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Crawlspace Repair Wiki

Crawl Space Questions & Answers by JES

Crawlspace Repair - Question & Answers by JES

Crawlspace Repair Wiki

The Crawlspace Repair Wiki is your guide to the most common crawl space repair questions. Learn about the causes of crawl space problems like musty odors, high energy costs, and why open vents and ‘venting’ your crawl space harms your home.

If you still have questions, give us a call at 757-301-4820 to request a crawl space repair inspection. Our experts will come out to your home for free and take a look at your crawl space, foundation, or basement.


Q: What is crawl space encapsulation?


A: Crawl space encapsulation is when a barrier is installed in your crawl space, like CrawlSeal™, over the dirt crawl space floor, walls and vents. The encapsulation process keeps water from entering the crawl space and is a proven method for keeping bugs out of your crawl space while saving you money on energy bills.

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Q: What is the “Stack Effect”?


A: The Stack Effect is the movement of air into and out of your home. The warm air rises because it’s less dense than cooler air. As the air rises it’s replaced with air that enters through lower sections of your home, like your crawl space. As the air warms, it rises and the cycle continues.

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Q: What causes the musty smell from my crawl space?


A: You have a crawl space moisture problem! Your musty crawl space smell is caused by mold growth, and mold loves moisture. The moisture in your crawl space is the primary cause of most crawl space problems including rotted wood floor joists, mold and mildew growth.

You could have black mold growing in your crawl space. Don’t wait to have your crawl space checked out; if you can smell your musty crawl space then the problem could be affecting the safety and health of you and your home.

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Q: Will crawl space encapsulation lower my energy costs?


A: Yes, crawl space insulation, aka encapsulation, will help lower energy costs. Encapsulating your crawl space can save you up to 15-25% in energy costs.

As you know, it costs a lot more to cool your home on a humid day. The same rule applies to a humid crawl space. Since your encapsulated crawl space will no longer have moisture, which will rise through your home, your home will remain more comfortable without having to crank up your HVAC system. Saving you money!

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Q: What is crawl space humidity?


A: Crawl space humidity is the moisture in your crawl space’s air. Crawl space humidity is your crawl space’s number one enemy!

The air in your crawl space is circulated through your home, thorough the Stack Effect. So the crawl space humidity is also circulated through your home. As the moisture passes through the floors and walls it leaves a path of destruction: wood rot, moldy subflooring, window condensation, high electric bills and mold growth.

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Q: I have bouncy floors. Is this something I can fix myself?


A: You should be cautioned that fixing your bouncy floors is not a DIY project. Here’s why:

• Sistering the boards may provide additional support but if the floor joist is over spanned or rotted through then you have some other problems. Wood rot tells you that you have a crawl space moisture problem. Crawl space moisture problems can lead to mold growth, high electric bills and damage to sub flooring – just to mention a few.

• If the floors are supported incorrectly then the bouncy floors still might be a problem and the floor could eventually collapse.

• If you use cinder blocks to support your floor joists they can tip or crumble. The sudden lack of support when the cinder blocks fail will damage your home.

• If you jack up the floor joists too quickly then you could be doing more harm than good. The floor could buckle, drywall cracks could form and you could even damage plumbing and electrical wiring.

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Q: Should I leave my crawl space vents open all the time?


A:  Open crawl space vents cause major problems. The open vents let moisture into your crawl space. Crawl space moisture is the cause of many crawl space problems and costs you up to 25% in increased electric bills alone.

Open vents are the “old school” way of thinking. Back in the day we all subscribed to the theory that venting your crawl space would help heat and cool your home and keep it dry. We now know this isn’t true.

The crawl space vents let in moisture. The moisture doesn’t just soak up into the dirt floor; it rises through your home. As warmer air rises it creates a vacuum that pulls up cooler air, this is also known as the “Stack Effect”. So, the moisture in your crawl space is pulled up with it and through floor joists, insulation, subflooring, walls and so on.

As the moisture is pulled up it damages everything it passes through, rotting floor joists, damaging dry wall and creating the perfect environment for mold growth. You can see how open vents can create a problem. It’s best to save yourself money on energy costs and eventual moisture damage by having your crawl space inspected by a professional. We’ll let you know if you have a moisture problem or if you can just seal your vents yourself.

