Important Considerations: Joint Cleanliness- A clean joint should have no visible signs of residual sealant or debris on the joint face and some form of backer rod or bond breaker tape be installed. For nonmoving joints, the width to2. For construction or contraction joints a bond breaker tape or back-up strip should be used. Aspal sealant bulk / asphaltic plug , joint sealant rigid beton. 3 mm). - Compatible with cold-applied sealants. The ratio of joint width of sealant to depth should be 2:1, however, in all cases, the sealant must be no wider than 30mm or deeper than 5mm. Mastic Sealant. Economic option for Joint Sealant in Waterproofing applications. This question is taken from book named – A Self Learning Manual – Mastering. 421. For construction or contraction joints, use a bond breaker tape or back-up strip. Economical Easy to install Readily compressible Rot proof and non-absorbent Provides bond breaker and minimum strain shape for joint sealants Provides a firm backing for sealant tooling Advantages The use of Expancell will also act as a bond breaker at the base of the joint thus preventing three sided adhesion and the accompanying additional. The sealant does not adhere to it, and no separate bond breaker is required. Most substrates only require priming if testing indicates a need or where sealant will be subjected to water immersion after cure. 01 WORK INCLUDED A. Use CRL Bond Breaker Tape to create proper two-way sealant bonds. This type of tape is made of polyolefin, or Teflon, and. PART 3 - EXECUTION. In this con-Compact sealant into joint with a wet wooden spatula and smooth off to the desired finish. Acceptable types of bond breakers shall include: (a)Closed cell expanded polyethylene foam backer rod. sealants are as follows: EIFS, primer, sealant backing or bond breaker, adjacent substrates and sealant (see Figs. Material shall act as a bond breaker and shall be circular in cross section. 800. JOINT PREPARATION The joint surface must be clean, dry and free from oils, loose mortar, laitance, release agents and other contaminants. Priming Priming is not usually necessary. Long term sealing protection at volatile areas. R. Visit your local store for the widest range of products. bond face. 03 APPLICATION A. 15 (After two weeks @ 190°F)Expanded PTFE joint sealant - Super Seal PTFE 3mm x 10mm x 15 m. Bond breakers can be a silicone or polyurethane sealant, or preformed bond breaking corners and tapes. When the joints are not deep enough to accept a backer rod, a polyethylene bond breaker tape should be installed. 7 (c) in the Standard doesn’t require a bond breaker at all. But when a sealant material is required, a portion of the filler is removed to form the necessary space for the sealant and its backing material (if required). Sika® Foam Backer Rod Closed Cell has excellent cpmression and recovery properties, is available and various sizes and lengths. The mortar in a rigid control joint must be raked out to the proper depth while it is still plastic. Polyethylene tape is commonly used as bond breaker tape. For use in hori-zontal joints in traffic areas, the absolute minimum depth of the sealant is 1/2” and closed cell backer rod is recommended. For joints greater than 1 inch (25. Control the depth of the sealant by using a Backer Rod that is 25% larger than the joint opening at its median temperature. )SECTION 07 9200 - JOINT SEALANTS. In deeper joints, a polyethylene backer rod must be used to act as the bond breaker, and at the same time set the joint depth and support the sealant. 6144. Sikaflex® MS has been formulated for sealing joints in and around concrete, brick, masonry, pre-cast panels, stone cladding, windows, doors and fibre cement sheeting. joint movement can be accommodated in a thin bead of sealant than in a thick bead. Nomaflex does not impede cure time. Contact CRL Customer Service. , measured at the center point of the joint width. polyethylene bond breaker tape to prevent three-sided adhesion. Joint Sealant Material To Be 8") (w +1 Tape Bond Breaker Or Crack Existing Joint Saw Cut Or Formed Joint 4"" to 1 8 1 4"" to 1 8 1 32" Max. Maximum sealant depth is 12mm and width is 38mm. Bastion 100mm x 10m Bond Breaker Joint Band is a. C. therefore, sealant wastage is reduced. Not Recommended for Backing Material. Nitoseal SC600 may bond to the tapes and result in the failure of the joint sealant. In a properly designed structurally glazed joint, the sealant is strong enough to support glass and other panel materials under high wind load. Flashing at lintels and sills (shown in Figures 2 and 