Crawlspace management

The truth about it

Crawl into the manifesto that demystifies crawlspaces

Suit up, we're going in.

We’ll begin with a common question:

Should you open your foundation vents in the summer and close them in the winter, or vice versa?  

The answer is neither. 

After reading this report, you will be able to answer that long standing question with the ease of a seasoned expert.

You’ll also explore the differences in two distinct schools of thought when controlling a crawlspace environment:

  1. Their thought: Encapsulation is widely used and considered the “cat’s meow” when it comes to crawlspaces. 

  2. Our thought: Thoroughly researched and tested alternative to the usual that has been presented to Home Inspector’s and Building Inspector’s around the Triangle. It has made them reconsider what the “code” is for crawlspaces and that maybe there is a better, cheaper way.

So grab your gear and get suited up because we’re about to crawl deep into the crawlspace.  

The web search

“What is the difference between conditioned and encapsulated crawl space?”

One of the first descriptions that pops up is the one shown below.

What is the difference between conditioned and encapsulated crawl space?

Where an encapsulated crawl space is sealed off completely, a conditioned crawl space only seals the floor, walls, and joists. Also, an encapsulated crawl space uses white plastic while a conditioned crawl space uses black plastic. Many people feel that an encapsulated crawl space is more visually pleasing.

A construction professional crouched in an attic, examining the wooden framework and insulation. He holds plans in one hand, and his expression is focused, suggesting careful assessment of the work to be done. Tools and building materials are within reach, indicating an ongoing installation or inspection process.

Well, based on that search result description, the only difference is that one uses a white plastic barrier and the other uses black. Oh, and one is prettier.

That’s the difference?

Hardly, but this does show that when it comes to the correct way to control your crawlspace, the answers can be all over the place and not everybody offering information on the web knows what they are talking about. Notice how the guy from the search result isn’t even in a crawlspace? 

An encapsulated crawlspace is not necessarily the best option. But somehow it has gotten the reputation as being the Cadillac of crawlspace management and in turn, a status symbol. “Buffy and I have an encapsulated crawlspace. Our contractor, Brad, says it’s the only way to go.”

Who made “Brad” the expert?
There is a better, more common-sense way. 

In the following, we explain the pros and cons of an encapsulated or conditioned crawlspace vs. our Restricted Air Crawlspace™.

First, here’s why you’d want to seal your crawlspace in the first place.

  • There is no dispute, sealing your crawlspace from the outside world is a good idea. What this does is keep outside air from entering your crawlspace where it can cause problems. Here in the Triangle of North Carolina, the outside air is hot and humid in the summer and the crawlspace will always be cooler than outside.
  • A typical ventilated crawlspace relies on outside air entering the through the foundation vents as a means of ventilation. But during the summer, it results in two air masses of contrasting temperatures mingling in a confined space. The result is elevated levels of condensation and moisture, and this can affect your insulation, the structure and in extreme cases, your health.

Encapsulated / Conditioned

  • Removal of floor insulation with no put back/replacement
  • Rigid foam insulation on the walls that is sealed to the barrier. In some instances, only the barrier is extended up the walls.
  • Barrier (mil varies) with 100% coverage of crawlspace floor, the seams are taped/sealed with a 12” overlap and support columns are wrapped.
  • Sealing of foundation vents, penetrations through the floor and foundation walls and the insulating/weather sealing of the access door.
  • Includes some means of utilizing the homes HVAC system to heat and cool the space (conditioning).

Restricted Air

  • Insulation in the floor system
  • Minimum 10mil barrier with 100% coverage of crawlspace floor, seams taped/sealed with 12” overlap and wrapped support columns
  • Sealing of foundation vents, penetrations through the floor and foundation walls and the weather sealing of the access door
  • Install of a dehumidifier as a means of environmental control.

Let's break down each element of the encapsulated / conditioned crawlspace approach.

They remove floor insulation with no put back/replacement. 

Their Theory:

Insulation in the floor system is removed and not reinstalled or replaced. The thought process behind this is, if you are heating and cooling the space, the crawlspace is essentially part of the living space envelope now and you do not need insulation between the living space and the crawlspace anymore. 

Our Theory:
If the crawlspace is dry, clean and properly cared for, why would you need to remove the insulation?

They use rigid foam insulation on the walls that is sealed to the barrier. In some instances, only the barrier is extended up the walls. 

Their Theory:
The rigid foam, typically 2” thick, is intended to take the place of floor insulation. 

There are varied ways to adhere it to the wall including adhesives, masonry screws, Ramset nails, etc. The foam must stop 3” below the top of the block foundation to allow for termite inspections. All seams should be sealed either with tape or mastic.

Our Theory: 
An example…Lowes has 2 choices when it comes to the 2” rigid foam. One offers an R value of 10 and the other offers an R value of 7.7. For comparison, the R-value of typical batt floor insulation is R-19. Why would you trade R-19 insulation in the floor where you need it, for R10 insulation on the foundation walls.

