R E S I D E N T I A LUnited States

Why You Should Insulate Foundations.

There is a science to adding value.

Within Every GreatHome Is Great Science.

Whether you buildyour homes withbasements, crawlspaces or slab-on-grade, rigid foaminsulation fromDow can helpany type offoundation

perform better.Depend on the

insulation scienceexpertise of Dow

to help you build more valueinto your homes.

No matter how well youbuild your home, it isn’tcomplete until you add alayer of rigid foam insulation from Dow.STYROFOAM™ extrudedpolystyrene and polyisocyanurate insulations from Dow provide the scientific footing tohelp solve the energyand moisture issuesthat can compromise building performance.

Built On Science.STYROFOAM™ extruded

polystyrene and polyisocya-

nurate insulations from Dow

are the only rigid insulation

products built on the scientific

expertise of The Dow

Chemical Company, a leading

global supplier of chemical,

plastic and agricultural

products and services.

More than 50 years ago,

Dow pioneered STYROFOAM

extruded polystyrene insu-

lation, which revolutionized

insulation science. Our

commitment to innovation

continues. Drawing on the

vast research, development

and technological resources

of Dow and an open

exchange of information

with building professionals,

STYROFOAM building

materials offer proven

thermal envelope solutions

for every application.

®™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow

I N S I D E I N S U L A T I O N

To insulate is to reduce the transfer of heat. Insulations areformed by trapping air in a material.But not all insulating materials arecreated equal. The more compart-ments of air across a given span ofmaterial, the greater the thermalresistance, or R-value**.

Rigid foam insulations from Dowcontain about a million tiny pocketsof trapped air in every cubic inch ofmaterial. Proprietary formulationsand manufacturing processes ensurethat these cells are closed, whichenables the insulation to resistmoisture and maintain R-value.

An insulation’s performance isgreatly reduced when the trappedair is able to circulate or movefreely within the insulation material.This happens primarily throughconvective air movement. Insulationperformance is also reduced whenthe trapped air is displaced, whichcan happen through compression ormoisture uptake.

Rigid foam insulation from Dowhas a closed-cell structure. Air can’tinfiltrate or circulate within theboards, and they resist moisture. Sothe trapped air stays trapped … andthe insulating value remains high.

A microscopic view of rigid foam insulation reveals millions of closed cells that effectively trap air.

1

All buildings have one thingin common: Their foundationsmust come in contact with theearth. So wherever you buildyour home, moderating theeffects of soil, water, temperatureand air on the foundation canimpact the performance andintegrity of the total structure.

Below Grade.Top Of Mind.

For new construction andretrofit foundation applications,STYROFOAM extruded poly-styrene and polyisocyanurateinsulations from Dow can help:• reduce energy loss• keep foundations drier• improve occupant comfort

Continuous insulation from

footing to sill plate can

reduce the average home

heating and cooling bill by

hundreds of dollars per year.

**R means resistance to heat flow. The higher the R-value, the greater the insulating power.

Concrete is a highly heat-conductive material. In anuninsulated or poorly insulatedbasement, heat escapesthrough two paths: horizontallythrough the wall into the earth,and vertically through theconcrete wall and into the airabove the grade line.

Insulating the outside orinside of the foundation wallslows both vertical and horizon-tal heat flow through the wall,helping to mitigate conditionsthat cause energy loss.

Reduce Energy Loss.

Basement walls can be the

major source of conductive

heat loss in the whole house.

In fact, heat loss from an

uninsulated, conditioned

basement can account for up

to 50 percent of total heat

loss in an otherwise tightly

sealed, well-insulated home†.

The gap between thefoundation wall and the

sill plate of a buildingcan enable significant air

infiltration and energyloss. Sealing the gap with

STYROFOAM Sill Sealfoam gasket reduces air

infiltration and moisturewicking from the concrete

foundation into the wood sill plate.

R-1.5 R-1.5

Alone, concrete offersvery little resistance toheat flow. For example,a 7-inch-thick slab ofpoured concrete has thesame R-value as a paneof glass (R-1.5).

