Like many Americans, we have an aging parent from the Baby Boomer generation who is now in need of care. We’ve looked at options to keep her close by so we can provide care, ideally in our home or backyard.
Accessory Dwelling Units (ADUs) have been gaining popularity as a solution to our growing housing shortage, and sometimes ‘tiny homes’ fall into that category.
Understanding Tiny Home & ADU Regulations
A growing number of states have statewide initiatives allowing ADUs — Massachusetts and Colorado are among the most recent additions. Often, states with very high housing costs have enacted these regulations to increase housing supply and improve affordability.
Pennsylvania and Maryland, by contrast, have stringent zoning limitations, making it challenging to place small dwellings, either as an ADU or as a stand-alone residence on your land. Neither state has statewide regulations specifically governing ADUs — instead, regulations are determined at the local level, meaning each municipality or county has its own zoning codes governing ADUs. For those willing to do the work, however, there are some pockets of deregulation and some creative strategies for getting ADUs approved.
Types of ADUs
1. Attached. Some municipalities permit an ADU only inside the existing structure — an independent living unit built in a basement, garage, or other part of the existing house. Often the most cost-effective strategy is converting a large master suite into a small studio apartment.
2. Detached. These are secondary, smaller housing units on a property with a primary residence — often a detached garage converted into an ADU, or a ‘tiny home’ placed in the back yard. If you have an aging family member you’d like to keep close by, look into an ‘ECHO housing’ option if it’s available in your zoning — a form of detached ADU meant to house family for a limited time, usually requiring the structure to be ‘temporary’ (like a mobile home) and occupied by a senior family member.
Types of Tiny Homes
If you have extra land and would like to place a tiny home, what does that mean legally, and is it permitted? One of the primary considerations for tiny homeowners in Pennsylvania is compliance with the Pennsylvania Uniform Construction Code (UCC), which applies to permanent homes but may not always cover mobile tiny homes. Understanding the classification of your tiny home is the first step in determining the applicable regulations.
1. Park Model Homes
These are tiny homes under 400 square feet, built on a trailer chassis designed to be towed. Under code, they’re considered RVs or temporary structures, and can be certified by ANSI A119.5, a standard for park model recreational vehicles developed by the Recreational Vehicle Industry Association. When placing this type of home, the certification is presented to the code/building inspection official to confirm it conforms to code and is safe for occupancy. Most zoning restricts them from ‘permanent occupancy,’ limiting them to recreational or occasional use. Many of these models are built with a sleeping loft, which won’t conform to UCC standards even if the home otherwise meets code requirements. Ownership is transferred via a vehicle title, not a deed, and real estate taxes are assessed on ‘personal property,’ similar to a mobile home.
2. Manufactured Homes
Manufactured homes, commonly known as mobile or trailer homes, are constructed under the federal Manufactured Home Construction and Safety Standards, known as the ‘HUD Code,’ and are commonly around 700–1,200 square feet. After installation, the HUD-licensed installer must provide a completed HUD Form 309 to the purchaser and retailer, keep a copy, and provide a copy to the local code official in order to receive a certificate of occupancy. Like park models, mobile homes transfer with a vehicle title, not a deed, with taxes assessed on personal property rather than real estate.
3. Modular Homes
Built in a factory by licensed builders and brought to the site, modular homes are assembled on a permanent foundation and must be built to UCC standards like traditional stick-built homes. These homes are fixed to the ground and become deeded real estate, with real estate taxes affixed.
A backyard ADU can take the form of any of the above, provided the zoning on your land permits it. The first step is determining what type of ADU you’re proposing and the associated code classification it will fall under. Tip: don’t call the zoning officer and ask if you can put a ‘tiny home’ in your backyard — that’s not a legal term, and they won’t know what classification to apply, which typically leads to a ‘no.’ Understand the classification first, and make sure you communicate which code will apply to your unit.
Steps to Getting Approved by Zoning
1. Research Local Zoning Laws. If you’re searching for areas to place or create ADUs, you’ll need to check with each township or county on their specific rules. While ADUs may be listed as permitted under many residential zonings, watch out for common restrictions:
- Minimum/maximum square footage requirements
- No secondary living structures permitted
- Setback requirements, impervious area limits, and lot sizes for secondary structures
- Parking requirements — many require an additional parking space
- Restrictions on who can reside there — many municipalities restrict ADUs to only family members or caretakers for family
Tip: some county planning commissions keep a running list of which municipalities allow ADUs. The detail on these lists varies, but it can be a good starting point — Lancaster County was one of the most comprehensive we found. While many townships restrict ADUs to family members only, a few municipalities within Lancaster County permit non-family occupied ADUs, opening the door for them to become rental units.
2. Meet Building Code Requirements. If placing a secondary detached structure for an ADU, that structure will either be temporary (like a park model RV) or permanent, built on a foundation like a modular home. Mobile homes are a mix of the two classifications — considered appropriate for permanent housing, but placed on a ‘temporary’ foundation.
Many builders looking for a small modular home in the 600 square foot range find that most modular home sizes start around 900 square feet or more. Some municipalities have minimum dwelling sizes starting at 700 square feet, which pushes many modular builders toward larger models — tiny homes are still a small portion of the market, which limits the options available. Whether stick-built or modular, the ADU will need to conform to the UCC and provide for basic health and safety.
Tip: if you’re struggling to get a detached unit approved in your zoning, research whether a detached building for other purposes might work instead — a game room, finished shed, office, or similar designation may provide the space you need under a different classification.
3. Apply for Necessary Permits. Once you confirm your ADU meets local zoning and building requirements, apply for the appropriate permits, which may include a zoning permit, building permit, and occupancy permit. Permit fees and processing times vary by municipality, so check with the local planning department.
Additional Considerations
Financing: Temporary structures like park model RVs and mobile homes may be financed like an RV, with options potentially more limited than traditional real estate financing. Permanent structures, whether detached or attached, may be paid for using a home equity line of credit, a refinance, or an ‘as-built’ financing loan. Since ADUs are still a relatively new concept in this region, many appraisals may not give full value to the ADU once completed — appraisals will often credit only about 75% of the actual cost, so be careful not to overspend.
Taxes: Keep in mind that if a building or occupancy permit is issued, it will likely result in higher taxes, either as personal property tax or real estate tax.
Homeowners Associations (HOAs): Even if permitted under your zoning, an HOA may have additional restrictions — make sure you check these before proceeding.
Conclusion
Getting an ADU approved in our region requires careful planning, research, and compliance with local zoning laws. While there’s no uniform statewide policy, understanding your municipality’s requirements and parameters can provide a successful solution for astute real estate investors.
As the need for affordable housing continues to grow, we encourage you to be an advocate at your local level to help make this practical solution more attainable. Many seniors will also benefit from more options that let them live close to their families — a benefit that reaches families just like ours.
Many of our clients successfully utilize unique strategies to create wealth that carries through the generations and leaves a legacy for their community and families. Call us today for expert insight into growing your success.
