1 Required design elements—Following are the minimum items that should be addressed in the construction Rebar Spacing Basics. . 18 bar 11/2″. or >) The minimum floor thickness shall be 6 inches. Rebar steel will be calculated for the bending moments “Mx” and “My. . g. worked on the rebar behavior inspection of a sustainable RC slab. • A beam-and-slab system, with a one-way slab, and beams cast compositely with the slab, is a highly efficient floor system. 3 Storey Building: Larger diameter rebars, such as 16mm and 20mm, may be used to accommodate the. 87 d Spacing of bar = Design of Continuous Slab Suppose a slab is supported at the ends and also at intermediate points on beams, the maximum sagging and hogging moments to which the slab is subjected to due to uniformly distributed load, can be computed as follows: Let = intensity of dead load per square metre. Concrete is cast on top to a depth of about 3 inches over the top of the forms, encasing the rebar in the beam pockets and the mesh. mk . 375 inches, which is equivalent to 9. Two-story buildings require a minimum of 15-inch wide footings for 1,500 LBV soil. SLAB ON GROUND—A type of foundation with a concrete floor which is placed directly on the soil. 561 kg/m. b. The imposed loads considered for various types of buildings can be. Cutting length of main bar = Clear span of slab + (2 × Development Length) ( 2 × D e v e l o p m e n t L e n g t h) + Inclined Length - Bend Length. The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. 3. rebar spacing o. In t e r p r etations of the ACI 318 code re q u i r ements (Ref. For example in a slab of 6-inch depth, a rebar of 6/8 inch will be used. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. #4 rebar is commonly specified to reinforce the thickened edge. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. Input all the dimensions in the input section of the above calculator. Concrete is strong under compression, but has low tensile strength. Download : Download high-res image (140KB)Others say rebar in the middle is a waste. Two-Way Concrete Floor Slab with Beams Design and Detailing . 3%. 00 m span 3. Rebar spacing in a slab footer will depend on the size of the slab, the load it will support, and local codes. Fa b r ic may also be supported at the center of the slab, or it may be installed in two flat layers with the top layer (nega-t i v e steel) extending on either side of the support for one-quarter of the span (See Fi g u r e 1). This part has a reinforced concrete slab on the 1st floor(2nd floor for any american readers) with several walls built right up to the underside of the slab. Labor Costs. The specified compressive strength of concrete shall be as set forth in Section R402. 1. For slabs. If the slab is more than 24 inches thick, #5 (#5/8 inch diameter) rebar may be required. The most common steel reinforcement or rebar sizes in residential construction are No. 2: Repeat and continue to draw complete (closed) shape. 1. 4 cm) based on the span to depth formula. Concrete slabs: Contractors often use the 1/8 rule for determining the size of steel for a slab. To define design strip rules, click the Slab Design Rules button on the Data Entry toolbar. And the rebar details of (1) is 10mmØ @ 8″ c/c. Click on Calculate button to get the total weight of the steel rod in the slab. Basement slabs and interior slabs on grade, except garage floor slabs: 2,500: 2,500: 2,500 c: Basement walls, foundation walls, exterior walls and other vertical concrete work exposed to the weather: 2,500: 3,000 d:. Fiber length shall be 1 / 2 inch to 2. You should still use reinforcement material, but there are other options besides rebar. ˘ ˘ˇ Spacing (Rebar) A-7 4-1/2” 4000 psi with 28 day aging #6 rebar 12 in. If consolidation of plastic soils is determined to be a potential problem a suspended slab may be the only effective solution, in which. 5 kPa), column spacing typicallyRepeat this process until you’ve laid all the necessary rebar. SLAB BOLSTER—Continuous bar support used to support bottom slab bars. Top Bars for Slab Continuity Properly designed top reinforcing bars installed above. 76 Slab designation: CS1 Check if one-way or two-way slab 1 Slab is one way since it is catilever slab Minimum slab thickness min t = 69. 1 Storey Building: Typically, smaller diameter rebars like 10mm or 12mm might be suitable, depending on the specific design requirements. Second, in cases where a T-beam is oriented so that it is parallel to the main slab reinforcement (e. 5 cm) thick footing, the rebar mat is usually placed about 4 inches (10. 