Prepare for Success, prepping your old roof for metal roofing
The modern trend to installing new metal roofing directly over failed roofing is growing,and with good reason. The installation of longer-life, more durable materials without removing the old roof surface is proving to be a sound environmental practice, reducing tear-off cost, time, labour, haulage, and landfill environmental fees. A direct install over old roofing also offers increased sound-proofing and a second line of defense, –even if minimal, should traumatic roof failure occur due to loss of shingles or sheet roofing by wind.
A new direct-over install can be a substantial time-saver, quickly and easily accomplished if old roofing remains relatively intact and even. Trouble is, we invariably run into problem roofs where sun-damaged, uneven asphalt shingles are severely curled, bubbled and warped, presenting a ragged, uneven, and difficult working surface to the roofer. The solution? Prepare the whole roof carefully before starting.
Why waste time preparing a roof? Doesn’t new roofing just cover it up anyway?
Fastening new roofing directly onto very rough surfaces can result in a less-than quality appearance, and worse yet, an unhappy customer or homeowner. The simple over-tightening of fasteners on new roofing on a rough, uneven surface can easily result in a wavy, uneven, and unattractive appearance . An accidental misstep on new steel roofing laying over jagged substrate can also result in unattractive marks, with visible “imprinting” on the new roof. Professionals know that smoother working surfaces inevitably save time, energy, and aggravation. For an optimal appearance, prepare the substrate carefully. Think “trim and smooth” as you prepare for success.
Structurally solid?
Almost any roof can be rebuilt. The edge of an older roof usually displays the most severe deterioration, but even the worst condition may be overcome with careful preparation. Partial sheeting replacement and / or the installation of strapping may be required. Cut out decayed, failed sheeting sections and replace where necessary. Fasten supports, or even new extensions on truss tails if required, then replace the sheeting, and you’re good to go.
Is the old sheeting straight?
Old roofs may be visibly wavy and sagging a bit between the trusses or rafters, which is usually caused by weak sheeting material or excessive snow load. Consider strapping the roof if this condition appears excessive.
Right on top of the old shingles, or strap?
Steel roofing can be fastened directly on the shingles if the roof is prepped adequately . Cut away any rough, curled, or excessively elevated, curled shingles to make the surface as smooth as possible. Trim off the old asphalt shingle reveal flush to the roof edges. On gable ends, ensure it is trimmed back far enough to avoid interference with the new steel edge finishing trim. Install a waterproof membrane if the pitch of the roof is less than 4:12 or as recommended by the roofing manufacturer of the system you have chosen.
Too crooked? Use strapping.
If the old sheeting sags excessively, consider strapping the whole roof across the trusses. Use suitable 1×4″ Spruce or other suitable dimensioned lumber spaced 12″, 16″, 24″ on center, — or at intervals required for your specific steel roofing system. Generally, the more support the better, but locating strapping to accommodate the new system fasteners correctly is paramount.
Begin by strapping the perimeter of the whole roof completely. Ensure the perimeter strapping is placed accurately and aligned squarely. Fasten strapping securely using 2″ or longer anodized screws. Let’s try and hit the rafters or trusses with those screws, they’ll hold much better than the old plywood or chipboard sheeting will. It may be a timely idea to use a few extra screws on the strapping too, with increasingly severe winds and the potential damage it can cause.
Install strapping progressively up the roof, ensuring spacing is placed correctly for the new system being installed. Pre-cut a set of spacers to speed up the strapping install.
Cut away old shingle material that prevents straps from sitting solidly when it is fastened in position. Try out that new straightedge to determine if the top mounting surface of the strapping is acceptably and consistently straight across several straps. Find any excessively high or low spots? Loosen and cut away offending shingle material to enable installation of the strap securely, or use opposing wedges under strapping placed at the trusses to raise a strap if required. Adjusting the plane of the strapping carefully at the onset will save a lot of aggravation and result in a straighter, better and more professional-looking job.
Tip: There’s nothing quite as annoying as trying to place visible roofing fasteners uniformly, accurately and neatly, only to discover newly-installed strapping “runs out” off center. If that problem occurs, (remember Murphy’s law, ‘if it can happen, it will ‘ ) simply relocate the offending strap. If long vertical sheeting has already been fastened in place preventing simple relocation of the strap, little choice remains but to install a second strap adjacent to the first one to maintain the desired pattern of fasteners.
Leave enough space between the last two opposing rows of strapping at the ridge to allow for a ridge vent cutout; allow 2″ or more as required along the full length of the roof. Install strapping around vent locations as required if other ventilation systems are used.
