1 Scope

1.1 This standard governs the design, specification, and construction of joints in cast-in-place concrete structures that must control water infiltration, accommodate movement, or both.

NOTE Covered joint types are construction (cold) joints where successive placements meet, contraction/control joints that induce cracking on a predetermined plane, expansion/isolation joints that permit differential movement, and seismic joints in structures subject to lateral drift. (1.1.1)

NOTE The covered assembly is the joint system as a whole: joint layout and spacing design, waterstop selection and performance criteria, preformed expansion-joint filler, surface sealant at the finish plane, splice and transition detailing at corners and intersections, and installation and inspection. (1.1.2)

NOTE Primary applications are water-retaining and water-excluding below-grade structures, water- and wastewater-treatment basins and channels, and below-grade building walls and slabs where groundwater exclusion is required. (1.1.3)

NOTE This standard also governs structural construction joints in above-grade walls and elevated slabs where joint preparation and bonding are specified for structural continuity. (1.1.4)

NOTE This standard owns joint system design, waterstop type-selection rationale and performance requirements, joint construction sequencing and preparation, and inspection. It cross-references the product-data scope rather than duplicating it. (1.2)

NOTE Waterstop product data, material certifications to COE CRD-C 572 and CRD-C 513, and waterstop layout shop drawings are furnished under Concrete AccessoriesConcrete Accessories and EmbedsResolves to the current edition.sync/concrete-accessories; this standard cites those submittals rather than re-specifying them. (1.2.1)

NOTE Concrete mix design, placement, consolidation, curing, and field-test cylinders are governed by Cast In Place ConcreteCast-in-Place ConcreteResolves to the current edition.sync/cast-in-place-concrete. (1.2.2)

NOTE Isolation-joint layout for slabs-on-grade and subgrade preparation are governed by Slab On GradeSlab-on-GradeResolves to the current edition.sync/slab-on-grade; the cold liquid-applied weatherseal and acoustical sealants that fill above-grade envelope joints are governed by Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants. (1.2.3)

NOTE Below-grade waterproofing membranes on the exterior face of foundation walls and slabs are governed by Below Grade WaterproofingBelow-Grade WaterproofingResolves to the current edition.sync/below-grade-waterproofing; joint reinforcement, lap splices, and mechanical couplers are governed by Concrete ReinforcementConcrete ReinforcementResolves to the current edition.sync/concrete-reinforcement. (1.2.4)

NOTE Precast panel-to-panel joints are governed by Precast ConcretePrecast ConcreteResolves to the current edition.sync/precast-concrete; repair of deteriorated or leaking existing joints by Concrete Repair And RestorationConcrete Repair and RestorationResolves to the current edition.sync/concrete-repair-and-restoration; shotcrete liner joints by ShotcreteShotcreteResolves to the current edition.sync/shotcrete; and site flatwork joints not subject to hydrostatic pressure by Site Concrete StructuresCast-in-Place Site Concrete StructuresResolves to the current edition.sync/site-concrete-structures. (1.2.5)

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.

2.2 Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

Standard	Title
ACI 301-20	Specifications for Concrete Construction
ACI CODE-318-25	Building Code Requirements for Structural Concrete and Commentary
ACI 350-06	Code Requirements for Environmental Engineering Concrete Structures and Commentary
ACI 504R-90 (R1997)	Guide to Sealing Joints in Concrete Structures
ACI 117-10 (R2015)	Specification for Tolerances for Concrete Construction and Materials
ASTM D8530/D8530M-23	Standard Guide for the Selection and Use of Waterstops
COE CRD-C 572	Specification for Polyvinylchloride Waterstops
COE CRD-C 513	Specification for Rubber Waterstops
ASTM D1751-23	Preformed Expansion Joint Filler (Nonextruding and Resilient Bituminous Types)
ASTM D1752-18	Preformed Sponge Rubber, Cork and Recycled PVC Expansion Joint Fillers
ASTM C920	Standard Specification for Elastomeric Joint Sealants
ASTM C1193	Standard Guide for Use of Joint Sealants
USACE EM 1110-2-2102	Waterstops and Other Preformed Joint Materials for Civil Works Structures

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following action submittals for review before fabrication or installation of any joint material:

Joint layout and design drawings showing every construction, contraction, expansion, and seismic joint with its type, location, and assigned waterstop profile.
Waterstop type selection schedule keyed to the joint layout, listing material, profile, width, and design hydrostatic head for each joint run.
Splice and transition details for re-entrant corners, T-intersections, and changes of waterstop profile, including factory-prefabricated transition fittings.
Manufacturer's installation instructions for each waterstop, filler, and sealant type, and the proposed field-splice procedure with welder qualifications.

