The hull is the part of a floating home that almost no one thinks about until there's a problem — and then it's the only thing anyone thinks about. The material a floating home hull is made from determines its maintenance requirements, its longevity, its insurance cost, and what a marine survey will be looking for during due diligence. Understanding the three main hull types in Sausalito's floating home market is basic buyer education.
Concrete Hulls (Ferro-Cement)
Concrete hulls are the most common material in Sausalito's floating home stock, particularly among older homes built in the 1960s through 1980s. A well-built ferro-cement hull — a steel armature wrapped in wire mesh and coated in Portland cement — is exceptionally durable. The material resists corrosion, doesn't suffer from the osmotic blistering that plagues fiberglass hulls, and has a lifespan that can exceed 50 years when properly maintained.
What to watch for: Concrete hulls are vulnerable to cracking from impacts or from improper repair of earlier damage. A marine surveyor examining a concrete hull will be looking for cracks, evidence of water infiltration behind the surface, and signs of rebar corrosion (rust staining or spalling of the outer surface). A clean concrete hull with no cracking history and regular professional inspection is among the most trouble-free floating home foundations you can own. A concrete hull with active cracks or a history of shoddy repairs is a serious concern.
Steel Hulls
Steel hulls were common in earlier generations of floating homes and are still found throughout Sausalito's dock communities. Steel is extremely strong and can be repaired relatively easily with standard welding equipment. The challenge with steel hulls is corrosion — steel in saltwater is in a constant battle with oxidation that requires ongoing maintenance to manage.
Maintenance requirements: Steel hulls need to be hauled out of the water periodically for inspection and recoating. Sacrificial zinc anodes (which attract corrosion preferentially to protect the hull) must be inspected and replaced regularly. Interior bilge areas in steel-hull vessels need to be kept clean and dry to prevent hidden corrosion that isn't visible from outside. A steel hull that has been consistently maintained is a sound foundation. One that has been neglected may have hidden structural compromise that significantly affects value.
A haul-out for out-of-water inspection is strongly recommended — sometimes required by lenders — when purchasing a steel-hull floating home. The cost is several thousand dollars but is money well spent before committing to a purchase.
Fiberglass Hulls
Fiberglass hulls are the least common material in Sausalito's floating home stock but are found in some of the newer or more extensively rebuilt vessels. Fiberglass is lightweight, strong, and doesn't corrode in the way that steel does. The main vulnerability of fiberglass in a liveaboard context is osmotic blistering — the absorption of water through the gelcoat that creates bubbles in the hull surface and, if untreated, can compromise structural integrity over time.
Marine surveyors examining fiberglass hulls will be checking for blistering, delamination, and any impact damage. Fiberglass hulls are generally cheaper to inspect than steel hulls because haul-outs are less urgently required, though a full survey still requires out-of-water inspection in many cases.
Hull type is one of several factors that affect a marine survey outcome and subsequent negotiation. Paul and Roman can help you understand the implications of a hull type before you make an offer — call (415) 332-7539.