Yes, it’s possible to replace drip edge flashing without removing shingles, but it’s not a good idea. You’ll have to lift the bottom shingles up to remove the old drip edge, install the new material, and then lay the lifted roofing material over the new drip edge. Bending roof shingles can cause damage, and if you have ongoing issues with roof leaks that prompt drip edge replacement, it’s a good idea to consider a roof and drip edge replacement to avoid ongoing issues.

A chimney cap costs about $300 on average to install, with prices ranging from $75 to $1,000. The final cost depends on several factors, including the professional you hire, the accessibility of your chimney, the cap's material and size, whether any repairs are needed, and if it requires custom fabrication. Chimney caps are usually made from galvanized steel, stainless steel, or copper. Copper caps are the most expensive, followed by stainless steel and then galvanized steel. Excluding labor, average material costs are around $100 for galvanized steel, $250 for stainless steel, and $600 for copper. You may also face additional costs, such as hiring a chimney sweep to clean the chimney before the cap is installed.

You shouldn’t put a new roof underlayment over an old one for a few reasons. Old felt must be removed in order to assess the condition of your roof decking, such as rotting wood or other structural issues. Also, if your roofer doesn't install a fresh layer of felt as is required by shingle manufacturers, your warranty may be voided. Finally, old underlayment removal is often included in the cost of roof repair or replacement, so there's no real benefit to leaving it on before installing a new layer.

Yes, shingles should overhang the drip edge, typically between 1/2-inch and 3/4-inch. An overhang shorter than 1/2-inch can allow wind-driven rain to get under the shingles and damage the roof deck or fascia. Conversely, an overhang longer than 3/4-inch increases the risk of shingles getting caught by strong winds, which can lead to roof uplift. Always check your local building code for exact overhang requirements in your area.