Crawl Space Insulation in Myrtle Beach & the Grand Strand

In most Myrtle Beach homes built over a vented crawl space, the insulation is fiberglass batting pressed between the floor joists. Along the Grand Strand that batting has a hard life. It sits in air that runs near saturation from May through September and catches condensation off chilled ductwork and subfloor. Over time it absorbs moisture until it sags, loses its insulating value, and falls.

This page covers why that happens in Horry County, how crawl space insulation removal and replacement work, how the right approach changes between a vented and a sealed crawl space, and what to ask before hiring anyone.

Why Does Crawl Space Insulation Fail in Myrtle Beach Homes?

Fiberglass insulates by trapping still air in its loft. Add moisture, and that loft collapses: the fibers mat together, the batt gets heavier, and wet fiberglass conducts heat instead of resisting it.

In a vented Grand Strand crawl space, every foundation vent pulls in outdoor air carrying summer dew points in the low 70s. That air meets ductwork and subfloor surfaces chilled by the air conditioner, and condensation forms right where the batting sits.

The paper facing on kraft-faced batts adds a second problem, because it is an organic material that mold readily colonizes. The batts are held up mostly by friction and thin wire supports, so gravity eventually finishes the job.

Homes closest to the ocean, the Intracoastal Waterway, and the marsh around Cherry Grove, Little River, and Murrells Inlet tend to see this soonest, because those areas hold elevated humidity later into the night.

Signs Your Crawl Space Insulation Needs Attention

• Batts hanging down or lying on the ground. This is one of the most common crawl space findings in Horry County home inspections.
• Darkened, matted, or damp-feeling insulation, often heaviest near duct lines and plumbing.
• White, gray, or black growth on the paper facing.
• Cold or clammy floors in winter, and a sticky lower floor in summer.
• A musty smell on the first floor. Wet batting holds odor and passes it upward. See why lower floors smell musty.

Crawl Space Insulation Removal: What It Involves and What It Reveals

Removal is low-clearance, dirty work. Damp fiberglass is heavy and sheds fibers, and material that has supported mold growth calls for respiratory protection and proper bagging and disposal.

The real value of removal is what it uncovers. Batting in the joist bays covers the underside of the subfloor and the sides of every joist, which are exactly the surfaces where water staining, decay, fungal growth, and termite damage would first appear. A crawl space can look acceptable from the access door while the framing behind the insulation tells a different story.

Once the bays are open, the framing can be checked with a moisture meter and treated if needed. If surface growth is present, crawl space mold remediation typically happens before anything is closed back up. The penetrations between the crawl space and the living space can also be air-sealed properly for the first time. For more on that decision, see whether to remove fiberglass before encapsulating.

Floor Insulation or Wall Insulation? It Depends on the Crawl Space

In a vented crawl space, the insulated boundary is the floor above, so insulation belongs between the joists. Replacing failed batts with new ones is an option, but in coastal Horry County the new batts face the same humid air that ruined the old ones.

In a sealed crawl space, the boundary moves outward to the foundation walls and rim joist, and the crawl space stays closer to indoor conditions. The common approach is rigid foam board on the inside face of the foundation walls, with sealed foam at the rim joist. Those materials tolerate incidental wetting far better than fibrous batts. This is why insulation work is so often done together with crawl space encapsulation, a sealed vapor barrier, and dehumidification.

Two coastal South Carolina details matter here:

• Termite inspection gap. Horry County sits in the highest termite-probability zone on the residential code’s map. Foam board on foundation walls is generally held up from the soil so piers and walls stay visible for the termite inspection a CL-100 report depends on.
• Ignition barriers. Foam plastics in crawl spaces generally need to meet the code’s ignition-barrier provisions or carry a listing for exposed use.

What Our Crawl Space Insulation Service Covers

• Inspection of existing insulation for sagging, fallen, wet, or mold-affected material
• Moisture readings on the subfloor and joists
• Removal, bagging, and disposal of deteriorated fiberglass batting
• Assessment of the framing and subfloor once exposed
• Air sealing of penetrations between the crawl space and the living space
• For sealed crawl spaces: rigid foam board on the foundation walls and sealed rim joist insulation
• For vented crawl spaces: replacement insulation between the floor joists
• Photo documentation of the work completed

What Affects the Cost of Crawl Space Insulation?

Several factors shape the scope of a crawl space insulation project:

• The square footage and number of joist bays
• The condition of the existing material, since wet or mold-affected batting takes more handling
• Clearance and obstructions in the crawl space
• Whether the exposed framing needs treatment
• Which replacement material is used and where it goes
• Whether the work is part of a larger encapsulation

A free inspection provides accurate pricing for your specific property.

What to Ask a Grand Strand Insulation Contractor

• Will the existing batting come out, and will the framing behind it be inspected and documented?
• Where will the new insulation go, the floor or the walls, and why for this crawl space?
• How will foam board be kept clear of the soil for termite inspection?
• Does the foam product meet ignition-barrier requirements as installed?
• If the home is in a flood zone, are the insulation materials suited to that exposure?

Insulation work is available throughout Horry County, from North Myrtle Beach and Surfside Beach to Conway and Carolina Forest. See all crawl space services.

Common Questions About Crawl Space Insulation