†Report, Kansas State University and the U.S. Department of Energy

Heat flows two ways throughan uninsulated concrete wall:horizontally into the earthand vertically to the air above the grade line.

Insulating with rigid foam(exterior insulation shownhere) slows both vertical andhorizontal heat flow throughthe wall.

2

STYROFOAM extrudedpolystyrene insulationis inherently moisture-resistant, helpingdefend against moisture penetration.

E N H A N C E D A M P - P R O O F I N G A N D W A T E R P R O O F I N G

Both damp-proofing and water-proofing involve applying an impermeable material to foundationwalls to help reduce moisture intrusion.This moisture intrusion is most oftencaused by bulk water movementthrough cracks, or capillary suctionthrough pores in the concrete wall.

Damp-proofing reduces moistureintrusion due to capillary suction.The typical 10-mil thickness ofdamp-proofing will not bridge thefoundation settling cracks that allowbulk water to enter the structure.Damp-proofing is also easily damagedby backfill, making it susceptible towater driven by hydrostatic pressure.

In comparison, waterproofingconsists of a spray-applied flexiblemembrane bonded to the foundation.Not only does the waterproofingmembrane reduce moisture intrusionby capillary action, it also has theability to bridge small cracks, reducingwater penetration through bulkwater movement.

Exterior foam insulation anddrainage are an important part ofdamp-proofing and waterproofingsystems. Exterior foam insulationprotects waterproofing or the damp-proofing membrane fromdamage caused by backfill. It alsokeeps the basement wall warmer,which reduces the potential for condensation on the basement wall.STYROFOAM extruded polystyreneinsulation resists water absorptionand compression under soil loads, so it retains its insulation value inwet environments. STYROFOAMPERIMATE insulation has patenteddrainage grooves in the long directionof the board. In addition to protectingthe waterproofing membrane andproviding insulation, the grooves inthe product assist drainage of wateraway from the foundation.

Foundation walls exist in atypically wet environment.Soil around the foundation isoften wet, due to rain, meltingsnow or the water table.

The porous materials usedto build most foundation walls– concrete and cement block –absorb water from the soil andallow it to move through thewall. Much of this movementis due to capillary suction:Water moves from an area ofhigh concentration to lowconcentration, often againstgravity. Water can also passdirectly through cracks in thebasement wall.

Manage Moisture.Exterior Insulated Basement

When building a new home,adding a continuous layer ofSTYROFOAM extruded poly-styrene insulation to the exteriorof basement walls is one of themost important steps you cantake to protect your homefrom the damaging effects ofmoisture.

The closed-cell rigid foamdoes this in three ways:1. It protects the waterproofing

or the damp-proofing membrane (see sidebar)

2. It keeps the wall warm,which reduces the potentialfor condensation on theinside surface of the wall

3. A specialized drainage insulation product (STYROFOAM PERIMATE*insulation) features a patentedgroove design that assists withthe drainage of water downand away from the basementwall, which reduces hydro-static pressure against thewall (see next page)

The most common problem homeinspectors find in homes less than12 years old is basement leaks.SOURCE: USA TODAY

3

Hydrostatic Pressure

A typical basement can becompared to a boat surroundedby water, because water in theground behaves in a mannersimilar to other bodies of water.Groundwater exerts hydrostaticpressure on submerged objects(like the basement wall), andthat pressure must be managed.

Hydrostatic pressureincreases at greater depths. Sothe pressure exerted on the

Underground water exerts hydrostaticpressure, which can push waterthrough foundation walls.

STYROFOAM PERIMATE insulationprovides a path of least resistance towater under high pressure, directing itaway from foundation walls toward thedrainage tiles. Plus, it warms the wall toreduce condensation on the interior andprotects the waterproofing.

4

Stand Up Under Pressure.bottom of a foundation wall –at the footer – is much greaterthan at the ground level.Without proper drainage,water can pool at the lowestpoint on the wall. Pressurebuilds up, and the water seeksthe path of least resistance –right through cracks in thefoundation wall.

