BUILDING CODES Presented by CORUM ENGINEERING

Transcription

1 BUILDING CODES Presented by CORUM ENGINEERING AGENDA I. The Basics of Foundations A. Footer Designs B. Foundation Walls 1. Non-Backfilled Walls 2. Backfilled Walls (Retaining Walls) C. Slabs vs. Crawl Spaces II. The Basics of Framing A. Floor Framing B. Wall Framing C. Ceiling Framing D. Roof Framing III. Structural Issues and Examples 1

2 Origin of Building Codes Hammurabi's Code of Laws (1790 BC) By the sixth Babylonian king, Hammurabi 229. If a builder build a house for some one, and does not construct it properly, and the house which he built fall in and kill its owner, then that builder shall be put to death. CODES Available International Residential Code (IRC 2006 Edition) Standard Building Code (SBC 1999 Edition) Council of American Building Officials (CABO 1995 Edition) Uniform Building Code (UBC 1997 Edition) 2

3 Elements of a Building Footer Designs Spread Footing Square Rectangular Continuous Pile Supported Monolithic System 3

4 Typical Footing TABLE R PRESUMPTIVE LOAD BEARING VALUES OF FOUNDATION MATERIALS Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC) = 2,000psf Footer Drainage R405 (IRC) Foundation Drainage: Drains shall be provided around all concrete and masonry foundations that retain earth and enclose habitable or usable space located below grade. 4

5 Typical Footing Diagrams R403.1 General - Footings shall be supported on undisturbed natural soils or engineered fill. R Minimum depth - All exterior footings shall be placed at least 12 inches (305 mm) below the undisturbed ground surface. R Moisture barrier. A 6-mil-thick (0.15 mm) polyethylene moisture barrier shall be applied over the porous layer with the basement floor constructed over the polyethylene. R Height above finished grade. Concrete and masonry foundation walls shall extend above the finished grade adjacent to the foundation at all points a minimum of 4 inches (102 mm) where masonry veneer is used and a minimum of 6 inches (152 mm) elsewhere. Monolithic Slab with Footings FIGURE R403.1(1) (IRC) 5

6 TABLE R403.1 Minimum Footing Width LOAD-BEARING VALUE OF SOIL (psf) 1,500 2,000 3,000 4,000 Conventional light frame construction 1-story story story inch brick veneer over light frame or 8-inch hollow concrete masonry 1-story story story inch solid or fully grouted masonry 1-story story story Graded Site Drainage R401.3 Drainage. Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection so as to not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 6 inches (152 mm) within the first 10 feet... 6

7 Example of Graded Site The Foundation There are Four Common Types Slab-on-Grade Full Basement Crawl Space Post or Pier 7

8 Slab On Grade R506.1 (IRC) General. Concrete slabon-ground floors shall be a minimum 3.5 inches (89 mm) thick R (IRC) Base. A 4-inch-thick (102 mm) base course consisting of clean graded sand, gravel, crushed stone. R Vapor retarder. A 6 mil (0.006 inch; 152 µm) polyethylene or approved vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the concrete floor slab and the base course or the prepared subgrade where no base course exists. Example of Slab on Grade 8

9 Basement Walls TABLE R (1) PLAIN MASONRY FOUNDATION WALLS MAXIMUM WALL HEIGHT (feet) MAXIMUM UNBALANCED BACKFILL HEIGHT c (feet) PLAIN MASONRY a MINIMUM NOMINAL WALL THICKNESS (inches) GW, GP, SW and SP 6 solid d or 8 6 solid d or 8 6 solid d or 8 6 solid d or solid d or 8 6 solid d or solid d or 8 6 solid d or solid d 6 solid d or solid d Footnote e Soil classes b GM, GC, SM, SM-SC and ML 6 solid d or solid d or solid d 6 solid d or solid d 12 solid d 6 solid d or solid d Footnote e Footnote e SC, MH, ML-CL and inorganic CL 6 solid d or solid d or solid d 12 solid d solid d Footnote e Footnote e solid d Footnote e Footnote e Footnote e 9

