Start with Water and Ground Moisture

Correct Water Entry First

Inspect the crawl space before installing insulation. Look for standing water, plumbing leaks, foundation seepage and signs that rainwater is entering around the building.

Correct the source of water entry before covering surfaces. Insulation does not repair a drainage problem, and enclosing wet materials can conceal damage.

Check the condition of wood framing and existing insulation. Materials affected by persistent moisture need evaluation before the assembly is closed.

Address Moisture from Exposed Soil

An exposed earth floor can release moisture into the crawl space. Ground moisture control is a separate part of the system, even when the floor above or foundation walls are insulated.

Use a continuous ground covering suited to the application. Detail seams, piers, edges and penetrations according to the selected system.

When Under Concrete Prodex Total is specified for a ground application, install it white side up, with the foil toward the soil. Follow the applicable instructions for substrate preparation, seam closure and perimeter details.

Plan Humidity Management

A crawl space’s moisture conditions depend on the ground, outdoor air, temperature and connections to the home.

An enclosed crawl space needs a deliberate humidity-management strategy. Closing vents alone does not establish a complete encapsulation system.

Coordinate insulation with drainage, ground moisture control, air sealing and any required conditioning or dehumidification.

Should You Insulate the Floor or the Crawl Space Walls?

Vented Crawl Spaces

Where the crawl space remains outside the conditioned enclosure, the insulation boundary generally follows the floor above it.

The floor assembly needs adequate thermal resistance and air sealing. Plumbing, ductwork and other services below that boundary may remain exposed to crawl space temperatures.

Choose materials and support methods appropriate to the conditions beneath the home.

Enclosed or Conditioned Crawl Spaces

In an appropriately designed enclosed crawl space, the thermal boundary generally follows the perimeter walls and associated transitions.

The system includes ground moisture control, air sealing, wall insulation and humidity management. Rim joists and connections to the floor above also need attention.

Required inspection access, clearances and protective coverings must remain available.

Follow One Coordinated Design

Avoid choosing insulation locations simply because a surface is easy to reach. Establish the intended thermal boundary first, then connect the insulation and air-control layers around it.

Our Nebraska house insulation guide explains how crawl spaces fit into a whole-home insulation plan.

Using Prodex Total Beneath Floor Joists

Provide Continuous Coverage Where Specified

Where the selected assembly uses a continuous Prodex Total layer beneath floor framing, carry it across the joists. Installing material only between joists leaves the framing outside that continuous layer.

Plan support, perimeter connections and access around plumbing, wiring and other services before beginning installation.

The finished system should remain securely supported without obstructing equipment that needs inspection or maintenance.

Seal Seams and Transitions

Air leakage through floor penetrations and perimeter connections can undermine comfort.

Where Prodex Total forms part of the air-control layer, use the seam and edge treatments specified for the selected product. Detail penetrations without leaving uncontrolled gaps.

Air sealing should connect with the surrounding assembly rather than stopping at the edge of each roll.

Preserve the Required Airspace

A reflective surface needs an adjacent airspace to provide its radiant-barrier function on that side.

Do not assume that every reflective installation has the same thermal performance. Airspace dimensions, orientation and heat-flow direction affect the result.

Our reflective insulation guide explains how to evaluate these conditions.

Using Prodex Total on Crawl Space Walls

A perimeter-wall installation requires details suited to the foundation and the intended enclosed-crawl-space design.

Where the specified method uses furring, coordinate the insulation, attachment and airspace with that arrangement. Keep ground and wall moisture-control layers connected as required by the system.

Plan around piers, access openings, rim joists and service penetrations. Maintain required inspection areas and protect materials where the application calls for a covering.

Layer placement matters because foil-faced insulation restricts vapor movement. Coordinate it with existing materials and the assembly’s intended drying paths.

Keep Ground Coverings and Floor Insulation Distinct

The insulation beneath the floor above and the covering over the soil serve different locations within the crawl space.

Use the product specified for each application. Do not assume that a standard foil-faced roll and Under Concrete Prodex Total can be substituted without reviewing their instructions.

For the specified Under Concrete ground application, remember the orientation: white side up and foil toward the soil.

A ground covering also needs protection from damage. Plan access routes and maintenance activities so that seams and surfaces remain intact.

Combining Prodex Total with Fiberglass

Fiberglass can provide bulk thermal resistance within floor cavities. Prodex Total can contribute additional insulation and air, radiant-heat and vapor-control functions when correctly incorporated into the assembly.

Inspect existing fiberglass before adding another layer. Correct moisture sources and evaluate insulation that is wet, damaged, compressed or poorly supported.

Pay particular attention to existing facings. Adding a vapor-resistant layer requires consideration of the assembly’s drying potential.

Read our Nebraska fiberglass vs. Prodex Total guide to compare the materials and their combined use.

Comparing Other Crawl Space Insulation Materials

Foam Board

Rigid foam board may be used in selected crawl space wall or floor assemblies. Attachment, sealed joints, perimeter details and required protective coverings must be planned together.

Our foam board insulation guide provides additional material guidance.

Spray Foam

Spray foam can provide thermal resistance and air sealing in suitable applications. Product type, thickness, substrate condition and protective-covering requirements affect its suitability.

For a broader material discussion, our spray foam insulation guide for metal buildings and pole barns explains considerations associated with spray foam. Crawl space installations still require details specific to that location.

Bubble Insulation

Bubble insulation uses an air-bubble core, while Prodex Total uses closed-cell polyethylene foam.

Compare product ratings under equivalent installation conditions. An assembly R-value that includes airspaces should not be treated as the standalone R-value of the material.

Our Nebraska bubble insulation guide explains these distinctions.

Choose the Product for the Application

10M Prodex Total Plus is the most popular and thickest reflective insulation roll in the Prodex Total range. It features a 10 mm, approximately 0.4-inch, closed-cell foam core with reinforced reflective foil on both sides and heat-welded seams.

Each roll measures 4 feet by 85.3 feet and covers 341 square feet.

The 5M Plus range offers thinner options, including products with a white, black or rustic finish on one side and reflective foil on the other. Ground applications should use the dedicated product specified for that purpose.

Select materials according to the complete assembly, attachment method and moisture-control plan.

Calculate Your Crawl Space Material Requirements

Measure each surface separately. The ground covering, perimeter walls and floor above can require different quantities and installation layouts.

Allow for specified overlaps, cuts, piers, corners and transitions. Include the accessories required to support the insulation and close seams.

Use the Advanced Insulation Calculator and review how much insulation you need before ordering.

Return to the Nebraska Insulation Guide to explore the complete series of building and application guides.

Cool in the Summer. Warm in the Winter. Dry all the Time.

Prodex Total = Insulation + Radiant Barrier + Vapor Barrier — All in One Product.