# Residential Basement Retrofit with a 3-Level Puzzle System

> Turning 8 surface bays in an apartment basement into 22 independent spaces without digging a pit.

- Sector: Residential
- System: Puzzle parking, 3 levels × 8 columns
- Spaces before: 8
- Spaces after: 22
- Gain: +175%
- Pit required: No

## Challenge

An existing apartment building had a single basement row of 8 bays and a waiting list of residents. The clear height was about 5.6 m, there was no budget for excavation, and residents needed to retrieve cars independently at any time.

## Solution

A lift-slide puzzle system with 3 levels and 8 columns keeps one empty space on each lower level for shuffling. Using the capacity formula (3 × 8 − 2), the same row now holds 22 cars. SUVs park on the ground level, where the height is limited only by the slab above; sedans use the upper levels. Residents call their car with an IC card, and the pallets move so it arrives at the entry level.

## Scope

- Layout drawing and foundation loads
- Galvanised steel frame and pallets
- Hydraulic cylinder + wire-rope drive
- PLC control with IC card and keypad
- Photo-eye vehicle detection and anti-fall locks
- Installation supervision and handover training