Installation, repair and estimating for nearly every type of roof covering available today in residential and commercial structures: asphalt shingles, roll roofing, wood shingles and shakes, clay tile, slate, metal, built-up, and elastomeric.
Covers sheathing and underlayment techniques, as well as secrets for installing leakproof valleys. Many estimating tips help you minimize waste, as well as insure a profit on every job. Troubleshooting techniques help you identify the true source of most leaks.
Over 300 large, clear illustrations help you find the answer to just about all your roofing questions.
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1 Level Roofs, 7
- Sloped Roofs, 10
- How to Measure Roof Slope, 12
- Perimeter of a Sloped Roof, 17
- Net Versus Gross Roof Area, 17
- Calculating Total Net Roof Area, 18
- Roof Overhangs, Hips and Valleys, 21
- Length of Ridge (Hip Roofs), 22
2 Roof Sheathing, Decking and Loading, 23
- Check the Framing, 23
- Solid Roof Sheathing, 24
- Spaced Board Sheathing, 29
- Roof Decking, 32
- Loading the Roof, 32
- Estimating Roof Sheathing, 34
3 Underlayment on Sloping Roofs, 35
- Saturated Felt Underlayment, 36
- Saturated Fiberglass Underlayment, 36
- Underlayment Requirements, 37
- Drip Edge, 40
- Installing Underlayment, 43
- Estimating Underlayment Quantities, 49
- Interlayment (Lacing), 57
- Eaves Flashing (Ice Shield or Water Shield), 61
- Valley Flashing, 64
4 Asphalt Shingles, 73
- UL Ratings for Shingles, 75
- Deck Requirements, 76
- Asphalt Strip Shingles, 78
- Flashing at Chimneys and Other Vertical Structures, 96
- Fasteners, 106
- Number of Shingles Required per Square, 108
- Number of Shingle Courses, 109
- Estimating Asphalt Strip Shingle Quantities, 113
- Ridge and Hip Units, 114
- Estimating Ribbon-Course Quantities, 124
- Individual Shingles, 127
- Estimating Asphalt Shingle Roofing Costs, 130
5 Mineral Surfaced Roll Roofing, 131
- Installing Mineral-Surfaced Roll Roofing, 133
- Valley Flashing, 134
- Estimating Mineral-Surfaced Roll Roofing, 144
- Waste from Non-conforming Roof Layout, 146
- Estimating Mineral-Surfaced Roll Roofing Costs, 157
6 Wood Shingles and Shakes, 159
- Installing Wood Shingles and Shakes, 164
- Covering Capacity of Shakes, 174
- Covering Capacity of Wood Shingles, 174
- Estimating Wood Shingle and Shake Quantities, 176
- Staggered Patterns, 185
- Sidewall Shakes and Wood Shingles, 185
- Roof Junctures, 192
- Estimating Wood Shingle Roofing Costs, 196
7 Tile Roofing, 197
- Underlayment Under Tile Roof Coverings, 199
- Installing Roof Tiles, 200
- The Starter Course, 202
- Fastening Roofing Tiles, 204
- Flashing at Vertical Walls, 217
- Replacing Broken Tiles, 224
- Estimating Tile Quantities, 225
- Estimating Total Tile Roofing Costs, 229
8 Slate Roofing, 231
- Slate Size, Color and Texture, 231
- Felt Underlayment, 234
- Installation on a Sloping Roof, 234
- Fasteners, 244
- Flashing, 245
- Estimating Slate Quantities, 249
- Estimating Slate Roofing Costs, 254
9 Metal Roofing and Siding, 255
- Modern Metal Panel Systems, 256
- Installing Metal Roofing Panels, 257
- Job-Fabricated Seams, 263
- Estimating Metal Roofing and Siding, 269
- Steel Roofing and Siding Quantities, 270
- Ribbed Metal Panel Quantities, 271
- Miscellaneous Metal Roofing Quantities, 275
10 Built Up Roofing, 291
- Roof Slopes, 292
- Substrate Design, 292
- Back Nailing, 297
- Base Sheets (Vapor Retarders), 298
- Roofing Membranes, 300
- Hot Bitumens, 303
- Cold-applied Bitumens, 305
- Surface Aggregate, 306
- Smooth-surface Roofing, 308
- Cap Sheets, 308
- Aluminum Roof Coatings, 309
- Phasing, 310
- Cant Strips, 311
- Temporary Roofs, 313
- Roof Traffic Pads, 314
- Water-retaining Roofs, 315
- Flashing on Flat Roofs, 315
- Roof Expansion Joints, 319
- Estimating BUR Systems, 323
- Testing BUR Systems, 327
- Built-up Roofing Warranties, 327
- Built-up Roofing Repairs and Re-roofing, 329
11 Elastomeric Roofing, 333
- The Advantages of Elastomeric Systems, 334
- Liquid-applied Elastomers, 335
- Single-Ply Roofing Systems, 338
- EPDM Elastomeric Systems, 337
- CPE Elastomeric Roofing, 342
- CSPE Elastomeric Roofing, 342
- Hypalon Roofing, 343
- PVC Elastomeric Roofing, 343
- Composite Roofing Systems, 343
- Flashings for Elastomeric Roofs, 344
- Estimating Elastomeric Roofing, 345
