The project
A 2001 colonial in the Scotts Mill neighborhood of Apex with a 12-by-16-foot concrete patio off the back of the house. The homeowners wanted to enclose and expand that space into a 320-square-foot four-season sunroom — not a screened porch, not a three-season room, but a fully conditioned, fully insulated living space that could be used year-round.
The existing patio slab was cracked in two places and hadn’t been poured to the depth or reinforcement standard required for a heated structure. It would need to come out. The new addition would require its own frost-line foundation, a tie-in to the existing roofline, connections to the home’s HVAC system, a new electrical subpanel, and a plumbing rough-in for a future wet bar the homeowners were considering.
The biggest constraint was the lot. Apex has a 30-foot rear setback in this zoning district, and the existing patio was already 22 feet from the property line. That gave us 8 feet of depth to work with before we’d need a variance. We designed the addition at 20 feet by 16 feet, keeping the rear wall 2 feet inside the setback line with room to spare.
What we did
- Demolished the existing patio slab — broke out the 12-by-16-foot concrete pad and hauled 6 cubic yards of debris
- Poured a new continuous footing foundation — 24 inches deep (below frost line), 16 inches wide, with #4 rebar, and a 4-inch slab on grade with 6-mil vapor barrier and 2 inches of rigid foam insulation beneath
- Framed the addition — 2x6 exterior walls at 16 inches on center for R-21 batt insulation, engineered headers over the 8-foot slider and two 4-foot windows, and a ledger board connection to the existing house with proper flashing
- Tied into the existing roofline — extended the rear gable with matching 5/12 pitch, architectural shingles color-matched to the existing roof, ice-and-water shield at the valley and tie-in point
- Installed HardiePlank siding — color-matched to the existing James Hardie lap siding on the house, with matching trim and corner boards
- Insulated and drywalled — R-21 batts in the walls, R-38 blown-in cellulose in the ceiling, 1/2-inch drywall throughout, smooth finish, painted to match interior
- Installed a ductless mini-split — Mitsubishi 18,000 BTU hyper-heat unit with a wall-mounted head, providing both heating and cooling independent of the home’s existing HVAC system
- Ran a new 60-amp subpanel from the main panel to the addition — supporting the mini-split, recessed lighting, outlets, and future wet bar loads
- Wired 8 recessed lights on a dimmer circuit, 6 duplex outlets, and 2 exterior weatherproof outlets
- Plumbing rough-in for a future wet bar — 1/2-inch hot and cold supply lines and a 2-inch drain stubbed to the wall, capped and pressure-tested, ready for future connection
- Installed LVP flooring — waterproof luxury vinyl plank, color-matched to the adjacent family room for a seamless transition
- Three Andersen 400-series windows and one 8-foot sliding door — Low-E glass, argon-filled, matching the window style throughout the house
Trades involved
This project required all three of our licenses:
- GC (NCLBGC #87341): Permitting, demolition, foundation, framing, roofing, siding, insulation, drywall, trim, flooring, window and door installation, paint, and overall project management
- Electrical (NC #28-LA-9214): 60-amp subpanel, branch circuits for lighting and outlets, mini-split electrical connection, exterior outlets, all to current NEC code
- Plumbing (NC #P1-22847): Hot and cold supply rough-in, drain rough-in, pressure testing, and capping for future wet bar connection
Four permits were pulled through the Town of Apex: Building, Electrical, Plumbing, and Mechanical. All four inspections — foundation, framing, rough-in, and final — passed on the first visit.
Timeline and budget
- Duration: 10 weeks, start to finish — 50 working days
- Budget: On budget — the final invoice came in within the written estimate range
- Crew: Three-person crew for the first 6 weeks (foundation through rough-in), two-person crew for the final 4 weeks (finish work)
- Permits: Building, Electrical, Plumbing, Mechanical — 4 permits, 8 inspections, all passed first visit
- Weather delays: One day lost to rain during the roofing phase. We had tarped the open framing the night before, so no interior damage occurred
Material lead times drove the schedule. The Andersen windows had a 4-week lead time, so we ordered them before breaking ground. The mini-split and subpanel components were stocked locally. We sequenced framing and roofing to have the building dried in before the windows arrived, which kept the interior trades on schedule.
The result
A 320-square-foot four-season sunroom that looks and feels like it was part of the original house. The matched roofline, siding, and window style make the addition invisible from the street. Inside, the LVP flooring transitions seamlessly from the family room, and the recessed lighting and mini-split keep the space comfortable and well-lit in every season.
The homeowners gained a room that works as a home office during the week, a reading room on weekends, and an entertaining space when guests come over. The plumbing rough-in is waiting behind the wall for whenever they decide to add the wet bar — a $400 investment during construction that would cost $2,500 or more as a retrofit.
The addition increased the home’s conditioned square footage by 15% without changing the home’s footprint from the street or requiring a zoning variance. That’s what careful design and setback awareness can do — maximize the addition while staying within the rules.