Roofing with Asphalt ShinglesThere's more to laying three-tab shingles

than just nailing them on as fast as possible

I guess I was destined to work for my fath-er's 63-year-old roofing company. I spent a lotof time on the roof learning the trade fromseveral old craftsmen. I learned slate roofing,tile roofing, copper roofing and, of course, as-phalt-shingle roofing. The most important les-son I learned was that there's more to install-ing shingles than just nailing them on fast. Asa roofer, I am also charged with preventingleaks, making a house more attractive and re-

by Todd A. Smith

membering that everything a person hasworked hard for is under my roof. In this arti-cle I'll describe the basics of installing a tight,durable three-tab asphalt-shingle roof.

Tools—You don't need many tools to install ashingle roof. A hammer, tin snips, utility knife,tape measure and chalkline will do it. I use adrywall hammer to nail shingles. Its lightweight doesn't tire my arm, and the larger

head makes nails an easy target. To carrynails and tools, I wear a leather carpenter'sapron, with suspenders to support the weight.Cloth aprons seem to wear out too easily. Be-sides, I like the extra pockets in my leatherapron for different nails.

I prefer the snips when I have to cut shin-gles that butt into flashing or siding because Ican make more accurate and intricate cutswith them. Otherwise, I use a hook blade in

With a column of shingles run up the center of the roof to the ridge, one roofer works to the left of center, the other to the right. This roof isshallow enough to walk on, but the roof brackets and scaffold provide a little extra room to stand and a place to rest bundles of shingles. Loopedaround the brackets, lengths of chain with hooks on the end make a handy place to hang a nailer or a bucket full of nails.

my utility knife because it's less likely than astraight blade to cut whatever is underneaththe shingle. When cutting a shingle on theroof, I use the back of another shingle as astraightedge, which saves me from having tocarry a square.

Our company's air-powered nailers speedup production, but they have their drawbacks.Nailers are heavy, and dragging 100 ft. of hoseis cumbersome. Our nailers hold only enoughnails to install one bundle of shingles, whichmeans we have to keep coils of nails on theroof, and they get in the way. Also, in areas thatrequire lots of cutting and fitting of shingles,power nailers are clumsy and impractical.

To make the nailers easier to handle on theroof, I made some portable utility hooks thatattach to our scaffold brackets. This gives mea place to hang my nailer when I'm not usingit (photo facing page), as well as a place tohang buckets of nails and coils of air hose.The hooks are made with loops of chain,spring latches and some utility hooks, all ofwhich I got at a hardware store.

Ladders and roof brackets—For us, safetybegins as soon as the trucks show up at thejob. Roofing can be hard on your back, andyou have to be careful just pulling the laddersoff the truck and setting them up, not to men-tion hauling heavy rolls of felt and bundles ofshingles up on the roof.

I've become accustomed to setting up ex-tension ladders alone because I have to exam-ine many roofs by myself. I slide the ladder offthe back of the truck until its feet touch theground, then tip it up on one edge. Squattingunder the ladder with a little over half itslength in front of me, I stand up, placing theladder on my shoulder, keeping my backstraight and lifting with my legs. With the ma-jority of the weight in front of me, I don't haveany downward pressure behind me to strainmy back.

To stand the ladder up, I set the foot of theladder against a solid object—usually a foun-dation, step or tree trunk—and push on thetop, walking my hands down the rungs. Oncethe ladder is straight up, I raise it to the appro-priate height, watching out for power lines,phone lines and tree branches.

There are two accessories I use with myladder when the needs arise. One is a ladderstandoff, which is a large U-shaped affair thatbolts to the ladder and prevents it from lean-ing directly against the eaves of the house.The other is a ladder scaffold, which is a plat-form supported by two brackets that hang overthe rungs on a pair of extension ladders.

I use the ladder scaffold to work along theeaves of a house. My steel scaffold platform is20 ft. long, and to be sure it overhangs thebrackets at least 12 in., I stand up two laddersabout 17 ft. apart. Once the ladders are up, Iset the brackets at the proper working height,which for me is about 3 ft. below the eaves.The brackets are adjustable and can be orient-ed in a horizontal position no matter what theladder's angle. Because of its size and weight,

getting the 20-ft. scaffold up the ladder andonto the brackets is a two-man job, and oncein place, I tie the scaffold to the ladders.

