Closed Crawlspace Construction Services PowerPoint by Todd Witt @ Synergy Airflow and Ventilation

LLC(256) 350-1779(256) 616-2264

Todd@SynergyAirflow.com

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For years, the building code incorrectly required foundation vents. It assumed

that foundation vents bring in the “good dry air” and let out the “bad

wet air”.

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Crawlspace vents work fine in moderate, dry temperatures.

However, in the southeast, warm, humid outside air hits a cool interior

surface and condensation occurs.

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Thermostatically controlled foundation vents are popular. Unfortunately, they open in warm

weather when they should be closed. Foundation vents should always be closed, or

better yet, eliminated.

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Issues we witness in traditional vented crawlspaces…

• High humidity results in condensation that leads to moisture, mold, and structural issues.

• Musty odors.• Condensation or “sweating” on air conditioning

ductwork and equipment.• Condensation on insulation, water pipes, gas pipes,

electrical wires, and framing.• Buckled and cupping hardwood floors.• High humidity and air quality issues inside the home.• Insect, termite, rodent, and animal problems.

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Condensation on wood framing in brand new homes promoting

“unidentifiable biological agent” growth due to high moisture levels

in the crawlspace.

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Could rusted gas lines be an issue? This house was less than 6 months old, on a flat lot that was properly graded and drained.

Notice the deteriorating wood flooring system.

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Notice how water is “raining” from this duct system in a vented

crawlspace. Notice the incomplete ground cover.

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If there are problems outside of the ducts, what is going on inside

the ducts?

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“Buckled” and “cupped” hardwood floors that eventually lead to structural issues are

prevalent in vented crawlspaces.

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Unfortunately there is a lot of misinformation concerning why hardwoods experience

“buckling” and “cupping”. Many companies sell and install motorized foundation vents that greatly increase moisture levels by pulling in

hot, humid air and wasting electricity.

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Other “crawlspace experts” sell products such as the Wave, EZ

Breathe, and Humidex that pull air from your home into your

crawlspace and create multiple issues and should be avoided. See www.greenbuildingadvisor.com for

more info.•14

“Bulk water management” is the leading cause of building failure in the U.S. and it must be addressed

first.

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Bulk moisture issues in crawlspaces result from…

• The interior grade of the crawlspace being much lower than the exterior grade and as a result it “pools” water.

• There are no gutters installed.• Proper exterior grading is not provided.• Proper interior and exterior drainage is not provided.• HVAC condensate is not properly drained away from the

crawlspace.• Landscaping material such as mulch is built up around the

exterior of the foundation.• Sprinkler systems direct water against the foundation.• Exterior “damp-proofing” is not provided.

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Note that this crawlspace has a lower interior grade than the

exterior grade.

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A lower interior grade than the exterior grade “pools” moisture.

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When building your crawlspace..

• Always build up the interior grade several inches above the exterior grade.

• Drain the foundation to its lowest point. • Add an additional row or two of concrete blocks. • Install multiple crawlspace accesses.• Install a “sacrificial layer of poly” during

construction.• Control bulk water entry during construction.

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Notice that the lack of gutters directs water straight into the

foundation.

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This sidewalk was trapping water from lack of gutters and directing it

into the foundation.

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This homeowner paid us $30k to correct the moisture issues caused by improper grading and drainage.

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Money spent during construction on gutters, proper grading, and french drains can save thousands of dollars later. It costs much more to fix later!

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Interior footings and trenches need to be backfilled so that they

do not collect water.

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We routinely see traditional fiberglass insulation installed in vented,

improperly built crawlspaces. It becomes wet and serves as a medium for “unidentified biological agents”.

Notice I didn’t say the “M” word.

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Keep in mind that floor insulation doesn’t work unless it is in complete contact with the sub-flooring. Homeowners have spent millions of dollars for a product that is not working. The 2009 IRC requires insulation to be in complete

contact with the floor system.Installed improperly Moisture and gravity

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Notice where the moisture had been trapped by kraft-faced/paper backing on the traditional fiberglass insulation. We remove existing fiberglass insulation and

dispose of it.

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Oftentimes we must clean the joist with an anti-microbial agent and

wipe it down.

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• I witnessed major vented crawlspace issues

growing up in the termite pretreatment and insulation business.

• Over ten years ago, I built one of the first, if not the first, closed crawlspace construction homes in Alabama.

• I knew almost immediately that this was the way to build crawlspaces.

• You would be comfortable taking a sleeping bag and spending the night in one of our crawlspaces.