10 TABLE R (2) 8-INCH MASONRY FOUNDATION WALLS WITH REINFORCING MINIMUM VERTICAL REINFORCEMENT b,c WALL HEIGHT HEIGHT OF UNBALANCED BACKFILL e Soil classes and lateral soil load d (psf per foot below grade) GM, GC, SM, SM-SC and ML SC, ML-CL and inorganic CL GW, GP, SW and SP soils soils soils feet (or less) 6 feet 8 inches 5 feet 6 feet 8 inches #5 at 48 o.c. #6 at 48 o.c. 4 feet (or less) 7 feet 4 inches 5 feet 6 feet #5 at 48 o.c. #5 at 48 o.c. 7 feet 4 inches #5 at 48 o.c. #6 at 48 o.c. #6 at 40 o.c. 4 feet (or less) 5 feet 8 feet 6 feet #5 at 48 o.c. #5 at 48 o.c. 7 feet #5 at 48 o.c. #6 at 48 o.c. #6 at 40 o.c. 8 feet #5 at 48 o.c. #6 at 48 o.c. #6 at 32 o.c. 4 feet (or less) 5 feet #5 at 48 o.c. 8 feet 8 inches 6 feet #5 at 48 o.c. #6 at 48 o.c. 7 feet #5 at 48 o.c. #6 at 48 o.c. #6 at 40 o.c. 8 feet 8 inches #6 at 48 o.c. #6 at 32 o.c. #6 at 24 o.c. 4 feet (or less) 5 feet #5 at 48 o.c. 9 feet 4 inches 6 feet 7 feet #5 at 48 o.c. #5 at 48 o.c. #6 at 48 o.c. #6 at 48 o.c. #6 at 40 o.c. 8 feet #6 at 48 o.c. #6 at 40 o.c. #6 at 24 o.c. 9 feet 4 inches #6 at 40 o.c. #6 at 24 o.c. #6 at 16 o.c. 4 feet (or less) 5 feet #5 at 48 o.c. 6 feet #5 at 48 o.c. #6 at 48 o.c. 10 feet 7 feet #5 at 48 o.c. #6 at 48 o.c. #6 at 32 o.c. 8 feet #6 at 48 o.c. #6 at 32 o.c. #6 at 24 o.c. 9 feet #6 at 40 o.c. #6 at 24 o.c. #6 at 16 o.c. 10 feet #6 at 32 o.c. #6 at 16 o.c. #6 at 16 o.c. Cracked Basement Wall 10

11 Repairs for Bowed Walls Cracked Basement Wall 11

12 Cracked Basement Wall Cracked Basement Wall 12

13 Cracked Basement Wall Cracked Basement Wall 13

14 Carbon Fiber Strips Tie-Back System 14

15 Example of Retaining Wall Garage Wall Crack 15

16 Crawl Space R408.1 (IRC) Ventilation The minimum net area of ventilation openings shall not be less than 1 square foot ( m2) for each 150 square feet (14 m2) of under-floor space area. R408.4 (IRC) Access. An access crawl hole 18 by 24 shall be provided to the under-floor space. R408.5 (IRC) Removal of debris. The under-floor grade shall be cleaned of all vegetation and organic material. All wood forms used for placing concrete shall be removed before a building is occupied or used for any purpose. All construction materials shall be removed before a building is occupied or used for any purpose. R Below-grade moisture barrier. A 6-mil-thick (0.15 mm) polyethylene film shall be applied over the below-grade portion of exterior foundation walls prior to backfilling. Joints in the polyethylene film shall be lapped 6 inches (152 mm) and sealed with adhesive. Pier Construction R606.6 Piers. The unsupported height of masonry piers shall not exceed ten times their least dimension. When structural clay tile or hollow concrete masonry units are used for isolated piers to support beams and girders, the cellular spaces shall be filled solidly with concrete or Type M or S mortar, except that unfilled hollow piers may be used if their unsupported height is not more than four times their least dimension. Where hollow masonry units are solidly filled with concrete or Type M, S or N mortar, the allowable compressive stress shall be permitted to be increased as provided in Table R R Pier cap. Hollow piers shall be capped with 4 inches (102 mm) of solid masonry or concrete or shall have cavities of the top course filled with concrete or grout or other approved methods. 16