Waterproofing can resisthydrostatic pressure, but amore effective way to managethe pressure is to drain the wateraway from the foundation.

STYROFOAM PERIMATEinsulation is an importantpart of a drainage system tohelp relieve hydrostatic pres-sure on foundation walls. Theinsulation boards have highcompressive strength, resistingincreased pressures near thebottom of the wall. And thepatented drainage grooveshelp direct water movementtoward the drainage tile,reducing hydrostatic pressureand pooling of water near thefoundation base.

The high compressivestrength of STYROFOAMextruded polystyreneinsulation resists lateralearth pressure, protectingthe integrity of thefoundation wall andmaintaining long-termthermal performance.

L A T E R A L E A R T H P R E S S U R E

Soil weighs about 80 to 120pounds per cubic foot. The pres-sure at any given depth in thesoil is a result of the weight of allthe soil above that depth. As thissoil weight presses downward, italso exerts a horizontal, or lateralpressure. This lateral pressureplaces a force on any insulationor drainage material placed onthe foundation. Materials withoutsufficient compressive strengthare unable to resist this pressure.And as they compress to a smaller thickness, R-value anddrainage capability are reduced.

5

Soil LoadsBelow grade, soil exerts a

pressure both downward andhorizontally (laterally). Thedeeper the soil, the greater thepressure. At eight feet belowgrade, this lateral soil pressureagainst the basement wall canbe as much as 1,000 lbs/ft2. Soto resist compression and loss ofR-value, foundation insulationmust be able to withstand thispressure.

STYROFOAM extruded polystyrene insulation productshave the necessary compressivestrength to fully resist soil

pressures over the life of thebuilding. Long-term perform-ance of STYROFOAM extrudedpolystyrene insulation belowgrade helps to save energy andreduce moisture problems inbasements.

Table 1 illustrates the importance of compressivestrength as it relates to aninsulation’s drainage ability.Compared to a typical fiberglassdrainage product, STYROFOAMPERIMATE insulation is far better at maintaining highwater drainage rates underincreasing soil pressures.

TA B L E 1

1" STYROFOAM PERIMATE 1-3/16" Fiberglass,gal/hr/linear foot, gal/hr/linear foot

Soil Pressure, lb/ft2 1.0 gradient 1.0 gradient

600 366 63

800 357 39

1,000 363 32

(1) Figures based on average soil pressures at average basement depths(2) Third-party testing by STS Consultants using ASTM D4716

Drainage Rate Comparison(1),(2)

STYROFOAM PERIMATE Insulation vs. Fiberglass Board

Crawl SpacesCrawl spaces are prone to

moisture problems and heat lossdue to their proximity to thesoil. The practice of adding ventsto crawl space walls is meantto address these moistureproblems and help dry out thecrawl space area. However, thevents actually allow moistureto enter the crawl space, andthey do little to help it dry out.

Moisture that entersthrough the crawl space ventsclings to floor joists, batt insulation, heating/coolingequipment and plumbing fixtures. In this moist environ-ment, mold and mildew canquickly degrade the integrity ofthe crawl space’s contents, aswell as compromise indoor airquality. And moisture isn’t theonly thing to worry about.Wood-eating insects, dust mitesand other small creatures cancrawl in through the vents totake up permanent residence.

A solution to this problem is gaining popularity: the non-vented, conditioned andproperly insulated crawl space.This type of foundation

construction can be a big con-tributor to a home’s overallenergy efficiency and comfort.

Rigid foam insulation is animportant component of anon-vented crawl space – ithelps to keep the crawl spacedry and energy-efficient. And THERMAX* Sheathingpolyisocyanurate insulationfrom Dow is the only rigidfoam insulation product thatcan be left exposed on crawlspace walls, as stated in theICC code report NER-681.

Rigid foam insulationon the interior of

non-vented crawl spacewalls keeps the crawl

space warmer. Thisreduces the potential forcondensation and related

moisture problems.

