Tiny home foundations and tie-downs in Tennessee: a guide by home type

Last checked 2026-11-04. This page summarizes public rules with links to the text. It isn't engineering, legal or zoning advice. Your local building and zoning offices have the final say.

Compare the four types at a glance

Each source link in the table opens the rule or document behind that row. Full list at the bottom of the page.

1. Tiny homes on wheels, RV-style tiny homes and park model RVs

Federal rules exempt a recreational vehicle from HUD's manufactured home code if it isn't certified as a manufactured home, is designed only for recreational use and not as a primary residence or permanent occupancy, and is either self-propelled or built and certified to NFPA 1192 (RVs) or ANSI A119.5 (park model RVs) (24 CFR 3282.15). For a park model sold under ANSI A119.5, the maker must give the buyer and post in the kitchen a "Manufacturer's Notice" saying it is for recreational use only (§ 3282.15(c), HUD 2018 rule).

The RV Industry Association describes park models as built on a single trailer chassis, mounted on wheels, generally no more than 400 square feet in set-up mode, and "not meant to be affixed to real property" (RVIA).

• What this means for setup: the home stays on its chassis. Leveling, blocking and any tie-downs follow the manufacturer's setup instructions plus the rules of the park or the local government. The HUD pier and anchor standards on our mobile home piers page don't automatically apply, but they are a useful reference for what solid blocking looks like.
• Living in it full time: an RV-certified unit is, by definition, not designed as a primary residence. Whether you can live in one on your own lot is up to local zoning. Ask before you buy.
• A tiny home on a trailer with no RV certification fits neither box neatly. Expect the building office to ask how it was built and inspected.

2. Prefab and modular tiny homes

Tennessee's Modular Building Act (1985) covers housing and commercial buildings that are mass-produced in factories and moved to a site; HUD manufactured homes are excluded (SFMO Modular Building Program, T.C.A. § 68-126-301 et seq.). A modular unit can't be made for sale or installation in Tennessee until its building system and compliance program are approved by a state-approved design review agency and filed with the state (Rule 0780-02-13-.09). The program publishes guidance on modular foundation plans (bulletin 2009-07) (SFMO).

• Ask the seller for the Tennessee modular certification label and the approved foundation plan before delivery.
• A "kit" home you assemble on site is generally reviewed as site-built construction (type 4 below). Confirm with your building office.
• A home with a HUD label is a manufactured home, not modular, and follows the manufactured home rules and a licensed Tennessee installer (T.C.A. § 68-126-403).

3. Shipping container homes

Tennessee has adopted the 2021 International Building Code (SFMO adopted codes). That code's Section 3115 covers ISO intermodal shipping containers repurposed as buildings (IBC § 3115):

• Foundations: a container used as a permanent building must sit on foundations or supports designed under the code's structural chapters (§ 3115.8.1).
• Anchorage: containers must be anchored to the foundation to give a continuous load path for all design and environmental loads, including wind (§ 3115.8.1.1). In practice, designers connect at the steel corner castings, often by welding to embedded plates or using engineered clips, but the specific detail must come from the design.
• Welds: new welds and connections must be at least equal to the originals (§ 3115.8.2).
• Cuts and openings: the simplified design path is only for a single stand-alone container whose top and bottom rails, corner castings and corner posts are not cut or notched, set level with the floor at the bottom. Containers with big cut-outs or stacked units need a detailed structural analysis (§§ 3115.8.4–3115.8.5).
• Data plate, floors and ventilation: the code expects the original ISO data plate (unless the official approves removal), decay and termite protection for wood floors, and ventilated under-floor space (§§ 3115.3–3115.5).

The ICC also publishes a guideline, ICC G5-2019, on repurposing containers for code-regulated uses (ICC G5). The residential code Tennessee adopted for houses (2018 IRC) has no container section, so for a container house your local building official decides how to review it. Expect to need stamped engineering drawings. If a company builds container homes in a factory for sale in Tennessee, ask whether they are approved under the state modular program.