Action Submittalscheckbox

☑ Joint layout and design drawings

☑ Waterstop type selection schedule

☑ Splice and transition details

☑ Manufacturer installation instructions and splice procedure

3.1.2 Waterstop product data, material certifications, and the coordinated waterstop layout shop drawings are submitted under Concrete AccessoriesConcrete Accessories and EmbedsResolves to the current edition.sync/concrete-accessories and shall be cross-referenced on the joint layout drawings rather than duplicated here.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following informational submittals:

Field-splice test reports for the required sample frequency, reporting tensile strength as a percentage of parent material and the result of the cold-bend test.
Surface-preparation records for each construction joint, documenting the method used and the depth of aggregate exposure achieved.
Hydrostatic test or flood-test reports for completed water-retaining structures where required by the contract.

Informational Submittalscheckbox

☑ Field-splice test reports

☑ Surface-preparation records

☐ Hydrostatic / flood-test reports

4 Quality Assurance

4.1 The Contractor shall not place concrete against any joint until the waterstop and joint preparation for that pour have been inspected and accepted.

4.2 Field splices of thermoplastic waterstop shall be performed only by personnel qualified in heat-fusion welding of the submitted product.

4.3 Field splices of rubber waterstop shall be vulcanized in accordance with the manufacturer's procedure.

NOTE Joint-circuit continuity is the single most important quality objective: the waterstop must form an unbroken pressure barrier around the entire joint perimeter, including re-entrant corners and intersections. A waterstop that is merely lapped or looped at a corner, rather than continuously spliced, leaves a break in the barrier through which water migrates. (4.3.1)

4.4 The waterstop layout shall be inspected for continuity at every corner, intersection, and profile transition before the second pour, and any discontinuity shall be corrected before concrete placement.

NOTE Skipping laitance removal at a construction joint and relying on a bonding agent alone is a leading cause of cold-joint delamination, because the bonding agent then bonds to the laitance, which separates from the sound substrate. Laitance is always removed first, and a bonding agent is applied only afterward where specified. (4.4.1)

5 Environmental and Service Conditions

5.1 Design Hydrostatic Head

NOTE Design hydrostatic head is the primary variable governing waterstop type and profile width. It ranges from negligible at interior slabs to more than 150 ft (45 m) at deep tunnels and reservoirs; for typical below-grade building construction the head is 15 to 30 ft (4.5 to 9 m). (5.1.1)

5.1.2 The Engineer of Record shall establish the design hydrostatic head for each joint run from the maximum groundwater or contained-fluid elevation, and the waterstop selection schedule shall list that head for each run.

Design hydrostatic head at jointrange

ft

0150

Default: 25 ft

5.2 Chemical and Service Exposure

NOTE Standard PVC waterstop is acceptable only for clean-water service. Concrete in contact with wastewater, seawater, petroleum products, or chlorinated water requires a chemical-resistant rubber (neoprene or EPDM) waterstop, or a hydrophilic type rated for the specific chemical exposure. (5.2.1)

5.2.2 The waterstop material for each joint run shall be selected for compatibility with the service exposure of that structure.

Service / chemical exposureselect

Clean water (potable, stormwater)

Wastewater / sewage

Seawater / brackish

Chlorinated process water

Petroleum or hydrocarbon contact

5.2.3 The surface sealant at a permanently wet or submerged joint face shall be an immersion-rated sealant tested per ASTM C1247; standard non-immersion ASTM C920 Class 25 grades shall not be used at submerged faces.

