Stone bathtubs in Singapore: weight, floors and HDB or condo rules

How heavy is a stone bathtub?

Sizes and weights converted from inches and pounds, and rounded. One litre of water weighs about 1 kg. *Stone Forest does not publish a volume; we used the larger Marblebee figure.

For comparison, a lightweight acrylic tub is often quoted at around 40 kg empty. The water and the person weigh the same in any tub: the stone is what changes the total.

What a Singapore floor is designed to carry

Floors in homes are designed for an "imposed load": the people, furniture and things that come and go. For a self-contained dwelling, the Singapore National Annex sets it at 1.5 kN/m², about 150 kg per square metre, plus a 2 kN point load, about 200 kg.

A freestanding tub of 180 × 80 cm covers about 1.44 m². At 1.5 kN/m², that area is designed for about 220 kg.

Key point This does not mean your floor would fail. Floors have safety margins and spread loads. It means a stone tub is outside what a standard home floor is designed for, and only an engineer who knows your building can say whether yours can take it.

In an HDB flat

Home & Decor Singapore and Women's Weekly Singapore, both in 2023, summarise HDB's renovation rules for bathtubs like this:

• The bathtub, including its supporting structure, should not weigh more than 150 kg.
• Bathroom works are allowed only three years after the block is completed, with an HDB permit.
• The floor slab must not be raised, lowered or otherwise altered to fit a tub.
• The space under the tub must stay empty: no mortar or fill to support it.

If these rules still apply, even the lighter stone tubs above weigh more than twice the limit before any water goes in. We could not check HDB's current text ourselves, so confirm with HDB or an HDB-registered renovation contractor before you plan a stone tub.

Stone still has a place in an HDB bathroom: a stone vanity or basin or smaller pieces weigh a fraction of a tub.

In a condo or a landed home

• Condo: renovation works need written approval from the management (MCST) before they start. Renovation guides in Singapore note that adding significant load to the floor slab can need a Professional Engineer's assessment and building authority approval. Ask your managing agent early.
• Landed home: no management to ask, but the same question applies to the floor. Have an engineer check the position you have in mind, and ask about the floor under a ground-floor bathroom too.
• Everywhere: plan the route. A tub of several hundred kilograms must pass doors, corridors, stairs and lifts. Check the lift size and the rated load on its plate. Our delivery guide lists what to measure.

Good to know Waterproofing, the drain position and an access panel for later maintenance matter as much as the weight. Agree them with your contractor before the tub is ordered.

Questions to ask before you order a stone tub

• What does this exact tub weigh empty, and how many litres does it hold?
• What is its footprint on the floor: full base, or feet?
• Where does the drain sit, and does it match my bathroom?
• Will it pass my door, corridor and lift, and how will it be carried in?
• Who checks the floor: HDB, the condo management, or a Professional Engineer?

Our stone bathtubs

We have 10 stone bathtubs on our site, from 170 to 190 cm long, 75 to 106 cm wide and 46 to 66 cm high. All are made to order with a quotation. Their weights are not on the site yet: ask for the weight of the piece you like with your quote, and share it with your engineer.