Ensure that defective or inadequate flashing is replaced and correctly installed where required. With a long-life steel roof, new flashing is always a good idea.
Should a waterproof membrane or a roofing felt be used?
When steel roofing is installed directly over existing roofing, the installation of a waterproof membrane is recommended for flat, low-pitch roofs (3:12 pitch or less) and may also be required for some specific steel roofing types. Ice & Water Shield( ™) edging is recommended for steel shingles. As a matter of interest, historically, most roofing was installed with a suitable felt or building paper over the complete roof surface, but with the exception of the application of the quintessential edging, most roofing is now installed without.
There are pros and cons; installing a paper barrier provides not only a second line of defense against leaks, but decouples the roofing to some degree for expansion and contraction. Barrier installation under some brands of steel roofing may be recommended for the same reasons. All recommendations made by the manufacturer should be followed to optimize the performance of any roofing system.
Ready now? Install that steel roof
Now it’s easier to install your roof. Attach starter strips all around and get that first row of roofing dead straight, whether it is steel shingles, long sheets of standing-seam roofing or a modern painted-steel corrugated type of roofing. If working across the roof, measure constantly to ensure the sheeting remains square. Go for it.
In preparing your roof for success, always work safely; use appropriate equipment and safety protocol on the roof at all times. We can see that new ridge cap up there already.
With so many modern roofing material choices, why would you choose to install cedar roof shingles on your house? Two reasons stand out:
1. Wood shingles form a natural, beautiful roof.
2. Cedar smells great, is non-toxic, lightweight, and easy to work with – perfect for DIY roofers.
17th century colonists arrived in America with limited tools and resources. Since the New World offered an unlimited supply of trees, wood shingles were the ideal choice for colonial roofs. It was one of our first “green” building materials, and remains popular 400 years later.
Here Is An Additional Video On How To Install Cedar Shingles
Materials:
Although colonial roofers utilized whatever wood species was handy, today’s wooden roof shingles are cut from cedar heartwood. Natural oils there protect against decay and insects, and additives are available for resistance to fire and fungus. Western red and Atlantic white cedar are both commonly available. “Squared and re-butted” shingles are the easiest to apply, and “fancy cuts” offer familiar shapes like fish-scale and v-cut on the exposed end.
You’ll use galvanized or stainless steel nails, and any valleys will require metal flashing. You can also include drip-edge and rake trims for all edges.
Preparation:
Cedar roof shingles require air circulation for proper drying. This is best achieved by nailing each course to spaced 1 by 6 “breather” boards, rather than to plywood sheathing. Roofing felt is used for wood shake installation, but not recommended for shingles.
If you already have plywood sheathing, various methods are available to ensure ventilation beneath your new shingles. Consult your local building department for guidelines. The Cedar Shake and Shingle Bureau (CSSB) offers general information.
Tools:
Measuring tape
Hammer
Utility knife
Framing square or straight edge
Chalk-line, spacing board, or gauge
Ladder(s) and, if desired, staging system
Optional: table saw
Installation:
Begin with a stable work set-up. This can be as simple as a step-ladder or as complicated as a double-plank system, depending on your situation. Always follow safe working practices for the method you choose.
Cedar shingles are applied from the bottom, up. Install edge trim first, then add a breather-type underlayment, if needed. Sort out blemished shingles for the first course – they won’t show. The thicker, butt end of each shingle faces down and overhangs the roof edge by about one inch. Space shingles 1/4″ apart; mix various widths as you go along. Shingles wider than 8″ should be split. Install nails an inch above your chosen exposure – typically either 5 1/2″ or 7 1/2″ – and no closer than one inch from side edges.
Add a second shingle course over your first layer. Offset overlying joints by at least 1 1/2″. This “double course” starts your roof and is not used in later courses. You don’t have to install each entire course of shingles before you begin next row. Instead, you can install shingles in stepped batches. Cut the final shingle to width using a utility knife or table saw. Be sure to carry shingles about an inch past each rake edge for water run-off.
Going up:
Use one of these methods to space each subsequent course:
Chalk-line to mark each next course. This requires you to complete one course at a time
Measuring gauge (some shingling hammers have one): Best for shorter runs, and allows you to do multiple courses at once.
Spacer-board cut to the exposure width. This approach works great, but can be more cumbersome than the first two techniques.
