Mobile Home Tie-Down & Anchor Calculator

This works out roughly how many anchors and frame ties your home should have, so you know whether what is under it now is obviously short.

It reports a range, never a single number, because the binding figure is the spacing table in your own home’s installation manual read against Florida Rule 15C-1.0104. Anything claiming to know the exact count without that manual is guessing.

Why anchoring matters inland

People assume tie-downs are a coastal issue. Sumter County is a long way from either coast and it is still HUD Wind Zone II, rated to 100 mph, and the record here says why. On February 2, 2007, an EF-3 tornado with winds of 155 to 160 mph touched down near Wildwood and ran 16.5 miles through the south side of The Villages and the mobile home communities of Lady Lake, killing eight people and damaging or destroying more than 1,500 homes and mobile homes. Irma put a 60-knot gust on Leesburg International Airport in September 2017. Milton’s gusts across Sumter County ran 40 to 50 mph in October 2024, and the county’s evacuation order that night was for mobile homes and low-lying areas.

The homes we worry about most here are the ones set before the 1994 HUD standards, which the Florida rule still treats as a separate anchor class. A great many of those are in the older parks along SR 44, in the original Lady Lake communities where The Villages began as a mobile home park, and in the 1980s parks around Leesburg, with their original anchoring, and a great many have never had it inspected, let alone retrofitted.

What the rule counts

• Diagonal ties: no more than five feet four inches on center, in all wind zones, with an anchor within two feet of each end. A 60-foot singlewide needs a dozen or more per side by that spacing alone.
• Longitudinal ties: at least four anchors and straps at the end of each section, sixteen on a double-wide. Most pre-1994 installations have none.
• Frame ties: a factory-fabricated strap to a department-approved I-beam clamp, not a strap wrapped round the beam.
• Anchor class: Type I (3,150 pounds working load) for homes built before July 13, 1994, Type II (4,000 pounds) after.

The Florida tie-down requirements page sets the whole rule out in plain terms.

What goes wrong with existing anchoring

Corrosion. Straps and anchor heads rust, particularly where they sit in damp sand under a home, and on the Sparr and Adamsville flats the ground is saturated at two or three feet for half the year. A strap that looks fine at the frame can be substantially gone where it enters the ground.

Loss of tension. As a home settles on sandy soil, the geometry changes and straps slacken. A loose strap is doing very little. This is why straps are re-tensioned as part of every relevel.

Anchors that stopped short. Sumter County is sand over the Ocala Limestone, and the soil survey labels whole map units around Wildwood with a bouldery subsurface. An anchor that hit rock before it reached its rated depth is not developing its rated holding power, and it looks identical from above.

Anchors loosened in saturated ground. Sand that has been wet for weeks holds an anchor differently from dry sand. After a wet season, or after Irma’s 8.57 inches on the Wildwood gauge, anchors that were adequate can have moved.

Missing ties at the ends, and no longitudinals. Common omissions on older installs.

Too few for the home’s size. Especially on homes that were widened, added to, or moved.

What to do with the number

Go and look underneath, or have somebody look. Count what is actually there and compare. If the count is obviously short, or if the straps are slack or rusted, that is worth dealing with regardless of whether anything in the home is sticking. The loose or rusted tie-downs page has the three-minute check.

Anchor and strap work runs $600 to $3,500 for a full retrofit or new install on our pricing page, with individual anchor or strap replacements quoted per anchor and strap re-tensioning included with a relevel.

That last point is worth knowing: if you are having the home releveled anyway, that is the cheapest moment to deal with anchoring, because the crew is already under there.

Licensing, which is not optional in Florida

Florida licenses mobile home installers through the state under section 320.8249, and installation work, which includes blocking, leveling, supporting, and tying down a sited home, falls under that licence. Ask for the number in writing, verify it is current, and ask for the insurance certificate separately. The installer licensing page explains how to check and what else to ask for.

The other two free tools

The settling self-check scores twelve visible signs and will tell you honestly if nothing is wrong. The cost calculator prices a relevel from the published table.

We cover Wildwood, Oxford, Lady Lake, Bushnell, Coleman, Webster, and Leesburg.