Rigid foam is the typical method for insulating a foundation wall but, spray foam has been gaining traction in the last few years. It is sprayed directly onto the foundation wall. It is also sprayed over the area where the vapor barrier meets the foundation, creating a seal.

Spray foam is touted as the latest and greatest and companies are spraying it everywhere. There is no doubt that it is a great insulating material but…there are downsides. We have found in many cases that spray foam can hide a problem, whether existing or new. Water problems can be a nightmare to find behind spray foam as the water can make its way to areas far beyond the source and then show itself. The only way to truly find it is to remove the spray foam and this is no easy task (and it’s a big ol mess).

Their method includes a barrier (mil varies) with 100% coverage of the crawlspace floor, and the seams are taped with a 12” overlap with wrapped support columns. 

Their Theory:
The barrier used for conditioned crawlspaces varies depending on experience level and competence. It can range from 4mil to 20mil.

Our Theory: 
A 12mil reinforced barrier is a widely used product and we see it the most.  However, in many cases, the 12mil reinforced barrier has a negative side in that once it gets wet (remember, it’s a vapor barrier, so it’s going to get wet), it tends to smell like cat urine. This has been disputed by the manufacturers for years but to those of us paying attention, it is a known issue. Ask any homeowner struggling with an undetermined smell permeating their house, it’s a real problem. 

It is unclear as to why one would want 20mil in their crawlspace unless it is a high traffic area frequently used for social gathering overflow, which is unlikely. Even if it is, there are better ways to provide paths of travel than an expensive 20mil vapor barrier.

The 12” overlapped seams are standard practice.

4 mil? Please, no. That’s the warning sign a contractor doesn’t know what they are doing.

Their method includes sealing of foundation vents, penetrations through the floor and walls and the insulating/weather sealing of the access door. 

Their Theory:
This prevents the outdoor environment from mixing with the crawlspace environment, where most problems stem from. The sealing can either be a result of the insulating foam or barrier that is installed on the walls or each vent can be sealed separately.

Our Theory: 
We mostly agree. The sealing of penetrations is key to the success of now being able to control the space although our methods may differ.

Their method includes some means of utilizing the homes HVAC system to heat and cool the space. 

Their Theory: 
The thought process behind this it that you are now turning the crawlspace into part of the heating and cooling envelope. You are supposed to gain some semblance of energy savings by doing this.

* This usually happens through a 4″ dryer vent exhaust that is installed into the outflow side of the HVAC system in the crawlspace. This 4″ port is intended to heat and cool your entire crawlspace. Size of the crawlspace does not seem to be a consideration in most that we have inspected but hopefully, before considering this option, a load calculation was performed to verify that it can handle the additional volume.

Our Theory: 
To heat and cool an unused space requires energy and energy has a cost associated. You could potentially spend just as much as you save to heat and cool your crawlspace. So, where’s the savings? If the concept really saves energy, shouldn’t this concept extend to the garage and attic spaces?

A very important component of fungal growth seems to be overlooked with conditioned crawlspaces and that’s moisture. Fungal growth doesn’t happen without it. It’s a simple equation, “No moisture, no mold.” A conditioned crawlspace controls temperature. Temperature is not part of organic growth’s diet.

Fact: By code, you cannot introduce crawlspace air into the heating and cooling system.

Now is the time for a brief lesson on mold and your HVAC:
You may think that your HVAC just heats and cools your home and that’s its primary function…and you would be right but, there is a very important function that your HVAC does that you may not know about and that’s moisture control. HVAC is a “must-have” in our region and it is a powerful tool for controlling mold growth.

You strive to keep your house clean and “mold=free” but, mold spores are everywhere, even though you can’t see them. When you come into your house, you bring mold spores with you. So does the dog. They come in through your windows. They are blown about by your heating and cooling system. They are everywhere. Unless you live in a bubble, you cannot be fully “mold free”. It’s just not feasible/practical. You can however, limit or control the possibility of them becoming a problem. The airhandler, usually located under the house or in the attic, does just that. This is where the moisture in the air is removed so that the air coming out of the supply side is dry.

Moisture laden air within your home is drawn into the system through your return vents (You know, the thing with the large filters that you are supposed to replace every so often but maybe forgot to do and as you read this you are thinking, “Darn, I really need to check that when I get home!”) It is really important to keep your return filters clean and free of obstructions.

When the moisture laden air enters your HVAC system via the return vents, it travels through the airhandler. As it makes its way through the air handler, the moisture is removed and the air coming out of the supply vents is dry…and the process repeats all over again. It is very important to make sure that you HVAC system is working correctly because it is a HUGE factor in the control of mold growth.

All you are achieving with a conditioned crawlspace is spending money to heat and cool a space that is supposed to save you money and…not removing the most important component of mold growth under your house – moisture.

We asked an AI to describe a restricted air crawlspace.

At first it had never heard of it, and it’s initial response was this: 
“I apologize, but I couldn’t find specific information on a “restricted air crawlspace” within my training data up until September 2021. It’s possible that the term “restricted air crawlspace” is not a widely recognized or standardized term in the field of building construction or home improvement.”

