Waterstops for Concrete Joints: PVC, Hydrophilic, Steel and Injection Hoses

A waterstop is a PVC, rubber, hydrophilic, bentonite or steel profile, or a cast-in injection hose, built into a concrete joint to block the water path through it. British practice calls the same component a waterbar, and German practice a Fugenband. Every construction joint, movement joint and pipe penetration in a basement, tank or tunnel is a planned break in the concrete, and the waterstop is the part that keeps that break watertight for the life of the structure.

Three documents carry the numbers a specifier can check. CRD-C572-74 of the US Army Corps of Engineers requires PVC waterstops to reach a tensile strength of at least 12.07 MPa (1,750 psi) and an elongation of at least 300 %, DIN 18541-1:2021-01 classifies thermoplastic waterstops in Germany, and BS 8102:2022 asks for waterstops designed as one continuous three-dimensional system. Waterstops are the joint component in this reference of construction chemicals.

This page follows the waterstop from its identity and sealing mechanism through uses, properties, the US, German and UK documents, selection, installation limits per named product, inspection, safety and VOC rules, one dated material price, alternatives and sourcing.

The summary table below lists the attributes a specifier checks first on any waterstop.

How we check: standards, codes and rules are read at the body that issues them, product values come from the data sheet named in the text, and each price carries its own source and date; the full method is in methodology and fact-checking.

What Is a Waterstop in Concrete Waterproofing?#

A waterstop is a joint component, not a coating: it is cast across or into a construction, movement or new-to-existing joint so that water meets a longer or swollen barrier instead of an open plane. The joint is the weak point because two pours of concrete never bond into one watertight mass, and shrinkage or movement opens a hairline path between them.

Waterstops close that path in three ways. A passive profile is embedded in both pours and lengthens the water path around its ribs and bulb. An active strip swells against the concrete when water reaches it. An injection hose stays empty until resin is pumped into the joint after the pour. Each of these components belongs to the joint layer of a wider system of waterproofing membranes and systems.

PVC, rubber, hydrophilic, bentonite and steel: which materials make a waterstop?#

Six material groups make waterstops: plasticized PVC, rubber, hydrophilic rubber, sodium bentonite strips, steel sheet and PVC or PE injection hoses. Each group arrives on site in its own form, from extruded profiles in rolls to strips, O-rings, cartridges of swelling sealant and hoses with fixing clips.

The six groups and their chemistry are listed below.

• Plasticized PVC (PVC-P), PVC-P/NBR blends and TPE, extruded as dumbbell, ribbed or center-bulb profiles for internal joints, or as surface (external) profiles cast against the outer face; CRD-C572-74 sets the PVC property values in the US.
• Rubber, such as SBR, chloroprene or natural rubber, extruded into profiles of the same shapes; DIN 7865 is the German document for elastomer waterstops.
• Hydrophilic rubber, a modified chloroprene with a hydrophilic resin, made into strips and O-rings that swell on contact with water; swelling sealants in cartridges extend the same principle to irregular faces and penetrations.
• Sodium bentonite strips bound with butyl rubber, the same swelling clay used in bentonite waterproofing sheets and panels.
• Galvanized or stainless steel sheet, cast across the joint like a passive profile.
• PVC or PE injection hoses, fixed on the joint face and later filled with polyurethane, acrylic or microfine cement injectate.

Material choice decides the document: PVC profiles carry CRD-C572-74 or DIN 18541 values, rubber profiles point to DIN 7865, and hydrophilic, bentonite and hose products are described by their own data sheets.

Regional names: waterbar, Fugenband and re-injectable hose#

Waterstops carry four regional names, and each describes the same joint component. The table below sets the names against their region and meaning.

The shower and doorway trims share the word but not the function, so this page treats only concrete joints in structures.

How Do Passive and Active Waterstops Seal a Concrete Joint?#

A passive waterstop seals by geometry, an active waterstop seals by swelling against the concrete when water reaches it, and an injection hose seals later, when resin is pumped into the joint voids.

