From a hairline crack in the block wall to standing water in the crawl space, our Somerville, NJ crews handle it with flat-rate pricing and same-day dispatch.

SGP Waterproofing is a licensed and insured Waterproofing contractor serving homeowners, property managers, and commercial building owners across Somerville, 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.
Older Somerville, NJ neighborhoods often have block foundations poured decades before modern drainage codes existed, while newer subdivisions tend to run poured concrete with a perimeter drain that was installed correctly but has since clogged with silt. Knowing which era of construction you're dealing with changes the repair plan before a single tool comes out of the truck.
We also see a lot of properties where a previous waterproofing attempt only addressed the symptom — a topical sealant painted over a cracked wall, for example — without solving the pressure or grading issue causing the crack in the first place. Part of every Somerville, NJ inspection is checking for that kind of prior patch job before we recommend anything new.

Most Somerville, NJ water intrusion problems don't start as a flood — they start small, and they get worse on a schedule. Here's what our technicians look for on a first inspection.
A persistent musty smell almost always means moisture is present somewhere in the wall assembly, even if you can't see a wet spot yet.
Efflorescence forms when water carries dissolved minerals through porous concrete and leaves them on the surface as it dries — a clear sign moisture is actively passing through.
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.
Drywall that feels soft, bubbles, or shows a tide line near the floor is already absorbing groundwater — by the time you see it, the insulation behind it is usually soaked too.
If your window wells hold water for more than an hour after a storm, that water has nowhere to go but toward the seal around your basement window.
Puddling near the foundation that doesn't drain within a few hours usually means grading, gutters, or a failing perimeter drain — and it's the fastest path to a flooded basement.
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 Somerville, NJ clients request most often.
Once the water is out, we run air movers and dehumidifiers to bring humidity down before mold has a chance to establish itself in drywall or subfloor.
For finished basements we route the drain tile beneath the existing slab edge, which limits how much flooring has to come up during installation.
Commercial jobs typically pair exterior membrane work with an interior collection system, since most existing commercial structures can't be fully excavated without major disruption.
Low-pressure epoxy injection bonds structural cracks back together, while polyurethane injection is better suited for cracks that are still actively leaking.
Encapsulation starts with removing standing water and debris, then sealing the space with a 12-20 mil liner and a dehumidifier sized to the cubic footage.
Extending downspouts another six to ten feet away from the foundation solves more Somerville, NJ drainage problems than people expect, and we'll usually check that before recommending anything more invasive.
A dispatcher walks through symptoms with you on the phone so the crew that shows up already has a rough idea what they're dealing with.
We walk the interior and exterior with a moisture meter and flashlight, tracing water back to its actual entry point instead of guessing.
You get a flat-rate, itemized quote before any work starts — no verbal estimate that changes once the crew shows up.
Once installation wraps, we test the sump pump under load and walk you through the warranty paperwork before we leave the site.
We quote the whole job as one flat number, so the price on the invoice matches the price we quoted on day one.
Same-day availability isn't guaranteed on every job, but our Somerville, NJ dispatch is built to prioritize it whenever the situation calls for it.
Every technician trains on interior drain tile installation, sump system sizing, and crack classification before they lead a job on their own.
We stand behind the installation with a written warranty, and we'd rather send a crew back for a free fix than lose a customer over it.

Warranty terms vary by scope of work, and our technician will walk through exactly what's covered before you sign off on the quote — nothing vague, nothing left to interpretation.


Our Somerville coverage area extends through most of the surrounding Somerville, NJ communities. Give us a call even if your address falls just outside the zone below; we'll let you know honestly if we can reach you same-day.

Zip codes we serve in Somerville, NJ: 08876 8876

"Our basement flooded during a storm at 2am and someone actually picked up the phone. The crew had pumps running before sunrise and came back two days later to install the drain tile system."
— Somerville 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."
— Somerville Seller
"The crawl space under our addition never dried out properly. Full encapsulation with a dehumidifier fixed it in one visit."
— Somerville 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."
— Somerville 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."
— Somerville 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."
— Somerville Homeowner
Most Somerville, NJ emergency calls get a technician on-site within a few hours; non-urgent inspections are typically scheduled within one to two business days.
Pricing is disclosed in full before you sign anything, and we walk through each line item so nothing is a surprise later.
Our emergency response covers water extraction, temporary pump-outs, and emergency crack sealing to stop active intrusion until permanent repairs are scheduled.
Cost depends on square footage, the type of system needed, and whether the fix is interior drainage, exterior membrane work, or both — we won't quote a number without an in-person inspection first.
No crack is too small to inspect; catching it early usually means a smaller repair bill down the road.
Depending on what the inspection finds, we'll recommend interior drainage, exterior grading and membrane work, or a combination of both.
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.
We can document moisture readings, photos, and scope of damage to support an insurance claim, though coverage and claim approval are ultimately determined by your carrier.
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.
Commercial scheduling is handled separately from residential dispatch so larger projects get the coordinated planning they need.
Call now for a free inspection and a flat-rate quote before anything gets worse.
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