Double story house design: how to plan both floors

Most families in Lahore split the house by privacy. The ground floor takes the rooms guests see: the drawing room and dining near the entrance, the kitchen, and often a family lounge. It is also the best place for a bedroom with an attached bath for parents or elderly relatives, who should not have to climb stairs every day. The first floor takes the remaining bedrooms and a small family sitting area.

Write this down before any drawing starts: how many bedrooms you need now, who will use the ground-floor bedroom, whether you want a separate upper portion that could be let out later, and whether a second floor may be added in the future. Each of these changes the plan, the stair and the structure, and they are expensive to change once the grey structure is up.

• Family house: one internal stair, open to the family lounge.
• House with a separate upper portion: a stair that can be reached from outside or from the entrance lobby without passing through the ground-floor living spaces, and space for a second kitchen upstairs.
• House planned for a future floor: the structure, the stair and the water tank position are designed for it from day one.

On a 5 marla plot (a common shape is 25 × 45 ft on the 225 sq ft marla used in DHA, Bahria Town and most planned societies) a double story house usually gives three bedrooms in total, with every room carefully sized. A 10 marla plot (commonly 35 × 65 ft) allows a proper drawing room, a double car porch and three bedrooms upstairs. A 1 kanal plot (commonly 50 × 90 ft) leaves room for a lawn, a guest suite and larger bedrooms on both floors.

The covered area of a two-storey house is larger than the plot itself, because both floors count. To see how much house your budget can carry before you fix the plan, try the budget-based build size calculator with your own rate, and check plot dimensions with the plot size calculator.

The most common problem in double story houses is an upper floor drawn as if it stood on its own. Columns and load-bearing walls upstairs should sit directly on columns and walls below. When a first-floor column lands in the middle of a ground-floor room, the beam that carries it has to be deep and heavily reinforced, and it shows as a bulky drop in the ceiling.

Bathrooms and kitchens should also be stacked: an upstairs bathroom placed over a downstairs bathroom or store keeps the drainage pipes short and vertical. A bathroom placed over the drawing room or a bedroom puts every future leak, and the seelan (damp) that follows it, straight into the best room of the house.

• Ask for a column layout drawing and lay it over both floor plans.
• Check that every upstairs bathroom has a bathroom, store or kitchen beneath it, or a plan for a dropped slab and proper waterproofing.
• Ask where the vertical pipe ducts run and how they will be opened for repair.

The structure itself must be designed by a structural engineer, using the Building Code of Pakistan's seismic provisions, which govern how columns, beams and slabs are sized and reinforced.

The stair is the one element that connects both floors, so its position shapes every other room. A stair near the entrance lobby keeps upstairs bedrooms private from guests and allows a separate upper portion later. A stair inside the family lounge feels open but makes the lounge a corridor. A stair along a side wall keeps the centre of a narrow 5 marla plan free.

Leave room for a comfortable stair: steep, narrow stairs are the most common way small houses save space and the most common complaint afterwards. Your architect sizes the risers, treads and headroom so the stair is comfortable and meets the approving authority's rules. Plan the landing under the stair too: it can hold a powder room, a store or the UPS and batteries, with ventilation.

Many 5 and 10 marla houses in Lahore are attached on both sides and get light only from the front and back. On two floors the middle rooms, often the stair hall and the lounge, end up dark. A light shaft or a small open-to-sky court in the middle of the plan brings light and air into both floors and lets hot air escape.

• Keep large glass away from the west where you can; the afternoon sun heats rooms long after sunset.
• Give every bedroom a window that opens to outside air, not only to a shaft shared with a bathroom.
• A double-height entrance or lounge looks generous, but it costs first-floor area and is harder to cool.
• The roof over the first floor takes the full sun: plan heat proofing and waterproofing for it at the design stage, not after the first summer.

Before construction, the building plans must be approved by the authority that controls your plot: the Lahore Development Authority (LDA) for areas under it, or the society's own authority in DHA, Bahria Town and other private schemes. Their regulations set the building line at the front, the open spaces at the rear and sides, how much of the plot may be covered, and the maximum height. The limits differ by plot size and by authority, and they are amended from time to time.

So the same 10 marla design can be allowed in one society and refused in another. Ask your architect which regulations apply to your plot and to show the setbacks and covered-area figures on the drawings submitted for approval. See how we handle approvals as architects in Lahore.

When the plans and elevation arrive, go through these points before you approve them. Each one is cheap to fix on paper and expensive to fix on site.

1. Every room you listed is there, with its size written on the plan.
2. The ground-floor bedroom has an attached bath reachable without steps.
3. Upstairs columns sit on downstairs columns (ask for the column layout).
4. Upstairs bathrooms sit over wet areas or stores, not over living rooms.
5. The stair is comfortable and has headroom at every point.
6. Every bedroom has a window to outside air.
7. The roof plan shows slopes, drains and the water tank position.
8. The drawings show the setbacks and covered area required by the approving authority.
9. If a future floor is planned, the drawings say so and the structural design includes it.

Once the plan is fixed, estimate the build with the construction cost calculator using a rate from a written quotation.

• Lahore Development Authority: downloads (building and zoning regulations)
• LDA Building and Zoning Regulations 2019, amended (text hosted by Khalid Zafar & Associates)
• IISEE: Building Code of Pakistan, seismic provisions (summary)
• World Bank: Building seismic resilience in Pakistan