It's the oldest suspicion in renovation, and an honest one: that somewhere behind your beautiful new tiles, the crew quietly mixed in more sand and less cement to save a few dollars — and that a year later you'll be tapping hollow, drumming tiles that have started to lift. For decades that fear was justified. The good news, which almost nobody tells homeowners: in Singapore, the part that used to go wrong has largely been regulated out of your hands.

Where the worry actually comes from

Underneath your floor tiles is a layer called screed — a cement-and-sand bed that levels the floor and gives the tiles something to bond to. Get the mix right and it's rock-solid for decades. Get it wrong — too much sand, too little cement, sloppy water — and it's weak, crumbly and prone to the hollow, debonding tiles everyone dreads. In the old days that ratio was mixed by hand on-site, by eye, so the quality of your floor depended entirely on whether that particular crew, on that particular day, mixed it properly.

What changed in 2015

Since 1 June 2015, HDB has required the use of pre-packed screed for laying new floor finishes in dry areas — and pre-packed waterproofing screed for wet areas like bathrooms before tiling. Pre-packed material is likewise required for wall plastering.

“Pre-packed” means just what it sounds like: the screed arrives as a factory-blended dry mix in bags, with the cement, sand and additives already measured to a consistent ratio. The crew adds water and applies it — they can't quietly tilt the recipe toward cheap sand, because the recipe was sealed in a factory. The entire point of the rule is consistency: a uniform, reliable quality of screed, which directly reduces the hollow tiles and floor cracks that hand-mixing used to cause.

The fix for “more sand than cement” wasn't trust. It was taking the mixing decision off the site and putting it in a factory.

So can you stop worrying?

About the mix itself — largely yes, for HDB work done by a registered contractor following the rules. The ratio is no longer a judgement call. But pre-packed material is only half the story; workmanship still matters, and that's where your attention should go:

  • Coverage and bedding. Even with perfect screed and adhesive, a tiler who “dot-and-dabs” five blobs under a tile instead of properly combing full coverage leaves voids — and voids are what sound hollow and crack later. Full bedding is the craft that pre-packed mix can't enforce.
  • Curing time. Screed and waterproofing need to air-cure before tiling, and wet areas need their water-retention test. Rushing the schedule undoes good materials.
  • Surface prep. The slab must be clean, sound and properly keyed. Lay good screed over a dusty or uneven base and it still fails.

What to actually ask

  • “You're using pre-packed screed and plaster, as required?” The right answer is an easy yes.
  • “How are you bedding the tiles — full coverage?” You want to hear about combed, full-contact bedding, not blobs.
  • “What's the curing and waterproofing-test schedule?” A crew that has one isn't rushing you.

The bottom line

The specific nightmare — a crew secretly stretching the cement with sand — is mostly a solved problem since 2015, because the mix now comes pre-blended from a factory, not a wheelbarrow. What's left is workmanship: coverage, curing and prep. Ask about those, and you can finally let the old fear go.