5 inches up to 12 inches. I was thinking of the following: basement wall 8 inches thick 10 feet high backfilled up to 7 to 8 feet. Thank ForSubscribeLikesShare. Welded wire fabric should be minimum WWF 6x6-10/10. The commentary R26. 1) for con-c r ete cover over re i n f o rc e m e n t h a v e not been consistent. 74 equals 1824 lbs per sq feet. -i::= ::::i. Rebar. Place the second bar parallel to the first bar and 1 inch beyond (see Figure 2). , interior beam dimensions = 14 in. Here, ∅ is the bar diameter. First step of the fixing of slab reinforcement was placed the bottom most R/F (B1) of the slab. Much of your need for reinforcement will be dictated by how well your site was prepared. Tie the rebar together. This steel runs vertically and should lap the same size reinforcing steel out of the footing. 1 For longerfloor slab rebar' • ~ #4 19 mk402 "rll ~ ii i i i i i i i i i i i i i i i i i i i k '&y ih:' ii~. Normally, it is assumed changes in deck slabs, and sloped slabs over beams. These cracks have little impact on durability. It create a bending of the slab. Contact*: Severity*: Description*:Problem #3 – Shrinkage cracks that allow moisture to reach the rebar. 6 For two‐way slabs, maximum spacing of bars shall not exceed two times the slab thickness h nor 450 mm. 5 bars; There shall be a minimum clearance between parallel reinforcement bars of 2 1/2 inches;. 34 and $7. most of the time). Rebar being #4 grade 60. rebar strength is in tension, so by adding rebar to BOTTOM of foundation, it counter acts the load of compression. for 500 MPa reinforcement it must be either 500PLUS® Rebar (Class N) or OneMesh500™ (Class L). -l. Floor Under Solids or Semi- solids and Single Axle load (15,000 lbs. European, which is a carbon/steel/manganese alloy. Also, a small hole in the concrete will be totally fine, given the fact that there is a rebar grid. One reason is simple ease of construction. Number of Required Bars Formula = (Length of slab / spacing) + 1. 5 m. . In this video, I'm sharing you the process of concrete pouring and sizes/spacing of rebars for the beams and slab concrete for the 2nd floor of this project. Care should be taken to locate any reinforcement bars away from any anchor positions of the specific lift. Concrete slabs: Contractors often use the 1/8 rule for determining the size of steel for a slab. 1 Wall Reinforcements of SS and NS (a) Minimum Reinforcement in SS or NS walls - refer to TABLE 3. You will be able to add radiant floor heat any time. The size of the columns depends on the total load on the columns. Minimum aging of new concrete slab: 28 days (cure time) Minimum thickness of concrete slab: See new slab table & figures below. The provision of adequate reinforcement, slab thickness, and. Jade Paul D. Often, concrete contractors don’t have solid runs of rebar anyway. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. Fabrication of rebars consists of cutting to length and required bending. Use f’c = 28 MPa and fy = 414 MPa for main rebars and fy = 276 MPa for shear reinforcement. Rebar being #4 grade 60. Sub-slab details (i. Detail A: “Snap Tie” (diagram upper left) is the simplest and is usually used for rebar in a flat horizontal position. I have an exiting two way concrete slab in which it is required to introduce new openings. Check the Buckling Capacity of Rebar. It has Spanish language descriptions, labels and diagrams and it also has default units in the metric system (SI). However, if the concrete slab is meant to be the footing of a small structure, #4 rebar with a diameter of 1/2-inch should be used. 6 Pedestrian Circulation--Stairs and. For example, at Column I-4 between the basement and first floor, building plans required four pieces of horizontal rebar through the column in both directions to connect it to the slab. get your rebar grid down, i would use 1/2" on 12" center. The steel rods help reinforce the strength of the concrete slabs giving the structure a strong form. Floor slab of bottom-most SS or NS and floor slab of NS located above an SS: (i) Slab reinforcements at both external face and internal face shall be H13-. bars at each corner 38mm clear 400 slab opening omit trimmer bars where typ. c. 34 inch (8. area elements and go to Assign > Shell/Area > Opening to create holes in the slab. • The slab is designed as a continuous slab, using theory of continuous beams (slabs), or the simplified ‘coefficient’ method (where applicable i. • Edge beams act as L-beams, and interior. , or 5 h, where h is the slab thickness. 