Then we pressed harder and it started to come around…  
“However, based on the term itself, it could potentially refer to a type of crawlspace that has limited or restricted airflow compared to a traditional or ventilated crawlspace. This could be achieved by implementing measures such as sealing off or reducing the number of vents, minimizing air exchange with the outside environment, or employing specific ventilation strategies to control airflow.”

It just about nailed it. So, if an AI can figure out the basics of a Restricted Air Crawlspace™, why can’t anyone else get it?

A closer look at a Restricted Air Crawlspace™... A.K.A. The Solutions Group approach.

Includes insulation in the floor system.  
If the crawlspace has been cleaned up, remediated, and is back to “square one”. Insulation in the floor provides the best R value for you money.

We use unfaced insulation because purposely placing a lot a paper in a crawlspace just seems like a bad idea. The paper on insulation is there to provide a vapor barrier, but that goes on the crawlspace floor.

Includes a minimum 10mil barrier with 100% coverage of crawlspace floor, seams taped/sealed with 12” overlap and wrapped support columns.  
To revisit some of the above information, it just doesn’t make sense to install a 20mil barrier in a crawlspace and who wants their crawlspace to smell like a litter box? 

We use solid 10mil poly sheeting to provide 100% coverage of the crawlspace floor. Support columns are wrapped and all seams are taped. “High traffic” areas such as the direct path to the HVAC unit receive an extra layer of barrier as an added measure of protection against penetrations. The barrier will roll up the foundation wall approx. 4”. Prior to install of the barrier, all debris that could potentially compromise our barrier is dealt with. 

We do not believe in adhering the barrier to the foundation wall for the following reasons: 

    • We do yearly inspections where we are checking for things that could possibly affect our past work in an adverse way. Moisture penetration from the outside is one of those items. What may be a non-drainage issue today, may not be in the future. We like to be able to see the foundation walls because they tell use a story about what is going on outside of your crawlspace with your drainage. We can then offer suggestions to fix the problem if one exists, in a timely manner. If the walls are covered, we have no idea what’s going on behind. Many contactors don’t think about what lies ahead (or even what is there now) when installing an encapsulated crawlspace. 

    • Termite inspectors have a considerable amount of trouble doing their job if the areas they need to get to are covered. Dismantling of the seal is necessary and putting that seal back costs money. 

    • It is unnecessary to cover the walls in order the control the space. It’s just an added expense. 

    • Many contractors use black, corrugated drainage pipe when installing underground drainage around the homes exterior.This piping is notorious for failure. The reason it is so ubiquitous is that it is cheap, readily available and easy to install. It is also prone to clogging, crushing and infiltration from plant roots. This can translate into water problems under your house. If you have an encapsulated crawlspace, you may never know until it’s too late. 

Includes sealing of foundation vents, penetrations through the floor and foundation walls and the weather sealing of the access door.
This is the one component that both systems agree upon. In order to control the crawlspace, you need to seal it off from the outside influence. 

Our Restricted Air Crawlspace™ is not designed as a means of insulating the access door is merely weathered in much like an exterior door on your house. Vents are sealed with rigid foam with expanding foam around the edges. All penetrations are sealed with expanding foam.

Includes the install of a dehumidifier as a means of environmental control.
This is the real remediation. A dehumidifier actively removes the problem causing moisture underneath your home. This is key in keeping your crawlspace dry and mold problems at bay.

The dehumidifier is a commercial unit appropriately sized for your specific crawlspace footprint and design. It is either hard-piped out with 3⁄4” PVC condensation lines or, depending on the particular crawlspace, pumped out via a condensation pump, just like an HVAC system would be. The dehumidifier only runs when it needs to. As humidity levels rise, the dehumidifier will engage to bring them back down based upon a predetermined humidity level set at install.

You never have to do anything!
We offer yearly servicing of the dehumidifier to keep it running strong for the longest period of time possible.

Hopefully, we have given you something to think about!

The Solutions Group, as a company, have tried all aspects of crawlspace maintenance, theories and applications in an effort to understand which of them work and which of them do not. Our many years of experience has led to our development of the Restricted Air Crawlspace™ because it is a system that works!

Conditioned vs. Restricted Air is definitely a concept that many people don’t even consider but, it is an important concept, nonetheless.

We hope we have helped to inform you of the differences so that your decision-making process can be an informed one. Afterall, information is what our company is based on!

Have you ever had mold testing done in your home?

  • When the test results arrived, was it just a bunch of data that had no explanation?
  • Or did some actually explain what was going on and what this data could actually mean? 

Nine times out of ten, it’s the former scenario.

That’s why we wanted to find a pretty straightforward explanation for our customers about air tests and what they mean.

We think this document is pretty good and can get you in the ballpark of enlightenment.

Per our MO. it isn’t scary.
It’s just the facts ma’am.

Grab a cuppa joe and have a read out on the porch. Pay attention because there will be a test. 

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We're here to help with everything mold and moisture, and your crawlspace is our specialty.