How to shingle a roof over existing shingles

how to shingle a roof over existing shingles

How To Install Metal Roofing Over Shingles

Sep 16,  · In this video we provide details on how to install roof shingles over existing elvalladolid.com discuss the nesting method, which helps minimize an uneven appeara. Oct 19,  · If you wish to install metal roofing over shingles, it’s recommended to do it one of two ways. The first is to apply an approved underlayment over the old shingles. This is the fastest way to install but it doesn’t provide the flattest surface for metal roofing installation. The second way is to install 1?4 purlins over the shingles.

If conditions are right, new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing. Installation is easier than for a tear-off job because you can use the existing shingles as guides for laying the new ones. But you must take care to install the shingles correctly so they lie flat. And a good job involves installing new flashings rather than relying on the existing ones. Reroof jobs are sometimes done without what is sexual activity definition flashings.

However installing new flashings—including special drip-edge flashings made for reroofing—will ensure a tight seal and a long life. Some roofers install a layer of waterproof shingle underlayment WSU over the existing shingles at the eave end, as would be done for a roof laid on bare sheathing. This provides added protection against ice dams. Asphalt shingles can be laid over cedar shakes or shingles, a job best left to pros.

Beveled wood pieces called "horsefeathers" must be laid along the thick edges of the shakes to make a fairly flat surface. In a reroof job, a special type of drip-edge flashing is installed at the eaves and rake to wrap around the existing shingles.

The starter course or strip is rip-cut so it butts up against the third courseof the existing shingles; its front edge is even with the front edge of how to drop to d tuning drip edge.

The rest of the shingles are full-width. The thicker the new shingle, the better it will hide any imperfections in the roofing below. It's a good idea to use at least year shingles; architectural shingles are an even better choice.

Install a course along the snapped line, then install succeeding courses using a guide or a snapped line. Remove the ridge caps. Doing it now will make it easier to keep the job clean. Use a roofing shovel or flat pry bar to pry out and remove the ridge shingles. Remove all nails. Remove air vents and pipe flashings by prying out or unscrewing the fasteners holding the fixture. If you damage shingles while doing this, repair the shingles see next step.

Reuse a vent or flashing only if it is like new; otherwise replace it with a new one that will fit the hole or pipe. If a shingle is torn or cracked, glue the broken piece back in place using roofing cement. If the broken piece is lost, cut a piece to fit. Using a large broom, brush away all broken shingle pieces, twigs, and any other debris that could become trapped under the new shingles that you install. Keep the roof clean as you work.

At the eave and the rake, install U-shape drip-edge flashing made for reroof jobs. Install the eave piece first, then the rake piece over it. The two pieces should meet neatly at the corners. Drive nails at high points on the underlying roof—the bottoms of the shingles. If you have an open valley, install new W-shape metal or vinyl valley flashing to fit directly over the old flashing.

Attach it by driving nails into the outside how to make a padded baby play mat only. Do not drive nails less than 6 inches from the center of the flashing.

Use a starter strip or cut pieces for a starter course. Rip-cut the starter strip or starter pieces so that they butt up against the second course of existing shingles and are even with the front edge of the existing roofing. Attach with nails along the top edge of the strip. Rip-cut the shingles for the first course so they butt up against the third course of existing shingles and are even with the front edge of the starter course. Their tab slots should not line up with the tab slots of the starter course, if there are any.

Nail the shingles just above the tab slots. Butt the succeeding courses of shingles how to get rid of ingrown hairs from waxing the bottoms of existing shingles and apply them by driving nails above the tab slots.

Snap vertical control lines; there is no need to snap horizontal lines. Be sure the new tab slots do not align with the old ones. Once you have installed shingles just past a plumbing vent, install the flashing piece so it will lie on top of roofing at its bottom but be covered with roofing at its top. Depending on the width of the pipe, you may need to tear away a segment or two of the rubber boot.

