Why Materials Are Regulated
HDB regulates renovation materials for two reasons: structural safety and the protection of shared building fabric. Materials that exceed prescribed floor loadings, compromise fire resistance ratings in party walls, or accelerate corrosion in shared sanitary stacks are a risk not just to the individual unit but to adjacent flats and the building's structural system. The approved materials list exists as a technical standard rather than an aesthetic one — contractors are free to select any products that meet the specified performance criteria.
The practical implication is that homeowners and their contractors must check material specifications against HDB's current published standards before procurement. Using a non-compliant material discovered during an HDB inspection will result in a reinstatement order, and the contractor is unlikely to absorb the replacement cost if the homeowner approved the original specification.
Flooring Materials
Ceramic and Porcelain Tiles
Ceramic and porcelain tiles are the most widely used flooring materials in HDB renovation and are unconditionally permitted. The key constraint is the total floor screed thickness — when laying tiles, the combined depth of adhesive mortar and tile thickness must not cause the finished floor to exceed the original structural slab level at doorway thresholds. Most renovation contractors manage this by specifying thin-bed adhesive for tile-on-tile applications (where existing tiles are retained as the substrate).
Large-format tiles (800mm × 800mm and above) are permitted but require contractors to use a flexible tile adhesive with a minimum Class C2 rating under the EN 12004 standard. This prevents cracking under thermal cycling in Singapore's climate. Several batches of substandard adhesive have caused tile debonding in HDB flats over the years, making adhesive specification an area where specifying a recognised brand matters.
Vinyl and Laminate Flooring
Rigid core vinyl (SPC — stone plastic composite) and click-lock laminate are both permitted over existing floor finishes without hacking, provided the existing floor is level within ±3mm per 2 metres and dry. HDB's guidelines specify a minimum board thickness of 8mm for laminate and 5mm for SPC vinyl to ensure adequate impact noise absorption. Thinner boards can result in a hollow sound underfoot that, in HDB blocks with concrete slabs, transmits noticeably to the unit below.
Floating floor installations must include an approved acoustic underlay that achieves a minimum ΔLw of 17dB. Several brands marketed in Singapore for HDB compliance include certification data — contractors should obtain and retain these certificates as they may be requested by HDB during inspections of noise complaints.
Timber and Engineered Wood
Solid timber flooring is permitted but uncommon in HDB renovation due to cost and its sensitivity to humidity fluctuations. Engineered timber (a real wood veneer bonded over a plywood or HDF core) performs better in Singapore's climate and is more widely specified. Both types must be glued directly to the substrate — floating installation of timber over an acoustic underlay is not permitted for engineered or solid timber boards wider than 90mm.
Bamboo flooring is classified under timber for HDB purposes and is subject to the same installation requirements. Reclaimed timber sourced from older HDB flats — a practice occasionally proposed by renovation contractors to reduce waste — must still meet the current thickness and installation specifications; the age of the material is not a compliance variable.
Wall Finishes
Cement Render and Skim Coat
Cement render and white or grey skim coat are the standard base for wall finishes in HDB renovation. These are unrestricted in specification — homeowners may select any Portland cement-based render or gypsum skim coat. The critical requirement is that any render applied to RC walls does not penetrate into the structural concrete. Render on RC walls must use mechanical anchors (wall plugs into the concrete) rather than adhesive bonding alone for any thickness above 15mm.
Wall Tiles
Wall tiles in wet areas (bathroom, kitchen) must be applied with a Type II mastic adhesive or cement-based adhesive meeting a minimum Class C1 rating. Grouting in wet areas must use a non-shrink, water-resistant grout. The use of standard grey grout in shower areas is a common shortcut that leads to seepage complaints within three to five years — epoxy grout or premixed polymer grout is specified in most quality renovation scopes for this reason.
Full-height wall tiling in bathrooms — from floor to ceiling — is permitted and does not require a separate approval. Tiling in living or bedroom areas is also permitted, subject to the weight loading constraints of the wall substrate.
Paint
Paint is unrestricted in type and colour for internal walls. Exterior-facing walls — the outer surface of the building — are managed by HDB and may not be painted by individual homeowners. The corridor side of the front door and the service yard parapet are in this category. Internal wall surfaces, including feature walls, may use any paint product; the contractor's choice of primer and the number of coats are not regulated but are relevant to the durability of the finish.
Bathroom and Kitchen Fixtures
Sanitary Fixtures
Toilets, basins, and shower enclosures may be replaced with any product that fits within the existing floor trap and waste connection positions. Relocating the toilet bowl beyond 300mm from the existing soil outlet pipe requires a permit and the installation of a properly sloped waste line with a minimum gradient of 1:50. Macerator pumps — which allow a toilet to be installed in a location without direct gravity drainage — are permitted but must use only HDB-approved models listed on the board's current published list.
Waterproofing Systems
All wet area works — whether in existing bathrooms or newly created wet areas — must use a waterproofing system from HDB's list of approved waterproofing systems. This list is updated periodically by the BCA and HDB. The standard application involves two coats of a cementitious or polyurethane membrane applied to the floor and at least 300mm up the walls in shower zones. The contractor is required to provide a waterproofing warranty certificate, typically for 5 years, upon completion.
Kitchen Countertops
Engineered quartz (composite stone) and natural granite are the most commonly installed kitchen countertop materials in HDB renovation and are unrestricted. Solid surface materials (Corian and similar) are also permitted. Stainless steel countertops, while uncommon in residential contexts, are fully permitted. Tiled countertops are permitted but their grout lines require particular attention to maintenance — the BCA publication on kitchen renovation for HDB flats notes tile countertops as a common source of seepage complaints where grout has failed.
Materials documentation: Retain all datasheets, CE marks or Singapore SS certifications, and installation warranties for any regulated material. HDB may request these during resale checks or post-renovation inspections. Contractors should provide a materials list with supplier information as part of the project handover documentation.
Structural and Partition Wall Materials
New partition walls in HDB renovation must use either autoclaved aerated concrete (AAC) blocks with a minimum density of 500kg/m³, or gypsum board framing with steel stud channels at maximum 600mm centres. Both systems must achieve a minimum Sound Transmission Class (STC) rating of 35 when tested in situ, though this is rarely verified formally in residential renovation — it represents HDB's design intent rather than an actively enforced post-completion test.
Timber stud partition walls are permitted in dry areas only and must use structural timber complying with AS/NZS 1748 or an equivalent standard. They are not permitted in wet areas or adjacent to wet areas where moisture exposure is likely over the flat's remaining lease term.
External Sources
HDB's renovation guidelines, including the current approved materials and waterproofing systems lists, are accessible at hdb.gov.sg. The Building and Construction Authority's CORENET portal contains the statutory framework for construction materials compliance in Singapore.