6 Joint Type Classification

NOTE Joint type classification determines the waterstop profile and whether a preformed filler is required. The three functional classes are: a construction (cold) joint, which transfers load with no intended movement and requires bond; a contraction/control joint, which induces a crack on a predetermined plane with no bond; and an expansion/isolation joint, which fully separates two concrete masses and must accommodate movement. (6.1)

6.2 Construction (Cold) Joints

NOTE A construction joint occurs where one concrete placement meets a previously placed, hardened surface. It is intended to behave as a monolithic section once bonded, so the joint requires no movement capacity but does require a sound, bonded interface. (6.2.1)

6.2.2 Construction joints shall be located only where shown on the accepted joint layout drawings or as approved by the Engineer of Record.

6.2.3 The waterstop at a construction joint shall be a flat-web or ribbed profile without a centerbulb, because no movement is expected and a centerbulb would add cost without function.

Construction joint waterstop profileradio

● PVC flat-web / ribbed, 6 in. (150 mm)

○ PVC flat-web / ribbed, 9 in. (230 mm)

○ Rubber / EPDM flat-web, 6 in. (150 mm)

○ Hydrophilic swelling strip

6.3 Contraction / Control Joints

NOTE A contraction joint induces cracking at a controlled location by creating a weakened plane, relieving restraint from drying shrinkage and thermal contraction. The joint opens slightly as the concrete shrinks; the waterstop must remain sealed across that small opening. (6.3.1)

6.3.2 Contraction joints shall be formed with a continuous bond breaker across the joint plane so the concrete is free to separate at the intended location.

6.3.3 A centerbulb waterstop should be provided at a contraction joint where the calculated opening, plus construction tolerance, exceeds the sealing capacity of a flat-web profile.

6.4 Expansion / Isolation Joints

NOTE An expansion or isolation joint fully separates two concrete masses to permit independent thermal, shrinkage, and differential-settlement movement. It must contain a compressible filler to maintain the gap and a centerbulb waterstop sized to flex through the full movement range. (6.4.1)

6.4.2 The waterstop at an expansion joint shall be a centerbulb profile not less than 9 in. (230 mm) wide.

6.4.3 A preformed compressible filler shall be installed for the full depth and width of the expansion joint to maintain the gap and allow the joint to close under movement.

Expansion joint waterstop profileradio

● PVC centerbulb, 9 in. (230 mm)

○ PVC centerbulb, 12 in. (300 mm)

○ Rubber / EPDM centerbulb, 9 in. (230 mm)

○ Rubber / EPDM centerbulb, 12 in. (300 mm)

6.5 Seismic Joints

NOTE A seismic joint is an expansion joint sized to accommodate the calculated lateral drift between adjacent structures or structural units under design seismic loading, in addition to thermal and shrinkage movement. (6.5.1)

6.5.2 The width of a seismic joint shall accommodate the sum of the design seismic drift and the thermal/shrinkage movement, as established by the Engineer of Record.

7 Joint Spacing and Layout

NOTE For water-retaining structures, ACI 350 governs joint spacing through a crack-width analysis that limits the crack width at liquid-exposed faces to 0.010 in. (0.25 mm), calculated per ACI 350-06 Section 10.6. This crack-width limit, not a fixed spacing table, is the controlling criterion. (7.1)

7.2 The crack width at faces exposed to contained or external liquid shall be limited to 0.010 in. (0.25 mm) by the combination of reinforcement and joint spacing, in accordance with ACI 350.

NOTE Contraction joint spacing in continuously reinforced concrete walls is typically 20 to 30 ft (6 to 9 m); where reinforcement is light or the wall behaves as lightly reinforced, 15 to 20 ft (4.5 to 6 m) is typical. (7.2.1)

NOTE Expansion joint spacing in water-retaining structures is typically 50 to 100 ft (15 to 30 m), set by the Engineer of Record from the temperature differential, member geometry, and restraint conditions. (7.2.2)

7.3 Contraction and expansion joint spacing shall be established by the Engineer of Record for each structure and shown on the joint layout drawings.