• Can you say that about your crawlspace?•29

Building scientists and building codes now confirm that unvented,

sealed, conditioned crawlspaces are the way to go!

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• Installing a 20 mil poly pool liner inside of your crawlspace looks great.

• It is incredibly expensive.• It does not pass code in new construction.• It fails to air seal the rim joist/band joist where much of the

air leakage occurs.• It is overkill. Save the pool liners for pools.• 10 mil poly works as well as a pool liner.• We install 1 ½ - 2” of closed cell foam on your interior

foundation walls and rim joists/band joists for less money.• We offer black or white poly.• That leaves you added money to spend on a home energy

audit that helps ensure your home is “Synergized”.• There is rebate money available well as low interest rate

loans for existing construction.•31

• Contact us and we will confirm your specific building department’s code requirements.

• A 2” to 3” termite viewing strip is required.• Contact your termite company before

installing a closed crawlspace system.• Note that several of the termite companies

that refuse to guarantee these systems actually sell foundation vents in an attempt to dry out the crawlspace.

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• Moving your HVAC unit and ducts into a closed, conditioned crawlspace greatly reduces your heating and cooling load.

• Moving your ducts inside the thermal envelope eliminates the code required need to duct test.

• We can help you design, size, and choose the proper HVAC equipment and ductwork.

• Atmospherically vented/B-vented gas appliances cannot be located in your crawlspace.

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• 50% of your home’s air originates in your crawlspace.• This air is pulled in due to the “stack effect” –

conditioned air leaks out through ceiling penetrations and is replaced by unconditioned air in the crawlspace.

• The lack of fresh air ventilation multiplies the problem.

• The lack of returns or jumper ducts in bedrooms multiples the problem.

• Leaking ducts outside of the conditioned space multiplies the problems.

• Encapsulating the attic with spray foam helps eliminate the “stack effect”.

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In new construction, we are required to install supply ducts. The air helps

condition the crawlspace and keep it dry. It also warms the floor in the wintertime

making it more comfortable.

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In existing construction, we recommend a commercial grade

dehumidifier to help remove moisture that may get into the

crawlspace. These units require routine maintenance.

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Appliance grade dehumidifiers do not work in crawlspaces.

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Notice the height above of the ducts. We see many homes with the supply and especially the return ducts sitting

in standing water.

Well above grade!Sitting in water and mud!

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Notice the multiple leaks around the ducts from the package unit and how the

fiberglass is dirty from filtering the air leakage. What do you think the interior

coil looks like?

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Notice how the ductwork and penetrations are completely sealed.

Unsealed penetrations are a common entrance area for insects, spiders,

small animals, and snakes.

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We routinely find leaking and restricted ducts.

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We find disconnected ducts. Keep in mind, these problems are

minimized when located inside of a closed crawlspace.

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We install hygrothermometers with remote sensors that monitor the

humidity and the temperature in the crawlspace as well as the home.

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Closed crawlspace construction and proper HVAC design helps control

Radon. Notice the improperly installed venting above, instead of

below, the ground cover.

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• A “Synergy Home” with low humidity and low moisture content controls dust problems due to dust mites as well as hardwood floor and carpet issues.

• Carpet and carpet pads are a main contributor to dust mites and indoor air quality issues.

• We recommend installing a central vacuum system.

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We inspect numerous homes with clothes dryers and exhaust fans

vented into the crawlspace.

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We make sure construction debris such as HVAC register cut-outs are removed from the crawlspace and

not covered up to prevent attracting termites.

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Properly installed sump pumps with sump basins and french drains

are often necessary.

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We have found that wrapping the piers completely is unnecessary. This is proper detailing of a pier.

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As added safety, we recommend…• Do not store combustion engines or toxic

substances in your crawlspace.• Bi-yearly crawlspace inspections. Immediately

inspect anytime flooding occurs.• Inform other trades not to disturb the ground

cover or spray foam.• Strongly against using inexperienced

contractors that lack proper understanding of building science principles for your closed crawlspace construction.

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When it comes to crawlspaces…. “out of sight, is out of mind” for

most homeowners but these problems don’t magically go away. Most often, they get worse…much

worse.

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What is going on inside of your crawlspace?

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Questions???

Contact Synergy Airflow and Ventilation LLC for a free crawlspace

inspection and consultation.

Todd Witt (256) 616-2264Gary Pace (256) 690-8849

Office (256) 350-1779

WeTestOthersGuess.com •53