A hillside lot decides more about an addition than the house does. Much of the housing in Bountiful steps down with the grade, whether as a split-level, a daylight basement, or living space set above a tuck-under garage, so a room added at the back may sit several feet below the floor it connects to or need a foundation that steps to reach solid bearing. We connect Davis County homeowners with general contractors who plan additions and structural changes around the grade instead of in spite of it.
On a level lot, an addition meets the house at one floor level and one foundation depth. On a hillside, neither is a given. The floor you are extending may sit well above finished grade at the back of the house and close to grade at the front, so the new foundation has to step and the connection between old and new becomes a decision: match the existing floor level and build the ground up to it, follow the grade and accept a step down at the doorway, or split the difference with a short run of stairs that becomes part of the plan.
Each choice moves cost and complexity somewhere different. Matching floor levels on the downhill side means a taller foundation wall with more excavation and backfill behind it. Following the grade produces a lower, simpler structure but leaves a level change to resolve where the two spaces meet. The version that tends to work is the one that respects how the house already steps rather than fighting it, which is why the grade should be measured and discussed before anyone draws a room.
Split-level houses concentrate their structure around the stairs. The half-flight between levels sits in the middle of the plan, bearing walls tend to run alongside it, and the landings tie the floor systems together. That makes opening up a split-level a different problem from opening up a single-level ranch. Removing a wall near the stair can affect two floor levels at once, and moving the stair itself is a structural project rather than a layout change, with consequences for framing above and below it.
It is still very much doable, and the common moves are well understood: widening the opening between the entry level and the main living level, reworking a landing so the two levels read as one space, or gaining ceiling height on the lower level where the framing allows. Each starts by identifying what carries load at that point and what beam and posts would replace it. Utah homes commonly have basements, and the path those posts take down to bearing is part of the same conversation.
Water moves downhill and so does everything else, so the parts of a hillside addition you never see take a disproportionate share of the attention. New foundation work has to reach undisturbed bearing soil, which on a slope can be considerably deeper on one side than the other. Backfill has to be placed and compacted in lifts rather than pushed back into the hole. Where the new structure holds back grade, a retaining element becomes part of the design and gets engineered rather than assembled by eye.
Drainage is the other half of it. Adding a footprint changes where roof water lands and where surface water travels, and on a lot that steps downhill that change reaches your neighbors as well as your own foundation. Roof drainage, foundation drains, and finished grade get planned together instead of separately. Requirements for excavation, retaining, and drainage on this kind of lot are set by the city, and your contractor confirms them with the local building department before work begins. If you are looking at an addition on sloped ground, call 801-644-9000 and we will find you contractors who build on it regularly.
Usually. Most split-level additions attach to a single level and connect through an existing opening or a new one in a wall that can be modified. The stair becomes a structural project only when you want to move it, change its direction, or open up the space it occupies. Your contractor should be able to tell you at the walkthrough which of those you are actually asking for, because they are very different scopes.
Depth, mostly, and everything that follows from depth. The footing has to reach suitable bearing soil, which sits lower on the downhill side, so the foundation wall is taller and there is more excavation and backfill than the same room would need on flat ground. It also raises retaining and drainage questions. None of this is unusual here, but it should be priced from a real look at the grade.
Sometimes, and the answer is under the garage rather than in it. A garage built into the slope with foundation walls and footings may support a level above with reinforcement, while a slab-on-grade garage often needs foundation work first. The existing walls, the header over the garage door, and the load path down to bearing all get evaluated before this is designed. It is a structural question before it is a framing one.
Describe the house and what you are planning, or call 801-644-9000.