4. Site-built tiny homes on a permanent foundation

Tennessee's residential rule adopts the 2018 International Residential Code and Appendix Q for one- and two-family dwellings (Rule 0780-02-23-.02). Appendix Q (titled "Tiny Houses") applies to dwellings of 400 square feet or less, not counting lofts. It allows 6 ft 8 in ceilings in habitable rooms and 6 ft 4 in in bathrooms and kitchens, and sets rules for lofts, loft stairs and ladders, and loft egress (IRC Appendix Q text). It does not relax foundation rules, so the home needs a standard code footing and foundation and must be anchored to it.

• Who issues the permit: many larger cities and counties enforce their own residential code. In some other areas the State Fire Marshal issues the residential permit, and some local governments have opted out by a two-thirds vote (SFMO FAQ). Even in an opt-out area, an owner can ask the state to inspect and issue a certificate of occupancy (SFMO opt-out page).
• Local adoption varies. A city or county may enforce a different code edition, and may or may not adopt Appendix Q. Ask your building department which edition and appendices it uses.

Wind and tie-downs

A light structure is more at risk from wind uplift than a heavy one. Tennessee isn't in HUD's high wind zones for manufactured homes (see the piers page), but tornadoes and severe storms happen statewide. Whatever the type, ask for anchoring that follows a written design: the manufacturer's setup manual, the approved modular foundation plan, or an engineer's drawings. Don't accept "we always do it this way."

Zoning and ADU caveats

Building codes say how a home must be built; zoning says whether it may be placed on a lot at all. Minimum home sizes, rules for accessory dwelling units (backyard cottages), bans on living in RVs outside campgrounds, and HOA covenants are set locally and vary across Tennessee. Call your city or county planning or zoning office with your parcel number before you buy or move a tiny home.

Checklist before you buy or set a tiny home

1. Find the label: RV or park model (NFPA 1192 / ANSI A119.5 seal), Tennessee modular label, HUD label, or none.
2. Get the setup manual or approved foundation plan for that label. For a container or unlabeled build, plan on an engineer.
3. Ask the zoning office whether that type may be placed, and lived in full time, on your parcel.
4. Ask the building office (or the SFMO) which permit you need and which code edition and appendices they enforce.
5. Check that footings sit below your county's frost depth and that water drains away from the home.
6. Get the anchoring design in writing and keep it with your records.

What to ask an installer or contractor

• Which document are you following for the foundation and tie-downs, and can I have a copy?
• Are you licensed for this work? For a HUD home, ask for the Tennessee installer license number (see how to check a license).
• Who pulls the permit, and who schedules inspections?
• For a container: who designed the corner connections and welds, and is the design sealed by a Tennessee engineer?
• What will you check and redo if the home is already set: blocking, anchors, straps, drainage?

For HUD-code manufactured homes, use our piers, footings and tie-downs checklist and the cost guide, then find a company in the directory.

Sources

• Tennessee State Fire Marshal's Office: currently adopted codes (2018 IRC, 2021 IBC)
• Tenn. Comp. R. & Regs. 0780-02-23-.02: 2018 IRC and Appendix Q adopted for one- and two-family dwellings
• Tennessee SFMO: residential permit FAQs (where the state permit applies, local enforcement, opt-outs)
• Tennessee SFMO: inspections in opt-out or non-code jurisdictions (T.C.A. § 68-120-101(b)(1)(D))
• 2018 IRC Appendix Q, Tiny Houses (model text as published; 400 sq ft definition, ceiling heights, lofts)
• Tennessee SFMO: Modular Building Program (Tennessee Modular Building Act, T.C.A. § 68-126-301)
• T.C.A. Title 68, Ch. 126, Part 3: Tennessee Modular Building Act
• Tenn. Comp. R. & Regs. 0780-02-13-.09: modular building systems and compliance assurance
• 24 CFR 3282.15: HUD exemption for recreational vehicles (NFPA 1192 / ANSI A119.5)
• HUD final rule (Nov. 16, 2018) clarifying the RV exemption
• RV Industry Association: what is an RV / park model RV
• 2021 IBC Section 3115, Intermodal Shipping Containers (excerpt as published by a local jurisdiction)
• ICC G5-2019: guideline for ISO shipping containers repurposed as buildings
• T.C.A. § 68-126-403: manufactured home installation standards
• 24 CFR 3285: HUD Model Manufactured Home Installation Standards