A passive profile is embedded half in the first pour and half in the second. Water entering the joint must travel around the ribs and the center bulb, and the bulb lets the profile stretch when an expansion joint opens. The profile works without water and without any chemical reaction, so its performance rests on correct position, full embedment and welded splices.

An active waterstop sits on one joint face and is cast over by the second pour. When groundwater reaches it, the strip takes up water and presses against both concrete faces, closing the gap from inside. Kryton, in a vendor article, describes bentonite strips as swelling in two stages, a short crystalline stage and a long-term diffuse double-layer stage, and states that ions in sea water stop the second stage. Swelling capacity is a product value: Sika gives up to 8 times volumetric expansion for Hydrotite CJ profiles with an expansion-delay coating (distributor listing) and up to 3 times for the Hydrotite O-ring.

An injection hose is the third principle. The hose is fixed on the first-pour face before the second pour, its ends are led out of the formwork, and the joint is injected once the concrete has hardened and any leak shows. Resin leaves the hose through its openings and fills the voids along the joint, so the hose seals the joint at the moment its leaks are known.

Where Are Waterstops Used?#

Waterstops are used wherever concrete is cast in stages against water: construction joints, expansion and contraction joints, new-to-existing joints, pipe penetrations, pile heads and slab-wall joints. Any structure below the water table or holding water on its inside has these joints.

Codes and federal rules name the joints directly. Where IBC 2024 Section 1805.3 requires waterproofing, Section 1805.3.3 requires joints in walls and floors, joints between the wall and the floor, and penetrations of the wall and floor to be made watertight with approved methods and materials. Under 40 CFR 264.193, a vault used as secondary containment for a hazardous waste tank system needs chemical-resistant water stops at all joints; this requirement sits in the EPA rule, not in an OSHA standard.

The five structure types that use waterstops are listed below.

• Basements and below-grade walls, where construction joints and wall-floor joints sit under groundwater; waterstops are one layer of basement waterproofing.
• Foundation walls with a positive-side membrane, where the joints behind the membrane still take a waterstop as a second line; see exterior foundation waterproofing.
• Walls cast against a pre-applied sheet where no outer face is accessible, whose joints take waterstops beside the blindside and pre-applied waterproofing layer.
• Tanks and reservoirs, where a new potable reservoir is designed as watertight concrete with waterstops; see water-retaining structures.
• Tunnels, where waterstops welded to the membrane form compartments so water cannot travel behind the lining, and injection hoses allow leak sealing without opening it; see tunnel waterproofing.

Undrained full-round tunnel linings combine compartments with injection hoses, while segmental linings bored by a tunnel boring machine seal their segment joints with gaskets instead. Pile heads and pipe penetrations take swelling strips or sealants, because a profile cannot be cast around a round element.

Which Properties Define Waterstop Performance?#

Waterstop performance is set by different properties per type: tensile strength, elongation, cold flexibility and splice strength for PVC, expansion and minimum cover for swelling strips, and water pressure and run length for injection hoses. No single property compares all six types, so a specification states the property that matches the sealing principle.

The table below sets each type against the property that defines it, the basis of the number and a named example.

Steel waterstops have no property value or document recorded here, so a steel waterstop is specified by its sheet material, galvanized or stainless, and by the project's own drawings.

Standard requirement or product value: how to read waterstop numbers#

A document requirement is the minimum every product must reach, while a data-sheet value describes one product. The CRD-C572-74 splice minimum of 6.89 MPa (1,000 psi) applies to every job-made and factory-made splice of a PVC waterstop bought to that document, whichever maker extrudes it.

Swelling strips have no such common minimum. The Sika Hydrotite O-ring installation guide asks for at least 51 mm (2 in) of concrete cover, more in lightweight or low-strength concrete, while the HauCon chart for HyDra RX 101 gives 80 mm (3.1 in). Expansion multiples are measured by each maker on its own basis, so an expansion figure is never compared across makers and never written into a specification as a class requirement.

