Chapter

2. 14 Chapter Roofing Materials and Methods

3. Objectives • List the covering materials commonly used for sloping roofs. • Define roofing terms. • Describe how to prepare the roof deck. • Describe reroofing procedures for both asphalt and wood shingles.

4. Objectives (Cont.) • Demonstrate correct nailing patterns. • Select appropriate roofing materials for various slopes and conditions. • Describe the application procedure for a built-up roof. • Describe the use and application of wood shingles in residential construction.

5. Objectives (Cont.) • Explain how various roofing products are applied. • Describe the different types of roofing tiles and how they are made. • Demonstrate the proper positioning of gutters. • Estimate materials needed for a specific roofing job. Monier Group

6. Roofing Materials • Protect structure and contents from weather and dust • Should offer some fire resistance and durability • Can add color, texture, and pattern to structure

7. Types of Materials • Roofing materials may be • Asphalt, wood, metal, and mineral fiber shingles • Slate, tiles (clay or cement), or sheet materials • Built-up roofs are fabricated on job • When selecting materials consider • Initial cost • Maintenance costs • Durability • Appearance

8. Roof Pitch • Manufacturers list minimum slope requirements for asphalt roofing products

9. Roofing Terminology • Square • Coverage • Exposure • Head lap • Side lap • Shingle butt

10. Preparing Roof Deck • Roof sheathing should be smooth and securely attached • Inspect roof deck for nails, holes, sharp edges • All types of shingles can be applied over solid sheathing • Skip sheathing is better in some cases • Attics should be properly ventilated

11. Asphalt Roofing Products • Widely used • Fall into three groups • Saturated felts • Roll roofing • Shingles • Architectural shingles have layers to look like wood shingles

12. Roof Underlayment • Consists of thin cover of asphalt-saturated felt • Protects sheathing • Prevents entrance of rain and snow • Prevents contact between shingles and resinous areas in sheathing

13. Drip Edge • Should be applied to roof edges along eaves and rake • Made from galvanized steel or aluminum • Causes water to drip free of underlying cornice construction

14. Ice-and-Water Barrier • Recommended for buildings in cold climates • Prevents leak-through from ice dams or wind-blown rain • Materials are self-sealing around nails and deck joints Owens Corning

15. Flashing • Water-resistant sheet that keeps roof joints watertight • Materials for flashing • Zinc-coated metal • Copper and lead • Aluminum • Ice-and-water barrier • Roll roofing

16. Valley Flashing • Flashing seals valleys against leakage • Should be smooth • Should move water quickly and handle backup • Open valley flashing is laid down before shingling begins

17. Woven Valley Flashing • Method that runs shingles across valleys • Often used when reroofing • Only asphalt strip shingles may be applied this way

18. Closed-Cut Valley Flashing • Two intersecting roof surfaces are individually shingled • Each strip is extended at least 12″ beyond center of valley

19. Flashing at Walls • Metal step flashing • Applied to waterproof joints • Should be used where sloping part of roof abuts wall • Siding serves as cap flashing

20. Chimney Flashing • Has two parts that move independently • Base flashing is attached to roof • Cap flashingis attached to chimney • Cap flashing must go over top of base flashing

21. Chimney Saddle • Auxiliary roof deck on sloping roof • Diverts water from behind chimney • Large saddles must be framed • Small saddles can be formed using pieces of exterior plywood

22. Vent Stack and Skylight Flashing • Lay shingles up to stack, fit last course around it • Install flange and apply shingles over upper side of flange • One-piece plastic skylights have one-piece flashing to go under shingles

23. Chalk Lines for Shingles • Snap chalk lines to keep shingles in alignment • Use lines as reference marks for starting each course • Space them according to type of shingle and layout pattern

24. Fastening Shingles • If available, use lift to hoist shingles to roof • Number of nails and correct placement are very important • Pneumatic-powered nailers are often used to install shingles Asphalt Roofing Manufacturers Assn.

25. Starter Strip • Backs up first course of shingles • Covers gap between tabs • Failure to install will damage underlayment and sheathing

26. First and Succeeding Courses • Start first course with full shingle • Three-tab shingles cutouts are centered over tabs in course directly below • Approved nailing pattern is important for appearance and weather protection Johns Manville

27. Hips and Ridges • Special hip and ridge shingles may be available from manufacturer • They can be made with three-tab shingles • Nail hip and ridge shingles 5 1/2″ back from edges Asphalt Roofing Manufacturers Assn.

