From basement flooding to foundation seepage, Arrow Tight Waterproofing has protected properties across Stony Brook, NY with industrial-grade waterproofing systems. Call now — crews are standing by 24/7.


Arrow Tight Waterproofing was founded on one principle: a dry basement shouldn't be a luxury. Our crew of certified technicians covers Stony Brook, NY with industrial waterproofing systems — the same membranes, drainage matting, and injection resins used in commercial construction, installed in your property at residential pricing.
Every technician on our team is IICRC-certified and carries full liability coverage. We pull permits where required, provide moisture readings before and after every job, and stand behind our work with a written warranty that transfers with the property.
Water damage rarely announces itself dramatically at first. It starts quiet — a damp smell, a hairline crack, a white powder on the concrete. By the time it's obvious, you've lost weeks of containment. Here's what to catch early.
White powder on concrete means water has been migrating through your wall. The mineral deposits are left behind when water evaporates after passing through the block or poured wall.
Vertical cracks are often settling. Horizontal cracks in block foundations indicate lateral soil pressure — a structural emergency, not just a cosmetic issue.
If your basement smells earthy or musty after every heavy rain, active water intrusion is feeding organic growth — likely behind the drywall or under the slab.
Water at the wall-floor joint indicates that groundwater pressure is pushing beneath your slab. This entry point worsens with every wet season if not addressed at the source.
If interior basement paint is peeling or drywall is soft and bubbling, you have elevated relative humidity at the wall surface — a reliable sign of ongoing water vapor migration.
Constant sump cycling means your drainage system is overwhelmed. This typically signals that your waterproofing perimeter needs to be upgraded, not just the pump.
Rust streaks on foundation walls mean moisture is reaching and oxidizing the rebar or metal lath inside your block or poured concrete — water that deep is already compromising structural integrity.
Hairline slab cracks that weep during wet weather indicate hydrostatic pressure building under the slab. Left alone, that pressure will widen the cracks and lift sections of the floor.
Every moisture problem has a different source. We identify yours specifically before we quote anything — then we deploy the right system, not the most expensive one.
When hydrostatic pressure is the primary culprit, the most effective long-term solution is a properly engineered interior drainage system. We install sub-slab perforated drain tile around the perimeter of your basement — capturing water before it can rise above slab level — and route it to a sump pit equipped with a dual-pump configuration.
Our sub-slab drainage systems use schedule 40 perforated PVC pipe in a stone bed, designed to handle high-volume water tables.
📞 Get a Free Drainage Quote →Full exterior waterproofing involves exposing your foundation to the footer depth, applying a crystalline or elastomeric waterproofing membrane, installing a geocomposite drainage mat, and placing exterior drain tile at the footing — the same specification used in new commercial construction.
This approach solves the problem at the source: water never reaches your interior wall surface.
📞 Schedule an Exterior Assessment →Poured concrete foundation cracks are repaired from the interior using high-pressure polyurethane or epoxy injection — the appropriate chemistry depends on whether the crack is actively leaking or dry. Polyurethane foam expands into wet, actively leaking cracks and cures flexible, accommodating minor future movement. Epoxy injection is used in dry cracks where structural bond restoration is the goal.
Block wall repointing involves removing deteriorated mortar joints to a minimum depth of 3/4 inch and repacking with waterproof hydraulic mortar.
📞 Get a Crack Injection Estimate →Crawl spaces are the most overlooked moisture source in residential structures. An unencapsulated crawl space — even one that "never floods" — pumps humid air into your living area through the stack effect, raising indoor humidity, feeding mold growth in floor joists, and accelerating wood rot in your subfloor structure. Full encapsulation seals that air pathway permanently.
Encapsulation turns your crawl space from an uncontrolled dirt floor into a semi-conditioned space.
📞 Schedule a Crawl Space Inspection →The sump pit itself matters as much as the pump. We construct 18-inch diameter pits with a gravel bed at the base for proper water collection, sealed lids to prevent vapor and radon entry, and a discharge line that terminates a minimum of 10 feet from the foundation at a positive-grade daylight point.
Sump pump replacement is one of the most time-sensitive repairs in waterproofing — a failed pump during a heavy rain event means an immediate flood.
📞 Get a Sump System Quote →We excavate and regrade window wells to the proper dimension, install a gravel drain bed with a perforated pipe tied into your perimeter drainage system, and apply waterproof flashing around the window frame — stopping the entry point at the source instead of managing it inside.
Window well covers are a maintenance measure, not a waterproofing solution — but paired with proper drainage installation.