Which Standards Govern Waterstops in the US, Germany and the UK?#

Waterstops are governed by documents rather than one product standard: CRD-C572-74 sets PVC properties in the US, DIN 18541-1:2021-01 classifies thermoplastic waterstops in Germany, and BS 8102:2022 and IBC 2024 set the design and code duty. No current ASTM standard for PVC waterstops is recorded here, and no EN product standard for waterstops is cited on this page. The table below sets the documents side by side; other documents of the product family are indexed under construction chemicals standards.

CRD-C572-74 requirements for PVC waterstops#

CRD-C572-74 requires extruded PVC waterstops to reach at least 12.07 MPa (1,750 psi) tensile strength and 300 % elongation, and splices at least 6.89 MPa (1,000 psi). The test methods it cites, CRD-C570, CRD-C571 and CRD-C573, are Corps of Engineers methods, so the whole property set can be read in one document.

The table below lists every CRD-C572-74 requirement with its test.

The document was revised on 1974-06-01 and is still posted by the Whole Building Design Guide, which publishes the CRD-C572-74 text. Its printed metric tensile figure, 12.17 MPa, does not match 1,750 psi; the exact conversion is 12.07 MPa, and the metric values on this page are converted from the psi values.

DIN 18541 thermoplastic types and DIN 7865 elastomer waterstops#

DIN 18541-1:2021-01 defines five thermoplastic waterstop types, D, A, DA, AA and FA, with their terms, shapes, dimensions and marking. Part 2 sets the material requirements and tests, and Part 3 sets factory production control, so a German specification names the part that carries each requirement. The 2021-01 edition of Part 1 follows the editions of 1991-01, 1992-11, 2006-09 and 2014-11, and it adds drinking-water information to the scope. Elastomer waterstops for sealing joints in concrete are covered by DIN 7865, whose edition is read on the DIN catalogue record before it is written into a specification.

IBC 2024 1805.3.3, BS 8102:2022 and potable-water listings#

IBC 2024 Section 1805.3.3 requires joints in walls and floors, wall-floor joints and penetrations to be made watertight with approved methods and materials. The section names no waterstop type, so the building official accepts the method that the design documents show for each joint.

BS 8102:2022, published on 2022-03-31 to replace BS 8102:2009, sorts protection into Type A barrier, Type B structurally integral and Type C drained systems, and in 8.1.5 and section 9 asks for waterstops designed with Type B concrete as one continuous three-dimensional system. Drinking-water contact is a separate question: NSF/ANSI/CAN 61-2025 tests whether wetted materials leach contaminants above health-based limits, it is not a performance rating, and a listing belongs to one product, as Hydrotite CJ profiles are stated to meet NSF/ANSI 61 in a distributor listing. Grades 1a to 3 and the three protection types are explained under BS 8102:2022 protection of below-ground structures.

How do you check a waterstop claim on a data sheet?#

Five checks confirm a waterstop claim on a data sheet, and they are listed below.

1. Name the document and its edition, for example CRD-C572-74 or DIN 18541-1:2021-01, and the type within it.
2. Match each property value to its test method, such as CRD-C573 for tensile strength and elongation.
3. Look for splice data: the welding method and the splice tensile strength against the 6.89 MPa (1,000 psi) minimum.
4. Read the installation limits of swelling products: minimum concrete cover and the instruction to keep the strip dry before casting.
5. Confirm a drinking-water claim in the NSF/ANSI/CAN 61 listing register under the exact product name.

How Do You Choose a Waterstop for a Joint?#

Choose the waterstop by the joint: a profile where it moves or carries water pressure, a swelling strip for a compact cold joint with enough cover, and an injection hose where it must be sealable after the pour. The joint type, the water exposure and the access after casting decide the type before any product is compared.

The table below matches common joint situations with a waterstop type.

Two structure types add their own rules. Tunnels use waterstops welded to the membrane, which divide the lining into compartments, and undrained full-round linings add injection hoses for later sealing. New potable reservoirs are designed as watertight concrete with waterstops at the joints, and any product in contact with drinking water needs its own listing.

