Building on a Hillside? Here’s Where to Start
“How you do anything, is how you do everything”
Every site has its challenges, but some more than others. I won’t sugarcoat it: regular construction is tough, but hillsides are even more challenging! If you’re building a custom home on a hillside, expect there to be more work and the price to be more than you expect.
My most recent hillside custom home project was one I did this year (2024); it was a new construction home. I remember getting the call from Diana and how excited she was to build her house.
“I just bought this property and have a baby on the way. I want to have a bigger home for our growing family,” Diana had told me over the phone, her voice elated as she spoke about the project.
“That's amazing news! Congratulations! What’s your address? I’d love to look into it,” I said, waiting for her to give me the details of her custom home. Then, while we continued to chat, I got to work!
1: Contact a Professional to Assess Your Lot and Learn What You Need
Once I saw that the property was on a hillside, I paused. These are not easy custom home projects, so our conversation turned serious.
“It seems like you’re on a hillside,” I told her, changing the subject from other custom home design elements she was interested in. She went quiet.
“What does that mean for me?” She asked. I sighed, knowing exactly what we would have to talk about next. Diana was not my first hillside custom home build.
“It means you should take a deep breath before I break down what we need,” I said. Diana took a deep breath, and then she spoke again.
“Should I be worried?” Her question is one that many of my clients ask, but as with Diana’s, you should not be worried at all!
Regular sites have their ups and downs, depending on what zone you’re in. You may have to create separate plans. However, regardless of what you’re looking at with your custom home design, hillsides require everyone to be hands-on.
The reason for this is that hillsides are treated a lot more strictly by the city. The only time it does not matter is if you're doing a remodel. Other times, you have to do a lot of preliminary work. A survey is always the first step when working on a hillside.
2: Conduct a Survey of Your Property
With a survey, you’ll gather a lot of insight about your lot and what you might need to do. Here are some of the questions you’ll get answers to with a proper survey:
What’s the height of the hill?
Are there any protected trees?
A survey is a drawing made by a surveyor or civil engineer. This drawing would create a topographic map of the hill showing the different elevations and how steep the slope is. Using this plan, we can plot how to best lay out the home and/or addition. Fortunately, Diana was quick to get hers completed in a matter of days!
“I have my survey! What’s the next step?” She asked me. I smiled. This was when the fun truly began!
“Now the fun stuff can happen!” I told her, already envisioning what to do for the floor plan.
3: Draw Up the Floor Plans and Experiment with Custom Home Ideas
The next step with a hillside lot like Diana’s is to begin drawing floor plans & tossing around ideas until we have a design we love! It didn’t take long for us to find something we both adored.
“The design is great, and I love everything we’ve done. Now that we have a plan, we can send this over to other consultants that we will need,” I told Diana. She agreed, and I contacted the other consultants to get the project to the next step.
4: Contact a Soil Engineer to Understand How Deep You Need to Dig
Once a design is ready, you can start talking to a soil engineer or geologist to prepare a soil report. This report will let us know how deep we need to dig for our foundation and how much shrinkage or bulkage our next consultant would need to know to complete their plans.
Next, we’ll get grading plans. These plans can be prepared by a civil engineer to show us how much we are excavating. We want to know our exact cubic yards to make sure we are excavating less than 1,000 cubic yards (our shrinkage and bulkage numbers from the soil report act as a multiplier against our cubic yards).
Our goal is to remove less than 1,000 cubic yards so that we can avoid doing a grading haul. A grading haul would take about one year to finalize before construction. We don’t want that happening!
After completing these plans, we just finished the major stuff. Now, we can start doing the standard plan stuff like getting a structural engineer and doing Title-24.
5: Confirm If You Need Shoring, a Sump Pump, or Erosion and Control Plans
The last step is to check the site's other characteristics. For instance, are we building too close to the property line or other buildings? If so, we’ll need shoring.
When foundation work is deep enough to potentially endanger a building and/or neighbor, we need to provide support. The support will mainly hold up the dirt so that it will not slide while the foundation is being built.
Another issue we’ll have to review is if we have a sump pump. If the property does, then we will need sump pump plans. These will be needed if our site is lower than the street level, making it harder for us to naturally drain the site. Also, if we have a basement, these will be required. Sump pumps will pump up any water up to the street to properly drain rainwater.
If our construction will occur during the rainy season, erosion and control plans will be needed! Out of all our plans, this one is the least technical. These plans will mainly be for how we will protect the construction site from having bad runoff to the street. When it rains, we want to make sure no harmful material from the construction site goes into the city sewer system.
We do not need to have these other plans ready to submit to the city for a building permit, but they will be required, so it is usually better to get them a little early.
Contact Us Today to Build Your Hillside Custom Home
With so many concerns for hillside lots, it pays to work with professional custom home designers and builders who know exactly what you need to create your dream home. If you’re eager to get your plans prepared so you can make a stunning custom house, contact us today. We can’t wait to help you build the property you envision!