15 1-1 CHAPTER 1 INTRODUCTION 1-1. In general, 6 inch (150mm) slab thickness is considered for residential and commercial buildings with reinforcement details as per design. The pri m a r y differe n c e s b e t w een each type are re i n f o rc e m e n t details and joint spacing. 125mm. 8 mm) when subjected to 50 pounds (23 kg) applied over 1 inch square (645 mm) of material and are greater than 1/ 8 inch (3 mm) in thickness in the uncompressed state shall not extend beneath walls, partitions or columns, which are fastened to the floor. 8 ). That has held up great over the last 8 years, no cracks at all. 1. The main bars are usually positioned in the slab’s bottom layer, with a minimum cover distance of 20mm from the slab’s bottom. For 2,000 LBV soil or greater, two-story buildings may have 12-inch minimum wide footings. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. This guide identifies the various classes of floors based on use, construction design details, necessary site preparation, concrete type, and other related materials. The footings included in this Part reflect the requirements of AS 2870 and apply to the most common types of soil conditions. It is possible to pour a concrete garage floor without installing rebar for reinforcement. The lengths are in meters and centimeters, the areas are in square meters, the volumes are in cubic meters, and the weights are in kilograms and metric tons. 8 of the Florida Building Code,. How thick should rebar be? Common Rebar Sizes Rebar in patios, basement floors, footings and driveways may vary from size 3 to 6. . 4th. HOUSE BUILDING IN THE PHILIPPINES - EPISODE 56: REBAR LAYOUT FOR C-JOIST SLAB Message us:Facebook: retir. Figure 1 shows an example of a floor plan with a composite slab including supple - mental reinforcing bars. A one-way concrete joist slab, employed in building construction, is a structural system featuring a reinforced concrete slab supported by parallel, slender joists. 00 m to 6. 1. For live loads of about 50 psf (2. 7. The Building Structural Standard defines a two-way slab system as a concrete slab system in which two rebars are arranged in two directions regardless of the presence or absence of a beam that transmits a load to. Most residential slabs contain reinforcement of less than. E. ( W) Width of the slab. Ch. There are many variables that influence the decision of how much space to leave, including the maximum load the slab is likely to. 3%. #4 is 4/8”, or 1/2”. This is one of the types of concrete slabs. For multi sided slab, first draw the shape: 1: Hit Clear + Start and enter Side Length of first side to draw, then hit appropriate direction (Arrow) button to draw. . In the case of the RCC slab, the maximum spacing between the two parallel main reinforcement bars should be 3D or 300 mm or whatever. The evaluation of rebar spacing results shows that the maximum standard deviation for rebar spacing is 0. The most commonly used rebar sizes for slabs up to six inches thick are #5 and #4. 5 bar or two No. No, you do not need rebar for a 4-inch slab of concrete on grade. unless otherwise noted in plans or specifications, camber all r. Size and spacing of rebar;secondary containment floor slabs on grade. e. The main reinforcement of the slab panel “A” is marked as (1). 9. Note: Cut the two side form boards 3 in. Sand is filled at a height of 0. 5. It create a bending of the slab. Ilang Araw Ang Pagbuhos Ng Simento? In this video, I'm sharing you the process of concrete pouring and sizes/spacing of rebars for the beams and slab concrete for the. 1) provides the code basis. 2: Repeat and continue to draw complete (closed) shape. Penetrations in PT slabs are possible when observing proper methods. Pool construction crews must place each steel bar and drop of concrete with precision to avoid future structural problems. Design of Two-way Slabs: Slabs are defined as two-way slabs when the ratio of long-to-short sides is less than 2. 74 sq feet 5000/2. Setting a Max Bending Check value controls the rebar which the program chooses for the slab design. On average are required, for 10 square meter with 12cm thick slab, 19 strips of 3/8” rods (9ml each one), are 171 ml. The top surface needs to remain wet while the curing process takes place. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright. 