Continue adding shingle rows. Stagger joints, and mix shingle sizes. Shingles with minor defects can be re-cut for row ends. Be careful working on top of your new shingles. For steeper roof slopes, use staging methods approved for wood shingles, and follow product directions.
Hips, valleys, ridges and flashing:
Roof intersections require special attention. Use metal flashing in valleys and on hips. Valleys can be open or closed, depending upon the look you prefer. Where your roof meets a wall (dormers, for instance), you’ll need step-flashing. This is placed beneath individual shingles. Allow about 1/2″ between cedar edges and vertical flashing.
Hips and ridge-lines can be finished using exposed metal trim. Various profiles are available, depending on your budget and taste. Proper application of this final step makes all the difference for looks and wind-resistance.
Maintenance:
Your new cedar roof will weather naturally to a grayish hue, or you can apply a stain. Other products can control mold and fungus. Keep your roof clean, and ensure that vents are unobstructed. The CSSB provides additional recommendations.
Installing cedar shingles can be a great DIY project. When you choose a high-quality cedar roof shingle and install it properly, your roof will last a lifetime with minimal maintenance. Your house will display a beautiful, classic look. All your neighbors will be jealous.
If you want to install your own asphalt shingles, all you need is a hammer and nails, right? If only it were that simple. Every shingle package shows you the steps to install new shingles on your roof, but it doesn’t show you what methods you’ll use. If you have the basic skills and ambition nail down your own roof, you’ll benefit from knowing more about the job.
Although asphalt-based shingles are the top choice for roofing, they are a bit temperamental. Cold makes them brittle, and heat melts them. Rough handling can damage your new shingles. A sudden rainstorm could ruin your project. YOU are fragile, too; and roofing is dangerous. Before you drive a nail, let’s review the basic…
Roofing Safety Guidelines:
Roofing is best done in shady or cloudy conditions between 30 and 80 degrees F.
Never work in icy, wet, or windy weather.
Avoid working alone. What if you fall?
Follow all ladder warnings. Secure tall ladders to prevent sliding.
Beware of any electrical lines. Never assume “it’s just the TV cable.”
Don’t work when you’re tired, taking certain medications, or after consuming alcohol.
Remove potentially dangerous objects on the ground below your work area. Lush bushes, good – iron fences, bad.
Should you re-roof it?
The best way to install a new Asphalt shingle roof is to start from scratch. Although re-roofing has been popular over the years, serious drawbacks remain. Many municipalities restrict re-roofing options, too. Removing the old shingles from your house is hard work, and also the most dangerous part of the job. Clean-up and disposal of debris can be a nightmare. If possible, leave this part to the pro’s.
Sometimes, your old roof has failed due to underlying roof deck problems. The only way to find out for sure is to tear the shingles off and have a look. Adding a layer of new plywood (or OSB) sheathing will add to the cost, of course, but goes a long way toward ensuring great results. This, too, is a good candidate for out-sourcing. The same roofers you use to do the tear-off will usually be happy to tackle re-sheeting as well. Once you have a nice, clean roof deck to work with, you can take over.
Tools you might need:
Ladder(s)
Staging for working at the eaves – planks or scaffolding
Standard and hook-blade utility knives
Work gloves
25′ Measuring tape
Chalk-line and straight-edge (framing square)
Tin-snips or shears
Tool belt or pouch for fasteners
Hammer-tacker and staples
Roofing hammer or pneumatic nailing system
Preparing for new shingles:
Your bare roof needs a layer of 15# roofing felt underlayment, sold in 400 sq-ft rolls. Staple this felt down, starting at the lowest point of your roof and working upward. Overlap each row at least 3 inches. Use plenty of staples and work carefully to avoid tearing the paper.
If your roof is too steep for walking (above a 7/12 slope), use roof jacks and planks for safety.
Add metal trim on all edges. Use drip-edge throughout, or add rake-edge for the sides. Square-off your corners, and point overlaps downhill. Tack with roofing nails. In snowy regions, add a starter row of nail-sealing glued underlayment. This product also works well for forming valleys.
Finally, lay down some Asphalt roofing shingles:
Once the prep is done, work from your staging to begin installing asphalt shingles. The picture on the package helps here. Your starter row is shingles with the tabs cut off. Cut these upside-down with a utility knife. Begin laying full shingles from an outside corner of the roof. To avoid traveling back and forth along the length of your eaves, work on 4 or 5 rows at a time.