3, respectively) is very similar. Always use bond breaker tape or closed cell backer rod for support on horizontal joints. If DOWSIL™ 991 Silicone High Performance Sealant cannot be installed whenProduct Description. High recovery rate. The shape of the sealant bead is also important for each application- see Figure 1. • APPLICATION Avoid applying sealants below 40 °F (4 °C) unless following specific instructions for cold weather caulking. Avoid brushing on the bond breaker tape. Allow for proper sealant tooling. E. The use of sealant joints is prevalent in building design and construction, aerospace, automotive, electronics, tank fabrication, and construction industries. Easy and time saving installation. Bond-Breaker Tape: Polyethylene tape or other plastic tape recommended by sealant manufacturer for preventing sealant from adhering to rigid, inflexible joint-filler materials or joint surfaces at back of joint where such adhesion would result in sealant failure. Thioflex 600 Gun Grade is a two-component joint sealant, based on a liquid polysulphide polymer which, when mixed and applied, cures to form a tough, rubber-like seal. Pour sealant into joint slot in one direction and allow sealant to flow and level out as necessary. A bond breaker must be installed at areas subject to movement, wall/wall junction, wall/floor junction, sheet joints and seams, penetrations and. joint sealing or in flooring applications such as saw cuts jointing. Sealants - the Professional's Guide. Inside Corner Joint: Where substrates are abutting and no-to-minimal joint movement is anticipated , provide bond breaker tape in the corner extending no less than ” (6 mm) out from the corner in BOTH 1/4 directions (see Image 2). Contact CRL Customer Service. the joint and completely fill the joint without spilling the material on the surface of the pavement. Apply the right amount of sealant. You can use bond breakers to improve joint performance. contraction to maximize accommodation of movement. Sika® Foam Backer Rod Closed Cell is manufactured from closed cell, low density, polyethylene foam. Approval of the backer rod or bond breaker tape shall be made by the manufacture and engineer. Tool as required to properly fill joints and force sealant against joint interfaces, maximizing bond. from adhering to the back of a raked joint or to the backup), allowing the sealant to freely deform in response to building movements (see Figure 1c). The maximum depth is 1/2 inch (13 mm) and the minimum is 3/8 inch (10 mm). Uses: BestBond Joint Sealant permanently fills and seals cracks in concrete, stone, masonry, and most rigid surfaces. internal brick reinforcement. Jakarta Barat Karya inti jaya. In all joints a bond breaker must be used to prevent sealant contact with the back of the joint, and hence allow optimum performance. Primers may be applied to the sides of joints to provide a good bond between them. • Three-sided adhesion limits the amount of movement that a joint can accept before failing. B. It is important for sealant to bond to joints in two places so it can expand properly. b. bridge joint in a variety of applications , including restoration of failed sealant joints. Sika Sikaflex 1A Polyurethane Elastomeric Joint Sealant And Adhesive - 20 Ounce Sausage. 020 8524 1931. e. 2 of AS3740, applicable to the Class of Membrane. 08 APPLICABLE PUBLICATIONS: A. Joint Sealant Material To Be 8") (w +1 Tape Bond Breaker Or Existing Joints Or Cracks. In fact, some types of joint fillers can serve as a backing material and bond breaker, in which the applicator can apply the sealant directly on the filler. The use of a bond breaker is not required in expansion joints containing cellular polyethylene joint filler, backing rod (Vetoflex PBR). For most effective results, dura. 3. Install tap flanges. 4. To prevent the sealant from adhering to the surfaces, bond breaker tape is applied along the whole width/length of the base of the joint. Read More. (See data sheet for the type of sealant to be used). 180. Click here to access Bastion 600mL Bond Breaker and MS Joint Sealant – User Guide. Sikasil®-728 SL is designed to seal horizontal saw cut and expansion joints in concrete pavements on highways, airports, bridges, walkways, parking garages and driveways. Filler: A sealant backing used behind a back-up rod. Bond Breaker Black Polyethelene Tape. 10 WARRANTY SPEC WRITER NOTES: 1. Use only the correct backer rod size. . bead of sealant to seal perimeter of partition. e. D. 1. Use bond breaker tape over the backer material. Consultmm) and width is 1/4 in. 1. Emer-Proof Joint Seal Tape is a wet area grade elastic joint bandage, designed for use in waterproofing critical movement zones within internal and external wet areas. 