Crawlspace 101

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Purpose of a Crawlspace

Many customers want to know, very basically, what the purpose of a crawlspace is. In essence, a crawlspace, as its name implies, is a variation of basement in which one crawls around. It may be as small as a foot tall, and the surface is often bare earth. Traditionally, crawlspaces are built on homes lacking either a basement or that are not built on a slab. Many buildings, especially commercial buildings, have a crawlspace between some walls. The primary purpose of a crawl space is to promote air circulation through the home and also allow easy access to plumbing, electrical and other such maintenance, repair and installation needs. Crawlspaces offer an expedient and efficient way to access pipes, substructures and a variety of other areas that may be difficult or expensive to reach otherwise. Older homes in areas where basements are rare have high foundations with crawl spaces that allow cooling air to circulate throughout the home.

Though a crawlspace cannot be utilized as a living space, it can be used for storage of infrequently used items. One should be cautious in doing so, however, as moisture from the damp soil, along with humidity from crawl space vents and water seeping through permeable concrete, can and will create a breeding ground for mold and mildew to form on any organic surface, including cardboard boxes, wood floors and even some types of insulation. Overall, a crawlspace can serve a variety of purposes, not the least of which is the actual foundation of a home. And, as such, it should be treated like the rest of the home.

Why Vented Crawlspaces Are So Yesterday

It was once thought and actually mandated by the International Residential Code, that homes built on crawlspace foundations should be vented to the exterior. The original purpose of these vents was to bring in fresh air from the outside and circulate it with the air in the crawlspace, along with providing an escape for accumulated moisture. Initially, it seemed that venting solved the problems of crawlspace moisture and air circulation. Many homeowners, however, who still experience mold and decay, termite and other pest problems, along with increased condensation, misunderstand the problem and simply increase this ventilation.

Lots of older homes were built without central air conditioning and were cooled by putting fans in the windows. These days most people consider air conditioning to be a necessity. And, in most cases, ductwork is installed in the crawlspace where the ducts can most easily connect to the various living spaces within the home. These conditions have radically changed how homes “breathe.”
We now know that venting is not a great solution for keeping crawlspaces clean and dry. Indeed, venting will only help increase moisture levels if the outside air is dryer than the air inside, or when enough hot outside air enters and warms the area. New studies have shown that as air enters the crawlspace through the foundation vents and comes in contact with surfaces that have been cooled by the cold air in the ducts, the dew point is reached and condensation occurs. And when condensation forms on various surfaces within the environment, you have the ideal environment for mold, mildew, and the accompanying problems they create in your home.

Installing a high-performance vapor retardant material to cover the crawlspace floor can help solve the problem. In a vented crawlspace, our system can be used to keep much of the ground moisture out of the living space. The Your Crawlspace vapor barrier effectively blocks water vapor and eliminates the need for vents altogether. As some building codes still mandate these sorts of vents, contractors must check local building codes prior to installation.

Contractors Will Recognize These Common Crawlspace Terms

Crawl Space Insulation

As many of us know, homes that are built over a crawlspace often suffer from moisture related issues due to the crawlspace’s surroundings. Naturally, when moisture mixes with wood it creates a recipe for mold and other problems like termite infestation, which often lead to the deterioration of a home. Because indoor airflow naturally rises, using a vapor barrier and dehumidifier together in the crawl space can dramatically decrease the amount of moisture and soil gas present in the crawlspace. This can greatly reduce the risk for:

  • Mold
  • Mildew
  • Wood rot
  • Floor failure
  • Decreased insulation R-values
  • Increased heating & cooling bills
  • Odors
  • Insects
  • Dust mites
  • Aggravated allergies
  • Poor storage environment
  • Poor indoor air quality (IAQ)


Water can permeate the crawl space through the earth around the customer’s home, from any number of plumbing issues or through moisture entering the crawlspace vents. What results is a transformation from a crawl space to an actual breeding ground for mice, rats, snakes and other creatures that can thrive in this damp, dark habitat. Keep in mind that as warm air rises through a customer’s home and leaves through the upper levels, crawlspace air is pulled up into your home with it. As the warm air rises, there is nothing to stop the humidity, mold spores, dust mite waste, and odors coming up with it.

Insulating a crawlspace that is vented is a sticky situation. Insulation will not keep humid summer air or cold winter air away from a structure’s floorboards. Most standard insulation vapor barriers will allow moisture and mold to soak through the material, weighing it down and causing it to crumple onto the floor. And, as we all know, that is no good for a home.