28. Wind Protection • Adhesive on shingles prevents wind from lifting and damaging tabs • In high-wind areas, use wind-resistant shingles • Self-sealing shingles are satisfactory for roofs with slopes up to about 60° • Interlocking shingles are designed to resist strong winds

29. Low-Slope Roofs • For slopes less than 4-in-12, follow special procedures • Use two layers of felt underlayment cemented together • Ice-and-water barrier can also be used CertainTeed Corp.

30. Roll Roofing • Used as main roof covering, and sometimes as flashing • In residential construction, double-coverage roll roofing provides good protection • It is usually applied parallel to eaves • Ice-and-water barrier can be used as underlayment along eaves

31. Parallel Layout Bird Division, CertainTeed Corp.

32. Reroofing • New shingles can be placed on old roof when • Strength of existing deck and framing is adequate • Existing deck is sound and will provide good anchorage for nails • Building code allows additional layer of shingles • If removing old roof, clear away all old materials down to sheathing

33. Reroofing over Asphalt Shingles Asphalt Roofing Manufacturer’s Assn.

34. Safety Note • Asbestos poses health hazards • Removal of asbestos shingles may release asbestos fibers that can be inhaled • Removing asbestos must be done by certified crews • If you are uncertain of asbestos content, have samples of material tested

35. Built-Up Roofing • Many flat roofs are covered with built-up roofing • Hot asphalt and saturated felt layers are laid down • More hot asphalt is spread over felt underlayment to bind gravel

36. Rubber Roofing • Made from recycled tires • Installed quicker than other roofing systems • Rubber roofing membrane is folded back so adhesive can be applied Johns Manville

37. Ridge Vents for Asphalt Roofing • Venting at eaves, gable ends, and ridge helps dissipate heat and moisture • Types of vents • Rolled over ridge opening • Rigid plastic fastened over vent opening

38. Wood Shingles • Available with or without polymer fire-retardant treatment • Made from western red cedar, redwood, or cypress • Best grade is cut so annular rings are perpendicular to surface • Exposure of wood shingles depends on slope of roof

39. Sheathing • Solid sheathing for wood shingles may be 1″ boards, plywood, or OSB • Open, skip, or spaced sheathing is sometimes used • Layer of shingle breather may be used to provide airspace Cedar Shake and Shingle Bureau, Benjamin Obdyke, Inc.

40. Underlayment • Normally not used for wood shingles • Exception is when applied over solid sheathing • If roofing felt is used to prevent air infiltration, rosin-sized building paper or dry unsaturated felts are suitable

41. Fire Resistance • Flame-spread and burn-through rates for wood shingles and shakes can be reduced • Shingles can be pressure-treated with fire retardants • Flame-penetration time can be increased by using 1/2″, Type X gypsum board under sheathing

42. Flashing • Eaves flashing strip or ice-and-water barrier is required in cold areas • Use good-quality materials for valleys and eaves flashing • Tight flashing around chimneys is essential

43. Nails • Use rust-resistant nails with wood shingles • Shingler’s or lather’s hatchet • May be used to lay wood shingles • Has blade for splitting and trimming Tru Value Hardware, Ashland, WI

44. Applying Shingles • First course of shingles at eaves should be doubled or tripled • Horizontally space all shingles 1/4″–3/8″ apart • Use board to line up courses of shingles

45. Shingled Hips and Ridges • Tightly cover ridges and hips to avoid roof leaks • Nails should not be exposed to weather • Use shingles of same width as roof exposure • Factory-assembled hip and ridge units available

46. Reroofing with Wood Shingles • If old wood-shingle roof is good, it need not be removed • Renail or replace all warped, split, and decayed shingles • Raise level of valleys by applying wood strips

47. Wood Shakes • Available as • Straight split • Hand split and resawn • Taper split • Should not be used on roofs with insufficient slope for good drainage • Proper nailing with rust-resistant nails is important Cedar Shake and Shingle Bureau

48. Roofing Tile • Commonly made from concrete or clay • Comes in many colors, textures, and shapes • Some types are glazed • Additional framing or bracing may be required to support tile Monier Group

49. Installing Tile Roofing Units • Requirements for underlayment depend on roof pitch and local climate • Two plies of 15 lb. felt are recommended • Battens are installed on roof to hold tiles in place Monier Group

50. Hips, Ridges, and Rakes • Install nailer boards on edge at hips and ridges • Set nose ends in bead of roofer’s mastic • Waterproof joints between field tile and trim tile • Apply flashing around chimneys, pipes, and vents