About 90% of the time I'm working on a roofthat's too steep to walk on (anything greaterthan a 6-in-12 pitch), so I set up roof brackets(photo facing page). These are triangular steelbrackets, some of which can be adjusted levelregardless of the roof pitch. Others are fixedand create a working surface that allows meto walk around on the roof easily (for more onscaffolding see FHB #36 pp. 34-38).

The basic materials—Asphalt shingles andfiberglass shingles are the most common roof-ing materials used today. Both are less expen-sive than slate, tile or metal roofing and aremore fire resistant and maintenance-free thanwood. The main difference between asphaltand fiberglass shingles is in the mat, or basesheet, that manufacturers begin with whenthey make shingles. Asphalt shingles have anorganic base, which, like felt underlayment, is

Estimating roofingRoofing shingles are sold by the square:a square of shingles is enough to cover100 sq. ft. There are 27 shingles in abundle of standard three-tab shingles,and three bundles to a square. Icalculate the square footage of the roofand divide that figure by 100 todetermine how many squares of shinglesI need. For every 5 ft. of hip or ridge, Ineed four shingles. I generally figure 30ft. to 40 ft. of hips and ridges for everysquare of shingles. When a roof hasmany hips, valleys and irregular shapes,I figure 10% to 20% extra for waste.

From the blueprint or specs, I alsodetermine if I will need drip edge,flashing or any other additionalmaterial. The drip edge and flashing arelinear dimensions. I figure 2 lb. of nailsfor each square of shingles. I use 1 in.galvanized nails for new construction. Idon't use staples to install shinglesbecause I feel the head of a nail holdsthe shingle on better. Manufacturers ofroofing felt assume a 2-in. overlap, so aroll of 15-lb. felt that will cover 400 sq.ft. of roof has 432 sq. ft. in the roll.

The cost of installing the roof is thesum of the materials, labor, overheadand profit. Most roofers determine thelabor cost based on a set price for eachsquare of roofing. The problem with thisis that not every square of roof shinglestakes the same amount of time to install.A square of roofing material on ashallow-roofed ranch house will takeless time to install than a square ofroofing three stories high on a steeplypitched Victorian. Instead, I break downthe roof into sections and determine thetime each one will take a specific rooferor group of roofers to complete. I amalways conscious of details that requireextra time, like valleys andflashings. — T . S.

composed of cellulose fibers saturated withasphalt. Fiberglass shingles have a base ofglass fibers and don't need to be saturatedwith asphalt.

Beyond that, asphalt and fiberglass shinglesare made pretty much the same way. The matis coated with asphalt on both sides, and thenceramic-coated mineral granules are applied.The granules help shield the asphalt from thesun, provide some fire resistance and add col-or. The seal strip, applied along the width ofthe shingle and just above the cutouts, is acti-vated by the sun and seals each shingle to theone below it.

On a standard three-tab shingle, the topedge of each shingle is marked with a notchevery 6 in. The notches are used to registerthe shingles in the next course, since alternatecourses are offset from each other by 6 in.Some manufacturers even notch the shinglesevery 3 in. to allow for a pattern that repeatsevery third row as opposed to every other row.

Fiberglass shingles are a little more difficultto install than asphalt. In hot weather, they be-come softer much faster, which makes themharder to handle and cut, and easier to damage.

Fiberglass shingles are lighter in weight,though. A square (100 sq. ft.) of standardthree-tab fiberglass shingles weighs 225 lb. Asquare of asphalt shingles weighs 240 lb.

The two most common types of roofing feltare 15-lb. felt and 30-lb. felt. The designationis based on the weight of a 100-sq. ft. area offelt. Although some people don't bother to in-stall felt under the shingles, we always do. Forone thing, felt protects the roof decking fromthe weather. Even though roof decks are madefrom exterior-grade plywood, they won't with-stand prolonged exposure to the elements.Second, roofing felt helps prevent ice andsnow from backing up under the shingles andleaking water into the house.

Installing felt and flashing—Felt is appliedin courses, parallel to the eaves. Generallycourses overlap each other by 4 in. The rollsare marked with white lines along the edgesto help you maintain a consistent overlap.There's also a pair of lines in the center of thefelt, in case you want to overlap the courses18 in. (half the sheet). You might want to dothis on a shallow-pitched roof, say 4-in-12, inan area prone to ice damming.

