Model Report: Triplex

Triplex Plan (Overall Footprint 60′×40′)

Each unit is 20′ wide × 40′ deep, 10′ wall height, sharing party walls.

Unit Layout (per 20′×40′ module)

1. Front Porch (6′ deep, full 20′ width)

2. Living Room (20′×16′)

   • Front-facing windows/door centered on 20′ wall

3. Half Bath (4′×6′)

   • Immediately off living area, near one side to align wet walls

4. Pantry/Laundry Closet (3′×6′)

   • Adjacent to half bath for shared plumbing

5. Kitchen (10′×12′)

   • L-shaped or straight run along party wall

   • Opens to living area

6. Hall (4′ wide)

   • Runs parallel to party wall, connecting kitchen to bedroom and full bath

7. Full Bath (8′×9′)

   • Off hall, backs up to pantry/laundry plumbing wall

8. Bedroom (12′×13′)

   • At rear of unit, window onto backyard/porch

9. Rear Porch (6′ deep, 20′ wide)

   • Accessed from bedroom or hall

Alignment & Mirroring

• Wet walls (half-bath, laundry, full-bath) all line up on the two party walls.

• Units 1 and 3 are mirrored copies of Unit 2 around the central party wall.

• Living rooms form three contiguous 20′-wide bays along the front porch.

1. Exterior Wall Areas

2. Interior Partition Areas

3. Roof Area (6:12 Pitch)

• Plan dimensions: 60′ (ridge length) × 40′ (span)

• Half-span: 20′ → rise = 20×(6/12)=10′

• Rafter length: √(20²+10²) ≈ 22.36′

• Slope area (each side): 60′×22.36′ ≈ 1341.6 sq ft

• Total roof: ≈ 2683 sq ft

4. Door & Window Count

• Windows: 2× living-room front + 1× bedroom rear per unit

• Interior doors: half-bath, pantry, full-bath, bedroom ×3 units

5. MEP Component Quantities

1. Exterior Wall Areas

2. Interior Partition Areas

3. Roof Area (6:12 Pitch)

• Plan dimensions: 60′ (ridge length) × 40′ (span)

• Half-span: 20′ → rise = 20×(6/12)=10′

• Rafter length: √(20²+10²) ≈ 22.36′

• Slope area (each side): 60′×22.36′ ≈ 1341.6 sq ft

• Total roof: ≈ 2683 sq ft

4. Door & Window Count

• Windows: 2× living-room front + 1× bedroom rear per unit

• Interior doors: half-bath, pantry, full-bath, bedroom ×3 units

5. MEP Component Quantities

Cost per Square Foot Ranges

Narrative (Cut-and-Paste)

1. House construction in Alabama: $90–140 / sq ft :contentReference[oaicite:2]{index=2} 2. National low-rise multifamily: $150–240 / sq ft :contentReference[oaicite:3]{index=3} 3. Adjust for tertiary market (–20%): $120–190 / sq ft 4. Montgomery AL reasonable triplex estimate: $110–150 / sq ft

Use $110–150 / sq ft as your budgeting range for the vertical component of affordable, SIP-framed, 20′×40′ triplex units in Montgomery.

 

Thought for 12 seconds

Value-Engineering to Hit $110–150 / sq ft

To close the gap, apply focused measures that shave several dollars per square foot. Below is a table of targeted strategies with rough savings estimates:

Revised Vertical Cost Range

• Baseline: $110 – 150 / sq ft

• Less VE Savings: –$3.65 – 7.15

• New Range: $102 – 146 / sq ft

Next Steps

1. Validate each strategy’s actual cost impact with subcontractors and suppliers.

2. Bundle procurements (windows, lighting, HVAC) under one purchase order to maximize volume discounts.

3. Pilot one unit to confirm installation efficiencies (ceiling finish, mini-splits) before full roll-out.

This targeted VE approach should bring your SIP-framed triplex comfortably within your $110–150 / sq ft budget.