Apply roofing cement, slide the flashing over the pipe, and push so it lies flat on the roof. Install air vents in a similar manner. For both plumbing-vent flashing and air vents, you'll need to cut the shingle above to go around the flashing and then install the shingle. Where you meet a chimney or side wall, install step flashing. Apply a shingle, then a piece of flashing, then a shingle, and so on, so that each piece of flashing rests on top of the lower course and is covered by the upper course.

You'll need to pry the siding outward to slip in the flashing; in some cases you'll have to remove the siding. Protect the step flashing with counterflashing. On a chimney use a grinder to cut an indentation into the mortar. Cut and bend the counterflashing to fit snugly into the cut mortar and to cover at least 3 inches of the step flashing. Apply mortar with a how to install vinyl tile squares gun inset and how to get registered in just dial the flashing into the mortar.

Install roofing on both sides of a ridge and cut them so they butt closely together but do not overlap. Cut shingles into ridgecaps. Snap lines on either side and install the caps. At the rake snap a line directly above the edge of the existing shingles. Cut with a utility knife; you may want to use a straightedge. You may find it easier if you first cut from below using the existing shingles as a cutting guide.

How to Roof Over Existing Shingles If conditions are right, new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing. Things to Know Before You Start:. Aligning Layover Shingles In a reroof job, a special type of drip-edge flashing is installed at the eaves and rake to wrap around the existing shingles. Choosing Shingles for a Layover Job The thicker the new shingle, the better it will hide any imperfections in the roofing below.

Step 1: Remove Caps Remove the ridge caps. Step 2: Remove Obstructions Remove air vents and pipe flashings by prying out or unscrewing the fasteners holding the fixture. Step 3: Repair Broken Shingles If a shingle is torn or cracked, glue the broken piece back in place using roofing cement. Step 4: Sweep the Roof Using a large broom, brush away all broken shingle pieces, twigs, and any other debris that could become trapped under the new shingles that you install.

Step 5: Install Flashing At the eave and the rake, install U-shape drip-edge flashing made for reroof jobs. Step 6: Install Valley Flashing If you have an open valley, install new W-shape metal or vinyl valley flashing to fit directly over the old flashing. Step 7: Starter Strip Use a starter strip or cut pieces for a starter course.

Step 8: Cut and Install Shingles Rip-cut the shingles for the first course so they butt up against the third course of existing shingles and are even with the front edge of the starter course. Step 9: Continue Shingles Butt the succeeding courses of shingles against the bottoms of existing shingles and apply them by driving nails above the tab slots.

Step Work Around Vent Once you have installed shingles just past a plumbing vent, install the flashing piece so it will lie on top of roofing at its bottom but be covered with roofing at its top. Step Air Vents Install air vents in a similar manner.

Step Work Around Walls Where you meet a chimney or side wall, install step flashing. Step Install Counterflashing Protect the step flashing with counterflashing. Step Cover Ridge Install roofing on both sides of a ridge and cut them so they butt closely together but do not overlap.

Step Cut Shingles At the rake snap a line directly above the edge of the existing shingles. No Obligation Estimate!

Can I Install a New Shingle Roof Over My Existing Roof?

Sep 16,  · So if there are already two layers, the choice is made for you. You need to tear off the roof and install a new one. Current shingles are curling or in bad shape - The new shingle roof should lay flat on your old one. But if the current roof is curling, this isn’t possible.

Installing a new roof over an existing one, also called a layover or nailover , is often possible although not always the best option. A properly installed layover roof can look and function as well as one installed after tearing off the existing roof and is typically more convenient and less costly. Although many metal roof systems can be applied over an existing roof, layovers are more commonly done with asphalt shingles. Choose a shingle style with the same dimensions as those on your existing roof to provide the best appearance.

Multiple layers of shingles can make it difficult or impossible for the nails to penetrate the decking sufficiently, causing shingles to blow off or fail to seal properly.