3. Use a size that will compress at least 25% when inserted into the joint. The surface of a building component or joint that serves as a substrate for sealant and to which the sealant is bonded. The B50 Joint Band is easy to install and provides for considerable time saving efficiencies and durable properties over conventional bond breaking sealants and tapes. Install shower angles and door angle, glue into position with sealant. • For joints subject to puncture by high heels or umbrella points, a stiffer or higher density backup material is required. 1-800-474-7570 [email protected]. JOINT BACKING BOND BREAKER Joint backing should be used to control the recommended joint depth and prevent 3-sided adhesion. provides a non-stick surface to prevent sealant 3-sided adhesion. Bastion 100mm x 50m Waterproof Reinforcing Fabric (0) $19. Place bond breaker tape in the bottom of the saw cut joint after it is cleaned and dried. Joint Width E. 800. Back-up Rod: A type of sealant backing. Most substrates only require priming if sealant will be subjected to water immersion after cure. Plus, it will retain its original diameter and is non-gassing when exposed to high sealant temperatures. 5 Bond Breaker Rod: The bond breaker rod shall be a closed cell, expanded polyethylene foam rod of the size and dimensions shown in the Plans. in deep joints, the sealant depth must be controlled by closed cell backer rod or soft backer rod. Contact CRL Customer Service. Bond Breakers. If using a sealant, use a scraper to flatten the corners. Closed cell backer rod should be about 1⁄ 8" (3 mm) larger in diameter than the width of the joint to allow for compression. When the joints have been filled with fibre filled board, this must be raked back to the required depth. General purpose polyutherane exterior grade joint sealant. 1. 1. This is when the sealant improperly adhereds to the bottom and sides of the joint, restricting movement. )it into the joint channel without stretching it lengthwise. 1 Blocking Media/Backup Materials 2. Priming Fosroc Primer MS2 is required for joints that are to beNeutral cure silicone used as a bond breaker. 6. A high-performance Bond Breaker Joint Sealant to provide extra protection and flexibility in vital joints for all waterproofing applications. Available in: - 100mm. Tooling: 915 comes ready to use. thickness of sealant, waste, application techniques, etc. is a cus tom extrusion or mold made of higher durometer silicone rubber used in custom applications. Cork or rigid non-ASTM C1193 – Standard Guide for Use of Joint Sealants. Bond breaker tape or backer rod must be used in bottom of joint to prevent bond. Three-sided adhesion can be eliminated by the addition of a bond breaker tape or backer rod. enhance bond. approximately 2” in length shall be made along the sides of the joint. Consisting of a unique grade of rubber, the Bond Breaker Waterproofing Joint. Features & Benefits . In joints too shallow for backer rod, a bond-breaker tape should be used to prevent three sided adhesion. A. Concrete and steel are typical substrates used with bond breakers, as they are non-metallic or metallic anti-stick materials. Tremco Dymonic. 6144. Still Not Sure? Call our 7 Day. SJ-03 Butt Type Sealant Joint with Latex Sealant Bond Breaker Butt-Type Sealant Joint Bonds two materials, typically 1/4” of adhesion needed on the surface, joint width varies by system. For construction or contraction joints a bond breaker tape or back-up strip should be used. Tel: +61 3 9279 9333. Remains flexible with expansion and contraction of building component, based on good joint design. Pour sealant into joint slot in one direction and allow sealant to flow and level out as necessary. contraction to maximize accommodation of movement. To ensure free movement in the joint, bond breaker tape is placed between the joint sealant and joint filler. Suitable as a back-up filler for most liquid sealants Ideal for stopping contaminants such as soil entering into expansion slots and joints. 