Duplex finishing

What is different about a duplex

A duplex has to be planned on both floors at once, because most of its systems pass from one floor to the other. The points that need early decisions:

• The internal stair, which is the most visible element in the home.
• A double-height space: it looks impressive, but cooling, lighting and cleaning it need planning.
• Electrics, air-conditioning pipes and plumbing that run between the floors, whose routes must be fixed early.
• Water pressure on the upper floor.
• Sound between the floors, especially if bedrooms sit above the living room.
• Sometimes a roof terrace or private terrace on the upper floor.

The internal stair

The stair is decided early, because its material and form affect the floors, the lighting, the balustrade and even the plaster levels.

The balustrade can be glass, steel, stainless steel or timber. What matters most is its height and the size of its openings, especially with children in the house.

Double height: lighting, curtains and cleaning

A double-height space needs a plan for access, because anything two floors up is hard to reach once the finishing is done.

• The main chandelier: fix its position and weight before the gypsum board goes up, so its hanger is anchored in the concrete slab, and think now about how bulbs will be changed and the fitting cleaned.
• Wall lights and concealed LED in the gypsum, so the space does not rely on a single chandelier.
• High windows: motorised curtains or shutters, because reaching them by hand is hard.
• Cleaning the high glass: plan it now, from an upper-floor balcony or from outside.
• Acoustics: a tall space echoes, and rugs, curtains and sound-absorbing ceilings reduce it.

Air conditioning on two floors

Warm air rises and cool air sinks, so the upper floor and the double-height space run warmer and need their own cooling calculations.

• Zone the air conditioning by floor and by use, so you are not cooling both floors while sitting on one.
• In the double-height space, calculate the load for the whole volume, not just the floor area, and place the outlets so cool air reaches the people below.
• Concealed ducted units need enough depth above the gypsum board and an access point for servicing.
• Copper pipe and condensate routes between the floors are fixed before plaster, and condensate goes to a proper drain, not onto the balcony.

Water pressure on the upper floor

If pressure is weak upstairs, the usual fix is a booster pump with a pressure tank, once you are sure the pipes themselves are sound.

• First rule out old or blocked pipes, or valves left half-closed.
• A booster pump with a pressure tank runs more smoothly and is easier on the pipes and water heaters.
• Place the pump where its noise does not reach the bedrooms and where it is easy to service.
• New supply pipes are PPR, and a separate water heater for the upper floor brings hot water to its bathrooms faster.

Sound insulation between the floors

The easiest time to deal with sound between the floors is before the floors and gypsum go in, because afterwards it means demolition.

• Footstep noise travels through the slab, and a resilient layer under the floor finish reduces it.
• A suspended gypsum board ceiling under the slab, with rock wool in the void, cuts the sound reaching the floor below.
• An open stair carries sound between the floors; if privacy matters, a door or glass screen at the top of the stair makes a difference.
• Drain pipes from upstairs bathrooms can be wrapped in acoustic lagging where they pass through a bedroom ceiling.

How Itmam finishes a duplex

We visit the duplex, measure both floors, and write you an itemised quotation that lists the stair, the ceilings, the air conditioning and the insulation item by item before any work starts.

Stone for the stair and floors is templated, cut and installed by the same team, and railings and other metalwork are made in our own workshop, as are the kitchen, wardrobes and doors.

On a finishing contract you pay each supplier directly and the tax invoice is in your name; our fee for supervision and execution is agreed in writing before work starts.

If your duplex has a roof terrace, our roof finishing page covers the waterproofing and the outdoor space.