17 Lot Grade Elevation R Height above finished grade Example of Grade Elevation 17

18 Damproofing R406.1 Concrete and masonry foundation dampproofing. Except where required by Section R406.2 to be waterproofed, foundation walls that retain earth and enclose interior spaces and floors below grade shall be dampproofed from the top of the footing to the finished grade. Masonry walls shall have not less than 3/8inch (9.5 mm) portland cement parging applied to the exterior of the wall. The parging shall be dampproofed in accordance with one of the following: 1. Bituminous coating pounds per square yard (1.63 kg/m 2) of acrylic modified cement. 3. 1/8-inch (3.2 mm) coat of surface-bonding cement complying with ASTM C Any material permitted for waterproofing in Section R Other approved methods or materials. Example of Dampproofing 18

19 Waterproofing R406.2 Concrete and masonry foundation waterproofing. In areas where a high water table or other severe soil-water conditions are known to exist, exterior foundation walls that retain earth and enclose interior spaces and floors below grade shall be waterproofed from the top of the footing to the finished grade. Walls shall be waterproofed in accordance with one of the following: 1. 2-ply hot-mopped felts pound (25 kg) roll roofing mil (0.15 mm) polyvinyl chloride mil (0.15 mm) polyethylene mil (1 mm) polymer-modified asphalt mil (1.5 mm) flexible polymer cement. 7.1/8inch (3 mm) cement-based, fiber-reinforced, waterproof coating mil (0.22 mm) solvent-free liquid-applied synthetic rubber. Example of Waterproofing 19

20 Basics of Framing Framing Types Platform Post & Beam Balloon Log Framing Systems There are Six Primary Components Studs Joists Rafters Posts/Columns Girders Sill and Sillplate 20

21 Floor Framing R Foundation anchorage. Sills on concrete or masonry foundations shall not be less than 2 thickness and anchored thereto by minimum ½ dia. bolts spaced not more than 6 o.c. and embedded a min. 7 into the concrete or masonry. R502.6 Bearing. The ends of each joist, beam or girder shall have not less than 1.5 inches (38 mm) of bearing on wood or metal and not less than 3 inches (76 mm) on masonry or concrete except where supported on a 1-inch-by-4-inch (25.4 mm by 102 mm) ribbon strip and nailed to the adjacent stud or by the use of approved joist hangers. R Joist framing. Joists framing into the side of a wood girder shall be supported by approved framing anchors or on ledger strips not less than nominal 2 inches by 2 inches (51 mm by 51 mm). Beams and Girders. Where 2 or more pieces of 2 lumber are nailed together to provide girders, the wide faces shall be vertical and the end joints shall occur over supports Exception: girder span over 3 or more may stagger ends ¼ the distances from intermediate supports. 21

22 Floor Girder Spans IRC Table R502.5(2) Floor Joist Spans & Notching IRC Table a(2) &

23 Overlap Floor Blocking R (IRC) Floor systems Floor Cantilever Ratio of back span to cantilever span shall be at least 3:1. (TABLE R (1)) 23

24 Notching & Boring FIGURE R502.8 (IRC) CUTTING, NOTCHING AND DRILLING Wood I-Joist 24

25 Deck Ledger & Flashing Wall Framing 25

26 Wall Typical Studs Sizing & Spacing 26

27 Notching & Boring Studs Header Spans for Ext. Bearing Walls Table R502.5(1)&(2) (IRC) 27

28 Masonry Veneer Fireblock Openings 28

29 Ceiling Framing Ceiling Joist Span 29

30 Roof Framing Roof Framing System 30

31 Roof Framing Collar beams of 1 x6 boards shall be installed in the upper third of the roof height to every third pair of rafters. FIGURE R502.8 CUTTING, NOTCHING AND DRILLING Notches on the ends of the joist shall not exceed onefourth the depth. Where rafters meet to form a ridge, they shall be placed directly opposite each other and nailed to a ridge board not less than 1 thick, and not less in depth than the cut end of the rafter. Roof Rafter Spans Table (2) (IRC) 31

32 Attic Ventilation (IRC) The ratio of total net free ventilating area to the area of the ceiling shall be not less than 1/150. Roof Crickets R (IRC) Chimney crickets 32

33 Roof Sheathing Issues & Examples 33

34 Issues & Examples Issues & Examples 34

35 Issues & Examples Issues & Examples 35

36 Issues & Examples Issues & Examples 36

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38 Issues & Examples Issues & Examples 38

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40 Issues & Examples Issues & Examples 40

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42 Issues & Examples Issues & Examples 42

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45 Issues & Examples Issues & Examples 45

46 Conclusion Buildings and Code Enforcements vary with region. Always be aware of your codes in your area. THANK YOU!! 46