Repair or replace is the question behind most of the calls we get, and it deserves a better answer than "it depends." Here is how we actually think it through when we are standing on the roof, so you can follow the reasoning when we give you ours.
How old is it?
Age sets the frame for everything else. A ten-year-old architectural roof with one leak is a repair; the same leak on a 24-year-old roof is a sign of what is coming. We ask when the roof went on, look at the shingle type to sanity-check the answer, and compare it to what that material typically lasts on Long Island.
How much of it is failing?
This is the real question. One chimney leaking is one chimney. A valley that has worn through is one valley. But curling across the whole south slope, or granule loss everywhere, is the roof itself. Our rule of thumb: when the repairs needed would touch more than about a quarter of the roof, replacing it is almost always the better money, because you would be paying repair prices to fix most of a roof and still have an old one.
What is underneath?
A repair assumes the deck is sound. When we lift shingles and find soft plywood, or we can see from the attic that the deck has been wet for years, patching the top does nothing for the problem. A replacement lets us replace the bad decking and start dry. This is also the reason we are cautious about a second layer of shingles over an old one: it covers exactly the thing you most need to see.
What kind of leak is it?
Leaks at penetrations, which is to say chimneys, vents, skylights and walls, are flashing leaks and usually repairable regardless of the roof's age, because the flashing is its own component. Leaks in the open field of the roof, away from anything, mean the shingles themselves are letting water through, which is a different story.
What are you doing with the house?
Selling in two years changes the math. A buyer's inspector will note the roof's age and condition, and a new roof is one of the few improvements that carries most of its cost into the sale. Staying twenty years changes it the other way: a repair that buys three years on a roof you will replace anyway is money spent twice.
Will a repair actually hold?
New shingles on an old roof rarely match, which is cosmetic, but they also rarely seal to brittle old neighbors, which is not. On a roof that is otherwise near the end, a repair can be the first of several. We would rather tell you that than have you back on the phone next spring.
What we will not do
We will not sell a roof to someone who needs a repair, and we will not sell a repair to someone who needs a roof. Either one comes back on us. The visit for the estimate is free, we look at the whole roof and the attic, and the answer we give you is the one we would give our own family.