2. The simplest type of two-way slab to construct is known as a flat plate. com Ezekiel Enterprises, LLC 301 Mission Dr. Use 2” rebar chairs to support the rebar in the center strata of the pad. For beams, these distances are 300 mm, 180 mm and 150 mm for grades of main reinforcement of Fe 250, Fe 415 and Fe 500, respectively. DETAILING OF SLABS (For class held on 6th March 07) By Dr. 3. Crazing is a result of poor surface curing and only visible in hard troweled slabs. 4. 2) Where the supported joist span exceeds 4. However, there is no need to tie the garage slab to the new foundation, and in fact a strong case against doing so. Two layers of steel bar reinforcement are needed for secondary containment floors because tank loads induce both positive and negative bending moments in the floor. Workmanship and jobsite conditions. then use 1/2 PEX tubing and create about 5 floor heating circuits, bring all of them to a convenient access point in the shop. 530 m Therefore, gross area of building = 201. Rebar Grid Calculator. Calculation Method For Find Out The Overlapping Length Of Beam, Column And Slab; Bar Bending Schedule For Slab And Estimation Of Steel Reinforcement In Slab; Calculation steps. (a) A flat plate which is a two-way slab supported on a column grid without the use of beams. REBAR SPACING: GP‐7 SERIES MODELS: 4‐1/​4" 3000 PSI / 28 Day Aging #6 Rebar:. 5, which correspond to diameters of 3/8-inch, 1/2-inch, and 5/8-inch, respectively. If the slab is more than 24 inches thick, #5 (#5/8 inch diameter) rebar may be required. , interior beam dimensions = 14 in. In either case, blocks should be used under the. AS3600-2009 P P Lsy. The thickened concrete slab. for slab depths up to 9 in. Check ACI 360R-10 Guide to design or slabs on ground. The span is 2. 1 the spacing of links along the FULL HEIGHT shall not exceed 6 times diameter of smallest longitudinal bar or 150mm. 3. S. It covers the principles, methods and best practices for various types of composite structures, including simply supported, continuous and cantilevered beams, and slabs with different decking profiles. HollowCore floor slab systems provide construction flexibility, fire separation, vibration isolation, and the structural support required to span almost any challenge that large or small multi-deck buildings require. MAX and #5 top placed at center of slab" I installed the #3 dowels 12" apart and 6" into the existing surrounding floor. Corner cracking and joint faulting are reduced by using these bars. (not reducing for cover/spacing, etc. 21 m 2. Use VERIA's free construction material quantity calculator to aide you in estimating for the materials and labor man-hours of all your construction projects. a) Slab depth does not exceed 250mm when the steel grade is 250. 3, No. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed l w /5. This table is span based since the bottom reinforcement is designed span by span. 3. LL = 6. The depth of slab needs to be increased if slab panel size (b) increases, but rebar requirement remains the same for slab (refer to point 3). the slab joint spacing should be the same as for an un-reinforced slab. Minimum clear cover to reinforcements in slab depends on the. In inches the diameter of a #5 rebar is 5/8″ and that of a #4 rebar is 1/2″. Before placing the re-bar, correct spacing given in the detailing drawing were marked by using piece of choke on the slab formwork. Minimum RCC beam size should not be less than 9″x 9″ (225MM X 225MM), with an additional slab thickness of 125 MM. 78 kg/m 3) in accordance with the manufacturer’s recommendations. In that case, a layer of rebar near the bottom or at. 1. Contractors sometimes use the “1/8 Rule,” meaning the size of the rebar is 1/8 the thickness of the slab. Two-Way Concrete Floor Slab with Beams Design and Detailing Design the slab system shown in Figure 1 for an intermediate floor where the story height = 12 ft, column cross-sectional dimensions = 18 in. It has a foot print of four tires about 10 inches by 10 inches time 4. Last year added on a 30 X 30 to the shop, 6" slab, with mesh. is crucial for the cost evaluation for the construction. C. Clear span of the two way slab = 5000 mm. To reinforce a 4” concrete slab or driveway with steel rebar, determine the grid spacing and rebar size – #3 or #4 in a 12” to 18” grid. Wet your concrete after the pour. We would like to show you a description here but the site won’t allow us. This new slab design does not account for second floor installations or installations in a. If too much water was. For flat slabs like driveways and patios, spacing is roughly 18″ to 24″. Its primary purpose is to increase the tensile strength of the concrete, helping it resist cracking and breaking. 