don't have issue with posting website here, I don't want to post his user name. so ...email. best of luck.

Q

Discussion
pbx2_gw
38

Looking into dehumidifier - what are the considerations?

Q

Comment
mike_home

A 2-stage heat pump should also provide good humidity control. The key pieces are a low stage which is small compared to the heat load, and a good cool to dehumidify thermostat.

Q

Reply to: A 2-stage heat pump should also provide good humidity control. The key pieces are a low stage which is small compared to the heat load, and a good cool to dehumidify thermostat.

Q

Comment
Dry_Dog

If you have an enclose crawlspace that is not vented to the outdoors, you might start with a freestanding dehumidifier in it. That may be enough to keep your crawl and first floor dry. You can always add a whole house dehumidifier to the HVAC system if you want dehumidified fresh air and good humidity control in the living space. Santa-Fe units are a good choice for the crawlspace. Ultra-aire units are great whole house dehumidifiers if you want fresh air ventilation as well. Here is a link that might be useful: santa fe dehumidifiers

Q

Reply to: If you have an enclose crawlspace that is not vented to the outdoors, you might start with a freestanding dehumidifier in it. That may be enough to keep your crawl and first floor dry. You can always add a whole house dehumidifier to the HVAC system if you want dehumidified fresh air and good humidity control in the living space. Santa-Fe units are a good choice for the crawlspace. Ultra-aire units are great whole house dehumidifiers if you want fresh air ventilation as well. Here is a link that might be useful: santa fe dehumidifiers

Q

Comment
weedmeister

Your HP will qualify as a 'whole-house dehumidifier'. Though it will do a better job of it if you get a variable (not variOUS) speed blower, or additionally a 2-stage unit.

Q

Reply to: Your HP will qualify as a 'whole-house dehumidifier'. Though it will do a better job of it if you get a variable (not variOUS) speed blower, or additionally a 2-stage unit.

Q

Comment
daburke

I just did this in my crawl space here in New England. This was a real DYI project since I am not handy. My contractor estimate was $5,200. I did it myself for $475.00. First remove all insulation and replace with new since it may be moist and not effective. I then ran construction foam board ( used on new exterior houses) horizontially along the walls of the crawl space. I attached them to the wall using "Good Stuff" the insulating foam in the can. I sprayed some between the foam board and wall and it's still attached. Then I applied 6 mil poly to the floor and up the sides of the walls ( now covered by foam board) for about six-eight inchs. THE KEY IS TO PREVENT ANY AND ALL MOISTURE FROM COMING UP THROUGH THE DIRT FLOOR. So you can leave / go over the exsisting poly. When done with laying the poly, where it met the walls I again sprayed "Good Stuff" where the floor met the wall still leaving the excess up the wall. When it dries to the poly, wall and floor you have a Tight seal. The worst part was working in the crawl space. Grab an old pillow or cushion for your knee's. Knee pads didn't work for me. Also a dehumidifier works on a "closed area prinsible" If the vents are open, it will just take the moisture out of the exteriior air. GOOD LUCK

Q

Reply to: I just did this in my crawl space here in New England. This was a real DYI project since I am not handy. My contractor estimate was $5,200. I did it myself for $475.00. First remove all insulation and replace with new since it may be moist and not effective. I then ran construction foam board ( used on new exterior houses) horizontially along the walls of the crawl space. I attached them to the wall using "Good Stuff" the insulating foam in the can. I sprayed some between the foam board and wall and it's still attached. Then I applied 6 mil poly to the floor and up the sides of the walls ( now covered by foam board) for about six-eight inchs. THE KEY IS TO PREVENT ANY AND ALL MOISTURE FROM COMING UP THROUGH THE DIRT FLOOR. So you can leave / go over the exsisting poly. When done with laying the poly, where it met the walls I again sprayed "Good Stuff" where the floor met the wall still leaving the excess up the wall. When it dries to the poly, wall and floor you have a Tight seal. The worst part was working in the crawl space. Grab an old pillow or cushion for your knee's. Knee pads didn't work for me. Also a dehumidifier works on a "closed area prinsible" If the vents are open, it will just take the moisture out of the exteriior air. GOOD LUCK

Q

Comment
SpringtimeHomes

I tend to agree with brickyee and contractor 2. This will yield the best year round indoor air quality. You could probably seal your vents up with this approach. It may not solve your bulk water problem in heavy rains though. It would be nice to get the french drain as well, if its done right and fixes the bulk water problem.