Some contractors usually lay down a very thin, non-fire-retardant 4 or 6-mil plastic liner that does very little good since air can still enter from crawl space doors, vents, pipes or other permeable openings. Furthermore, most standard vapor barriers will either be attached by a seal tape or be stapled to the wall. The problem with this is that in one case it defeats the purpose of a liner by injecting holes into it. And the other creates a rumpled-looking effect in the crawl space. Utilizing an adhesive liner not only ensures longevity, but customers will also appreciate the cleaner and tidier aesthetic. The vapor barrier must cover all areas, including the foundation walls and piers.

The bottom line is that a durable, 12-mil, adhesive strip, water-proof, anti-microbial, fire-retardant and puncture resistant vapor barrier like the Your Crawlspace system can transform a moist, unhealthy crawlspace breeding ground into a clean, sanitary environment that no longer promotes mold, odors, pests and even potential infestation. The customer can rest assured that the crawlspace can even be used for storage purposes and ultimately fulfill its purpose of promoting healthy air circulation and reducing overall humidity in the house. And, of course, a vapor barrier just makes the crawlspace look a whole lot more attractive!

Your Crawlspace FAQ

Where can I find a reputable contractor to do my installation?
We are in the process of putting together a list of contractors who install the Your Crawlspace vapor barrier and encapsulation systems. It will be posted on our website shortly. In the mean time, give us a call (877-442-7295) and we’ll put you in touch with an installer who uses our system. Or email us at

How do I know if the job will require a sump pump?
A sump pump is typically used to discharge excessive water build-up that accumulates in the crawl space. It’s usually only required if drainage by gravity is not possible. As you probably know, some sub-areas have what is called a “drain to daylight” drainage system that allows water to pass through or under the foundation wall.

Where can I find information regarding crawl space building codes?
Our Research & Resources section provides access to documentation regarding most crawlspace issues, including building codes and research and reports. Always check with the local building department, however, for specific codes relevant to your job site’s area.

I want to share my Your Crawlspace experience. How do I do that?
If you want to share you experience with Your Crawl Space, please email