PVC profile or hydrophilic strip: which joint takes which?#

A PVC profile is cast into both pours and does not depend on water to work, while a hydrophilic strip sits inside one joint face and needs water and enough concrete cover to seal. A profile suits movement joints and joints under constant water pressure, because it bridges the gap and stretches with it. It needs space in both pours, correct centering and welded splices.

A hydrophilic strip suits compact construction joints, new-to-existing joints and penetrations, because it needs only one face and no split formwork. It seals only after water reaches it, so a strip that swells before the pour loses capacity, and a strip with too little concrete over it can spall the edge of the joint when it swells. The minimum cover is a product value, 51 mm (2 in) and 80 mm (3.1 in) in the two data sheets named in the installation table below, so a thin wall can rule out one strip and allow another. Bentonite strips follow the same rules and add one more: saline groundwater is a recorded failure mode, so a bentonite strip is not chosen where the groundwater carries sea-water salts.

When is a waterstop the wrong product?#

Four situations call for another product class, and they are listed below.

• A joint that needs only its surface sealed against rain, traffic or debris takes an elastomeric joint sealant over a filler; see expansion joints in concrete.
• A leak in a joint that is already hardened takes injection with polyurethane or acrylic resin, which seal wet or moving cracks; see polyurethane injection resins.
• A static crack in sound concrete can take a crystalline coating, whose sealing claim covers static cracks only and is a manufacturer claim, never a moving joint.
• An active leak spurting through a hole or crack takes a fast-setting hydraulic cement plug before any other repair.

How Is a Waterstop Installed? Fixing, Splicing, Cover and Injection#

A waterstop is installed before or during the pour, so the specification fixes four things: position and fixing, splices, concrete cover for swelling strips, and the hose layout with its vents. None of these can be corrected once the concrete is placed, which makes the pre-pour inspection the decisive step. The concrete contractor places cast-in waterstops, and hose injection after the pour is work for a specialist applicator.

Fixing PVC and rubber profiles and welding splices#

PVC profiles are centered in the joint, tied to the reinforcement and spliced by heat welding, never by lapping. Centering puts half the profile into each pour, so the water path is equally long on both sides, and ties on the flanges hold the profile flat while concrete is placed and vibrated around it. A profile that folds or shifts during the pour leaves one side short, and the joint leaks along the fold.

Splices are the weak link of a profile run. CRD-C572-74 requires job-made and factory-made splices to reach at least 6.89 MPa (1,000 psi) in tension, so a lapped or taped joint between two lengths does not meet the document. Factory-made intersections, such as tees and crosses, keep the job splices to straight butt welds. Heat welding of PVC releases fumes, a recorded hazard in tunnel practice, so welding is done with the ventilation and protection the contractor's safety plan sets.

Hydrophilic and bentonite strips: concrete cover and keeping them dry#

Hydrophilic strips go on clean, sound, dry-to-damp concrete, adhered or fixed with mesh or fasteners, and must not swell before the pour. Laitance, loose particles and standing water stop the strip from bedding on the first-pour face, and a strip that lifts during the pour leaves a channel beside it. Sika states that pre-hydrated hydrophilic strips lose effectiveness, so rain on the strip before casting is a reason to replace it.

Hydrophilic and bentonite products are kept dry from delivery until the concrete covers them. Minimum concrete cover differs by product, from 51 mm (2 in) to 80 mm (3.1 in) in the two data sheets listed in the table under injection hoses, and the larger figure governs where a project uses both. Low cover lets the swelling strip spall the joint edge, so a strip is placed where the drawings show enough concrete on the water side and on the dry side. Swelling sealants from cartridges follow the same rules: a clean, sound face, no early wetting and the cover stated on their data sheet.

Injection hoses: fixing, run length and injection volume#

Injection hoses are fixed every 20 to 25 cm (7.9 to 9.8 in), as one maker's instruction gives, with vented ends led out of the formwork. The hose lies on the first-pour face along the joint, held by clips so the second pour cannot lift it, and each run ends in an inlet and a vent in a junction box or at the formwork face.

