This case study describes a primary suite addition type we build in Northland KC-area suburbs — ranch homes from the 1960s–1970s that were built without primary suites and where the homeowner wants to stay in the school district but needs more space. The cost figures reflect KC market conditions in 2025–2026.
The house
A 1968 ranch in Liberty, MO, 1,350 square feet. Three bedrooms, one full bath, one half bath. No primary suite — the “master” was the front bedroom with slightly more square footage than the other two, sharing the one full bath.
The homeowners had two kids in the Liberty school district and were explicit: they were staying. The house needed a primary suite or the plan was to eventually move. Adding was substantially cheaper than transaction costs on a move, and the post-addition home value would support the investment in the Liberty market.
The setback assessment
Before any scope was finalized, we pulled the property survey and confirmed the applicable setback distances.
The lot: 80’ wide x 130’ deep. The rear setback in this Liberty zoning district: 25 feet. The house sat at 85 feet from the rear property line. Available build distance: 85’ - 25’ = 60 feet of rear yard depth before the setback.
The proposed addition: 20 feet deep off the rear of the house. At 20’ deep, the addition would sit 40’ from the rear property line — well within the 25’ setback requirement, with 15’ to spare.
Side setbacks: 7.5 feet each side. The existing house sat 12 feet from the east property line and 18 feet from the west. The addition was planned center-rear, not extending to either side, so no side setback issues.
Setback assessment time: approximately 45 minutes with the survey in hand. This is standard pre-scope work we do before quoting any addition.
The foundation
A 1968 ranch on a full basement — common in Liberty and across Northland where the freeze depth makes crawl spaces marginal and the flat lots support full basement excavation.
The addition’s foundation: poured concrete full basement to match the existing home. The homeowner wanted the basement addition space usable as an unfinished storage area, and the cost difference between a full basement and a slab-on-grade for this scope was approximately $6,000 — worth it for the additional usable footage in a Liberty basement.
Excavation, footing, and poured concrete foundation walls: $14,200.
The structural connection
Where a new addition connects to an existing structure, the wall opening and the transition framing are critical. In a 1968 ranch, the existing exterior wall that becomes the interior partition between the original house and the addition is typically 2x4 construction — not a structural concern if it’s not a load-bearing wall.
In this case, the east wall of the existing third bedroom (which became the wall between the bedroom and the new primary suite closet) was non-load-bearing. Opening it required a simple header and jack stud installation — $800 in framing.
The roof connection was more involved: the new addition roof had to tie into the existing roof at a valley intersection. A valley connection on a 1968 ranch roof that’s had multiple shingle cycles requires careful flashing and sometimes substrate repair at the intersection. We found soft sheathing in one area at the valley — expected on a 55-year-old roof that’s had three or four shingle replacements. Substrate repair: $600.
Mechanical integration
HVAC: The existing furnace had capacity to add one additional register and return for the new bedroom space. The bathroom required a dedicated exhaust fan. No system upgrade required. Ductwork extension and bath fan: $2,800.
Electrical: New circuits for the bedroom and bathroom (GFCI in bath, arc-fault throughout bedroom per 2021 NEC as adopted by Liberty). Recessed lighting in bedroom (6 cans), vanity lighting in bathroom. Panel had capacity. Total: $3,400.
Plumbing: New drain stub for the bathroom — the addition was over a basement with access, not slab, so the drain routing was straightforward. New supply lines. Double vanity, zero-threshold shower, freestanding tub. Plumbing rough-in and trim: $7,200.
Finishes
Framing and insulation: 2x6 exterior walls (slightly overbuilt for a 1968 ranch aesthetic match, but better energy performance). R-21 batt insulation in walls, R-49 blown-in attic. Total framing + insulation: $9,800.
Drywall: Bedroom, closet, and bathroom. $3,200.
Tile: Zero-threshold shower in 4x8 stacked white subway, Schluter KERDI waterproofing system. Heated floor (Nuheat mat under 12x24 porcelain). Total tile work: $5,400.
Vanity and fixtures: Double vanity in a painted shaker style, quartz top, rectangular undermount sinks, matte black faucets. Freestanding soaker tub (owner-supplied). Frameless glass shower enclosure. Total: $4,800.
Flooring and paint: Matching LVP to the existing bedroom flooring in the adjacent rooms. New closet system. Paint. Trim and doors to match existing. Total: $5,600.
Exterior: Fiber cement siding to match existing (the 1968 ranch had T1-11 siding that had been replaced previously with fiber cement in a similar profile). Roofing at the addition, matching existing 3-tab. Gutters and downspout. Total: $6,800.
Permits (Liberty MO) and engineering: $2,400 combined.
GC overhead and PM: $5,300.
Final cost breakdown
| Category | Cost |
|---|---|
| Foundation (basement) | $14,200 |
| Framing, insulation | $9,800 |
| HVAC extension | $2,800 |
| Electrical | $3,400 |
| Plumbing | $7,200 |
| Drywall | $3,200 |
| Tile work | $5,400 |
| Vanity, fixtures, shower | $4,800 |
| Flooring, paint, trim | $5,600 |
| Exterior (siding, roof, gutters) | $6,800 |
| Permits and engineering | $2,400 |
| Roof valley repair (change order) | $600 |
| GC overhead and PM | $5,300 |
| Total | $71,500 |
Wait — the title says $88,000. The $71,500 above is the base scope. After the homeowners saw the space taking shape, they added:
- Walk-in closet system (custom wood system from a KC closet company, owner-arranged + we installed the structural backing): $6,800
- Exterior covered entry for the new addition (small covered stoop, 4x6, matching roof line): $4,200
- Upgraded to radiant-heat floor throughout the bathroom addition (full bathroom, not just shower area) using a larger Nuheat mat: $2,100
- Structural upgrade to insulated concrete forms (ICF) on the basement foundation walls for thermal performance (decision made after framing started, before insulation): add-on $3,400
Change orders: $16,500. Total: $88,000.
This is a normal pattern: the base scope represents the functional minimum; change orders represent improvements the homeowner chooses during construction when they can see the actual space. Every one of these was written, priced, and approved before proceeding.
Result
The post-addition appraisal for a refinance came in at $354,000 against a pre-addition value of approximately $285,000. The $69,000 value increase on a $88,000 investment = 78 cents on the dollar recovery, before accounting for 15+ years of daily use in a neighborhood the family specifically chose.