0m To ensure that the correct joint width-to-depth ratio is achieved and to prevent the sealant from adhering to the bottom of the joint, it is highly recommended to use a tight- Sikaflex-PRO Sikaflex-PRO is a one component, thixotropic, polyurethane based joint sealant. Bond breaker tape approved by the sealant manufacturer may be used in lieu of bond breaker rod when sealing random cracks. Bond Breaker Tape is used in joint sealing applications to ensure sealant only adheres to two faces of the joint. Easy Seal Bond Breaker is a waterproof sealing band that is used at. Bond Breaker Tape is a polyethylene tape used to prevent 3-point adhesion in shallow caulk joints or joints where backer rod cannot be used. Priming is typically not necessary. A further 2 full coats, at 900bond free, thereby allowing the sealant to adhere only to the sides of the joint. In joints where polystyrene or bitumen impregnated fillers have been used, Abelflex is ideal as a bond-breaker. This clear, tough plastic tape with a clear polyethylene adhesive backing is eight mils (. There are two major purposes of sealants in joints: (1) the sealant fills space, creating a seal, and must maintain that seal throughout the useful life of the structure. Bastion 100mm x 10m Bond Breaker Waterproofing Joint Band (1) $25. Self-adhesive, non -woven, polyester fabric for strengthening membranes. Add to cart. Flexible Joint Sealant. The installation of solvent based polyurethane joint sealants beneath water based membranes can result in a breakdown in the membrane through solvent release. (6. - An extra 900-micron (0. Deep joints should incorporate a backing strip such as Sika PEF Rod to support the sealant while also acting as a bond breaker. The 2” sealant tail shall be pulled at an angle of 90° or more from the wall face until the. Bond Breakers: A type of sealant backing. Bond Breakers. When you’re in need, we’re here to help!Features. Where hydrostatic pressure exists, only bond breaking tapes must be used, notBond Breakers Bond breakers prevent three-sided adhesion of the seal-ant (i. The correct size grout joint is also a factor that helps with movement accommodation. Often necessary because of the sealant in-compatibility with these forms of fillers. Service temperature -50˚C to +120˚C. Without bond breakers, the joint sealer tears apart from. Backer rod Sealant. Closed cell backer rod diameter should be larger (i. 08 APPLICABLE PUBLICATIONS: A. 99. 7 We r eh NA 1740 ends on any penetration, apply a bead of silicone or urethane sealant. Closed cell backer rod or bond breaker tape must be installed at the bottom or base of the joint prior. 3 Hot rolled acc. All joint facings must possess an open surface texture. Email Us. Typical expansion joint Thioflex 600 Pouring Grade Bond Breaker Tape Recess Hydrocorr Typical construction joint Thioflex 600 Pouring Grade Bond Breaker Tape. Polyethylene tape is the most. Closed cell backer rod should be 25 % larger than joint width; do not compress more than 40 %. a. Add to Cart. Sealant works like a rubber band or a shock absorber bonded between two surfaces, stretching back and forth as the two surfaces move. Help centre;Crommelin Reinforcing Fabric is a non-woven, rot proof polyester fabric for use in conjunction with Crommelin liquid applied waterproofing membranes. 1. Sealing joints must be accessible and repairable. Open cell polyurethane foam or closed cell polyethyleneBastion 300ml Bond Breaker Joint Sealant (0) $9. For sealing shallow joints Bond Breaker Tape is applied to the bottom of the joint so the sealant will bond only to the walls. Euco 700 Sealant Calculator. Features Snapshot. Davco K5 Bond Breaker is a neutral cure silicone designed to be used as a bond breaker in the installation of Class II & III waterproofing membranes. sticking to the bottom of the joint and then tearing when the joint opens. 5m / 3. The cured. A further 2 full coats, at 900of the sealant to maintain minimum or maximum depth of sealant. A narrow deposit of sealant applied to a building. Expansion/Contraction: 50% (±25%) as per ASTM C719. Sealant Melting. • Wider joints (minimum of 1/4" width): as wider joints can accommodate more movement than narrow joints. Types of bond breakers. Simply raking debris out of the joint with hand tools is not sufficient. As the sealant joint width becomes larger than 1", the depth should be held to approximately 3/8". Use a sealant backing or. Allow the primer to dry as per the specification. In shallow joints self adhesive polyethylene tape can be used. C. Use CRL Bond Breaker Tape to create proper two-way sealant bonds. Bond Breakers Sec 2 2-3 ® ® Guide to Tilt-Up Bondbreakers A bond breaker is a ‘material used to prevent adhesion of the newly placed concrete to the substrate’*. When cured it forms a tough, flexible seal and bond, capable of cyclic expansion and compression movement. The back rod and breaker tape shall be installed in the saw-cut joint to prevent the joint sealant from. Bond breaker tape or backer rod must be used in bottom of joint to prevent bond. Tape Bond Breaker 1 84 1 8 to D (D=Conc. Bond Breaker or Backer Rod Installation: Install bond breaker or backer rod as specified to regulate depth of sealant. External walling and cladding Expandafoam Closed Cell is used as a backing strip forMasterSeal NP 2 sealant. Masking: Mask adjacent surfaces to prevent staining or damage by contact with sealant or primer. Documents. Sealants will fail in cohesion (split) if bonded on. You can simply use a bond breaking sealant or preformed bond breaking corner, tape and pipe sleeves. Do not prime or damage the surface of the bond breaker. 