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Local: (877) 442-7295


Your Crawl Space, Inc, Waterproofing Materials, Mount Pleasant, SC

Evan Claus
Evan Claus
19:22 20 Jun 17
Great service, great product, and I am very happy with the final results of my crawl space. I called several times to ask for help on the installation process and the individuals who I spoke with were extremely helpful and took the time to properly explain the installation process. Along with the results, I was highly impressed with the knowledgeable group of employees who are willing to go that went the extra mile to help me through the install.
Erica Hanway
Erica Hanway
23:08 29 Mar 17
Excellent product, excellent customer service. We used their wall curtain, adhesive tape, caulk and 36mil vapor barrier. I am wrapping up an installation of an encapsulated crawl space in a new construction house by myself (a female) in North Florida. I was dead-set on us doing the encapsulation ourselves and not hiring it out in order to save money. My husband and neighbor chuckled/rolled their eyes when I said I would just do it myself...and I showed them! I think I have watched every video out there about every product that exists for an encapsulation and when I saw Your Crawlspace's system and the fact that it didn't need bolts screwed into our new stem wall, I was immediately interested. The owner called me soon after I submitted questions online and answered them. Their prices were below other products and were SO much easier to work with than what I would expect had I needed to drill into the stem wall. They estimated what I would need and I had very little waste. They called or emailed me to answer any little questions I had along the way. You can tell they know the issues in a crawl space, they've invented proven products that work, and they are a good family-owned business. I know I saved a bunch of money doing it myself. I was patient and did a few hours at a time, but it wasn't anything that a halfway fit person couldn't do on the their own. I hope I can make it up to Charleston to shake their hands, because they've been great to work with and it's a great product!
Bob Landuyt
Bob Landuyt
21:04 17 May 17
Both Bennie and HB were very helpful in assisting with what was needed to complete my encapsulation project the right way as well as with what was not needed and would have been unnecessary expense. Their system is user friendly which in turn made for an efficient installation. This was our first time doing a crawl space encapsulation and I would recommend their product for both the experienced or the novice like myself. Thanks again for all your help Your Crawlspace!
Tom H
Tom H
19:57 02 Aug 17
The folks at YCS were very helpful and friendly in deciding which products to use. Pictures are before and after of our crawlspace project. Hanging the crawl curtain with the sealant was easy, cutting the 36mil ground vapor barrier to size and placing it was easy, using the seam tape to secure the crawl curtain on the piers to the floor vapor barrier and to open floor seams was fairly easy (pulling the stuff off the roll takes some effort, is there a quick release backing version?), taping the seams around the perimeter was a pain because of how sticky the tape was and needing to make it a 90 degree corner. It often got stuck to itself, the curtain, or the vapor barrier where it wasn't intended (even when taking our time). We finally decided to pull out about 3' of tape, fold it lengthwise with non-sticky side against itself, attach to the floor material first, then roll up the side. Approaching the end, we found I hadn't estimated enough seam tape (left out a seam, cuts in material to go around piers, or both); needed about 40 feet more. Left a message on the YCS web site with a follow up phone call the next morning for another roll. They shipped immediately and billed me. I recommend YCS put out a video on the best way to tape wall curtain to floor material with seam tape. Perhaps the answer is to use Seam Weld tape on top of the 36 mil product with the curtain material on top, but I thought the wall curtain belonged underneath. We got it done (well, most of it) and it looks good, has dropped the radon level to .4 and falling (with an extraction fan/pipe under the fabric), and I think the humidity level will drop as soon as the last few seams are done and given a little time for the insulation/wood to give it up.
Gretchen Thigpen
Gretchen Thigpen
16:15 11 May 17
We received everything we needed to do a complete encapsulation of a crawlspace in Texas. Crawling around with about 18" of clearance wasn't the most ideal conditions, but the YCS system made it fairly easily. We use the wall curtain which was super easy to put up with the adhesive. The 36 mil vapor barrier was easy to work with. It was flexible enough for us to squish it underneath plumbing pipes about 3" off the ground. The ordering was easy as YCS calculated everything we needed based on the information we gave and we had very little waste at the end. I would highly recommend these products.
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17:22 23 Aug 17
I found the your crawlspace information online after doing a google search. I needed to replace a 10 year old installation that that was failing. Bennie was very helpful and spent a lot of time with me making sure I had everything I needed to have a successful install. The new system is much better than my previous one. I used a 2 foot wall curtain and the magic adhesive which went on flawlessly. The 36 mil floor barrier is also far superior than the previous 12 mil liner that I used and much easier to work with. The new tape also made sealing the floor seams much easier. Took about 2 days total to tear out the old system and install the new with just 2 people. I saved about $6000 doing it myself as apposed to hiring a company who would have installed an inferior system. Thanks very much
Aaron Robel
Aaron Robel
15:37 16 Sep 17
I found the products provided by your crawlspace after 3 months of research and prep to replace my crawlspace vapor barrier. Mostly that was a debate with myself on encapsulated or not. Primarily I have been on a 2 year tear with my crawlspace after smelling a musty odor in the home and finding a lake under my home. The first thing I did was build an external french drain around the home. This mitigated 80% of the issue the next year but I did still have water. So... This year I trenched another french drain inside my crawlspace. But I was still concerned about water so I wanted a water tight vapor barrier system. Yes, here is finally the part you care about. Specs: 1. 18" crawlspace - I'm 6'4" so this is VERY challenging to work in. It's also a good workout. Just got to adjust your perception. 2. 1090 sq ft of crawlspace 3. 14 round pilings to wrap 4. Poured concrete foundation walls I chose this system for the following reasons: 1. Wall Curtain system: This was a dream. The simple use of the sealant and 2 foot curtain is something I didn't see from any other system and it made a huge difference in effort. I was able to hang the wall curtain in 3 hours by myself. The system made this possible. I was worried about the strength of just using sealant after so much research showing butyl tape and pins but it's strong I tested it a number of times through the process. 