Contraction joint spacing (reinforced walls)range

ft

1530

Default: 25 ft

Expansion joint spacing (water-retaining)range

ft

50100

Default: 75 ft

NOTE Over-restraining contraction joints by spacing them too closely in heavily reinforced walls is a common error: the reinforcement carries the shrinkage tension, the joints never open, and distributed micro-cracking occurs elsewhere - defeating the purpose of the layout. Contraction joint spacing should not be reduced below the analysis-based spacing merely to add joints. (7.3.1)

8 Waterstop Selection

NOTE Waterstop selection follows from four inputs: the joint's movement class, the design hydrostatic head, the chemical exposure, and the access available for installation. Profile geometry follows movement; material follows exposure and head; the installation method (welded versus swelling) follows access. (8.1)

8.2 Waterstop Material

NOTE PVC is the standard waterstop material for clean-water service and is economical, weldable, and widely available. Rubber (neoprene or EPDM) is selected for aggressive chemical exposure and for water- and wastewater-treatment plants. A hydrophilic swelling strip is selected where welding is impractical - most often blind-side or post-pour joints with restricted access - because it requires no field splice. (8.2.1)

8.2.2 The waterstop material shall be specified for each joint based on the chemical exposure and field-splice accessibility of the joint.

Waterstop materialradio

● PVC (polyvinyl chloride)

○ Rubber / neoprene / EPDM

○ Hydrophilic swelling strip (bentonite or acrylamide)

○ External surface-mounted (crystalline / hydrogel strip)

8.2.3 PVC waterstop shall conform to COE CRD-C 572 with a minimum tensile strength of 2,000 psi (13.8 MPa), minimum elongation at break of 350%, and a low-temperature bend at -35°F (-37°C) without cracking.

8.2.4 Rubber waterstop shall conform to COE CRD-C 513 with a minimum tensile strength of 1,500 psi (10.3 MPa), minimum elongation at break of 400%, and a hardness of Shore A 40 to 65.

8.2.5 Each PVC waterstop product submittal shall state a hydrostatic head rating not less than the design head for the joint, because COE CRD-C 572 sets material strength minimums but does not itself certify a head rating.

NOTE Without a specified head rating tied to the design pressure, a contractor may submit a lighter-gauge product that passes the material test yet fails at pressure; the head rating is therefore a mandatory submittal datum, not an optional one. (8.2.6)

8.3 Waterstop Profile

NOTE Profile geometry follows the joint function. A centerbulb accommodates movement at expansion (and high-movement contraction) joints; a flat-web or ribbed profile, having no movement capacity, is correct at non-moving construction joints. A split-web or re-entrant profile is used where concrete is placed against existing concrete on one side only - blind-side or post-pour conditions. An external surface-mounted profile is a retrofit applied to a formed face where an internal waterstop was omitted or damaged. (8.3.1)

8.3.2 Specifying a centerbulb where no movement occurs wastes material, and specifying a flat-web where differential settlement or thermal expansion occurs creates a leak path; the profile shall match the joint's movement class in every case.

Waterstop profile geometryselect

Centerbulb (movement joints)

Flat-web / ribbed (construction joints, no movement)

Split-web / re-entrant (blind-side, post-pour)

External surface-mounted (retrofit)

8.4 Waterstop Width

NOTE Minimum waterstop width per USACE EM 1110-2-2102 is 6 in. (150 mm) for construction joints with no movement and 9 in. (230 mm) for expansion joints with movement. The profile is widened to 12 in. (300 mm) when the head exceeds approximately 50 ft (15 m) or where chemical exposure is severe. (8.4.1)

8.5 Construction joint waterstop shall be not less than 6 in. (150 mm) wide.

8.6 Expansion joint waterstop shall be not less than 9 in. (230 mm) wide.

8.7 Waterstop width shall be increased to not less than 12 in. (300 mm) where the design head exceeds 50 ft (15 m) or the chemical exposure is severe.

Waterstop widthselect

6 in. (150 mm)

9 in. (230 mm)

12 in. (300 mm)

8.8 Hydrophilic Strips

NOTE A hydrophilic strip swells on contact with water to seal against the surrounding concrete, requires no welding, and is nailed or adhered to a formed face before the second pour - its primary advantage at restricted-access joints. Its swell pressure must meet or exceed the design hydrostatic pressure, and it must be a delayed-swell (buffered) grade so it does not exhaust its expansion capacity before the joint is closed. (8.8.1)

8.8.2 Hydrophilic strips shall have a rated swell pressure not less than the design hydrostatic pressure at the joint.

8.8.3 Hydrophilic strips at joints that may be wetted during construction shall be a delayed-swell (buffered) grade.

NOTE Specifying a non-buffered hydrophilic strip where the concrete will be permanently wet before the second pour causes premature swelling that fills the expansion capacity before the joint is sealed; the delayed-swell grade exists specifically to prevent this failure. (8.8.4)

8.8.5 Where a hydrophilic strip is specified, its cross-section dimensions shall be specified based on the design hydrostatic pressure at the joint.

