A residential-commercial building is an investment project before it is a building. The layout of apartments, the size of shops, residents' entrances and the number of parking spaces are all design decisions that set rent, occupancy and ease of sale for many years. A single mistake early on, such as a residents' entrance squeezed between shops or a basement short of parking, can reduce the value of the whole project. This guide covers the principles of designing a residential-commercial building for higher returns, from studying the requirements and market to shops, apartments, parking, unit sorting and safety.
1. Start With the Requirements and the Market
- The permitted use (residential, commercial, mixed) and number of floors under the building regulations for the site and street. Read: Regulations for residential and commercial buildings and Setbacks and building ratios in Riyadh.
- Demand in the district: large family apartments, or studios and two-bedroom units? Small shops or showrooms?
- The investment plan: long-term letting, selling units, or a mix? It changes the design decisions.
2. Shops
- Wide frontages on the commercial street, and a suitable depth for a range of activities.
- A height that allows a mezzanine when needed, within the requirements.
- Pre-installed provisions for air conditioning, drainage and ventilation so tenants do not have to break into the structure, especially restaurants and cafés.
- A defined place for shop signs consistent with the facade. Read: Shop and commercial building facades.
- Flexibility to merge two shops or divide a large one.
| Shop element | Effect on returns |
|---|---|
| Frontage width | Raises rent and attracts premium activities |
| Suitable depth | Widens the range of possible activities |
| Ready provisions | Shortens vacancy and speeds up tenant fit-out |
| Mezzanine | Extra lettable area without enlarging the footprint |
3. Apartments
- A separate residents' entrance away from shop traffic, with a well-served lift and stair.
- A layout that minimises corridors and gives each apartment natural light and ventilation.
- A variety of unit sizes to widen the pool of tenants or buyers.
- Sound insulation between shops and apartments and between units.
- Storage and laundry space inside each apartment.
4. Parking
The required number of parking spaces depends on the use and areas, and may require a basement. The basement decision affects cost and structural design, and may need shoring when excavating next to buildings. A traffic study may be required depending on the activity.
5. Designing for Unit Sorting
If the plan is to sell apartments with separate title deeds, design from the start to ease unit sorting: clear unit boundaries, separate meters and defined common areas. And avoid the design mistakes that block sorting. Read: Design mistakes that prevent sorting.
6. Safety
A mixed-use building needs separation between uses, emergency exits, and alarm and fire-fighting systems to code. See our safety systems design review service, and read: Civil defense requirements for residential buildings.
7. Cost and Structure
Good structural design balances wide spans for shops with columns that do not obstruct apartment and parking layouts. Read: How structural design affects cost.
Common Mistakes
- A residents' entrance shared with the shops.
- Deep shops with a narrow frontage.
- Columns in the middle of parking that reduce the number of spaces.
- Neglecting provisions for commercial kitchens.
- Not thinking about unit sorting from the start.
Frequently Asked Questions
Does every building need a basement?
No, it depends on the required parking and the area available on the plot.
Which is a better investment: large or small apartments?
It depends on demand in the district; a mix reduces risk.
Can the ground floor be converted to shops later?
It depends on the permitted use, and needs a modification permit. Read: Modifying building components.
Can the apartments be sold off-plan?
Yes, through the Wafi programme under its conditions. See our Wafi services.
How long does designing the building take?
It depends on the project size and approval stages; the engineering office determines it after studying the site.
How Abak Engineering Consultancy Helps
Abak is an accredited engineering office in Riyadh that designs residential-commercial buildings from an investment perspective: flexible shops, varied apartments, well-planned parking, a design ready for unit sorting and approved safety systems, plus the building permit. Learn about our design services, or For professional support, see our Residential & Commercial Unit Subdivision Drawings service. contact us.
Regulatory information is based on the Balady platform and the Ministry of Municipalities and Housing, and procedures may be updated by the competent authority. Last reviewed: October 2026.