Things like leaves sticks and branches need to be removed periodically, they hold dirt and moisture against the roof which can cause early deterioration of the shingles.

Yes, all too often the downspouts are clogged from one leaf that has fallen out of the sky from heavy winds, next dirt and dust builds up on top of the leaf and makes what we call gutter-crete. Minerals from the shingles mix with fine dust and form a hard layer that will block your downspouts, causing water to be forced on and into the facia causing water damage there. The below video is wet gutter-crete. This entire gutter was clogged with only a few leaf's blocking it from draining. When this stuff is dry it's as hard as concrete, that is why we have named it gutter-crete. This gutter was overflowing and damaging the facia or the area that the gutter is connected to.

They are properly disposed of at the Solid Waste management facility.

Yes, ninety percent of leaks are never detected until it is too late. You may be leaking and never know it. Most leaks are just enough to get the wood and trusses wet but never makes it inside the living area making it undetected. That leads to unexpected wood replacement which means more material and expenses to fix the situation. The best thing that you can do is to keep trees and greenery off of your roof along with any organic material that may build up as any of these situations hold the moisture and minerals against the roof leading to pre deterioration and loss of life span.

Depending on the company and policy things can change dramatically. Generally, if a tree falls on one side of the roof they will pay for that side. The type of policy has a big influence on what happens and why. It is always good to contact your agent to clarify where you stand if the situation should arise.

If the grit is falling off or if there are cracks in the shingles are the two main signals that your shingles have past their life expectancy. This is a photo of the grit falling off.

Making sure they have liability insurance, contractor's license and any other credentials needed to work in the industry for that area.

Generally speaking, the generic shingles last 12 yrs. and the name brands are 20 plus. Depending on the brand, that is why we recommend doing research before installing a new roof to decide which one you like best.

Flashing is a piece of metal or aluminum that transitions from the roof to siding, chimneys or any other protrusion through the roof. Also added at the bottom of the valleys on dormers or any other reason a valley does not end at the bottom of the roof. On an incline step flashing is installed with each shingle reassuring that if and when water gets in there it is forced back on top of the shingle below it. Averting any water from penetrating the roof. Generally, there is a counter flashing that covers the top end or siding covers the top. The pictures show Step flashing being installed and then the finished product with counter flashing installed.

The answer isn't an easy one. There are a lot of variables that are at play, and they change with every situation. First you should always want to check with your local codes to see if it is even an option. If it is allowed in your area, then yes you can. Consider the pros and cons about removing, or an overlay.

Let's start with the pro's. Saving time and money are the answer. Let's go with the cons. Increased weight, potential for hidden damage, difficulty inspecting roof deck, reduced life span, uneven appearance, voiding shingle warranty, making it generally not recommended. Your flashing can't be weaved into the shingles since it is already part of the lower roof, all of those areas are a potential for water to get trapped in between the layers leading to the nails that hold the roof down rusting, the plywood is next then a truss or two now we are already running down a rabbit hole of potential problems. The fact that the structural integrity of the wood hasn't been checked is enough. Thats how shingles blow off, the plywood is already rotten, and you put another layer on top. The nails don't hit solid wood and are begging to be blown off.

There are a lot of boxes to fill to get this answer and every situation is different. How steep, how big or small and the complication level, all have a major impact on the price. The answer can change with companies, areas or region, shingle brands excreta. The best way to find out is to contact three different companies and get a quote from them all and that will give you a number that you can rely on.