Structuring Your Remodel: Additions
Your location is perfect – close to work, school, hobbies, and family, but the house is just too small. Add a kid or two, or a family gathering and there is literally no space left. A lot of times, the next logical step is to add on. There are a handful of limitations to look in to depending on your property and jurisdiction. Some things to consider include: height limits, set-backs, easements, existing conditions (such as a septic tank, drain field, or gas line location), as well as whether or not you’re permitted to remove trees, or how much lot coverage is allowed. Moreover, you may find even more limitations if you’re part of a home owner’s association – this is definitely a case where doing your research ahead of time could pay off down the road. It’s important your design takes these items and more into consideration at the beginning of the project, or that there is a plan in place to be non-conforming, that will be acceptable to the jurisdiction.
Next I’ll dive into the structure of it all. There are several “directions” you can go with your addition. If there is space on your property, you can build out to the side. If there’s no place to go but up, you can consider jacking up the house to build a new level underneath, or tearing off the roof to add a second story.
Adjacent Additions
In a perfect world, your new addition to your home, on the same level as your home, will be completely self-supporting. With shear walls on all four sides, and a roof structure supported by its own new walls. When the purpose of your addition is to open up the space, however, extra walls aren’t necessarily available. Being sure the existing home can handle the load of the addition is the main issue in this case. Similar to our interior remodel criteria, when portions of your home are removed to make way for an addition, structure must be put back in place to accommodate the new configuration. In some cases, your addition is localized to one area, but other nearby areas of the existing house may need some retrofitting as well.
Second Story Additions
A second story addition brings new space to your home above your main living space. Often over a single level house, you’re essentially adding a whole new house on top. Your structure will be most efficient if you and your designer work together to align the structural elements between the two levels. Additionally, a survey ahead of time of the existing wall stud size and foundation will help your engineer determine how much additional load can be applied. Keep in mind your main floor will have a new chunk of space given up to your stairs, which may require some rearranging of the spaces.
Finally, today’s older homes don’t frequently have the spacious 9 foot ceilings that the newer homes have. You’re probably working with a 7.5 – 8 foot ceiling at most depending on the age of your home. There are some important things to consider when planning to raise the ceiling height of your existing house as a part of a second story addition. In order to properly resist wind loading, and transfer that load to your new second floor (and main floor), your wall studs must be full height. The process of raising the ceiling up involves replacing the wall studs with full height studs. At this point you’re basically tearing down the whole level of the house. Alternatively, a new full height stud can be “sistered” to each existing stud. The benefit of this method is that you can keep the exterior finishes intact, however all electrical and plumbing running through the wall would need to be removed and replaced as part of that process. Interior wall studs that are not load bearing may not be as big of an issue.
Building Below
Lastly, there is the option of jacking up your home and adding a new main floor below what will become your second floor. In a lot of areas, there are companies that specialize in doing the bulk of the work including preparing your house for and jacking up the house, placing support beneath it, and then lowering the house back down once the lower level has been constructed. The benefit is that you leave your existing home mostly in tact, and add the structure beneath to accommodate the upper floor.
To conclude, when space is the necessity, there are several angles to look at with your home. Doing your research on jurisdictional and HOA requirements is important to be sure your design and construction can flow smoothly through the permitting process. What would your dream addition look like?
Check out the entire Structuring Your Remodel series!
1 - Structuring Your Remodel - Interior, Kitchen & Bath
2 - Structuring Your Remodel - Exterior, Roof & Decks
3 - Structuring Your Remodel - Basements
Disclaimer: Although I am an engineer by profession, I am not YOUR engineer. All content and information in this post (and on this website) is for informational and educational purposes only, does not constitute professional advice and does not establish any kind of professional-client relationship by your use of this website. Refer to my full disclaimer for more information.