Manufactured Home Foundation Certification and Design
Manufactured home foundation certification for lenders, plus engineered piers, anchors and modular home foundations sealed by a licensed PE.
- Stamped by a PE licensed in your state
- Built to IBC, IRC and local amendments
- Plan-check comments answered
Foundations, anchorage and letters for factory-built homes
Manufactured and modular homes are built in a factory, but the foundation and site work happen locally, and that is where most permit and financing questions come up. A county wants a plot plan and pier layout before it issues an installation permit. A lender wants a manufactured home foundation certification before it will close an FHA or conventional loan. A sloped lot, flood zone or tall crawlspace takes the installation outside what the manufacturer’s instructions cover.
PE Engineer designs and certifies foundations for manufactured homes built to the federal HUD Code and for modular homes built to state and local building codes. We design pier and anchor systems, perimeter foundations, slabs and engineered alternatives, and we prepare the sealed permanent foundation letters that lenders and appraisers ask for. We also prepare the plot plans and grading and drainage plans many counties require for the installation permit.
Every design and letter is sealed by a Professional Engineer licensed in the state where the home is located. Dealers, installers, contractors and homeowners can all order directly, with a fixed-fee quote usually returned the same day.
What you receive
- Pier, footing and anchor layout
- Perimeter foundation or slab design
- Permanent foundation certification letter
- Plot plan with setbacks and pad elevation
- Grading and drainage details
- PE stamped drawings and calculations
Manufactured and modular home services
We support every stage of a factory-built home installation, from the first permit sheet to the lender's final letter.
Permanent foundation certification
Sealed letters confirming the foundation meets the HUD Permanent Foundations Guide for Manufactured Housing and lender requirements for FHA, VA or conventional financing as real property.
Pier and anchor system design
Pier spacing, footing sizes, ground anchors and stabilizing straps for wind zone, soil and frost conditions where the manufacturer's installation instructions do not fully apply.
Perimeter and slab foundations
Concrete or masonry perimeter walls, crawlspace foundations and slabs that give a manufactured home a permanent foundation and a finished, site-built appearance.
Modular home foundations
Basement, crawlspace and slab foundations for modular homes, designed to the IRC and the modular manufacturer's support points, marriage line loads and set requirements.
Plot plans and site grading
Plot plans showing setbacks, home footprint, driveway and utilities, with pad elevations and drainage that keep water away from the home and its foundation.
Additions and attached structures
Decks, porches, carports and garages next to manufactured homes, designed to be self-supporting or properly connected without overloading the home's frame.
Your Stamped, Permit-Ready Plans Start With One Upload
Send your drawings or describe the project. A licensed engineer reviews it and sends a clear, fixed-fee proposal, often within hours.
- Free and no obligation
- Reviewed by a licensed PE
- Secure file upload
HUD Code homes, modular homes and the rules for each
The type of home determines which rules apply to its foundation. Manufactured homes are built on a permanent steel chassis to the federal Manufactured Home Construction and Safety Standards in 24 CFR Part 3280, often called the HUD Code. Their installation is governed by the Model Manufactured Home Installation Standards in 24 CFR Part 3285, or by a state installation program that meets or exceeds them, along with the manufacturer’s installation instructions.
Modular homes are different. They are built in sections to the same state or local building code that applies to site-built homes, usually based on the International Residential Code, and are set on a conventional foundation. A modular home’s foundation is designed like any other house foundation, using the manufacturer’s support locations and loads.
Key factors for manufactured home installations include:
- Wind zone, based on the HUD wind zone map, which affects anchorage and the home’s design.
- Roof load zone and local ground snow load.
- Soil classification and bearing capacity, often confirmed with a torque probe test for anchor selection.
- Frost depth, which sets how deep footings must go unless a frost-protected design is used.
- Flood zone, where the home must be elevated and anchored against flotation.
We identify which rules apply at the start so the foundation, anchorage and paperwork all line up.