We try to run the length of the roof with apiece of felt, trimming it flush with the gableends. But if we have to splice in the middle ofa course, we overlap the ends 4 in. We run felt6 in. over all hips and ridges (from both sides).Valleys are lined with a full width (36-in.)piece of felt first, and then the courses are runinto it, overlapping the sides of the valley feltby 6 in. Where a roof butts into a sidewall, werun the felt 4 in. up the wall.

When we come to a vent pipe, we cut a 3-ft.piece of felt, make a hole in it the size of thepipe, slip it over and seal around the pipewith roofing cement. Then, we overlap the felton both sides of this piece. To avoid having tochalk horizontal lines later as a guide for the

shingles, we install the felt as straight as pos-sible so that we can measure off of it to keepthe shingles straight.

We nail along the seams and edges of thefelt. In the center of each course, we nail ev-ery 2 ft. or so. Although you can nail by hand,I usually use a power nailer filled with in.roofing nails, which are the shortest pneu-matic nails I can get. When I need to install asmall area of felt quickly and don't want tobother with a compressor and hoses, I usean Arrow Hammer-Tacker (Arrow FastenerCompany, Inc., 271 Mayhill St., Saddle Brook,N. J. 07662). It's a staple gun that is used likea hammer, but tends to gum up with felt aftera lot of use. When that happens, we soak theheads in kerosene to break down the tar.Then we scrape them clean and spray themwith lubricant.

Once the felt is on, we nail strips of lathalong the edges of the roof and along theseams in the felt to prevent the felt fromblowing off. Until the roof is done, the felt isthe only material keeping the house dry.

The edge of the roof sheathing should al-ways be protected from the elements. I use ametal drip edge, installed with roofing nails,along the gables and eaves. At inside cor-ners, I cut the vertical face of one piece 1 in.long and bend it around the corner, and thencut the other piece so that it butts into thecorner. I cut the tops long on both piecesand overlap them in the valley. At outsidecorners on a hip roof, I cut a "V" out of thetop section and simply bend the drip edgearound the corner. Gable ends are cut flushwith the rake board at the bottom. At thepeak, I cut a "V" out of the vertical flangeand bend the top section over the ridge. Anysplices in the drip edge are overlapped 2 in.

Houses without overhanging eaves are par-ticularly susceptible to damage from ice dam-ming. On such houses we also install a 36-in.wide strip called an ice shield, or eave flash-ing. Although you can use roll roofing, weuse any of several membrane products spe-cifically designed for this like Ice & WaterShield (W. R. Grace & Co., 62 WhittemoreAve., Cambridge, Mass. 02140) or WeatherWatch (GAF Corp., 1361 Alps Rd., Wayne,N. J. 07470-3689). We roll them out along theeaves, tacky side down, and nail them onlyacross the top.

Loading the roof—Shingles should be storedin the shade, or covered with a light-coloredtarp. Otherwise, the sun will heat them upand seal them to each other. For this reasonwe seldom unload shingles directly onto theroof, even though some suppliers have lifttrucks that make it possible. We either carrythe bundles up by hand, or we use a gas-powered hoist (ours was made by LouisvilleLadder Division, Emerson Electric Co., 1163Algonquin Pkwy., Louisville, Ky. 40208).

Some roofers carry the shingles up to theridge and lay the bundles over it. This isn't agood idea, especially with fiberglass shin-gles. The shingles can heat up, take a set

from being bent and then not lie properly.We spread the bundles out around the roof,on approximately 6-ft. centers. Any fartherapart and you'll work yourself to death. Evenon shallow roofs, the bundles can slip on thefelt and slide off, so we drive a pair of 10dnails into the sheathing and set the bundlesabove them. The nails can make a dimple inthe edge, especially in hot weather, so we al-ways lay the bundles with top edge of theshingles against the nails.

Starting the shingles—Before the firstcourse of full shingles goes on, starter shin-gles are installed along the eaves. Their pur-pose is to protect the roof under the cutoutsand joints in the first full course and to pro-vide a seal strip for the tabs. Although somepeople use whole shingles installed upsidedown as starters, I use full length shingleswith the tabs cut off (top drawing, facingpage). This puts the seal strip in the rightplace to hold the tabs.