Crawl space moisture problemsdon’t stay in the crawl space forlong. Moist air can migrate into theinterior of the home, increasingindoor humidity levels. One conse-quence of increased humidity iswood components and furnishingsabsorbing moisture, which causeswarping and swelling.

Poorly constructed

crawl spaces are a major

source of moisture

problems and a big

contributor to poor

indoor air quality in

many of today’s homes.

6

Design Fundamentals.

Photos courtesy of Jeff Tooley, owner of The Healthy Building Company

foundation design†† allows the construction of a muchshallower foundation, whichsaves on building costs. Theinsulation regulates heat lossand changes the depth of frostpenetration into the soil,resisting frost penetration intothe building foundation.

RADIANT FLOORSIn a slab-on-grade radiant

floor heating design, radiantheat tubes are installed in theslab and concrete becomes theconductive medium, dispersinghot water heat across the surfaceof the floor. But without adequate insulation, this heat can be lost as it flowshorizontally to the edges ofthe slab and the outside ofthe building, or downward tothe soil beneath the slab.

Rigid foam insulation at flooredges and under the slab helpsmaintain a comfortable floortemperature, and keeps heatin the house to save energy.

††As found in section R403.3 of the International Residential Code.

In states with heavy termite infestation (Florida, South Carolina, Georgia, Alabama, Mississippi, Louisiana,

Eastern Texas, California and Hawaii), rigid foam in new construction is not allowed in contact with the

soil on the exterior foundations of homes or light construction where wood is found in the structural

components of construction. Your Dow representative can provide recommendations for alternative

insulation methods for these areas.

As part of a frost-protectedshallow foundation, STYROFOAM extruded polystyrene insulation regulates heat loss andchanges the depth of frostpenetration into the soil.This allows a much shallower footing to be used in the foundation.

Rigid foam insulationat floor edges and underthe slab helps radiantfloor heat stay in thebuilding, enhancingcomfort and savingenergy.

When soil under the foundationfreezes, it expands with greatforce and can cause foundationsto shift and crack.

Slab-On-GradeDigging a conventional deep

foundation is not always feasibleor desired. Building codesrequire that a foundationextend below the local frostline. In cold climates, this canmean digging a foundationmore than 60" below grade.

FROST-PROTECTED SHALLOWFOUNDATION

STYROFOAM extruded polystyrene insulation as partof a frost-protected shallow

7

Interior Insulated Basement

Installing rigid foam insulationon interior basement walls is afast and easy way to extend theliving space of your home. Butwhen insulating a basement,it’s important to do it right.

Rigid foam insulations fromDow can be installed right overmasonry walls with no needfor studs or a vapor barrier,providing a solid wall of mois-ture-resistant insulating comfort,without cavities or thermalbridges.

STYROFOAM WALLMATEinsulation is designed for easy installation. The required drywall finish is easily attached to the furring strips slotted into the insulation.

Just Right Inside.Specially designed and

formulated insulation productsfrom Dow are available to helpmeet specific application needs.For example, STYROFOAMWALLMATE* extruded polystyrene insulation withslotted vertical edges isinstalled with furring strips andcovered with gypsum boardfor a finished appearance. Forareas such as a laundry roomor storage space, THERMAXSheathing, with its reflectivefoil facers, can be left exposedwithout a thermal barrier, fora semi-finished appearance.

Rigid foam insulationwithin insulated concrete walls helps maintain interior comfort – above andbelow grade. The insu-lated wall mass alsocontributes to superiorsound dampening.

Continuous foam

insulation – from footer

to sill plate – is the

most effective way to

reduce foundation

energy loss up to

75 percent. In addition

to offering reliable

R-values from 5.0 to

6.5 per inch, rigid foam

insulations from Dow:

• enhance drainage

• insulate the below-

grade wall to reduce

condensation

• protect the damp-

proofing/waterproofing

membrane

• resist movement of bulk

water and water vapor

through foundation

walls above and

below grade

• provide a more

comfortable

environment

throughout the home

Learn more about

building value into

your homes with

rigid foam insulation.