Hydrophilic strip cross-sectionselect

3/4 in. x 1 in. (19 x 25 mm)

3/4 in. x 1-1/2 in. (19 x 38 mm)

1 in. x 1 in. (25 x 25 mm)

Hydrophilic strip rated swell pressurerange

psi

30100

Default: 60 psi

9 Preformed Joint Filler

NOTE Preformed filler maintains the gap at an expansion or isolation joint and must compress as the joint closes. Common materials are bituminous-impregnated fiberboard (ASTM D1751), sponge rubber or cork (ASTM D1752), and closed-cell polyethylene foam; the choice is driven by joint width, expected movement, and recovery requirements. (9.1)

9.1.1 Preformed filler at expansion and isolation joints shall conform to ASTM D1751 or ASTM D1752 as appropriate to the application.

Preformed filler materialradio

● Bituminous-impregnated fiberboard (ASTM D1751)

○ Sponge rubber (ASTM D1752)

○ Cork (ASTM D1752)

○ Closed-cell polyethylene foam

9.1.2 Where the joint receives a field-applied surface sealant, the filler shall be compressible and shall allow the joint to close through its full movement range.

NOTE Leaving a rigid filler in place at a sealed expansion joint prevents the joint from compressing, so the joint cannot accommodate movement and the waterstop buckles. Filler at sealed joints is specified as compressible and removable to the sealant depth for exactly this reason. (9.1.3)

9.1.4 The preformed joint filler thickness shall be specified for each expansion or isolation joint based on the joint's required movement range.

Joint filler thicknessselect

1/2 in. (13 mm)

3/4 in. (19 mm)

1 in. (25 mm)

1-1/2 in. (38 mm)

10 Surface Sealant at Joint Face

NOTE The surface sealant at the exposed joint mouth is a secondary line of defense above the embedded waterstop; the waterstop, not the sealant, is the primary pressure barrier. The sealant chemistry, backer rod, bond breaker, primer, and tooling are governed by Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants, and this standard references that scope rather than re-specifying it. (10.1)

10.1.1 The surface sealant at exposed joint faces shall conform to ASTM C920 and shall be installed per ASTM C1193 and Joint SealantsJoint SealantsResolves to the current edition.sync/joint-sealants.

10.1.2 For non-traffic concrete joints the surface sealant shall be ASTM C920 Type S, Grade NS, Class 25, Use NT - single-component polyurethane is the common selection.

ASTM C920 sealant designation (joint face)select

Type S, Grade NS, Class 25, Use NT

Type S, Grade NS, Class 35, Use NT

Type S, Grade P, Class 25, Use T

Type M, Grade NS, Class 25, Use NT

10.1.3 A closed-cell polyethylene backer rod shall be installed at the joint mouth at a diameter 25% to 50% larger than the joint width, to set the sealant depth and act as a bond breaker.

10.1.4 For joints up to 1 in. (25 mm) wide, the sealant shall be tooled to a width-to-depth ratio of approximately 2:1.

11 Splices and Transitions

NOTE A waterstop is only as good as its weakest splice, and the joint circuit must be continuous and unbroken around the entire perimeter. Straight-run splices are field-made, but re-entrant corners, T-intersections, and profile changes require factory-prefabricated fittings spliced into the run. (11.1)

11.2 PVC waterstop field splices shall be heat-fusion butt welds developing not less than 75% of the parent material tensile strength.

11.3 Rubber waterstop field splices shall be vulcanized in accordance with the manufacturer's procedure.

11.4 Corner, intersection, and transition fittings shall be factory-prefabricated and spliced into the straight runs in the field; corners and intersections shall not be field-fabricated from cut straight stock.