7736 m 2. For example, a slab that is 6 inches thick might have rebar marked as size 6 or 3/4-inch. 5 to 7. Slab Design Rules - General. 15 feet x 12 inches per foot = 180 inches. 3. 00 m 14 over 6. My main building is 6" concrete with #4 rebar on a 6X6 grid. Inclined length = 0. 1R and 421. If your concrete will be stamped, ask about the best ways to avoid interrupting the pattern. Spacing (Rebar) A-7 4-1/2” 4000 psi with 28 day aging #6 rebar 12 in. So, there exist guidelines for spacing rebar inside a concrete slab. The shear reinforcements are provided from the support. b) Slab depth does not exceed 200 mm when the steel grade is 460. 3 Slabs-on-ground with turned-down footings. . reqd identifying no. Concrete doesn't dry out; it undergoes a chemical curing process that creates a dry, solid mass. 5 rebar, then measure and mark for your dowels at a 18. Figure 5. shear stresses at the columns and bending moments in the slab con-3 trol the design. square poured concrete beams and columns. Shrinkage cracks are probably the most common type of cracks in concrete. L. 53 Compute moments At support: ( - ) M1 = 3. Generally, a #4 (1/2″) diameter reinforcing bar with a minimum grade of 40 is used for standard residential slabs. 3 For long, narrow panels, place rebar at 0. And a cross-sectional area of 0. : Regarding reinforcement in slabs, please clarify whether you find a rebar spacing of 16 inches as good in reducing crack widths as a spacing of 6 or 8 inches, assuming there is the same total area of reinforcement in any case. The maximum spacing of temperature steel is the smaller of 5 times the slab thickness or 18 in. * BEAMS SHEAR CONNECTORS (IF PRESENT) For M15 concrete, lever arm = 0. The slab will be 3" thick with 2. 00 m 21 reinforced concrete slab 3 mm for every 3. In low- to. One Way Slab Bar Bending Schedule Calculation. 006 inch; 0. The current British Standard or guideline for tying reinforcement can be found in the document BS 7973-2:2001 (Spacers and chairs for steel reinforcement and their specification — Part 2: Fixing and application of spacers and chairs and tying of reinforcement). Figure B-10: Alternative Floor Slab Detail. 1 can be used for these purposes. How far apart should rebar be spaced? approximately 12 inches Place rebar in a grid pattern with a spacing between bars of approximately 12 inches. Figure 1. MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES) b, c: Soil classes and later soil load d (psf per foot below grade) GW, GP, SW and SP soils 30: GM, GC, SM, SM-SC and ML soils 45:Concrete Floor Slabs On Grade Course# ST-702 EZ-pdh. If you want, you can cut out of a section of the steel for testing too. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. The first step in getting reinforcement design for an elevated slab floor is defining design strip rules. Maximum spacing of bars for slabs • Main bars: 3h ≤ 400mm. x 27 in. I maintain a concrete cover of 40 MM. There's no generally-accepted rule of thumb as to how to space rebar in a concrete slab. If the pressure on the concrete is to come from the top of the slab, the reinforcement should be laid deep near the bottom of the slab. Slabs, walls, joists: No. Total Volume of concrete in cubic yards. 2. The minimum spacing between two reinforcement bars should be at least equal to the maximum coarse aggregate dimension plus a margin of 5 mm. Unless you are going to park a very large truck on the slab the 2'x2' oc #4 rebar is over kill IMHO. 4 bar at the top and the bottom of the footing or one No. Low-carbon st eel is mostly iron and ferrit e with 0. A rebar slab calculator is a tool used to determine the quantity and spacing of reinforcing bars (rebars) needed in a concrete slab. ( rS) Rebar Size (2,3,4,5,6,7,8,9,10,11,12,14,16,18,20) Use Size "0" for. The Rebar Calculator is now available in Spanish. Advertise Here. If a concrete slab is 4 inches thick, the depth of the control joint should be 1 inch. The basic building block of this application is further known as a composite floor slab. The spacing of the main steel in a slab should not exceed the following: First, the American Concrete Institute (ACI) Residential Code Requirements for Structural Concrete (ACI 332-14) requires contraction joints and provides a table to determine joint spacing for plain and reinforced concrete containing up to 0. The nominal building width should be calcu-lated as follows: 1. Understanding the Importance of 2nd Floor Slab Thickness for