Marble Dusting
Marble dusting, also called marcite, is the traditional plaster finish on concrete and gunite pools: white cement mixed with ground marble aggregate and trowelled onto the shell. Refinishing is a drained pool project, best done off season. Call (800) 670-3391.
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What is marble dusting?
Marble dusting is a plaster finish. White cement is mixed with finely ground marble aggregate and
trowelled onto the pool shell, giving the smooth bright surface most people picture when they think
of a concrete pool. It has been the standard interior finish for decades, which is why so many
commercial pools on Long Island have it.
It is a wearing surface rather than a permanent one. It sits in chemically treated water, takes
abrasion from swimmers and cleaning, and eventually reaches the end of its life. Ours is referenced
across our pool renovation,
pool liner and
pool installation work, because the finish interacts
with all three.
When does a pool need refinishing?
Plaster degrades gradually and then starts to matter quickly. The useful thing is that the signs
appear well before the surface is unusable, so the work can be planned into an off season instead of
forced during one.
- Rough or chalky texture underfoot where the surface has etched
- Cracking or crazing across the finish
- Staining that no longer responds to normal cleaning
- Exposed aggregate or patches where plaster has delaminated
- Water loss that traces to the shell rather than the plumbing
Water chemistry drives most plaster failure. Water left aggressive over a winter attacks the
surface directly, which is why a finish that should have lasted many seasons sometimes does not.
Consistent pool maintenance is the cheapest life
extension available for any plaster finish, by a wide margin.
How is marble dusting and pool plaster refinishing done?
Refinishing is a drained pool project. The pool is out of use for the duration, which is the main
reason it belongs in the off season.
- Drain and inspect the shell properly, which is when hidden problems surface
- Chip out failed plaster and cut out hollow or delaminated areas
- Repair the substrate and address structure before anything cosmetic
- Apply and trowel the marble dust and cement finish
- Acid wash and clean down
- Refill and manage startup chemistry
The startup is not a formality. New plaster is chemically active while it cures, and how the
water is handled in those first weeks affects how the surface looks and how long it lasts. It is
also the step most likely to be rushed when a facility is trying to open, which is precisely why
scheduling matters.
Compared with other finishes
| Finish | Suits | Character | Notes |
|---|---|---|---|
| Marble dust plaster (marcite) | Concrete and gunite | Traditional smooth white | Most common commercial choice |
| Quartz aggregate | Concrete and gunite | Harder wearing, more colours | Costs more than plain plaster |
| Pebble aggregate | Concrete and gunite | Longest wearing, textured | Texture does not suit every facility |
| Vinyl liner | Liner pools only | Replaced, not resurfaced | See pool liner |
If your pool is vinyl rather than concrete, this is not the work you need. If the finish is one
part of a larger project taking in coping, tile or decking, it is almost always cheaper to combine
them into a single shutdown than to return year after year.
What decides how long a finish lasts
Facilities often assume the answer is the quality of the application, and that matters, but it is
not the main variable. Two pools finished by the same crew in the same week can be in visibly
different condition five years later. The difference is what happened to the water in between.
- Water balance. Aggressive water dissolves plaster. Consistently balanced water
is the single largest factor in how long a finish survives - Wintering. A pool closed with unbalanced water spends months attacking its own
surface with nobody watching - Bather load. A busy club pool wears faster than a lightly used building pool,
and needs its chemistry watched more closely to compensate - Startup. How the first few weeks after refinishing are handled affects the
surface permanently, not temporarily - Cleaning practice. Aggressive brushing of a curing surface causes damage that
shows up much later
The practical conclusion is uncomfortable but useful: if a finish failed early, refinishing
without changing how the water is managed will produce the same outcome again. That is why we would
rather talk about the maintenance regime at the same time as the refinish, and why a facility with
no consistent water management should fix that first.
Where we work
We cover both counties from our Valley Stream office. For what marble dusting involves in a specific area,
including local facility types and the health department that inspects them:
Want to talk it through?
Call (800) 670-3391 or use the Contact Us page.
Frequently asked questions
How long does a marble dusting finish last?
It varies with water chemistry, bather load and how the pool is wintered. Two identical finishes can have very different lives depending on how consistently the water was balanced. Anyone quoting a fixed number without seeing your pool is guessing.
Can it be done without draining the pool?
No. Marble dusting is a drained pool project. The shell must be dry to chip out failed plaster, repair the substrate and trowel on new finish. Any process claiming otherwise is doing something different.
When should it be scheduled?
Off season, so the pool is back in service before opening. Booking in autumn or winter gives the schedule room. Booking in spring means competing with every other facility trying to open, and this is not work that benefits from being rushed.
Will the new surface look different?
Yes, and it should. New plaster is uniform and bright in a way a worn surface is not. Some mottling as it cures is normal rather than a defect, and startup chemistry affects how evenly it settles.
What if problems are found once it is drained?
They are addressed before the finish goes on. Draining routinely reveals things invisible when the pool is full, which is part of why the inspection at that stage matters. Plaster applied over an unsound shell fails early.
Is marble dusting the same as a pool renovation?
It can be part of one. Refinishing addresses the interior surface. A renovation may also take in coping, tile, decking and equipment. If several of those are due, doing them together in one shutdown usually costs less than separate visits.
Last updated September 4, 2026