Manufactured home foundation certification for financing
Manufactured homes are often financed as real property rather than personal property, and lenders require proof that the home sits on a permanent foundation. For FHA-insured loans, the foundation must comply with HUD’s Permanent Foundations Guide for Manufactured Housing, and a licensed professional engineer or registered architect must certify that it does. VA and many conventional lenders have similar requirements, and appraisers often ask for the certification before an appraisal can be completed.
A permanent foundation generally means the home is supported on footings or a slab below frost depth, connected to the foundation with anchorage that resists wind, seismic and uplift forces, and enclosed with a perimeter that is appropriate for the site. Ground anchors with straps alone may or may not qualify, depending on the guide’s provisions and the lender.
For a new installation, we design the foundation to meet the guide from the start and issue the certification once it is built as designed. For an existing home, the certification is based on an inspection of the foundation, piers, anchorage and perimeter. We arrange that inspection through a local licensed engineer in your area, and if the foundation falls short, we design the upgrades needed to qualify, such as additional anchorage, new footings or a perimeter wall.
The letter is sealed by a PE licensed in your state and written to the format lenders expect. For other types of engineering letters, see our engineering letters and certifications service.
Have a Question? Get a Real Engineer's Answer in Minutes
Skip the guesswork. Chat live with a licensed engineer about your drawings, code requirements or permit comments, free and with no obligation.
- Free and no obligation
- Reviewed by a licensed PE
- Secure file upload
Engineered piers, anchors and perimeter foundations
Most manufactured home installations follow the manufacturer’s installation instructions, which provide pier spacing, footing sizes and anchor requirements for typical conditions. The federal installation standards allow designs prepared by a registered professional engineer or architect where a site is not covered by those instructions. Common reasons a design is required include:
- Pier heights above the limits in the manufacturer’s tables, common on sloped lots.
- Soil with low bearing capacity, expansive clay or fill.
- Flood zones, where the home must be elevated and the foundation and anchorage must resist flood forces.
- Heavy snow areas or high wind zones where standard tables do not apply.
- Basements, garages or other conditions the instructions do not address.
Our designs show pier locations under the chassis beams and marriage line, footing sizes, anchor types and spacing, and the connections between the home and foundation. Where a perimeter foundation is used, we design the wall, footings and any vents and access openings, and coordinate whether the perimeter is load-bearing or a non-structural skirting enclosure.
For multi-section homes, marriage line piers carry significant concentrated loads at openings in the mating wall, so we use the manufacturer’s data sheets to place piers where the home actually needs them. For modular homes, our foundation design team designs basements and crawlspaces to the IRC.
Plot plans, grading and installation permits
Many counties require a plot plan before they issue a manufactured home installation permit. The plan typically shows property lines and setbacks, the home’s footprint and orientation, driveway and parking, utility connections, septic or sewer location, and the finished pad elevation. In some areas, especially where drainage or flood issues are common, the county also requires a grading and drainage plan with spot elevations and slopes.
Drainage matters for the foundation as much as for the permit. Federal installation standards require the site to be graded so water drains away from the home, and water ponding under a manufactured home can weaken pier footings, raise humidity and damage the floor system over time. We set the pad elevation and grades so water moves away from the home and off the lot in a controlled way. Our grading and drainage plans service covers sites that need more detailed design.
We work with dealers, installers and land developers on single homes and multi-lot projects. Send the home’s make, model and data plate information, the installation manual or foundation plan from the manufacturer, the parcel address and any survey. Most residential packages are delivered within a few business days, and if the county issues comments, we respond and revise within the original scope at no extra charge.
You likely need this if
- Your lender requires a foundation certification
- The county asked for a plot plan or pier layout
- Piers exceed the manufacturer's height tables
- The home is in a flood zone or high wind zone
- You are setting a modular home on a basement
- You are adding a deck, porch or garage to the home
How it works, start to finish
From your first message to stamped drawings, you work directly with the engineering team.