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Q: Will a dehumidifier fix the water problem in my crawl space?


A:  A crawl space dehumidifier will not solve water problems but is meant to remove crawl space moisture. As you know, crawl space moisture or humidity is a problem.

A dehumidifier, such as the JES Dehumidifier dehumidifier, is used to control humidity levels and water vapor in the air and also purifies the air as it removes the moisture.

If you’re seeing water in the crawl space a dehumidifier will not correct the water problems. You may need a waterproofing system installed, or have to fix a pipe leak, or stop water entry from an outside source – like a loose crawl space door.

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Q: Why is my crawl space door so important?


A:  If you encapsulate your crawl space and don’t replace your crawl space door you could be letting unwanted moisture into the crawl space. Just like your crawl space vents the loose or open doors can create humidity and moisture problems.

A water tight seal on your crawl space door is important: it keeps moisture and unwanted pests out of your crawl space. If you spend the money to encapsulate your crawl space, keep it clean by installing water tight doors. Remember, the waterproofing and encapsulation system is only as good as its parts.

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Q: How do I fix wet crawl space insulation?


A:  Every situation is different. Your best option is to let one of our experienced, certified inspectors come out and perform a free crawl space evaluation. That way, we can give you the best answers to all of your crawl space questions.

Wet crawl space insulation is a sign that you have a humidity problem, which is creating other issues.

When the insulation in your crawl space is wet, it looses its R value. The R value is the measure of an item’s ability to resist heat flow or insulate an area. Wet insulation in your crawl space isn’t doing you any good since it’s now costing you more money to heat and cool your home. Remember, crawl space humidity doesn’t stay in your crawl space; it’s circulated through the rest of your home.

Wet crawl space insulation is also a breeding ground for dangerous mold and mildew. Mold needs three things to survive and thrive in your crawl space. Organic material (like wood, cloth, dirt, etc.), moisture, and the correct temperatures. If you’re not controlling these three factors in your crawl space you could have mold.

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Q: What’s a crawl space liner, and won’t plastic sheeting work as well?


A:  A crawl space liner is part of an encapsulation system and acts as a vapor barrier for the interior of your crawl space. This barrier helps prevent moisture from coming up through the ground and forming in your crawl space.

There are many options when it comes to crawl space liners. Your typical home improvement store will sell a thin plastic “vapor barrier” that is 3-6 mil thick and you can install in your crawl space. While these liners seem like the cheapest option, they can end up costing more than a professional grade liner. These thin liners tear easily and often, so you’ll need to replace them – and that cost adds up!

A sturdier, professional grade crawl space liner is the best solution for lining your crawl space. We use the CrawlSeal Crawl Space Encapsulation System for many reasons. It’s 20 mil thick – that’s 3-7 times thicker than your typical vapor barrier! And it’s guaranteed for 25 years to never tear or rip!

In the end, the crawl space liner is one part of a complete system. You may need to address other issues, like ground water leaks, relative humidity levels, as well as internal moisture issues (such as a pipe leak), in order to create a true conditioned crawl space.

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Are You Looking For Local Crawl Space Contractors In Virginia, DC, Maryland, or Northeastern North Carolina?

At JES Foundation Repair our team of in-house crawl space experts have warranted solutions for crawl spaces and foundations of all types.

If you would like a free quote, we’re ready to help you! Call or e-mail us today to schedule an on-site consultation and written quote!

We’re proud to serve all of Hampton Roads, from Virginia Beach throughout Williamsburg and surrounding areas; Northern Virginia, DC, and Southern Maryland. View a complete list of our service area here.

The Experts at JES can Help!request-free-inspection-jes

If you’re not sure of the source of your crawl space problem, give us a call at 757-301-4820, and schedule a free inspection. We’ll find out the cause of the problem and help you find the perfect solution.

We now have a crawl space to be proud of and feel very secure that we will not have any future problems. Pauline and I will not hesitate in recommending your company to anybody. We thank you for your services.

~ Burt & Pauline S., Williamsburg, VA

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Our Homeowner’s Guide to Crawl Space Repair is your resource for learning about why you have crawl space problems, and what to look for to see if you have a problem.

Request your free crawl space repair inspection and download your own copy of the e-book immediately, as our thanks for putting your trust in JES.

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