New shingles over old ones can be time- and labor-saving while giving your roof a fresh new appearance. However, adequate preparation is key to longevity. Begin by examining the old roof for damage and repairing it where needed. Then, clean the surface and put down a firm underlayment to provide a moisture barrier.
Guidelines for marking will keep straight rows before adding layers of new shingles. Proper shingle roof installation requires correct nailing to prevent water entry, while ridge caps and flashing provide additional sealing. A final check guarantees correct placement. By following these steps, you can safely install shingles over shingles while ensuring durability and protection.
Equipment and Materials Needed
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- Tape measure
- Hammer
- Power nailer or roofing hatchet
- Drill
- Roofing shovel or flat pry bar
- Carpenter’s square
- Utility knife
- Broom
- Chalkline
- Straight-cut tin snips
- Flashing
- Nails for flashing
- Nails long enough to penetrate sheathing
- WSU sheet
- Roof cement
- Shingles
13 Steps to Install Shingles Over Shingles
Follow these steps to install shingles over shingles:
1. Take Out Ridge Caps
Begin by taking out the ridge caps. Removing the ridge caps first helps keep the installation process cleaner and more manageable. Pry out and take off the ridge shingles using a flat pry bar or roofing shovel. Take out all the nails.
2. Remove Obstructions
Take out air vents and pipe flashings by prying out or unscrewing the fasteners. If you break shingles in the process, repair or replace them as needed. Reuse vents or flashing only if they’re in good condition. Otherwise, replace them with new ones that fit the existing hole or pipe.
3. Repair Broken Shingles
If a shingle is cracked or torn, fix the broken fragment by gluing it with roofing cement. If you notice a leak, addressing damaged shingles is essential to fix a leaking shingle roof. If a piece is missing, cut a new one to fit the space, ensuring a smooth surface that prevents water from seeping through gaps larger than 1/2 inch.
4. Sweep the Roof
With a big broom, sweep off all the shattered pieces of shingles, sticks, and any other material that might get caught beneath the new shingles that you will put in place.
5. Install Flashing
At the rake and the eave, install a U-shaped drip-edge flashing. Put in the eave piece, followed by the rake piece. The two pieces should fit nicely at the corners. Nail the flashing at high points on the roof, ensuring the nails beneath the shingles’ bottom edges.
6. Install Starter Strip
Cut the starter strip in such a manner that they meet the second row of installed shingles and lie even with the front edge of the installed roof. Nail up along the upper edge of the strip.
7. Continue Installing Shingles
Fix the next rows of shingles into the bottoms of the lower shingles and secure them by nailing over the tab slots. Snap control lines vertically only; avoid horizontal lines, as they can misalign the shingles. Ensure new tab slots do not fall over old ones.
8. Work Around Vent
After installing shingles around a plumbing vent, install the piece of flashing so it will be on top of roofing at its bottom but covered by roofing at its top. You might have to remove a section or two of the rubber boot, depending on the size of the pipe. Use roofing cement, push the flashing over the pipe, and press so it will be flat on the roof.
9. Install Air Vents
Put air vents in a corresponding fashion. When you do air vents as well as plumbing-vent flashing, you have to cut the shingle up to go around flashing and then place the shingle.
10. Work Around Walls
Where there is a junction with a chimney or side wall, install step flashing. Overlap a shingle, and then a bit of flashing, and then another shingle, and so forth. Pry the siding back to tuck in the flashing securely.
11. Install Counterflashing
Keep the step flashing covered with counterflashing. Cut the counterflashing to fit close in the sliced mortar and also cover at least 3 inches of the step flashing.
12. Cover Ridge
Install roofing on each side of a ridge and trim them so they join together but don’t overlap. Snap lines on both sides and put on the caps.
13. Cut Shingles
At the rake, snap a line straight above the edge of the current shingles. Cut with a utility knife — a straight blade works best for clean edges. You may find it simpler if you cut first from underneath, using the current shingles as a guide.
Conclusion
To properly install shingles over shingles, begin by examining and fixing the old roof to establish a strong base. Surface cleaning and the application of an underlayment provide increased protection against moisture. Correct layout markings ensure evenly spaced rows, and correct fastening prevents leaks.
The ridge cap and flashing installation strengthen the roof against high winds and heavy rains. By following these steps, you can correctly install shingles over shingles for a solid roofing upgrade. Precision Roofing, a trusted roofing company, offers professional services for a smooth and durable installation. Our professionals adopt industry standards of durability and weather resistance and are trusted for quality roofing services.