12 Insulation, Vapor Retarders and Waterproofing, 347
- The Benefits of Insulation, 347
- Insulation Materials, 348
- Reducing Heat Loss, 355
- Insulation Values, 361
- Vapor Barriers, 362
- Weatherproofing Existing Homes, 364
- Caulking and Sealants, 364
- Wall Flashing, 370
- Waterproofing, 37l
- Dampproofing, 377
13 Roofing Repair and Maintenance, 381
- Finding the Source of Leaks, 381
- Repairing Leaks, 384
- Roof Maintenance, 386
- Assessing Hail Damage, 388
- Roofing Demolition, 390
- Re-Roofing, 394
- Estimating Re-Roofing Quantities, 401
- Attic Ventilation, 402
- Gutters and Downspouts, 407
14 Estimating (and Maximizing) Production Rates, 411
- Labor Unit Prices, 411
- Estimating with Published Prices, 415
- Roofing Labor Tips, 420
Appendix A Roof Slope Factors, 428
Appendix B Valley Length Factors, 429
Appendix C Equations Used in This Book, 430
Measuring and Calculating Roofs
If you're like some roofing contractors, you estimate roofing quantities by calculating the area of a roof, then adding 10 percent for waste. That might be OK in a fat building market, but in a tight market you'll need a sharper pencil to compete successfully for the good jobs, and then make money on them. In this book, I'm going to show you how to make a quick and accurate takeoff for any kind of roof.
You'll also learn the latest and most acceptable roofing methods in an industry where installation practices are closely related to warranties. That's because material warranties may be invalid if you don't follow the manufacturer's recommendations for installation. Look here for general guidelines, but always follow the manufacturer's instructions to the letter.
New products come on the market every day to solve the complex roof covering requirements presented by modern building technology. Your job is to know as much as you can about those products. You also have to know how to install them so the job passes inspection and presents no future repair and maintenance problems. Callbacks are hard on your profit margin and they don't do your reputation any good either. Know as much as you can about your roofing business, and you'll avoid them.
This book is more than an estimating book for roofing contractors. It develops a system, beginning with Chapter 1, for all types of roofing materials and installation methods. We'll cover the entire roofing trade, including how to manage your crews and keep them safe. So let's get started.
Before you can bid any job, you have to figure your costs. And before you can figure the costs, you have to know the size of the job. So you have to do two things: First, measure the roof and calculate the total area. Then find the lengths of the eaves, gables (or rakes), ridges, hips and valleys.
When you construct a roof on a new building, you can get these measurements from the plans. On repair or replacement jobs, you'll probably have to take your pencil, clipboard and tape measure, haul out your ladder, climb onto the roof, and start measuring.
To avoid mistakes, or a second trip to the job site, develop a system for taking measurements. Use a 100-foot flexible tape which has a 1/2-inch grout hook at the "stupid" end of the tape. Flexible tapes are made of metal, or fiberglass-reinforced nylon fabric. Find a tape that's marked with highlights at 5-inch intervals to match the exposure of most composition shingles.
There is no cardinal rule for the sequence you use to measure a roof, as long as you don't miss anything. Here's a system that works for me:
Start by measuring the length of the eaves. On a gable roof, you only have to measure in one direction. On a hip roof, you'll have to measure the eaves in two directions.
Next, measure the width of the roof. On a gable roof, hook the tape over one of the eaves, and run it over the ridge to the opposite eave. On a hip roof, measure the width the same way. To measure the length, hook the tape to the eaves at the ridge rafter (look ahead to Figure 1-16 on page 13 for an illustration of the parts of a roof), run the tape the length of the ridge and down the opposite ridge rafter. Measure the ridge at the same time.
Now, measure the hips and valleys by hooking the tape to a building comer and running the tape to the ridge. You use these measurements to calculate material requirements such as valley flashing and hip-covering material.