Each row will step back a half-tab. For architectural shingles, you’ll measure and cut each series of starters. For tabbed shingles, use the marks provided by the manufacturer. When you reach the row that starts with just a half-tab, start the next one with a full shingle again. At the other end, cut the final shingle to fit the edge, valley, or hip as needed – use a hook-blade to make face-up cuts. As you go up, use a chalk-line to keep rows straight (and tabs aligned, if needed).
If your roof meets a wall, use step-flashing beneath each tab row and the wall siding. For vent pipes and protrusions, use vent boots and cut the shingles around them.
Nearly all modern roofs use ridge venting – the sheeting stops short on each side. End your final shingle row here, using the hook-blade for cutting. To cover the ridge, install vented cap shingles or continuous ridge vent.Climb down carefully, take a picture, and call it a day.
Would you like to enjoy the beauty of a slate or cedar shake roof without the high cost and skill required? Consider installing one of the newest vinyl composition roof shingles on your home. Even the most expensive asphalt-based shingles can’t match the distinctive 3-dimensional appeal of vinyl-blend roof shingles. These products mimic classic roofing materials well enough to fool the eye from curbside. Even if you can afford real slate or wood shakes, consider these…
Advantages of installing synthetic “slate” vinyl shingles:
Ability to select custom color blends
Choice of unique shape profiles
Lower cost per square
Dramatically lower roof weight
Can be installed over plywood
Uniform product dimensions
Resistant to work damage
Easier to handle and cut than stone roof tiles
Reduced reliance on special metal trims
Factory warranty supplied (50 years or LLW, typical)
Class A fire rating
Documented freeze/thaw, heat, impact and wind resistance
While both natural slate and cedar shake roofs require special skills and unique roof-deck preparation, vinyl-based shingles are designed for easy installation over standard sheathing. Each product will offer documentation, even DVD video instruction. Some may require that you use proprietary roofing underlayments. The techniques involved are all well within the abilities of most do-it-yourself roofers.
Tools required for Vinly Roof Installation:
Standard ladders and staging, (possibly) product-specific roof brackets
Measuring tape, chalk-line, framing square
Utility knife, power- and jigsaw, shingle-shear tool (optional)
Hammer, stapler, and fasteners
Heat gun (for ridge caps)
Once you’ve decided to install a vinyl roof on your home, make your selection based on budget and aesthetics. For all but the smallest jobs, arrange for delivery of all materials. Read the manufacturer’s instructions and watch the video, if supplied. Schedule your roofing job based on the weather and the other usual factors related to finding helpers and taking time off work. Pay someone else to tear-off and dispose of your existing failed roofing. Seriously, you don’t want to do this part unless you’re a pro.
Getting started:
Like all roofs, you new vinyl shingle roof begins with a clean roof deck and plenty of staging for easy access to the eaves. Pay attention to ladder and staging safety warnings, and note these two important roofing safety rules:
* Never work alone
* Never work in bad weather
Step one is to lay down the correct roofing underlayment. This could be basic roofing felt or a designed product for your shingles. Use only specified fasteners. Underlayment provides a clear work surface and protects from dust and moisture penetration. Many systems also specify an ice/water shield adhered product at the eaves and in valleys. Just follow the directions.
Next, add trim on all edges. You might be using off-the-shelf drip-edge or a product detailed in your product’s instructions. Work on one roofing surface at a time to avoid resetting your access staging. Set up any adjacent valleys next, using rubber membrane and/or metal valley flashing as directed. Prepare step-flashing if your roof section meets a wall or dormer; you’ll add this as you install the shingles.
Movin’ on up:
With preparation complete, it’s time to begin laying shingles. Every design uses some sort of “starter shingle.” Usually, this involves modifying the standard shingles in some simple way. This first row is always hidden, so it’s a great place to use up any blemished shingles. To avoid color problems later, mix shingles from several bundles at a time before you start nailing them up.
Vinyl shingles may come in assorted sizes to mimic the variation of shake or slate roof materials. If so, be sure you understand the proper approach for mixing these. Like the roof tiles they imitate, vinyl shingles use overlapping in two directions – side-to-side and up-and-down – to prevent leaks. Uniform sizing and (usually) molded-in exposure gauges make this job much easier for you.
You’ll still want to use chalked lines to keep everything nice and straight. Pay special attention to the manufacturer’s nailing instructions – most often, holes are provided and MUST be used correctly.
Cut your start and end shingles using a knife or shear. Add wall flashings as you go, if needed. You should be able to use a jigsaw with the appropriate blade to cut shingles around vent pipes and outcroppings. For angled cuts, at valleys and hips for instance, you may be able to use a table- or power saw. Again, read the directions.