Call your Dow

representative today.

Insulated concretefoundations createa thermally efficient, below-grade wall that cansave constructiontime and materials.

Insulated Concrete Wall Systems

Today, precast, poured-in-place, tilt-up and other types ofinsulated concrete wall systemsare being used to constructenergy-efficient foundationwalls and entire homes.

Insulated concrete wallseliminate many of the chal-lenges of frame wall assemblies.Sandwiching rigid foam insulation between layers ofconcrete puts the insulation inthe optimum position to helpmaximize the thermal mass ofthe concrete. And, insulatedconcrete wall assemblies minimize construction time,maximize a home’s interiorusable space and offer a varietyof attractive, fast and easy finish options.

Rigid foam insulation fromDow can be used in all types ofinsulated concrete panels or“sandwich walls.” Dow alsooffers complete systems of rigidfoam insulation, patented com-posite fiber connectors, softwareand technical service, as wellas licensing opportunities.

Build Green With Dow

Dow supports initiatives thathelp preserve our environment,and we strive for environmentalsensitivity in our manufacturingprocesses and in our products.Dow produces insulatingfoams that:• contain no CFCs• are formaldehyde-free• are not a known food source

for mold or insects• contain post-industrial

recycled content• are recyclable (extruded

polystyrene)

Ask your Dow representativefor more information.

Printed in U.S.A. Form No. 179-07771-1004P&M®™Trademark of The Dow Chemical Company (“Dow”)or an affiliated company of Dow

NOTICE: Changes to the International Residential Code require the installation of a weather-resistive barrier (WRB) within most exterior wall assemblies in residential construction. The following Dow insulated sheathing products qualify as a WRB when installed according to the installation instructions developed for“installation of foam sheathing as a weather-resistive barrier”: STYROFOAM™ DURAMATE™ Plus, STYROFOAM Residential Sheathing, STYROFOAM Tongue andGroove, STYROFOAM Square Edge, STYROFOAM Residing Board, THERMAX™, TUFF-R™ and Super TUFF-R and therefore do not require the use of a build-ing paper or a housewrap as a WRB. When a WRB is not needed, these Dow foam sheathings may be installed according to standard installation instructions forfoam sheathing from Dow. Be sure products and installation instructions meet code requirements for your particular location. Note: STYROFOAM WEATHERMATE™and WEATHERMATE Plus housewraps have already qualified as weather-resistive alternatives to the prescribed felt (see Evaluation Reports NER 593 and NER 640for approved alternative).

NOTICE: No freedom from any patent owned by Dow or others is to be inferred. Because use conditions and applicable laws may differ from one locationto another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriatefor Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and other government enactments.Dow assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OFMERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.

STYROFOAM™ Extruded Polystyrene and Dow Polyisocyanurate Insulation Other Than THERMAX™ Products

COMBUSTIBLE: Protect from high heat sources. Local building codes may require a protective or thermal barrier. For more information, consult MSDS,

call Dow at 1-866-583-BLUE (2583) or contact your local building inspector. In an emergency, call 1-989-636-4400.

THERMAX™ Products

COMBUSTIBLE: THERMAX products should be used only in strict accordance with product application instructions. THERMAX products, when used in a building

containing combustible materials, may contribute to the spread of fire. For more information, consult MSDS and/or call Dow at 1-866-583-BLUE (2583).

In an emergency, call 1-989-636-4400.

WARNING: THERMAX insulation does not constitute a working walkable surface or qualify as a fall protection product.

Building and/or construction practices unrelated to insulation or housewrap could greatly affect moisture and the potential for mold formation. No

material supplier including Dow can give assurance that mold will not develop in any specific system.

THE DOW CHEMICAL COMPANY • Building & Construction • 200 Larkin • Midland, MI 48674

FOR TECHNICAL INFORMATION: 1-866-583-BLUE (2583) • FOR SALES INFORMATION: 1-800-232-2436

www.insulateyourhome.com

McKAY187318-06/06