Bathroom Remodeling in Mastic, NY

Mastic is Town of Brookhaven. Closer to the water, and in any house that has had a slow leak, the subfloor under a bathroom is the thing to check before pricing anything else.

What we see in Mastic bathrooms

The first thing we check in a Mastic bathroom is the subfloor, and closer to the water we check it harder. A toilet flange that has weeped for years, or a tub apron that has taken splash without a seal, leaves a subfloor that looks fine and is not. Tile laid over it cracks, usually within the first year.

If a floor flexes underfoot near the toilet, or the tile grout at the base of the tub has been cracking and getting regrouted, assume the subfloor is coming out and price it in rather than treating it as a surprise.

What needs a permit in Mastic

Vanity swap, retiling, new fixtures in the same places — finish work, generally no permit. Toilet or shower drain moves, tub converts to a walk-in shower, a bathroom gets added, or a bathroom goes in a basement — permitted work, every time.

The Suffolk catch: adding a bathroom to a house on septic rather than sewer can trigger a Suffolk County Health Services review, because the system was sized for a set number of fixtures. It runs separately from the town permit, on its own timeline. Redoing an existing bathroom does not raise it. Filing detail for Town of Brookhaven Building Division.

Four things decide whether a bathroom lasts, and none of them are the tile: the subfloor, the venting on a moved toilet, the waterproofing membrane behind the tile, and where the exhaust fan actually terminates. What to ask about each. We measure on site for free and put the number in writing as a scope with a total.

Verified August 2026. Requirements and fees change and each department publishes independently. Confirm anything here with the Town of Brookhaven Building Division at (631) 451-6333 before you order materials or sign a contract. One Independence Hill, Farmingville, NY 11738.

Also serving, near Mastic

We are based in East Patchogue and work across Suffolk County. If you are inside an incorporated village, the village building department governs rather than the town.

• Patchogue
• Medford
• Islip
• Bay Shore
• Smithtown

If your town is not on the list, call anyway — the list is where we work most, not a boundary. Anything from Nassau through the Twin Forks is fair game; we tell you honestly if travel makes a small job uneconomical.

Frequently Asked Questions

How do I know if my bathroom subfloor is bad?
Stand near the toilet and shift your weight. Any flex or sponginess means water has been getting in. Grout at the base of the tub that keeps cracking after being redone is the other reliable sign. Tiling over a soft subfloor guarantees a cracked floor, so it is worth knowing before the quote rather than after demolition.

Do I need a permit for a bathroom remodel in Mastic?
Replacing a vanity, retiling or swapping fixtures in the same locations is generally finish work and needs no building permit. Moving the toilet or shower drain, converting a tub to a walk-in shower, or adding a bathroom is permitted work. There is far more plumbing in a bathroom than a kitchen, so that line gets crossed more often.

Does adding a bathroom in Suffolk County need Health Department approval?
It can. If the house is on a septic system rather than sewer, adding a bathroom may trigger review by Suffolk County Department of Health Services, because the system was sized for a set number of bedrooms and fixtures. That review is separate from the town building permit. Redoing an existing bathroom does not raise it.

Is tile waterproof?
No. Tile is not waterproof; the membrane behind it is. Ask specifically what waterproofing goes in behind the tile, because it is the part you never see and the only part that decides whether the wall lasts.

Related Reading

• Bathroom permits by town — the full breakdown
• Bathroom remodel cost — 2026 Long Island numbers
• Walk-in showers — the conversion that needs a permit
• Septic and Suffolk projects — when SCDHS gets involved
• Bathroom remodeling in Suffolk — local considerations