The additional weight of multiple layers may also be more than the roof supports can bear. Inspect your attic for cracked or sagging rafters -- a sign that a layover could cause more damage. If you already have multiple layers of shingles or signs of damage to your roof supports, you should avoid a layover. Some manufacturers will not cover product failure if their shingles are installed as a layover and some municipalities limit the number of layers you can have.

The condition of the existing roof is critical. The roof should be in sound condition with no unrepaired leaks. This can indicate problems with the wooden deck or rafters supporting it. Soft spots are signs that your decking needs to be repaired or replaced. If there are numerous soft spots, it is typically best to avoid a layover. You can trim or remove these shingles before applying a layover, but your new roof will not be as even-looking and may have problems sealing properly.

Drip edge, or edge metal, is a piece of metal that extends approximately 0. To install it, slide the flat, wide flange underneath the first row of shingles as far as it will go. Check to see that the bottom edge is positioned over the gutter; if not, adjust the flange underneath the shingles until the drip edge is properly positioned.

Use a felt-tip marker to make a short line on the drip edge to indicate proper position. Remove the drip edge and apply a thin strip of roofing cement at the top edge above the line you marked and slide the drip edge back under the shingles to the mark you made.

You can also use roofing nails to secure the roof edge. The first row of shingles is called a starter strip. You can either purchase starter strips or make your own by cutting shingles to size.

To make your own, use the flat, solid part of the shingles and a heavy-duty utility knife to cut pieces that are approximately 5 inches wide. Place the top of each starter shingle firmly against the bottom of the shingle immediately above it and even with the eaves, then nail it into place. Use 1. Your second row of shingles should be cut to 10 inches wide.

Butt these against the bottom of the old roof's third row and nail into place. Flashing must be installed correctly around elements, such as vents or chimneys, that penetrate the roof, as well as in valleys where different parts of the roof meet.

When doing a layover, the thickness of the layers can make it difficult to use any method other than metal valley flashing. To install, line the valley with underlayment secured with roofing cement. Cut the flashing into 6- to 8-foot lengths to help prevent buckling after installation.

Apply roofing cement to the back of the flashing, then nail it into place, keeping all nails a minimum of 6 inches from the flashing's centerline. The edges of the valley flashing should be under the new shingles.

Continue installing the rest of the shingles by butting each new row snugly against the bottom of the existing row of shingles immediately above and nailing into place. Depending on the type of shingles you have selected, you may need to use a special type of shingling material, called hip and ridge , to cover the peak where your roof planes meet.

If you are using three-tab shingles, however, you can cut shingles to make your own. Use a heavy-duty utility knife to separate the shingles into thirds by cutting them at each tab. Mark the center of each section and use a compass to mark degree angles along the sides of each section from the end to the center line. Cut along these marks to make a piece that resembles a trapezoid topping a rectangle. Folding each piece over the ridge and nail it into place.

Nails should be placed in the trapezoidal area formed by cutting the angles. Overlap each piece so that the section without angles covers the trapezoidal area. Bill Goodwin has more than three decades of experience in commercial, residential and industrial building maintenance and construction.

He has been certified in refrigerant recovery, recycling and transition. Goodwin has been the author of numerous home improvement articles from to the present. By Bill Goodwin Updated July 30, Related Articles.

Determine the Feasibility Multiple layers of shingles can make it difficult or impossible for the nails to penetrate the decking sufficiently, causing shingles to blow off or fail to seal properly. Install Drip Edge Drip edge, or edge metal, is a piece of metal that extends approximately 0.

Install Starter Strips The first row of shingles is called a starter strip. Flashing and Additional Rows of Shingles Flashing must be installed correctly around elements, such as vents or chimneys, that penetrate the roof, as well as in valleys where different parts of the roof meet.

Finishing the Job Depending on the type of shingles you have selected, you may need to use a special type of shingling material, called hip and ridge , to cover the peak where your roof planes meet.

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