Attic & Loft Conversion

URA may allow an attic as incidental space inside your house's permitted two-storey or three-storey envelope, the outline of height and setbacks the house has to stay within. Its handbooks for terrace, semi-detached and bungalow houses say so in the same words, and the word "may" means each design is checked, not that every roof qualifies. On an existing terrace, semi-detached or detached house, adding an attic counts as A&A under URA's guideline only if it increases the gross floor area by less than 50%, and a new roof, even a higher one, mustn't add a storey. Otherwise URA treats the job as reconstruction, not A&A works. A roof terrace on an attic roof has to sit at least 3 m below the top of the envelope. Your Qualified Person checks the design against these rules. That's a registered architect or professional engineer with a valid practising certificate, whom you engage to advise on the approvals needed from BCA and URA.

Yes, unless your Qualified Person confirms the work is one of BCA's insignificant building works. BCA needs approved structural plans and a permit before building works start for everything except the insignificant works listed in its regulations. For URA, a design that meets its lodgment criteria for A&A to a landed house, including the limit on how much floor area the attic adds, can be lodged instead of going through a planning permission application, but lodgment isn't open to houses in conservation areas, Good Class Bungalow Areas or special control areas. Outside those criteria, ask your Qualified Person which URA application applies. An attic built without the approvals it needed is unauthorised building work, which is an offence under the Building Control Act.

BCA's headroom rule depends on the attic's size. In a house built for the owner's own use, the requirement that every room has adequate headroom and height for its use doesn't apply to an attic of 10 square metres or less, and BCA's Approved Document sets just those two conditions. A bigger attic has to meet the requirement, and the Approved Document treats it as met with a ceiling height of at least 2.4 m and headroom of at least 2.0 m. Ask your Qualified Person how that's measured under your sloping roof. Either way, the low space near the eaves suits built-in storage better than a bed, as long as the cupboards don't block a service hatch or a window, and a dormer can give standing height where URA and BCA approve it. For fresh air, BCA doesn't require natural ventilation in a landed house built for the owner's use, so an attic bedroom can rely on mechanical ventilation or aircon with mechanical ventilation instead. Using the attic as a bedroom, study or storage covers what each use needs.

For a room you'll use every day, we recommend a fixed stair with a handrail. That's our advice rather than a BCA requirement, because BCA's staircase requirements for handrails, landings and width, tread and riser don't apply to landed houses built for the owner's use. Your Qualified Person still checks the stair against the rules that do apply, such as its structural design. A folding loft ladder takes less space but suits occasional trips to storage, not carrying a laundry basket down at night. Our staircase renovation page covers stair types and handrails.

Not on its own. Insulation slows heat coming through the roof, but it does nothing about sun shining through roof glass and it doesn't cool the air. So the room also needs shading on any skylight and its own cooling, which means planning where the aircon's pipes run and where its outdoor unit goes. Making a hot attic more comfortable goes through the roof, glass and cooling choices together.

We can't point you to a current independent price for attic conversions in Singapore, so here's what sets the price, from the smallest job up. Lining and insulating roof space that already has a floor and standing height is the smaller job. A new floor and a new opening for the stair add structural work, plus changes to the room below where the stair lands. A dormer or a raised roof adds roof and waterproofing work and makes the URA and BCA submissions bigger. A bathroom adds water and waste pipes up to roof level, and aircon adds its own pipes and power. The Qualified Person's fees and the submissions are separate lines on top. Two attics the same size can end up at very different prices for these reasons, so ask for each of these steps to be priced as its own line. The attic conversion buying guide shows how to compare complete quotes.

Opening up the roof is a contractor's job at height, so from inside the house you only look and note. Every new skylight, dormer or vent makes new joints in the roof, and joints are where rain finds its way in if they aren't detailed properly. Each one needs flashing, the shaped strip that sheds rain over the joint, plus waterproofing, and both should be checked and photographed before the ceiling closes over them, because a leak found later means opening up the finished room. Ask who checks them and who answers for a leak at those joints afterwards. Roof waterproofing covers the rest of the roof.

It's possible, but water has to get up there and waste has to get down. Supply pipes have to reach roof level, and waste pipes need a fall to the existing drain pipes, which can mean raising the bathroom floor. That floor then needs waterproofing over the rooms below. PUB requires a Licensed Plumber for regulated water and sanitary plumbing work, leaving handymen only simple jobs such as replacing a tap or fitting a basin. If the water has to be pumped or stored in a tank to reach the attic, PUB requires a Professional Engineer to design and supervise that system, and for building works the owner engages a Qualified Person to prepare and submit the sanitary plans. How bathroom waterproofing prevents leaks after renovation explains the checks before tiling.

The time goes on stages, so ask for a date against each one rather than a single finish date. The Qualified Person's design comes first, then the URA and BCA submissions and their replies. BCA's own targets for processing a complete structural plan application are 20 working days for a submission through CORENET X, which BCA says new projects must use from 1 October 2026, or 7 working days through CORENET 2 (10 days for a first submission with an accredited checker's certification), then 7 working days for the permit, and possibly longer where more evaluation is needed. Your Qualified Person knows which system the job goes through. Windows and skylights have to be ordered, and roof work waits for dry weather, as whether roof waterproofing can be done in the rain explains. Staying inside the existing roof shape means fewer of these stages than adding a dormer or rebuilding the roof. While the roof is open and the stair opening is cut, the rooms right under the attic and the room where the stair lands get dust, noise and a risk of rain, so agree in writing which rooms are out of use for which stage and how they're covered. Living at home during A&A works helps you decide whether to stay.