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LI
/// Service

Foundation Crack Repair

Foundation cracks on Long Island range from cosmetic hairlines to active structural failures, and the repair has to match the diagnosis. We measure crack width, direction, and growth rate, then identify the root cause — whether that is normal concrete curing, hydrostatic pressure from Nassau and Suffolk's high water tables, or lateral soil movement driven by freeze-thaw cycling in Long Island's clay and sandy loam soils. Epoxy injection seals settled hairline cracks and restores structural bond. Polyurethane foam injection handles cracks with active water seepage. When cracking signals wall movement or footing settlement, we move to carbon fiber reinforcement or pier systems. Most single-crack injection jobs complete in a half day, with costs starting around $500.

Book Free Assessment (516) 529-6996
/// What's included

Engineered. Documented. Warrantied.

  • 01Written diagnosis of crack type (vertical, horizontal, stair-step, diagonal)
  • 02Root cause analysis — settlement, hydrostatic pressure, active movement
  • 03Epoxy or polyurethane injection based on condition, not price
  • 0430-year material warranty on all injection products
  • 05Documented with photos before, during, and after
Foundation Crack Repair
/// Typical investment
$500 – $3,000 typical
Exact number after on-site assessment.
/// Process

4 Steps. No Theatre.

01

Inspect

On-site measurement of crack width, depth, and direction. We use a feeler gauge and a laser to check for active movement.

02

Diagnose

Written report identifying crack type, probable cause, and whether injection alone is appropriate or engineered repair is required.

03

Repair

Epoxy for structural bond on settled cracks; polyurethane for active seepage. Full perimeter port installation, pressure-fed to refusal.

04

Verify

48-hour cure check. We return to confirm seal. Photo documentation sent to your email with warranty registration.

/// Deep-Dive Guide

Foundation Crack Repair in Nassau County: Full Cost + Method Breakdown

Crack types, repair costs, Nassau-specific soil factors, permit requirements, and how to know whether to call today or monitor for 90 days. Everything a Nassau County homeowner needs in one place.

Read the Nassau County Guide
/// FAQ Count
6
Common Questions Answered
/// Questions

FAQ.

01Is my crack serious?+
Vertical hairline cracks under 1/8" are usually cosmetic settlement. Horizontal, stair-step, or growing cracks need a structural inspection. Send us a photo and we'll give you a read before you book.
02Will injection fix a bowing wall?+
No. Injection seals a crack — it doesn't stop wall movement. If the wall is bowing inward, you need carbon fiber or wall anchors. We'll tell you honestly during the inspection.
03How much does foundation crack repair cost in Nassau County?+
Foundation crack injection in Nassau County runs $500–$3,000 depending on crack length, depth, and how many ports are required. We assess and give a written quote before any work starts. Structural cracks that indicate wall movement or settlement require a different diagnosis — crack injection alone won't solve those.
04Do I need a permit for foundation crack repair on Long Island?+
Most crack injection jobs do not require a permit. Structural repairs that involve excavation or load-bearing modifications may require a Nassau County or Town building permit. We tell you at the assessment which applies to your job.
05What type of foundation crack is most common in Nassau County homes?+
Nassau County's 1940s–1960s block foundations most commonly develop horizontal cracks from lateral clay soil pressure, and stair-step cracks from differential settlement. The clay-heavy glacial till soil in Nassau expands when wet and contracts when dry, cycling pressure against basement walls every year. Horizontal cracks at mid-wall height are the most structurally significant — they indicate the wall is bending inward. Stair-step cracks in block mortar joints signal differential settlement between footing sections.
06What does foundation crack repair cost in Nassau County?+
Nassau County foundation crack repair costs depend on crack type and severity. Epoxy injection for a settled vertical crack: $500–$1,500. Carbon fiber strap installation for horizontal or bowing walls: $2,000–$8,000 depending on wall length and strap count. Interior waterproofing with French drain: $6,000–$12,000. Exterior waterproofing: $15,000–$30,000. We provide a fixed written quote after the free on-site assessment — no changes once you sign. Read our <a href='/blog/foundation-crack-repair-nassau-county/' class='underline'>complete Nassau County crack repair guide</a> for full cost breakdowns.
/// Related Services

The Other Six Fixes.

01
Wall Repair
02
Pier Systems
03
Carbon Fiber
04
Waterproofing
05
Crawl Space
06
Settlement
/// Book

Free Assessment.
Engineered Report.

A LI Foundation Co. tech will be on-site within a week. Assessment is free, report is included, no pitch at the end.

(516) 529-6996
/// Request

Assessment Request

No sales pitch. No “today only” nonsense. We call back within 4 business hours. Prefer to talk? (516) 529-6996