Reading the actual guideline text below — never a general AI guess

Here's what we mean by an unpermitted garage conversion: When someone converts a garage into living space without following the legal building process, we can only count that converted area as part of the home's finished square footage if three conditions are met—the space connects to the main house through an interior doorway, it has permanent heating, and it matches the style and quality of the rest of the home. FHA guidance makes clear that conversions do get treated the same way as room additions for appraisal purposes, but only when those three requirements are satisfied. The passages shown here don't address whether a conversion that was done without permits can actually meet those standards or how we handle it in practice.

Straight from HUD/FHA Single Family Handbook 4000.1 — nothing added.

UAD 3.6 adoption and FHA guidance on garage conversions

FHA HB 4000.1 (pages 499–500) provides current guidance on treatment of garage conversions in appraisals, with criteria for counting converted space as GLA that do not explicitly require permits—relevant to understanding when to include or exclude unpermitted conversions.

Permitted vs. Unpermitted Garage Conversions: ROI Data for 2026

This source discusses that permitted garage conversions typically increase home value by 10-30% with ROI of 60-80%, while unpermitted conversions can decrease value by triggering lender refusals and appraisal exclusions.