Unlike slate or cedar, vinyl shingles include matching trim and venting products. When you finish applying these caps, your hard work is done. Clean up your debris, put away the tools, and have a cold one. Nice job!
You may surprised to learn that you can install slate shingles. When you think of slate roofs, images of churches and historic Victorian homes come to mind. You can’t run down to Home Depot and grab slate tiles at 20% off. Still, when you drive around neighborhoods of slate-topped homes, you can’t help but admire the subtle beauty of natural stone roofs.
If you live in a slate-shingled house, you might need to make repairs or want to add-on a room with a matching roof. Perhaps you’d like to build an authentic shed or gazebo, and want to use slate for the crowning touch. While it’s best to employ professionals for large or steep roofs, you can tackle smaller projects yourself with great results.
Slate Roofs Are Different
Asphalt shingles are of uniform size and are easy to install. Not so for slate! Each slate tile is unique in size, thickness, and hue. This variation is what makes a natural slate roof so beautiful. Consider the installation of slate an artistic challenge, rather than a chore.
You probably don’t own the right tools. Rent or borrow what you need; don’t take shortcuts. In addition, slate roofs aren’t walkable. One industry expert asserts: “Roof slate is not to be walked on – period. It is not a floor…” (source: Joseph Jenkins of traditionalroofing.com – Grove City, PA) Techniques for staging on asphalt are useless for slate. Consult your supplier for cutting tools, ladder hooks and roof scaffold brackets.
Find The Right Slate First:
To get started, use the Internet to locate a supplier in your region. If slate roofing is common in your area, chances are there’s a quarry less than 500 miles away. Slateroofers.org, for instance, lists 27 suppliers in 13 states. In addition, “salvage slate” may be an option.
Slate is described by color and origin: Vermont green or Spanish black, for example. To match an existing roof, you’ll need samples and/or good close-up pictures. Slate tiles come in various standard sizes, too. You may want to pay a consultant for a site visit. Your slate source can also help you find the right flashing and cap materials.
Before you begin, sort your delivered slate by thickness. Typically, you’ll install the thickest pieces first and graduate to thinner tiles closer to the ridge. Cull out damaged slates and set them aside for cuts. If your job involves more than one pallet, thoroughly mix the tiles. Be sure all of your slate is from the same lot source!
What Goes Under A Slate Roof?
If you’ve done any roofing, you know about plywood sheathing and felt paper. The ideal deck for slate, however, is solid wood at least 3/4″ thick. In addition, the rafters beneath MUST be strong enough to carry the extreme weight of slate roof tiles (from 8 to 15 lbs/sq ft). As for underlayment, one expert notes:
“Properly installed slate roofs need no underlayment. The main purpose of underlayment is to keep water out … until the slate and flashings are installed.” (Jenkins)
* A correctly installed slate roof will not leak. *
That a bold statement places the right emphasis on your efforts.
Note these critical steps:
Starter rows at the eaves
Correct headlap (the overlap layer to layer)
Correct sidelap (the overlap of successive shingles)
Proper nailing
Flashing design and materials
Cap and other trim details
Slate Shingle Installation Starter Course:
Your first row sets the stage for success. A slate roof’s starter course uses full tiles installed face-down, with a “cant strip” (or raised drip edge) to induce the right angle from the beginning. Even this first, hidden row of shingles will have headlap: the bottom edge of the second row above it will overlap the top of the starter shingles by at least 3″ (depending on roof pitch).
Headlap and sidelap:
As noted, all tiles should overlap those two rows below by about 3″ (varies by roof slope) – that’s the key for preventing leaks. Sidelap is the shift of joints from one row to the next, ideally about 1/2 the width of a tile. If you get either of these wrong, be prepared for failure.
Nailing Slate Roof Shingles:
Each slate has 2 drilled, recessed holes for nailing. Add 2 shingles’ thickness plus the roof deck to find the correct nail length. Neither over-drive nor under-drive the nails; broken tiles will result from either error.
Flashings, caps, and trims:
Most slate installations use soldered or folded copper trim. Your roofing supplier should provide complete documentation for these crucial transition materials.
Once you understand the important differences between slate and asphalt shingles, covering your roof with stone tiles isn’t quite so scary anymore. Work carefully from the bottom-up, using the proper tools and techniques, and you’ll be proud of the gorgeous roof you build.
Jim Bessey
Raymond Kukkee