The intent of this page is to lay out the different options homeowners have for expanding living space on their pre-existing homes. These options include building up (e.g. adding a living space above a garage), building down (converting existing basement space into a living space), building a new attached structure (e.g. an additional wing), or bringing in a modular tiny house. While the topic of accessory dwelling units (ADUs) have been brought up in public meetings, there hasn't been a formal discussion about introducing them to the new zoning code. Therefore we delay the publication of this page on additions (and ADUs)
Notes from meeting with Greg McCall (12/13/2018)
What are questions you should ask before you consider building an addition to your house?
1. Identify your need
What purpose is the new space trying to serve?
2. Can the cost of the improvement be absorbed by the value of the house?
Homeowners will usually have to finance the cost of the improvement by taking out a HELOC. Is there enough equity built into the house to finance the cost of the improvement? Once an addition is built, will the cost of the improvement be covered by appreciation on the housing value?
3. Site feasibility
Are there structural constraints to building an addition? Can public and private utility lines be connected to the new structure? What about the grade of the site? Is there enough space for construction equipment to come through the site? What about insulation for the new structure? Will the current heating system be able to handle it or would you need to introduce a whole new heating system?
If you are building an additional wing to your house you will need to connect the new structure to the existing foundation of the house. Is this feasible?
4. Asbestos and Lead Paint
In older homes, asbestos and lead paint will need to be addressed. While asbestos removal may not be as costly, lead paint removal will be quite costly.
Weighing the options
1. Building down
If you already have an unfinished basement space, then converting it to a finished living space is probably most cost-effective
2. Building up (e.g. adding a living space above a garage)
Here there is no need to worry about connecting the new structure to the foundation of the house. You need to make sure though that the load of the new structure can be handled by the foundation. Almost always the foundation will be able to handle the new load (unless the foundation is in a very bad condition)
3. Adding a wing
More expensive to do than building down or up because the new structure can be connected to the foundation, new exterior walls and roofs have be constructed.
4. Bringing in a modular tiny house to your backyard
Building off-site rather than on-site is less expensive. Bringing in a new modular house may be one of the more cost-effective way of expanding living space. Check out dweller.com