We diagnose the real source of the water before quoting anything — no guessing, no upsell, just a plan sized to your property.

SGP Waterproofing is a licensed and insured Waterproofing contractor serving homeowners, property managers, and commercial building owners across Cranbury, NJ. We didn't start as a marketing company that added waterproofing to a service list — our crews came up running sump pumps, pouring interior drain tile, and injecting epoxy into foundation cracks long before the trucks had our name on the door.
Because we staff locally instead of subcontracting out to whoever's available, the estimate you get over the phone tends to match the invoice you get at the end of the job — no surprise line items, no upsell script.
Freeze-thaw cycles, seasonal rainfall patterns, and water table depth all shift how urgently a given crack or seep needs attention in Cranbury, NJ specifically. We track these patterns because they change how we prioritize scheduling during storm season versus a slow drip in the middle of a dry month.
Because we've worked enough Cranbury, NJ basements to recognize patterns, we can often tell within the first ten minutes of an inspection whether a problem is isolated or connected to a larger drainage issue affecting the whole block. That context shapes whether we recommend a small crack repair or a full interior system.

Water damage rarely announces itself with a flooded basement on day one. It usually shows up as one of these smaller signals first, and Cranbury, NJ's seasonal moisture swings tend to speed the timeline up.
That damp, earthy smell in a finished or unfinished basement is usually mold or mildew feeding on moisture that's already gotten past your walls.
Those white, chalky mineral deposits on block or poured concrete walls are salt left behind after water has migrated through the concrete and evaporated.
A crack that's a sixteenth of an inch wide today can become a sixteenth of an inch wider by next spring if the pressure behind the wall isn't relieved.
Bubbling paint or soft drywall near the baseboards is one of the last signs to show up, which means moisture has typically been present for weeks already.
A window well that fills with water during heavy rain is putting direct pressure on the glass and frame, and it's one of the most common entry points we find in older Cranbury, NJ homes.
Water that pools against your foundation after every rain is telling you the drainage system, whatever's left of it, has stopped doing its job.
Every job starts with the same on-site inspection, whether it's a single crack or a full interior drainage retrofit. Below are the services Cranbury, NJ clients request most often.
When a sump pump fails during a storm or a foundation wall gives way, we dispatch a crew with portable pumps and extraction equipment within hours, not days.
Interior drain tile systems, sump pump installation, and vapor barrier wall systems make up the bulk of our residential basement work across Cranbury, NJ neighborhoods.
We coordinate directly with building engineers and HOA boards so the scope, timeline, and access requirements are agreed on before a crew ever shows up on-site.
We classify every crack before injecting it — structural cracks get epoxy, active leaks get flexible polyurethane that expands to fill voids behind the wall.
We install heavy-gauge vapor barriers, seal foundation vents, and add a dedicated sump basin so a damp Cranbury, NJ crawl space stops feeding moisture into the floor joists above it.
Exterior French drains paired with corrected grading are usually the first thing we recommend for a property that's flooding from the outside in, not the inside out.
You describe what you're seeing and we ask a few questions to gauge urgency before anyone gets in a truck.
We walk the interior and exterior with a moisture meter and flashlight, tracing water back to its actual entry point instead of guessing.
We put the scope, materials, and price in writing so you can compare it against anyone else's estimate line for line.
Most residential jobs finish in one to three days, and we walk the property with you afterward to confirm every drain, pump, and seal is working.
You'll know the total cost before we start — no hourly billing, no surprise add-ons once the walls are already open.
Because our crews are based in and around Cranbury, NJ, we're not routing your call through a national scheduling system that books you two weeks out.
Our crews run truck-mounted extraction units, moisture meters, and thermal imaging cameras — not a shop-vac and a guess.
If a sealed crack reopens or a sump system underperforms within the warranty window, we come back and make it right at no extra charge.

We document every job with photos, moisture readings, and a copy of the warranty terms, so there's a paper trail if you ever need to reference the work again.


We dispatch crews throughout Cranbury and the surrounding Cranbury, NJ service area, including the zip codes listed below. If you're just outside the boundary, call anyway — we often still make the trip.

Zip codes we serve in Cranbury, NJ: 8512

"We had water coming in around the window well every time it rained hard. They regraded the area and sealed the well, and we haven't had a drop since."
— Cranbury Homeowner
"The crack in our basement wall had been leaking for a year before we finally called. Injection took less than an afternoon and it's been dry since."
— Cranbury Seller
"Our crawl space had standing water and a mold smell we couldn't get rid of. They pumped it out, encapsulated the whole thing, and added a dedicated sump discharge line."
— Cranbury Homeowner
"Our old sump pump died during the biggest storm of the year and we got water in the finished basement. They replaced it with a battery backup system so we're covered even during a power outage."
— Cranbury Customer
"Property management hired them to fix water coming through the garage ceiling. They scheduled the membrane work in phases so we never had to close the whole garage."
— Cranbury Property Manager
"We'd been dealing with musty smell in the basement for years and finally found out it was efflorescence building up behind the paint. Interior drain tile solved it for good."
— Cranbury Homeowner
For active flooding we prioritize same-day dispatch across our Cranbury, NJ coverage area; routine inspections usually book within 48 hours.
Yes — every job gets a flat-rate, written quote before work begins, and that number doesn't change once the crew is on-site.
We handle active flooding, sump pump failures, and failed foundation walls with same-day dispatch, portable extraction pumps, and temporary water mitigation.
Pricing varies with scope, but every Cranbury, NJ customer gets an itemized written estimate before any work is authorized, so there's never a guessing game.
No crack is too small to inspect; catching it early usually means a smaller repair bill down the road.
We install both — interior drain tile and sump systems for most residential jobs, and exterior membrane or French drain systems when the source is surface water or when excavation is practical.
A single crack injection can be done in an afternoon, while a full interior drainage system typically runs two to three days start to finish.
Documentation from our inspection often helps speed up the claims process, but final approval is always the insurer's call.
In most cases yes — a French drain collects water, but it still needs a sump pump to actually move that water out and away from the foundation.
We back our work with a written, often transferable warranty — useful if you sell the property before the coverage period runs out.
Standing water doesn't stop us from starting; we extract it as the first step, then proceed with vapor barrier and drainage installation.
Yes — our commercial work covers parking garages, retail basements, and multi-family buildings, usually scheduled in phases to minimize tenant disruption.
Call now for a free inspection and a flat-rate quote before anything gets worse.
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