Inspiration
Overview
- Clarify what you want
- Find inspiration
- Estimate project cost
Getting inspired for your ADU project is what many feel is “the fun part” – you’ll think about your goals and the value an ADU will bring, look for design and layout inspiration, and start to figure out what will work on your property.
Project Timeline
Getting inspired is part of the Planning phase, which typically takes 1-3 months. Most ADU projects take 12-18 months to complete, but some extend to 24 months or more.
FAQs
Do I need to tell my neighbors?
You’re not required to tell your neighbors about your ADU, but it’s always a good idea to communicate with them early in the process. Your project will run more smoothly if they are kept informed, and they may have great ideas for your project!
If you live in a Neighborhood or Homeowners Association, talk with your representative or board early in the process. HOAs or subdivision deeds can explicitly restrict ADUs, rentals, multi-dwelling units, and similar uses.
What’s the difference between a site-built and a prefabricated or manufactured ADU?
There are two types of construction to consider and both have pros and cons, so think about the level of customization you want and how the ADU will work on your property.
Site-built ADUs
Traditionally constructed and built from scratch on your property (AKA “stick-built”), which often slows for a lot of customization and smaller changes throughout construction.
Typical benefits:
- More options for customization
- Can be easier to get financing and permits
- Can be easier to place on unique properties (steep slopes, rocky terrain, small spaces)
- Can typically be paid for phase-by-phase
Prefab, modular, and panelized ADUs
Built in a factory, then shipped to your site and assembled or placed on a foundation. Some companies provide “turnkey” service with support through the entire process (permitting, construction, etc.). If not, you’ll need to hire other professionals to help.
Prefab ADUs are categorized based on how they are built and inspected.
- Partially-fabricated (panelized, framing kits) Parts of the ADU are built off site at a factory, and construction follows a traditional site-built pattern. Local inspectors check work at different stages and a local general contractor and their crew are responsible for putting all the pieces together and passing inspections.
- Prefabricated (modular, manufactured, factory-built) The ADU is built and inspected for building code off site at a factory, then delivered and put in place on your property by a crane or tow. Local inspectors only check work like foundation and utility hook-ups. These types are all built similarly but are called different things based on what building code they meet (state, federal, etc.).
It’s important to note that prefab ADUs may cost the same as site-built ADUs – transportation, crane, foundation, and sales tax can end up being 20-40% of the total cost. When you get in touch with prefab companies, be sure to ask what is included in the price. Some companies do offer a lower price point.
Typical benefits:
- Lower design and engineering costs
- More clarity on what you’ll get in the end
- Faster construction with less on-site disruption
- Quality inspections from the start
- Fewer permits and inspections
Getting Inspired, Step-by-Step
Before you begin Make sure you understand the types of ADUs and the other content covered in our ADU 101 and that you’ve done research about what you can build on the ADU Rules page. You may also want to check out our Glossary to make sure you understand key terms.
Step 1
Think About What You Want
Ask yourself:
- Who will live in the ADU now? In 10 years?
- What features are must-haves (e.g., laundry, ADA access)?
- How much privacy do you need between units?
Sources of Inspiration:
- Browse our Maine ADU floorplans gallery
- See real stories from Maine homeowners
- Use our design checklist to sketch ideas
Keep in mind your plans might change once you hire a professional. It’s also a good idea to talk with your neighbors about your project, and to think about what it means to share space with tenants (and if that impacts your design and layout).
Step 2
Consider Different Types of Plans
There are multiple kinds of ADUs and ADU plans for you to consider:
Site-Built vs. Prefab, Modular, Factory-Built
There are two types of construction to consider and both have pros and cons, so think about the level of customization you want and how the ADU will work on your property.
Site-built ADUs
Traditionally constructed and built from scratch on your property (AKA “stick-built”), which often slows for a lot of customization and smaller changes throughout construction.
Typical benefits:
- More options for customization
- Can be easier to get financing and permits
- Can be easier to place on unique properties (steep slopes, rocky terrain, small spaces)
- Can typically be paid for phase-by-phase
Prefab, modular, and panelized ADUs
Built in a factory, then shipped to your site and assembled or placed on a foundation. Some companies provide “turnkey” service with support through the entire process (permitting, construction, etc.). If not, you’ll need to hire other professionals to help.
Prefab ADUs are categorized based on how they are built and inspected.
- Partially-fabricated (panelized, framing kits) Parts of the ADU are built off site at a factory, and construction follows a traditional site-built pattern. Local inspectors check work at different stages and a local general contractor and their crew are responsible for putting all the pieces together and passing inspections.
- Prefabricated (modular, manufactured, factory-built) The ADU is built and inspected for building code off site at a factory, then delivered and put in place on your property by a crane or tow. Local inspectors only check work like foundation and utility hook-ups. These types are all built similarly but are called different things based on what building code they meet (state, federal, etc.).
It’s important to note that prefab ADUs may cost the same as site-built ADUs – transportation, crane, foundation, and sales tax can end up being 20-40% of the total cost. When you get in touch with prefab companies, be sure to ask what is included in the price. Some companies do offer a lower price point.
Typical benefits:
- Lower design and engineering costs
- More clarity on what you’ll get in the end
- Faster construction with less on-site disruption
- Quality inspections from the start
- Fewer permits and inspections
Pre-Designed Plans
Instead of starting from scratch with a totally custom plan, you may be able to save significant time and money by using or purchasing a design that already exists and customize the design from there. Check with local staff if they know of any options, or do research to see if any local architects/designers offer pre-designed plans.
Pre-Approved Plans
More and more cities and communities are adopting “pre-approved” ADU plans that allow you to get through permitting more quickly with an existing design that’s already been reviewed for compliance. Note that pre-approved designs typically don’t allow much customization and still require additional permitting for your specific site and location.
While few Maine towns currently offer pre-approved plans, GPCOG is working to expand these options in the future. Some Maine municipalities, such as Portland and Brunswick, have expressed interest in developing pre-approved plans, but most do not yet offer these. Homeowners are encouraged to work with local architects or design/build firms familiar with local zoning and permitting requirements.
Step 3
Make an Informal Sketch
Make a rough sketch of your property, including the existing home, any other structures, and space for a possible ADU. Eventually you’ll have a professional produce a more detailed version, but it can be helpful to start with a rough sketch. Start with the info you learned about your property during the ADU Rules phase (LINK). If possible, use graph paper to make a roughly to-scale version.
Make sure you include:
- Property lines
- Driveway
- Building footprints
- Trees
- Other significant features like pools, steep slopes, etc.
This sketch can help you understand what space you have available to work with and what areas will be easily accessible to construction equipment – which can significantly reduce your construction costs.
Ready to ADU?
Navigate project phases using this section on each page.
Looking for inspiration?
Check out these resources for help.
Floorplans Inspiration