- 1Share your projectSend the address, scope and any drawings, photos or plan-check comments. Two minutes is enough.
- 2Receive a fixed-fee proposalAn engineer reviews the scope and replies with a firm price and delivery date for your manufactured & modular home foundations drawings.
- 3Engineering and draftingWe run the calculations and prepare drawings to the codes your jurisdiction enforces, checked before sealing.
- 4Stamped set deliveredYou receive a sealed PDF set ready to submit, and we answer any plan-check comments within scope.
Codes and standards we design to
Manufactured and modular home foundations follow federal standards, state programs and the codes your jurisdiction has adopted:
- HUD Manufactured Home Construction and Safety Standards, 24 CFR Part 3280
- HUD Model Manufactured Home Installation Standards, 24 CFR Part 3285, and state installation programs
- HUD Permanent Foundations Guide for Manufactured Housing
- International Residential Code (IRC) for modular homes and site-built additions
- ACI 318 and local code provisions for concrete footings and walls
- FEMA and local floodplain requirements in flood zones
How licensing works. Engineering drawings must be sealed by a Professional Engineer licensed in the state where your project is located. PE Engineer works with a network of state-licensed PEs, so every set is reviewed and stamped by an engineer with an active license in the state where your project is located. Their name and license number appear on the seal, exactly as your building department requires.
Related services
Grading & Drainage PlansEngineered grading and drainage plans for new homes, additions, ADUs, manufactured homes and commercial pads, prepared to local ordinances and PE stamped.Explore More
Engineer Letters & CertificationsSealed letters for lenders, building departments and installers: manufactured home foundations, solar roofs, wind and snow loads, beams and changes of use.Explore More
Foundation DesignFootings, slabs, stem walls, piers and pile foundations designed and PE stamped for your soil, loads and local code.Explore MoreFrequently asked questions
What is a manufactured home foundation certification?
It is a letter sealed by a licensed professional engineer stating that a manufactured home’s foundation meets the requirements of the HUD Permanent Foundations Guide for Manufactured Housing, or other lender criteria. FHA-insured loans require it, and many conventional and VA lenders and appraisers ask for it before closing.
Can you certify an existing manufactured home foundation?
Yes. The certification for an existing home is based on an inspection of the piers, footings, anchorage and perimeter, which we arrange through a local licensed engineer. If the foundation meets the guide, we issue the letter. If not, we design the upgrades needed and certify once they are completed.
Do tie-downs and ground anchors count as a permanent foundation?
Sometimes, depending on the system and the lender. Some engineered anchoring systems are designed to meet the Permanent Foundations Guide, while basic ground anchors with straps may not satisfy every lender. We review your system and tell you whether it qualifies or what is needed to qualify.
What is the difference between a manufactured home and a modular home?
A manufactured home is built to the federal HUD Code on a permanent steel chassis. A modular home is built to the state or local building code that applies to site-built homes and is set on a conventional foundation. The foundation requirements and permitting paths are different for each.
When do I need an engineered pier design?
When site conditions fall outside the manufacturer’s installation instructions, such as tall piers on a sloped lot, weak or expansive soil, flood zones or high snow and wind loads. The federal installation standards allow a registered engineer’s design in those cases, and many counties require it.
What do you need to get started?
The home’s make, model, year and serial or data plate information, the manufacturer’s installation manual or foundation drawings, the property address, the lender’s requirements if you are financing, and photos of the site or existing foundation. A survey or plot sketch helps for plot plans and grading.
Get your free manufactured & modular home foundations proposal
Tell us where the project is and what you need. Attach any drawings, photos or plan-check comments. A licensed engineer reviews every request.
- Upload your filesPlans, sketches, photos or comments
- Get a fixed-fee proposalUsually the same day
- Receive stamped drawingsSealed by a PE licensed in your state