When you measure, some dimensions need to be more accurate than others. For instance, you could miss the length of ridge, hip or valley by a foot or more, and the error wouldn't affect your total bid price too much. But don't make a mistake in the length and width, because that error could be substantial. For example, assume you measure a roof at 100 feet by 200 feet, while the actual measurements are 100'6" by 200'6". The difference between the two measurements is 150 square feet, or 11/2 squares of material.
Always make a sketch of the roof layout, including dimensions, roof slopes, location of penetrations and any unusual circumstances such as rotten deck areas, ventilation problems, or overhanging tree branches or other obstructions.
Once you have the measurements, you'll use them to calculate areas, slopes, angles, and allowance factors. Lets begin with an easy example.
The dimensions on the plans give you the actual measurements for a level roof. To get the area of a rectangular roof, multiply its length by its width.
Area of a level rectangular roof = L x W
where L is the length and W is the width.
Of course, not every roof you work on will be a single rectangle. You may need to figure the area of a roof like the one in Figure 1-1. There are two ways to calculate this area:
The positive method
The negative method
In the positive method, you divide the roof into rectangular areas, then add the parts to get the total area. See Figure 1-2.
With the negative method, you extend the roof lines to form a single rectangle. Calculate the area of this rectangle, and subtract the areas of the rectangular spaces which lie outside the actual roof. Figure 1-3 illustrates this.
Figure 1-1 Roof Plan of Level Roof
Right: Figure 1-2 The Positive Method
Example 1-1: The Positive Method
Divide the roof into rectangles as shown in Figure 1-2. Calculate the area of each rectangle, then add them together:
Area A = 20 feet by 60 feet, or 1,200 square feet
Area B = 20 feet by 40 feet, or 800 square feet
Area C = 20 feet by 20 feet, or 400 square feet
Then, the total area =
1,200 SF + 800 SF + 400 SF, or 2,400 SF
Figure 1-3 The Negative Method
Example 1-2: The Negative Method
Extend the roof lines to form one rectangle, as in Figure 1-3. Calculate the total area of that rectangle, then subtract the areas of any rectangles which aren't in the actual roof:
Extended rectangle = 60' x 60' = 3,600 SF
Area A = 40 feet by 20 feet, or 800 square feet
Area B = 20 feet by 20 feet, or 400 square feet
Total area outside the roof layout is 800 SF + 400 SF, or 1,200 SF. Subtract that from the extended area to get the total area:
3,600 SF - 1,200 SF = 2,400 SF
You get the same answer both ways. So you might as well use the easiest method - the one that requires the fewest calculations. For example, in Figure 1-4 you'd have to calculate three areas, then add them together. But in Figure 1-5 you only have to calculate two areas, and then subtract one from the other.
Construction & Estimating
by Daniel Atcheson
If you estimate, install or repair roofing in residential or commercial structures, this book will show you the methods and materials the real pros use - the tricks, shortcuts, and estimating formulas that will get you the job, keep your labor and material costs on target, and bring you a healthy profit. In the competitive roofing business, it's not enough to just measure the roof and add 10 percent for waste. The estimating system you'll find here will help you make a quick, accurate take-off with a realistic waste factor.
To make money in this business, you've got to provide a roof that's attractive and durable enough to last for years, with a minimum of maintenance and repair problems. Callbacks are hard on your profit margin and on your reputation. With the help of this book, you'll know which roofing methods and materials will do the job best, and provide the best value.
You'll learn how to estimate and install:
Wood shingles & shakes
Mineral-surfaced roll roofing
Tile & slate roofing
Metal roofing & siding
Built-up & elastomeric roofing
Hundreds of large, clear, illustrations and easy-to-understand tables, charts, calculations, examples, and step-by-step installation and repair procedures will help you find the answers to just about all your roofing questions.The Author
Dan Atcheson, the son of a Texas architect, began working in construction in his teens, as a draftsman and as an apprentice in plumbing, electrical and carpentry. During his career, he has worked in all areas of construction, from earthwork, through framing, to roofing.
He added estimating to his skills in the 70’s, then started teaching construction cost estimating at Texas Tech University. Finally, he began touring the country, giving estimating seminars and speaking at estimating conventions. He now devotes his time to his construction consulting business, and to writing for the construction industry.
His technical papers on construction and estimating have been published in numerous trade magazines, and he has published three other books: Estimating Earthwork Quantities, Earthmoving Equipment Production Rates & Costs, and Estimating Framing Quantities.