Along the gable end, I like to let the shin-gles overhang the drip edge by 1 in. Thiskeeps water from blowing under them. Tokeep this line of shingles ends straight, I runa course of shingles vertically up the gable,like a starter course (top drawing, facingpage). I lay them end to end from eaves toridge, with the cutouts toward the roof andthe top edge overhanging the drip edge aboutone inch.

Once the starter course is in place, thefield shingles can be started. I begin in thecenter of the roof and work outward, if thereis a large open area, or if I'm on a hip roof. Ibegin on the gable end when there is nolarge open area to nail shingles, or whenthere are dormers in the way and I won't beable to get a proper chalkline on the roof.

I install the first five or six courses withoutchalking any lines, following the eaves withthe first course, and then following the notchesand cutouts of the previous course. If I need toinstall roof brackets, I usually do so after thesixth course. This puts them at a comfortableheight from which to get on and off the ladder.Also, I can nail two or three more rows ofshingles beyond the roof brackets while stillstanding on the ladder, which is easier thannailing these rows from the scaffold.

Once you're up on the roof, you can workhorizontally across the roof, installing severalcourses as you go. Or you can work verticallyup the roof, installing the first two or threeshingles in each course all the way to theridge. I prefer a combination of the two. Onour crews one roofer sets the pattern by nailingvertically up the roof (in the center when pos-sible). The other roofers nail horizontally, oneto the left and one to the right (photo, p. 84).This increases productivity by allowing threeroofers to install shingles on the same roofwithout getting in each other's way.

We chalk lines on the roof to help us keepthe shingle courses aligned and straight. Istart with a pair of vertical lines, one in thecenter of the roof and another 6 in. away (on

either side). All subsequent courses are be-gun from these lines.

If I'm starting from the gable end ratherthan in the center of the roof, I don't chalkany vertical lines as long as the gable isstraight. Before I go up on the roof, I make apile of full shingles and a pile of shinglesthat have 6 in. cut off of them. Then when I'mon the roof, all I have to do is alternately pullshingles from each pile and work my way upthe gable. Successive courses are automati-cally offset by 6 in.

When you reach the opposite gable with acourse, the shingles are simply trimmedflush with the starter course running up thegable. Rather than trim the last shingle ineach course individually, some roofers letthese shingles run long and trim them later.If the shingles are not cut as they're installed,I insist that they be cut at least every fewhours. If left any longer, they will droopagainst the side of the house, making it diffi-cult to get a straight cut.

Unless I installed the felt and know that it'sstraight, I chalk horizontal lines every six toeight courses. (Roofing felt is often installedby the frame carpenters before we get to thejob.) I measure 5 in. for each course, whichis the amount of shingle exposure (this varieswith the manufacturer, so be sure to checkthis by measuring the depth of the cutout onyour shingles). I periodically measure from mychalklines to the ridge to make sure I'm run-ning parallel to it. If not, I adjust the chalk-lines in small increments.

These horizontal lines help align the topedges of the shingles. Yet because individualshingles may vary in height as much as in.,aligning the top edge doesn't guarantee astraight course. But chalking lines for the topedge means that we can chalk all the lines atonce, which saves us time.

If the courses are running off and we needto straighten them out, we'll chalk a linealong the tops of the cutouts of the lastcourse installed. This aligns the bottomedges of the shingle and results in a perfectlystraight course. If the shingles are runningway off, we'll straighten them out graduallyover several courses. We always use bluechalk, which washes away in the rain. Redchalk can permanently stain the shingles.

I use four nails to a shingle—one at eachend and one over each cutout. On steeproofs I may install a fifth nail at the top centerof the shingle. Contrary to conventional wis-dom, I always nail right above the seal strip,not on it or below it. Nailing on the seal stripprevents proper adhesion. Below the sealstrip, the nails are too close to the edge andcan rust or corrode, causing the shingles toslip and the roof to leak. I have never had ashingle blow off or slip because I nailedabove the seal strip.

Field shingles that end up over a hip arejust run long, nailed and then cut down thecenter of the hip with the hook blade of autility knife. At the ridge, we trim one side ofthe roof flush and fold the shingles from the

Working his way up an open valley lined with mineral-surface roofing, Smith uses tin snips totrim shingles flush with the chalkline. Blue chalk is preferred because it washes away in the rain;red chalk will permanently stain the shingles.

other side over the top. This is just a tempo-rary measure to seal the ridge until the capsare installed.