📞 Book a Window Well Assessment →There are a lot of waterproofing companies in NY. Here's what separates the ones who fix the problem from the ones who fix the symptom — and why Arrow Tight Waterproofing consistently lands on the right side of that line.
Our process starts with a thermal imaging scan and moisture meter readings at the wall surface, floor, and any visible crack or staining.
We purchase materials from professional waterproofing suppliers, not retail channels.
Arrow Tight Waterproofing holds an active contractor's license in NY and carries $2M general liability plus workers' compensation on every crew member.
Our proposals are itemized: materials, labor, drainage footage, discharge line run, and any accessory items listed separately.
Our drainage system installations carry a written warranty against water intrusion through the protected area for the life of the system.
Water emergencies don't schedule themselves around business hours.
Reach our live dispatch team at any hour. We'll take your address, ask about what you're seeing, and schedule a free on-site inspection — typically within 24 hours or same-day for emergencies.
Your technician inspects the perimeter, scans the walls with thermal imaging, measures moisture content at every crack and stain, and maps the likely water path from grade to interior. This takes 45–90 minutes and is completely free.
The proposal covers every item: materials, drainage footage, labor, discharge routing, and any permit fee. The number on the proposal is the number on the invoice.
{Our crew completes the installation to the approved scope. On completion, we conduct a post-installation moisture check, walk you through the system, and provide the written warranty documents registered to your property address.|Installation is completed by our direct-employee crew. We clean up the jobsite, verify pump function and discharge routing, take post-install moisture readings, and hand you the warranty documentation before we leave.}
If you've noticed any of the warning signs above, the damage is compounding with every wet event. A free inspection costs you nothing; a delayed repair can cost thousands more.
📞 Call +1-866-476-1348 — Free Estimate"The crew showed up within 3 hours of my call at 9 PM on a Tuesday. I had water coming in through a crack in my poured wall at the floor joint — had been watching it for two seasons and finally called when it started spreading. They installed an interior drain system along two walls and a new sump pit. The work took two days. I've had three major rain events since then — completely dry. Worth every dollar.That kind of result speaks for itself."
"I've had two other companies look at my foundation crack before these guys. Both gave me vague proposals and neither one could tell me exactly why I had water or where it was coming in. Arrow Tight Waterproofing came out, brought a thermal camera, and showed me on screen exactly where the moisture was concentrated. The polyurethane injection they did on the crack has held for 18 months now with zero seepage. That's the most competent inspection I've ever gotten from a contractor.That kind of result speaks for itself."
"I bought a house in Stony Brook, NY knowing it had a moisture issue in the crawl space — previous owners had put down a thin plastic sheet that was doing nothing. Arrow Tight Waterproofing encapsulated the entire crawl space with a 20-mil liner, sealed the vents, and installed a dehumidifier. Within two weeks my downstairs floors stopped feeling cold and damp and the musty smell completely disappeared. The technician walked me through every step before starting. No surprises on the invoice.That kind of result speaks for itself."
"We had a window well that flooded every time we got more than an inch of rain. The well was filling up and water was coming straight in through the window sill joint. The fix was a regraded well with a perforated pipe tied into our existing interior drain. The whole job took one day. The crew was professional, cleaned up completely, and the well has handled every storm since without an issue.That kind of result speaks for itself."
"Called Arrow Tight Waterproofing after my old sump pump failed during a storm and I had 4 inches of water on my basement floor. They answered at midnight, arrived within an hour, and had a temporary pump running within 20 minutes of showing up. Once the emergency was managed, they walked me through a permanent drainage system upgrade. That was 8 months ago — I've had 6 rain events including one significant storm and the basement has stayed dry.That kind of result speaks for itself."
"As a commercial property manager overseeing several buildings in Stony Brook, NY, I've worked with a lot of waterproofing contractors. Arrow Tight Waterproofing is the first one that showed up to the initial walk with a written inspection checklist and completed it on-site before quoting. Every other contractor just eyeballed it and sent a number. Their exterior membrane on the building we had done 3 years ago is holding perfectly with zero callbacks.I'd recommend them to anyone dealing with the same problem."

We've built our service infrastructure in NY around regional crew staging rather than a single central office — which means your technician is driving 20 minutes to your property, not two hours. Coverage covers urban cores, suburban communities, and rural properties throughout Stony Brook, NY.
Our Stony Brook team handles everything from single-family residential basements to commercial foundations. If you're in Stony Brook, NY and have a water intrusion problem, we service your area. Call +1-866-476-1348 to confirm your address is covered — it almost certainly is.
📞 Confirm Your Address is Covered — Call +1-866-476-1348