Build to order (BTO) is a real estate development scheme enacted by the Housing and Development Board (HDB), a statutory board responsible for Singapore's public housing. First introduced in 2001, it consists of a flat allocation system that offers flexibility in timing and location for owners buying new public housing residences in the country. Singaporeans planning to shift into a new HDB apartment in the near future apply for apartments in their preferred location from specific sites launched. Tender for construction will be called only if the number of applicants is at least 70% of the number of apartments in a specific contract (50% since 2011), otherwise, the project is not built. History BTO replaced the predecessor Registration for Flats System (RFS) scheme, whereby the waiting time for new flat applicants was relatively shorter because flats were built ahead of demand. In comparison, the new BTO system requires a waiting period of about 3–4 years instead as such a system removes the need for the government to make projections ahead of demand. For eligible flat buyers in urgent need of accommodation, they can ballot for leftover units that are reintroduced into the market, known as Sales of Balance flats (SBF). In February 2019, it was announced that starting from the middle of 2019, flat buyers will be able to apply for unsold BTO flats online anytime on a first-come, first-served basis, and book a flat by the next working day. This is to help citizens with urgent needs for housing. All BTO projects are designed by Surbana Corporation, an infrastructure and urban development conglomerate owned by Temasek Holdings. To allow private sector a share of the public housing pie, HDB launched the Design, Build and Sell Scheme (DBSS). The first pilot DBSS project at Tampines was built by private developer, Sim Lian Group, before subsequently being maintained by the HDB after construction. In 2011, then National Development Minister Khaw Boon Wan eventually ended the DBSS scheme indefinitely and all BTO projects are now strictly within the public sector. Unique features ASSURE 3 – New Extended Warranty Scheme Covering Ceiling Leakage (5yrs), External Water Seepage (5yrs) and Spalling Concrete (10yrs) for New HDB Flats such as Tivela launched from March 2005. Defect Liability Period (DLP) – Previous HDB projects are offers a standard one-year to all purchasers of its new flats. During this period, any building defects are repaired at no