605-2. CHARACTERISTICS / ADVANTAGES Esay to use Closed cell Asists with joint design Assists with sealant profile Provides bond breaker Compatible with cold applied sealants (polyurethane, silicone) sealing slot before positioning a bond breaker. (Vetoflex PBR). 932-1. The portion of the sleeper slab on which the polyethylene bond breaker is to beClick here to access Bastion 300ml Bond Breaker Joint Sealant – User Guide When you’re in need, we’re here to help! We offer a range of services including plumbing, electrical, gas fitting, handyman services, appliance repairs, bathroom renovation and much more. Add to Cart. Joint Filler, Backer Rod and Breaker Tape a. 1 DESCRIPTION: A. Ad. , measured at the center point of the joint width. Pavt. Features. The combined system will satisfy the criteria of AS 3740 “Waterproofing of Wet Areas Within. 3. To facilitate free movement, it can be achieved by adding bond breaker tape in between the joint sealant and joint. joint sealant to the recommended thickness. Sealant Pouring Fill the sealant in the ready joint by hand or. 4. • For a joint size larger than 1 inch, the depth should be kept to between . Meets ASTM C920, Type S, Grade NS,. If depth exceeds 1/2", use backer rod. NOTE: Although good in principle, it is difficult to place bond breaker tape in the bottoms of the grooves such that the tape will not move during application of the sealant. 3 Low Modulus Silicone Sealant: 932. e. 4. Joint Sealant 300ml Cartridge| Exterior polyurethane joint sealant, general purpose by James Hardie. compounds, tilt up bond breakers or other contaminants 1 Application: 3. For contraction joints a bond breaker tape or back-up strip must be used. Add to Cart. Acceptable types of bond breakers shall. Des Moines County . Provide backup material that is a compressible, non-shrinking, non-staining, non-absorbing material, nonreactive with the joint sealant. Use joints greater then the minimum of 1/4 inch (6 mm width), since wider joints can accommodate more movement than narrow joints and can also result in a greater joint spacing. 94. Both the structure and the sealant will expand and contract with temperature changes. Proper design is 2:1 width to depth ratio. The cured sealant is durable and flexible enough to accommodate ± 50 percent movement of original joint dimension when installed in a properly designed weather seal joint. With a. 7. 6144. Dampfix Platinum Bostik Australia Pty Ltd, Level 1, 6 English Street, Essendon Fields, Victoria, 3041, Australia. narrow joints. 2:1 width to. 2. after the sealant is cured, as it is extremely difficult to apply such materials onto the surface without contaminating the joints. Closed cell backer rod or bond breaker tape must be installed at the bottom or base of a dynamically working joint prior to sealant installation to prevent three sided adhesion. For use with all Bastion Waterproofing Membranes. Pavt. Bastion 300ml Bond Breaker Joint Sealant (0) $9. • Three-sided adhesion limits the amount of movement that a joint can accept before failing. WPA MS is a single component, moisture cured silane modified hybrid sealant free of solvents and isocyanates, with a very low VOC content. - Bostik Dampfix Platinum waterproofing membrane can be applied as soon as the bond breaker joint can be over coated without deformation of the coved sealant profile. In addition, many backup materials also serve as bond breakers. Joint dimensions should allow for 6 mm (1/4 in) minimum and 13 mm (1/2 in) maximum depth of sealant. 