The PLURAFLEX technical information limits each injection run to 10 m (33 ft) and lists 0.20 kg/m (0.13 lb/ft) of injection material to fill the hose plus 1 to 3 kg (2.2 to 6.6 lb) of additional material for the joint voids. Polyurethane, acrylic and microfine cement are the injectates, and their chemistries are compared under injection resins for concrete.

The table below lists the installation limits recorded for named products.

How Are Waterstops Inspected, and Why Do Joints Still Leak?#

Waterstop joints fail at six recorded points, from lapped splices and displaced profiles to honeycombing, pre-swollen or under-covered strips, saline groundwater and long or blocked hose runs. Each is checked before the pour or by a leak test after backfill or filling. The table below pairs each failure with its cause and the check that catches it.

Leak tests close the record. Basements are checked after backfill once groundwater returns, and water-retaining structures are filled and tested; ACI SPEC-350.1-22, which supersedes ACI 350.1-10, is the tightness-testing specification for environmental engineering concrete structures, and ACI CODE-350-20 (published in 2021, 544 pages) places liquid-tightness within serviceability. Injection records for hoses list the pressure and the volume per run.

What Health, Safety and VOC Rules Apply to Waterstops?#

Extruded PVC and rubber waterstops are articles without a hazard classification, so the safety questions sit with bentonite strips that contain crystalline silica and with polyurethane sealants and hose resins that contain diisocyanates. The table below lists each topic with its rule and instrument.

Bentonite strips and respirable crystalline silica#

Bentonite (CAS 1302-78-9) has no Annex VI entry, and most ECHA C&L notifications report it as not classified, but bentonite strip products are classified by their own SDS. The US SDS of Waterstop-RX 101T, revision 2018-07-23, classifies that strip as Carc. 1A and STOT RE 1 with the signal word Danger, because of its respirable crystalline silica content. The substance line therefore never stands for a product: each bentonite strip is read on its own SDS. For quartz (crystalline silica), CAS 14808-60-7, the line is "No Annex VI entry; product-specific, see supplier SDS (ECHA C&L: no majority; not classified 27.5 %, H372 25.2 %, H373 18.8 %, H350 7.7 %)". Where a task generates respirable crystalline silica dust in US construction work, OSHA 29 CFR 1926.1153 sets a permissible exposure limit of 50 µg/m³ as an 8-hour time-weighted average and an action level of 25 µg/m³, effective 2016-06-23; the OSHA standard text lists the exposure-control duties. In the EU, Directive (EU) 2017/2398 sets a binding limit of 0.1 mg/m³ for respirable crystalline silica.

Diisocyanates in swelling sealants and hose injection resins#

Polyurethane swelling sealants and hose resins can contain diisocyanates, and REACH Annex XVII entry 74 (Regulation (EU) 2020/1149) applies at 0.1 % by weight or more, individually and in combination. Since 2022-02-24 the supplier prints the training statement on the label, and since 2023-08-24 industrial and professional users need training before use, renewed at least every five years. Directive (EU) 2024/869 sets an EU limit of 6 µg NCO/m³ as an 8-hour time-weighted average and 12 µg NCO/m³ as a short-term limit, with transitional values of 10 and 20 µg NCO/m³ until 2028-12-31 and transposition due by 2026-04-09. The polyurethane product class has no Annex VI entry, so its classification is "see the product SDS"; where an SDS lists 4,4'-MDI (CAS 101-68-8), that monomer carries harmonised Annex VI index 615-005-00-9 with H315, H317, H319, H332, H334, H335, H351 and H373. The chemistry of these sealants and injectates is described under polyurethane resins.

VOC rules for swelling sealants and profiles#

VOC content rules do not apply to extruded profiles; a swelling sealant falls under the sealant rules of its jurisdiction. EPA AIM rules (40 CFR 59 subpart D) set no federal VOC content limit for adhesives or sealants, and Directive 2004/42/EC leaves sealants and adhesives outside its scope. In the South Coast district, SCAQMD Rule 1168 (amended 2022-11-04) sets limits by sealant category, so the category and the VOC value in g/L are read on the sealant's data sheet before it is used there.