Valleys—There are three different types ofvalleys used on shingle roofs: the closed val-ley, woven valley and open valley (drawingsprevious page). A closed valley is created byrunning shingles from one side of the roofacross the valley (at least 12 in. beyond thecenterline), and then overlapping them withshingles from the other side, trimmed flushwith the centerline of the valley. It is thecheapest, easiest and least durable option.

The woven valley is created by alternatingand overlapping each row of shingles fromthe left and right sides of the valley. The shin-gles should overlap the valley by at least 12in. and nails should be kept at least 8 in.away from the valley centerline.

An open valley is created by lining the val-ley with a separate material (roll roofing orcopper, for instance), and then cutting theshingles back so the lining materal remainsexposed. We use open valleys on 90% of ourroof installations because they are the mostdurable. An open valley allows water to floweasily off the shingles. Depending on thebudget, the type of shingle and the style ofthe house, we'll line open valleys with miner-al-surface roll roofing, copper or lead-coatedcopper. One material we never use for val-leys is aluminum because it expands andcontracts more than other materials, whichcauses it to wear out much faster.

For mineral-surface valleys, I use strips ofmaterial 18 in. wide and 8 ft. to 10 ft. long. Alonger piece is difficult to work with and mayrip during installation. It comes in 36-in. widerolls, which I cut down the middle. I cut thevalley material on the ground, using a utilityknife, and loosely roll it up to make it easierto carry on the roof. Some manufacturersproduce roll roofing in colors to match their

shingles. But both black and white roll roof-ing are pretty common and look good withmost shingles.

To install the valley, I start from above andunroll the material. I center it, nail one of theupper corners, then work my way down, nail-ing the same side every 12 in. to 18 in. It isimperative for the valley material to be tightagainst the sheathing. If it is not, it can breakunder the weight of ice and snow. To avoidmisalignment, only one person should nailthe valley, always working from top to bot-tom. First one side, and then the other. WhenI need a second piece to complete the valley,I overlap the first piece 4 in., but don't usual-ly seal between them.

Metal valleys are installed pretty much thesame way. Again, I use 8-ft. to 10-ft. lengths. Ilike to crease the center of the valley metalon a sheet-metal break. The job looks neaterand cleaner this way.

I use a standing-seam valley when a steeproof drains onto a flatter shingle roof. I bendthe valley metal on a sheet-metal break, cre-ating a ridge in the middle of the valley (bot-tom right drawing, previous page) that pre-vents water from the steep side of the rooffrom flowing across the valley and runningup under the shingles of the shallower roof.To finish off a standing-seam valley at thebottom, I cut the sides flush with the eaves,but let the standing seam run about 1 in. long.Then I simply fold the seam back on itself andcrimp it tightly. At the top, I start about 6 in.from the ridge and bend the standing seamover with a rubber mallet so that it lies flatacross the ridge.

It is important to seal valleys at the top tokeep water from getting under them. With amineral-surface valley, I use a 4-in. widepiece of roofing fabric and apply one coat ofroofing cement under it and another coat ontop of it. Roofing fabric is a cheesecloth-likematerial or fiberglass mesh, saturated with

Using a hook blade in a utility knife, Smithcuts ridge caps on the ground (photo left), ta-pering the tops so that, once installed, the lapportion will be neatly hidden beneath the ex-posed portion of the succeeding shingle. Thecaps are centered on the ridge and held inplace with one nail on each side (photo above).The last cap on the ridge will have the lap por-tion trimmed off, and because the nails will beexposed, they'll be sealed with caulk.

asphalt. It comes in 4-in., 6-in. and 12-in.wide rolls. The 4-in. rolls cost about $7 for100 ft. of fabric and are available at mostbuilding-supply stores.

When I don't have anything to solder to, Iuse the same technique to seal the tops ofcopper valleys. However, when two coppervalleys meet at a ridge or when a copper val-ley meets copper flashing, I prefer to solderthem. To solder two valleys at a ridge, I endone valley at the ridge and bend the othervalley over the ridge about 1 in. (again us-ing a rubber mallet).

After installing the valley material, I chalklines along both sides of the valley, 2 in. to2 in. from the center. These are the marks Ifollow to install the shingles. The exposedsections of my valleys are between 4 in. and5 in. wide total. Anything smaller is impracti-cal and anything larger doesn't look good.