2. Seam sealer: I didn't see any other system recommend to use a seam sealer tape as recommended by this system. This was key in my application because I wanted to have a watertight installation. I had seen too many reviews and mistakes with just tape sealing and how water will seep through. I didn't want this. This installation was VERY challenging for me in my tight crawlspace. I wish that there was an option to have this preinstalled on at least the wall curtain. I wasn't able to do the quality job I was looking for just because of variations in the ground as I tried to put down the seal tape. Part of this was my fault. I should have pre-installed it myself before putting up the wall curtain but hindsight is 20/20. 3. Service: I called HB at your crawlspace and he was quickly able to determine my needs answer my questions and get my order sent out quickly. Much appreciated. 4. Videos: I really appreciated all the how to videos provided. It's really all you need to get things going. You will run into challenges like how to wrap pilings and how to manage sealing around plumbing and other things in your crawl but as far as the system goes the videos are all you need. Youtube the rest.
Bill M
Bill M
10:40 18 Oct 17
I decided to go diy to seal up my crawl space. I already had a 16mil vapor barrier on the floor. I used the wall curtain/adhesive and the install went really well. It is much faster than the old way with foundation pins and butyl tape. I didnt even clean the walls. Apply the adhesive with a caulk gun and press the wall curtain into it. The next day I went back and taped up all my seams. Shipping was fast and the product worked great. Great company.
Laura McGourthy
Laura McGourthy
17:33 23 Oct 17
After watching the instructional videos I called to order the supplies I needed to install the vapor barrier. I was pleasantly surprised that when I called I Benny himself answered! He helped walk me through the products and quantities I needed, the product was shipped same day and exactly the right amount of product I needed was delivered. The adhesive with the tape attached does need one day to cure before applying the wall curtain. The adhesive is SUPER strong, the vapor barrier was easy to roll out. We were applying over dirt, rock and gravel and the vapor barrier did not puncture. The space transformed from dark,dirty and unusable to bright, white, clean and usable. Thanks for all your help, Bennie! Very professional and was there to take my follow up calls also! I tried to post more photos but it would only allow me to upload 3.
Tim Capriani
Tim Capriani
10:45 01 Nov 17
We use these products commercially. You can't ask for a better product and service. Great system!!! Awesome service!!
Jay Cunningham
Jay Cunningham
18:55 13 Nov 17
Bought a whole system with a Aprilaire 1820 dehumidifier. HB gave me lots of tips and was very helpful. Total cost was around $1800 for all of the materials and dehumidifier. Saved a boatload of money. My son and I did the whole thing over a weekend. Humidity was over 90% before and now is down to to 50%. Quality materials. I would recommend them to anyone wanting to do this themselves.
Tom Fenimore
Tom Fenimore
22:03 20 Nov 17
My crawlspace installation has just been completed and I couldn't be happier with the results. The crawlspace is completely sealed and it looks great. The humidity is already down in the crawlspace and the house. YCS products are awesome. The install is clean and complete with no holes in my foundation. The wall curtain system is simple but ingenious! If I had used the "christmas tree" plug method or a Hilti gun approach to attach the wall curtain from other vendors there would be over 500 holes in my foundation and piers. Not sure how you feel about that but I don't like holes in my foundation. This instillation method is superior to everything else on the market and provides the most completely sealed system you can get. It also is the fastest installation method. Don't bother looking elsewhere. Just call Bennie or HB and get on with it. The Aprilaire 1820 humidifier I purchased is really nice and much more functional and advanced than the Santa Fe Compact 2 I was going to buy. I bough the Aprilaire from YCS as well. I am so glad I did. Three big differences I see: 1) The Aprilaire has a digital control system with readout. The SantaFe has an analog dial with no readout. 2) The Aprilaire has a filter that can be cleaned. The SantaFe has to have the filter replaced every six months. 3) The Aprilaire has a ventilation function that will circulate the air for a user set time in minutes per hour. The SantaFe can only have the fan on full time or on Auto.
Steve Miller
Steve Miller
03:04 19 Dec 17
I encapsulated my own crawlspace. It was a big job. Took me quite a while, but I'm very happy with the results. I used the heavy duty drain mat on both the walls and floor. I used the special adhesive caulk and the seam tape just as Bennie instructed. I'm impressed with the materials. They were of very high quality. I also appreciated the help YCI gave me over the phone prior to ordering and doing the job. They were patient and very helpful. Without hesitation, I would highly recommend them to anyone thinking of doing this on their own.
Andrew roesch
Andrew roesch
10:40 04 Feb 18
Excellent product and customer service. From the start the communication was excellent products where delivered quick .They followed up to see how the project was progressing (who does that anymore? :) The product is of top quality and perform perfectly . Humidly is below 50% (in Durham, NC) in the crawl . The heat cycles a lot less and has been able to maintain 70 F even on 15 f mornings in our double wide with a heat pump. If your looking to seal your crawlspace you found the source for your material Andy
Scot Cottick
Scot Cottick
01:09 26 Feb 18
When I decided to encapsulate my crawlspace myself, it was difficult to decide what products to choose. Bennie and HB at Your Crawlspace made it really easy to choose once they explained their wall system and adhesive over the phone. the pre-cut wall system and adhesive saves on time and truly creates an unmatched seal to keep out unwanted moisture. Not to mention that they had what seems like the best floor barriers. It would have cost me $10K+ to have a contractor complete the work. I did it myself for less than $2K and I couldn't be happier with the results.
Rich Orta
Rich Orta
23:40 05 Mar 18
They were just amazing. The sales rep HV walked me through everything I needed step by step it was great. I was quoted 10k to do my massive crawl with dehumidifier. In the end I had about 1500 in mine and it just looks great. I had a few hiccups with my material and they took care of me and rushed me what I needed to make me happy! Just 5 stars. Material and videos make it very easy to do it yourself!
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