How Much Do Waterstops Cost?#

One dated material price is on record: a carton of Waterstop-RX 102 bentonite strip, 61 m (200 ft), cost USD 454.92 at a US distributor in October 2026, calculated as USD 7.46 per m (USD 2.27 per ft). The carton holds strips of 9.5 by 19 mm (3/8 by 3/4 in) in rolls of 10.16 m (33 ft 4 in). The table below records the price with its basis.

Material price of one named product; installed prices are not on record.

Installed waterstop costs and prices for PVC profiles or hydrophilic strips have no dated source here, so a project price rests on a quote. The quote factors are the joint length in m (ft), the waterstop type, the number of welded splices and factory intersections, the hose runs with their injection, and whether the work falls before or after the pour.

What Are the Alternatives to Cast-In Waterstops?#

Six product classes compete with or complete cast-in waterstops, and each wins where the joint is already built, only the surface can be reached or water must be stopped after the pour. The table below compares them with the cast-in waterstop.

Injection and cast-in waterstops are not exclusive. A hose is cast in and injected later, and polyurethane or acrylic resin can seal a hardened joint that had no waterstop at all, while epoxy injection is kept for dormant, dry cracks.

Waterstop Grades, Packaging and Sourcing#

Waterstops are sold by length, profiles and strips in rolls, swelling sealants in cartridges and hoses with fixings and vent ends, and buyers compare them on the document met, the splice and cover data and the listing.

Data sheets from several makers are compared under construction chemicals manufacturers and suppliers.

The five checks for a waterstop order are listed below.

• Document and edition, such as CRD-C572-74 or DIN 18541-1:2021-01, with the type or profile shape.
• Splice data: welding method, factory intersections and splice strength against 6.89 MPa (1,000 psi).
• Cover and dry-storage limits for hydrophilic and bentonite strips, from the data sheet.
• Hose run length, fixings, vent ends and the approved injectate.
• An NSF/ANSI/CAN 61 listing under the exact product name where drinking water touches the joint.

Supply and installation split by type. Cast-in profiles and strips are placed by the concrete contractor during formwork, while hose injection after the pour is work for a specialist applicator with injection equipment and records.

Where Do Waterstops Fit in a Waterproofing System for Concrete Structures?#

A waterstop seals the joints of a structure whose surfaces are protected by other systems: BS 8102:2022 combines waterstops with Type B concrete, and membranes, coatings and drains handle the faces between the joints. The joint and the face are two layers of one design, and a gap in either lets water in.

Watertight concrete design and integral waterproofing admixtures are concrete topics. A Type A barrier on the faces between the joints can be a sheet, a liquid membrane or cementitious waterproofing.

Waterstop FAQs#

Is a waterbar the same as a waterstop?#

Yes: waterbar is the British name for a waterstop, and Fugenband is the German one. All three names describe the same cast-in joint component.

Can a waterstop be fitted where new concrete meets existing concrete?#

Yes: new-to-existing joints are a listed use, served by hydrophilic strips adhered to the existing face or by surface profiles. The existing face is cleaned to sound, dry-to-damp concrete before the strip is fixed.

Is hydraulic water-stop cement a waterstop?#

No: hydraulic water-stop cement is a fast-setting plug for active leaks in hardened concrete, while a waterstop is cast into the joint.

Leak plugging is covered under hydraulic cement.

Does a bentonite waterstop work in saltwater?#

Not reliably: bentonite strips in saline groundwater are a recorded failure mode. Kryton attributes it to sea-water ions that stop the second stage of swelling.

Is a branded hydrophilic strip a separate type of waterstop?#

No: a trade name such as Hydrotite names one maker's hydrophilic strip, so its expansion, cover and listing are read on its own data sheet. The type stays hydrophilic, and the data sheet values describe that product only.

Can a waterstop stop water coming through a basement wall?#

No: a waterstop prevents leaks at joints when it is cast in; water already coming through a basement wall is treated from the inside or by injection.

Negative-side methods are compared under interior basement waterproofing.