I prefer to cut the shingles even with thechalklines while they are being installed, us-ing a pair of tin snips (photo facing page). Inail the full shingle in place, use anothershingle as a straightedge, scribe a line withthe point of a nail, then bend the shingle upand cut it with my tin snips. I can install andtrim the valley shingles on both sides as Iwork up the valley to the ridge.

Some roofers let all the shingles run long.As each side is completed, they chalk linesdown the valley and use a utility knife to cutthe shingles (being very careful not to cut thevalley material). With either method, it's im-portant to keep the nails 4 in. to 6 in. awayfrom the edge of the shingles in the valley.

Flashing—I use step flashing along thesides of a wall or chimney (wood or mason-ry). Step flashing consists of small squarishpieces of metal, bent in an L-shape. The indi-vidual pieces are installed with each courseof shingles so that the shingles in the suc-ceeding course hide the exposed metal (for

more on installing step flashing see FHB #35p. 50). You can buy precut pieces of alumi-num step flashing, but I prefer copper, so Ihave to make my own from 18-in. wide rolls.I make my steps at least 9 in. wide by 8 in.long, which is equivalent to 5 in. of exposedshingle and 3 in. of headlap. I nail the piecesof step flashing on sidewalls before the sid-ing is installed. Then the siding acts as thecounterflashing. In the rear of a chimney, Iinstall a copper cricket, which is a saddlethat diverts water around the chimney (seeFHB #47 pp. 61-63).

To flash around soil and vent pipes onmost houses, we use a manufactured metalflange with a neoprene gasket (bottom draw-ing, p. 86). It's important to remember thatall soil and vent-pipe flashings lie on top ofthe shingles from the center of the pipe for-ward and lie under the shingles from the cen-ter of the pipe back. We shingle up to thecenter of the vent pipe, either by notching theshingles around it, or by actually cutting ahole in one of the shingles and slipping itover the pipe. Next we slip the metal flangeover the pipe and nail the top corners. Thenwe continue applying shingles, notching themaround the pipe and being careful to keepnails away from the pipe (for more on flashingsee FHB #9 pp. 46-50; reprinted in Construc-tion Techniques I , The Taunton Press 1984).

Capping hips and ridges—Hips and ridgesare capped with shingles that are only onetab wide. The caps are made by cuttingthree-tab shingles into three pieces (photosabove). Once again, this is done on theground. The shingles are cut with a utilityknife, starting at the top of the cutouts andangling slightly inward, toward the top of theshingle. This assures that the lap portion ofthe shingle will be neatly hidden beneath theexposed portion of the succeeding shingle(photo above right).

Of all the areas where I have installed shin-gles, the hips are the most difficult to keepstraight without a chalkline. I snap a line paral-lel to the hip, about 6 in. away (it doesn't mat-ter on which side). This acts as a guide for theouter edge of the hip caps. I start at the bot-tom, cut the first cap even with the eaves shin-gles, then I work my way to the ridge.

I nail hip and ridge caps on or just abovethe seal tab. Nailing higher will cause thebottom of the shingle to pop up. Hip andridge caps are nailed with about a 5-in. expo-sure. The bottom of each cap is aligned withthe top of the cutout on the previous cap.

Most roofers install ridge caps from one endof the roof to the other, orienting them so thatthe prevailing winds blow over the caps, notunder them. I prefer to work from both endstoward the center. I can't really say why, ex-cept that it's the way I was taught. On steeproofs, where the centerline of the ridge is moredistinct, I don't usually chalk a line for theridge caps. On shallow roofs, I do. Once bothsides of the ridge reach the center, the lastridge caps have to be trimmed so that they butttogether, otherwise the ridge will have a lumpin it at this point. One last cap piece will coverthe butt joint. It should be only about 5 in. longand installed with two exposed nails, both ofwhich are caulked with clear silicone caulk.

Where the ridge of a dormer meets a roof, Iwork from the front of the dormer back towardthe roof to install the caps. The last capspans across the seam between the valleys(which is sealed with solder or roofing fab-ric). And the field shingles on the roof lieover the last dormer ridge cap.

Todd A. Smith is a roofing contractor in Ver-ona, New Jersey. For more on asphalt-roofingtechniques, contact the Asphalt Roofing Man-

Rockville, Md. 20852) for a copy of their Resi-ufacturers Association (6288 Montrose Rd.,

dential Asphalt Roofing Manual, $10.