Below-grade and foundation waterproofing with a cold fluid-applied membrane costs $10.50–$13.75 per square foot of wall in 2026, including surface prep, primer, detailing and the membrane. Specified systems with a 90-mil membrane, epoxy primer, drainage panel and manufacturer warranty run $15.75–$21 per square foot. A penetrating water-repellent sealer for concrete or masonry runs $1.85–$2.65 per square foot. Excavation to expose the foundation, utility locating, shoring and backfill are not included and are priced separately. Jobs start at the $3,750 minimum.
Waterproofing cost per square foot
Estimates for budgeting only, not an offer, bid or quote. Permits, government fees and testing are extra unless listed; your signed written proposal sets the price.
| Item | Price | Unit | Includes |
|---|---|---|---|
| Below-grade and wall waterproofing, fluid-applied membrane | $10.50 – $13.75 | per square foot | Surface prep, primer, membrane |
| Below-grade waterproofing system, specified (90-mil membrane, epoxy primer, drainage panel, manufacturer warranty) | $15.75 – $21 | per square foot | Surface prep, 2-coat epoxy primer, detailing, 90-mil membrane, drainage panel, manufacturer inspections and warranty |
| Penetrating concrete or masonry sealer | $1.85 – $2.65 | per square foot | Cleaning, sealer application |
Budget ranges for 2026, not a quote. Prices include what the Includes column lists. Not included: permits and other government fees, and testing, engineering and utility disconnects by others. Minimum charge: $3,750 per job.
Permit or notice: Usually none, or covered by the project’s building permit. Permit fees are not included; we pull or coordinate the permits our work needs, billed at cost plus administrative time.
Waterproofing cost by wall size
| Project | Price |
|---|---|
| Foundation wall, 8 ft high, 100 LF (800 SF), standard membrane | $8,400 – $11,000 |
| Below-grade wall, 12 ft high, 250 LF (3,000 SF), specified system | $47,250 – $63,000 |
| Water-repellent sealer on a block wall, 2,000 SF | $3,750 – $5,300 |
What’s in the price
Cleaning and preparing the concrete to the surface profile the membrane needs, patching voids, routing and sealing cracks, detailing inside and outside corners, joints and penetrations, primer, and the membrane at the specified thickness. Below grade, the foundation has to be dug out first, with buried utilities located and often with shoring; that work is priced separately, and the membrane is covered before backfill.
Included
- Pressure washing or grinding the concrete to a clean, sound surface
- Patching voids and routing and sealing cracks
- Primer and detail coats at corners, joints and penetrations
- Fluid-applied membrane at the specified thickness
Not included
- Excavation to expose the foundation, shoring and backfill (see the excavation page)
- Utility locating and potholing before digging along the foundation
- Protection board, drainage mat and subdrains unless listed
- Structural repairs, engineering or a water-intrusion investigation
- Interior finishes damaged by past leaks
We price this work as part of our removal and site projects; specialty trades are performed by appropriately licensed subcontractors where the law requires.
How we measure
Per square foot of wall or slab surface waterproofed. Crack and joint detailing is part of the price; larger concrete repairs are priced by the area repaired.
Waterproofing cost questions
How much does it cost to waterproof a foundation?
$10.50–$13.75 per square foot of wall for a cold fluid-applied membrane in 2026, with surface prep, primer and detailing, so 800 square feet of wall runs $8,400–$11,000. Specified systems with a 90-mil membrane, epoxy primer, drainage panel and manufacturer warranty run $15.75–$21. Excavation to expose the foundation, utility locating, shoring and backfill are not included and are priced separately, and jobs start at the $3,750 minimum. See the excavation and grading cost guide.
How much does below-grade waterproofing cost for a basement or underground room?
The membrane runs the same $10.50–$13.75 per square foot of wall, or $15.75–$21 for a specified system with drainage panel and manufacturer warranty. The bigger variable is getting to the wall: depth, shoring, access for equipment, and what has to be protected or replaced at the surface. Send plans or photos for a lump-sum price.
How much does a concrete or masonry water-repellent sealer cost?
$1.85–$2.65 per square foot for a penetrating water-repellent sealer, cleaning included. It helps above-grade concrete and masonry shed water; it isn’t a substitute for a membrane on a wall that holds back soil.
For architects, engineers and contractors
Scope: Below-grade and building envelope waterproofing
Per-square-foot rates can be used as budget unit prices, and contract unit prices are set in the proposal or bid. Excavation and shoring usually carry as separate line items. Cost terms glossary · Printable unit-price sheet
What to send for a firm quote
- Plans, specs or the waterproofing scope
- Wall height and length, and depth below grade
- Photos of the wall, access and anything at the surface
- Any water-intrusion or soils report
Request a project review or call (949) 446-0000
More cost guides
Demolition cost · Pool, wall and fence removal cost · Concrete cutting and coring cost · Concrete and asphalt removal cost · Excavation and grading cost · Land clearing cost · Hydroseeding and irrigation cost · Asbestos removal cost · Lead paint removal cost · Tanks and hazardous materials cost · Hauling and disposal cost · Testing cost · Drywall and patch-back cost · Fire-damaged demolition cost · Interior demolition cost · Commercial demolition cost · Demolition permit and AQMD fees · Popcorn ceiling removal cost · Floor tile and mastic removal cost · All 2026 prices · Cost terms glossary · All SoCal Removal services
Disclaimer: a guide, not a quote.
These prices are a guide for budgeting, not a quote. They are our 2026 price ranges for common projects in Southern California. Your written price depends on the site, access, quantities, the materials found, the schedule and the documents you provide, and it can come in above or below these ranges; the written proposal governs.
Permits, inspections and other government fees vary from city to city and county to county and are not included. Neither are plan preparation, engineering, utility planning, agency submittals and coordination, inspector standby, return trips or administrative time, other than the asbestos air-district notice we prepare and file. Testing is priced on the testing page. Worked examples illustrate their stated assumptions and are not quotes. When a project needs any of these, they’re listed in the written proposal.
A written proposal follows a site walk or a review of your plans, reports and photos.
SoCal Removal is the business name of Abajian Enterprise, a California corporation. CSLB #980451 (A, B, C-21). Certifications: HAZ, ASB (ASB for bidding only). Verify the license · Insurance and project bonding