Spray Foam Insulation in St. Marks, FL

Spray Foam Insulation in St. Marks means working with homes built for water. The town sits at about 13 feet of elevation on Apalachee Bay, and Wikipedia records that storm surge from Hurricane Dennis on July 10, 2005, severely flooded the town and damaged homes and businesses, and that St. Marks has flooded with saltwater on other occasions. On raised houses, the space under the floor is open to the weather, which makes the floor a main place we work.

One of Florida's oldest places

St. Marks began as the Spanish settlement of San Marcos de Apalache, centered on a fort, with Spanish settlement dated from 1679. In about 1836 the Tallahassee Railroad linked the port to the capital some 20 miles inland. The city was incorporated in 1963. It is small: Wikipedia lists 274 residents in 2020.

Raised floors and closed-cell foam

Under a raised house, wind, damp air and cold fronts reach the underside of the floor directly. Fiberglass batts here tend to fall, get wet or get pulled out by animals. Closed-cell spray foam bonded to the underside of the subfloor works better: it seals the floor, holds R-5 to R-7 per inch in HomeGuide's figures, and does not soak up water the way batts do. We look at how the floor is framed, how much clearance there is, and what the local flood rules require before quoting.

After a flood or storm

Insulation that has been underwater or soaked by a roof leak usually has to come out. Saltwater and mud make it worse. Once repairs are done, we remove the damaged material, let the framing dry, and reinsulate. We do not cover wet wood.

The attic and the heat

The bay keeps St. Marks humid all summer. In the attic, sealing gaps around lights, fans and the hatch and then blowing in insulation to the R-38 ceiling level in the 2023 Florida energy code for Zone 2 usually gives the most for the money. Wakulla County is in IECC Climate Zone 2A.

Air conditioning near the water

The bay keeps the air moist most of the year, so an air conditioner here spends a lot of its effort pulling water out of the air. Every gap in the floor and ceiling lets more humid air in. Sealing the floor and the attic does not just save on bills; it helps the system keep the indoor air dry, which protects floors, furniture and walls. A smaller, tighter house is also easier to dry out after a storm.

Costs

HomeGuide's 2026 guide puts closed-cell spray foam at $3.00 to $5.00 per square foot installed, and its crawl space guide puts closed-cell on crawl space walls at $2 to $5 per square foot. Access under a raised house changes the price, and our written estimate is the price you pay.

Getting started

Tell us whether the house is raised and how high, what is under it, and whether it has had water damage. We visit and send a written plan. Get a free estimate