NOTE A transition between two joint types on a continuous run - for example a construction joint that meets an expansion joint - requires a single factory-prefabricated piece that joins the two profiles. Field-fabricating this transition from two incompatible profiles is a common failure mode and is prohibited. (11.4.1)

11.5 A transition between differing waterstop profiles on a continuous run shall be made with a single factory-prefabricated transition fitting.

Field-splice test sampling frequencyselect

1 sample per 5 splices

1 sample per 10 splices

1 sample per 25 splices

12 Construction Joint Preparation

NOTE Construction joint preparation removes the weak surface layer of laitance and exposes sound aggregate so the second placement bonds to the substrate, not to laitance. The required result is clean, sound, roughened concrete with exposed aggregate; the method may be hydroblasting, sandblasting, bush-hammering, or a chemical surface retarder washed off before the next pour. (12.1)

12.2 Laitance shall be removed and aggregate exposed to a depth of approximately 1/4 in. (6 mm) at every construction joint before the adjacent concrete is placed.

12.3 Surface preparation shall be performed by hydroblasting at 3,500 to 5,000 psi (24 to 35 MPa), sandblasting, or a chemical surface retarder applied before the first pour and washed off before the second.

12.3.1 Where a bonding agent is specified, it shall be applied only after laitance removal and only to a clean, sound substrate.

Construction joint surface preparation methodradio

● Hydroblast 3,500-5,000 psi (24-35 MPa)

○ Sandblast to exposed aggregate

○ Bush-hammer to exposed aggregate

○ Chemical surface retarder (applied then washed)

13 Installation

13.1 Waterstops shall be installed centered on the joint plane within the ACI 117 tolerance of ±1/4 in. (6 mm) from the joint centerline.

NOTE A waterstop that migrates out of the joint plane and contacts the form face instead of centering in the concrete is effectively non-functional, because half its flange ends up against the form rather than embedded; centering tolerance is therefore a controlled installation parameter. (13.1.1)

13.2 Waterstops shall be continuously supported and secured against displacement during concrete placement and consolidation.

13.3 Concrete shall be consolidated around both flanges of the waterstop so that no voids form adjacent to the embedded flange.

NOTE The reinforcement cage must be detailed with gaps and hooks at the joint centerline so the waterstop can be centered and fully encapsulated. Where the cage interferes with the waterstop, concrete cannot consolidate around the flange and a void forms - a leak path. (13.3.1)

13.4 The waterstop layout shall be coordinated with the reinforcement placement of Concrete ReinforcementConcrete ReinforcementResolves to the current edition.sync/concrete-reinforcement so that the waterstop is centered and fully encapsulated without interference.

13.5 Hydrophilic strips shall be installed in continuous contact with the formed concrete face and secured per the manufacturer's instructions so no gap remains behind the strip.

NOTE Below-grade water-retaining walls require both an embedded waterstop at every joint and the exterior waterproofing membrane of Below Grade WaterproofingBelow-Grade WaterproofingResolves to the current edition.sync/below-grade-waterproofing; these are complementary systems. Relying solely on the exterior membrane is a design gap, because the membrane's weakest point is always at the joint. (13.5.1)

14 Testing

14.1 Field-splice samples shall be taken at the specified sampling frequency and tested for tensile strength and cold-bend performance, with results reported as a percentage of parent material strength.

14.2 Completed water-retaining structures shall be hydrostatically tested or flood-tested where required by the contract, and any leakage at a joint shall be corrected before acceptance.

Hydrostatic / flood test requiredradio

● Yes - per ACI 350 leakage criteria

○ No

15 Delivery, Storage, and Handling

15.1 Waterstops shall be delivered in original packaging and stored under cover, protected from direct sunlight, ozone sources, oils, and physical damage.

15.2 Hydrophilic strips shall be kept dry and in their sealed packaging until immediately before installation to prevent premature swelling.

15.3 Preformed filler and sealant shall be stored within the manufacturer's temperature and shelf-life limits and shall not be used after the stated expiration.

16 Warranty

16.1 The Contractor shall warrant the watertightness of all joints in water-retaining and water-excluding structures against leakage for the contract warranty period.

16.2 The Contractor shall repair any joint leakage discovered within the warranty period at no cost to the Owner, including restoration of finishes disturbed by the repair.