Building Safety and Stability in the Philippines The safety and stability of a building depend on various factors, and one of the most crucial is the thickness of the second-floor slab. However, in some cases, 10mm dia bars are taken for the floor slab, when there is no extra external load other than reinforcement mesh load. Detail B: “Wrap and Snap Tie” (diagram upper right) is normally used when tying vertical wall reinforcement to hold the bars securely into. Concrete slabs-on-ground shall contain micro- or macro-synthetic fiber reinforcement. roof and floor inertia forces only. It requires input values for the dimensions of the slab, the size and spacing of rebars, and other parameters, providing an estimate of the required rebar quantities. Figure 1a: Joint Spacing in Meters. Annex. 00 m span 3. a car weight. Finite elements 1st example 2nd example 3rd example. 64 mm) between longitudinal rebar 2 and 3, which is the same as the rebar construction and traditional tape measurement results. For example, if you’re calculating rebar for a slab, input the slab dimensions, reinforcement spacing, and desired rebar size. for early-entry sawed joints. Similar “uncontrolled” or “random. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. Reinforcing bars that are spaced too far apart could result in relatively large flexural crack widths. 2. that is 2. UB 610 x 179_BP_Pinned. 83-6. Level, straighten and brace the second form board. We’ll run through these ties now: Saddle ties:As per clause 11. Reduce evaporation over the slab by using a fog spray or slab cover. See full list on everything-about-concrete. The second table describes the negative (mid-span) moment demand and the bottom reinforcement. The load needs, and the span of the slab decide the spacing, size, and placement of the bars. square columns and concrete block wall supporting 10in beams @ 12ft on centers front to back. 25 inches (13 to 56 mm) in length. Cracking Unexpected cracking of concrete is a frequent cause of com-plaints. FIrst, find number of rods required for main reinforcement and distribution. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. 2. Fill in the price and. Since this is a patio, you could use 6x6 10/10 wire mesh instead of the rebar. I am confused about the grid. Figure 5. 25" 3,000 PSI / 28 Day Aging #6 Rebar: 12 in: D2-12C: 6. 5 Slabs on Grade - “the purpose of isolation joints in slabs on grade is to allow horizontal and vertical movement between the slab and adjoining structures such as walls, columns, footings, or specially loaded areas (machinery bases). Normally, it is assumedchanges in deck slabs, and sloped slabs over beams. For this case, the lift should not be. For footings that are poured before the slab, two #4 horizontal pieces of rebar are required – one 3” from the top and the other 3” from the bottom. Assessing General Pier Spacing Requirements In addition to the type of soil or backfill, structural loads , and weather conditions, pier spacing specifications will depend on a few other factors, such as the square footage of the home, floor plan, location of any openings, types of piers used, whether the home has one or two stories, and. 2 m top bars @ discontinuous edge Compute temperature bars 250 Using 10 mm f bars:. The support for reinforcing steel in floor slabs is shown in figure 7-24. the calculator will give you the default spacing values (for rebar – rebar it’s 40cm, and for edge – grid it’s 8cm). ACI 330R-08, Guide for the Design and Construction of Concrete Parking Lots is. ( D) Depth of slab. ) slabs are plate elements used to form the floors of buildings. If the steel grade. 3. a – Main bars. Unit 571 New Smyrna Beach, FL 32128 386-882-EZCE(3923). Floors shall be a minimum 3 1 / 2 inches (89 mm) thick (for expansive soils, see Section R403. The preparation of field placing drawings and bar lists is termed detailing. 1) for con-c r ete cover over re i n f o rc e m e n t h a v e not been consistent. Pour 6" fiber reinforced concrete over it. Rebar is typically used to provide additional strength and rigidity to concrete slabs, so if the slab is intended. Methods used for finding slab thickness varies for different types of slabs. 5 try 100 mm Dead load Slab weight = 2. 15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the concrete. 1 Introduction: A structural member used for covering spaces in the form of roof or floor is called a slab. For general purpose concrete slabs with 2,500 pounds compression strength, like patios, use a 1:2:4 concrete mix ratio.