Q

Reply to: I tend to agree with brickyee and contractor 2. This will yield the best year round indoor air quality. You could probably seal your vents up with this approach. It may not solve your bulk water problem in heavy rains though. It would be nice to get the french drain as well, if its done right and fixes the bulk water problem.

Q

Discussion
kimbermanny
5

moisture in crawl space - navigating my options

Q

Comment
User

I'm not aware of any code that accepts a dehumidifier in a sealed or closed crawlspace. The IRC applies to almost all of the US and this is what it says: 2006 & 2009 IRC 2006 - Section 408.3 - UNVENTED CRAWLSPACES Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be required where: - Continuously operated mechanical exhaust ventilation at a rate equal to 1.0 cfm for each 50 ftò of crawlspace floor area, including an air pathway to the common area, and perimeter walls insulated in accordance with Section N1102.2.8. - Conditioned air supply sized to deliver at a rate equal to 1.0 cfm for each 50 ftò of under-floor area including a return air pathway to the common area, and perimeter walls insulated in accordance with Section N1102.2.8. 2006 IECC Section 402.2.8 and 2009 IECC Section 402.2.9 - CRAWLSPACE WALLS - As an alternative to insulating floors over crawlspaces, crawlspace walls shall be permitted to be insulated when the crawlspace is not vented to the outside [excerpt]. "Common Area" is the living space of the house. "Conditioned Space" is the space within a building that is provided with heating and/or cooling equipment or systems capable of maintaining, through design or heat loss/gain, 50ðF during the heating season and 85ðF during the cooling season, or communicates directly with a conditioned space. For mechanical purposes, an area, room or space being heated or cooled by any equipment or appliance.

Q

Reply to: I'm not aware of any code that accepts a dehumidifier in a sealed or closed crawlspace. The IRC applies to almost all of the US and this is what it says: 2006 & 2009 IRC 2006 - Section 408.3 - UNVENTED CRAWLSPACES Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be required where: - Continuously operated mechanical exhaust ventilation at a rate equal to 1.0 cfm for each 50 ftò of crawlspace floor area, including an air pathway to the common area, and perimeter walls insulated in accordance with Section N1102.2.8. - Conditioned air supply sized to deliver at a rate equal to 1.0 cfm for each 50 ftò of under-floor area including a return air pathway to the common area, and perimeter walls insulated in accordance with Section N1102.2.8. 2006 IECC Section 402.2.8 and 2009 IECC Section 402.2.9 - CRAWLSPACE WALLS - As an alternative to insulating floors over crawlspaces, crawlspace walls shall be permitted to be insulated when the crawlspace is not vented to the outside [excerpt]. "Common Area" is the living space of the house. "Conditioned Space" is the space within a building that is provided with heating and/or cooling equipment or systems capable of maintaining, through design or heat loss/gain, 50ðF during the heating season and 85ðF during the cooling season, or communicates directly with a conditioned space. For mechanical purposes, an area, room or space being heated or cooled by any equipment or appliance.

Q

Comment
User

Most building codes require a crawl space to be vented unless the air in it is "conditioned" thus the terms "closed" and "sealed" should be accompanied by the term "conditioned" to avoid misunderstandings.

Q

Reply to: Most building codes require a crawl space to be vented unless the air in it is "conditioned" thus the terms "closed" and "sealed" should be accompanied by the term "conditioned" to avoid misunderstandings.

Q

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