Foundation Certification Letter
Lender, insurer, or building department asking for engineering documentation on your unit and its foundation? Get a PE-sealed certification letter — one flat fee, no subscription, no inspector visit to schedule.
Start Your Certification Letter — $495When You Might Need This
Most Boxabl homeowners never need this letter. But when you do, you need it fast.
Refinancing Your Home
Your lender needs foundation documentation before approving a refinance — and modular units are sometimes misfiled in the manufactured-home bucket, which costs you on rate. Our letter documents the foundation AND states plainly that your unit is not a HUD-code manufactured home.
Insurance Request
Your insurer is asking for engineering documentation of the foundation. This letter gives them exactly what they need, sealed by a licensed PE.
Selling Your Property
Buyers and their lenders want current engineering documentation of the foundation and anchorage. A PE-sealed letter removes objections and speeds up closing.
Code Compliance Review
Your jurisdiction is requesting updated structural documentation. A PE-stamped letter demonstrates compliance with current building codes.
Investor Due Diligence
Investors acquiring Boxabl properties need third-party engineering documentation. This letter satisfies due diligence requirements.
Peace of Mind
You just want a professional engineer to confirm everything is in order. One letter, one fee, done.
What's Included
One flat fee. Everything you need in one letter.
How It Works
Three steps. Typically 1\u20132 business days after your photos are in.
Start Online & Take Guided Photos
Open your case at box.engineerletters.co, then walk your unit with your phone — the app shows you exactly what to photograph, shot by shot (about 35 minutes on site). You will also upload your approved plan set; it is what the engineer certifies against.
Licensed PE Review
A licensed Professional Engineer reviews every photo against your approved plan set and the manufacturer’s installation manual. If a shot needs another try, the app reopens just that item.
Receive Your Sealed Letter
Your PE-sealed certification letter is delivered by email with a durable download link, typically 1–2 business days after your photos are in — ready to forward to your lender, insurer, buyer, or building department.
Foundation & Installation Certification Letter
One-time fee — no subscription, no recurring charges
Common Questions
Is this a subscription?
No. You pay once, you get your letter. If you need another letter in the future (for a new transaction or a different reason), you can order one then. There are no recurring charges.
Do I need this if I just had my foundation built?
Probably not. Your original PE-stamped foundation plans typically satisfy lenders and insurers for the first few years. This service is for when someone specifically asks for updated or current documentation.
What if my original foundation was engineered by someone else?
That works. The letter certifies your as-built installation against the approved plan set on file with your building department, regardless of who designed it. You upload that plan set during the guided photo session \u2014 it is the one document we cannot proceed without.
Does this work for non-Boxabl homes too?
Yes \u2014 with the right letter for the right home. Modular and factory-built units order at box.engineerletters.co. HUD-code manufactured and mobile homes are a different product with different federal requirements: see manufactured home certifications.
Explore Our Other Services
Need a new foundation design or wondering if your lot is suitable? We can help with that too.