5”use a 1:1 width to depth ratio and joints wider than . This repair method has the advantage of avoiding costly sealant removal, but can only be used if. Sealants in a rigid control joint with mortar are installed over a bond breaker tape, while sealants in an open expansion joint are installed over a sponge backer rod. Widths from 1" (25 mm) to 12" (300 mm) and custom shapes are available in a wide variety of colors and textures. To facilitate free movement, it can be achieved by adding bond breaker tape in between the joint sealant and joint filler. The sealant does not adhere to it, and no separate bond breaker is required. The round profile assists in providing the correct joint sealant profile allowing optimum movement. C. 5 m ~ 4. Using braided sealant backing to compensate for a joint opening that is too large for the backing material. D. polyethylene bond breaker tape to prevent three-sided adhesion. JOINT DIMENSIONS Joint size should not exceed 1/2" wide x 1/2" deep. While the principle of bond breaking is not new and applies to waterproofing and other industries such as joint. • Sanitary grade for interior and exterior use. Bond breaker tapes are available in following width:15mm, 20mm, 25mm, 50mm. 1 litre can, average coverage 10m2Bond breaker and closed cell back-up material for use with joint sealants. SKU: EUCO7002G. , 11 Saw Cut Or Formed Joint Compression Seal 16" Preformed Elastomeric 9 Not Required For Construction Joints. The sealant does not adhere to it, and no separate bond breaker is required. Sealant that does not bond to the concrete surface of the joint walls, contains voids, or fails to set toJoint Sealant: ASTM D5893. It is applied to the casting slab to function as a bond breaker between the casting slab and the tilt-up or lift-slab panel. This clear, tough plastic tape with a clear polyethylene adhesive backing is eight mils (. 4 BACKUP MATERIAL. bond breaker tape sealantnext audible sale 2022. Contact CRL Customer Service. Bond breaker tape: primarily a self-adhesive polyethylene or teflon material. 1 Introduction. Add to Cart. It is suitable for movement and connection joints for indoor and outdoor applications. The cured. Bastion 4L Exterior. Working joint depths should never exceed 1/2" (12 mm) or be thinner than 1/8" (3 mm). A WATER REPELLENT, WAX BASED BOND BREAKER MATERIAL DESCRIPTION Sika® BondBreaker W is a water repellent, wax based bond breaker material. Follow the manufacturer’s instructions. Rod Closed Cell provides bond breaking, assists in the control of joint depths for correct joint design and re-ducing sealant consumption. Bond Breakers Sec 2 2-3 ® ® Guide to Tilt-Up Bondbreakers A bond breaker is a ‘material used to prevent adhesion of the newly placed concrete to the substrate’*. Bolt down the collar to the drain flange. Joint Depth The joint must be deep enough to allow proper placement of the sealant and a bond breaker/backer rod. D. Bond. debris and failed sealants, such as in recaulk-ing applications. A clear or translucent type of packing tape is preferred and can be purchased from most Dow silicone pavement sealant distributors. Clean all surfaces. 4 MAINTENANCE OF SEALING JOINTS Sealing joints fulfill an important role when it comes to protecting the bond line from environmental influences or simply prevention of moisture or water ingress. (See Figure 1, page 27. "Min. This is when the sealant improperly adhereds to the bottom and sides of the joint, restricting movement. EN 13108-6 8. SAW-CUT CONTROL JOINT SEALANT AND BACK-UP BOND COAT CONCRETE OR MASONRY BACK-UP STRUCTURAL JOINT FLEXIBLE SEALANT BOND BREAKER TAPE CERAMIC TILE Expansion Joint – CEJ171 Construction Joint – CEJ171a Isolation/Expansion Joint – CEJ171d Technical Services 800-282-8786. Bond Breaker D. Bond Breakers or masking tape Bond breakers prevent three-sided adhesion of the sealant (i. b. typically up to 25% larger) than the actual width of the joint to provide a friction fitfrom the driving surface and should show necessary joint fill-ers, sealant backing, bond breakers, and bonding surfaces. • Suitable for use as a waterproofing membrane bond breaker or as a highly durable finishing sealant. Remove any masking tape immediately after applying Paraseal. Tool as required, although minimum tooling is necessary. This article discusses the features of mastic sealants in the construction industry. Approved bondbreaker system conforming to AS 3740; Time saving simplified installation • Eliminates need for sealant bondbreakers and tapesContractor Polyurethane Sealant Permanently flexible with ± 25% movement capability. Find out more. Contact CRL Customer Service. The round profile assists in providing the correct joint sealant profile allowing optimum movement. 1 "Min. To properly install sealant, you need to provide a joint between two materials. All bond breaker rods installed shall be covered by a sealant at the end of2. Joint walls must be sound, clean, dry, frost-free, and free of oil and grease and any other contaminants. 2 cm) thick.