Tear Off vs Roofing Over: Should You Put a Second Layer On?
It saves real money on the day. Here is what it costs you later, what Illinois code allows, and the three situations where we will not do it at all.
What roofing over actually is
A roof over, also called a recover or a second layer, means new shingles are installed directly on top of the existing ones instead of tearing the old roof off to the deck. It saves the labour of removal and the cost of disposal, which is a meaningful share of a replacement invoice. It is legal in Illinois within limits and it is not automatically bad work. It is, however, a decision that trades a lower number today for a shorter roof life and less certainty, and homeowners are often not told that part.
What code allows
Illinois and local municipal codes generally permit a maximum of two total layers of roof covering, which means one recover over an existing single layer. If your roof already has two layers, a tear off is not a preference, it is required. Individual municipalities in our service area apply this differently and some are stricter, so the permit question has to be answered for your specific village rather than in general. We check that before quoting rather than after.
The real cost: you cannot see the deck
This is the argument that matters most and it has nothing to do with code. When the old roof comes off, we see the deck. We find the soft sheathing over the bathroom where a fan has been venting into the attic for fifteen years, the split rafter, the rot along a valley where flashing failed years ago. On a recover, none of that is visible and none of it gets fixed. It stays under the new roof, and it keeps getting worse under a warranty that does not cover it. Roughly speaking, the more suspicion there is about the deck, the less defensible a recover becomes.
Heat, weight and shingle life
A second layer sits on top of an old layer that holds heat. The new shingles run hotter, and heat is what ages asphalt shingles. A recovered roof commonly gives up several years of service life against the same shingle installed on a clean deck, which quietly erases much of the money saved. There is also dead load: two layers of architectural shingle is a real weight addition, which is usually within structural capacity on a normal house but is worth checking on older structures and on anything with a history of sagging.
The surface telegraphs through
New shingles follow the contour of what is underneath. If the existing roof has curled, cupped or lifted shingles, or an uneven deck, the new roof will show it, and it will show more as the new shingles settle. On a street where the house is being sold or where curb appeal matters, this is not a small consideration. A recover over a flat, clean, single layer looks fine. A recover over a wavy twenty year old roof looks like exactly what it is.
Flashing is where recovers go wrong
A proper replacement renews the flashing: step flashing at walls, the valley metal, the pipe boots, the chimney counterflashing. On a recover, there is a strong temptation to leave the old flashing in place and shingle up to it, because renewing it properly means cutting into the existing layer anyway. Most recover failures we get called to are flashing failures, not shingle failures. If a recover quote does not say explicitly what happens at every wall, valley, chimney and penetration, that is the question to ask before signing.
When a recover is genuinely reasonable
One existing layer, laying flat, no known leak history, a deck with no reason for suspicion, a roof of straightforward geometry, and an owner with a defined shorter hold on the property. That combination makes a recover a rational choice rather than a shortcut, and we will do it and stand behind it. A rental with a five year horizon and a sound single layer is a reasonable recover. So is a detached garage.
When we will not do it
We will not recover a roof that already carries two layers, because it is not permitted. We will not recover where there is any active leak or any sign of deck damage, because we would be burying a problem under our own warranty. And we will not recover a roof with widespread curling or an uneven deck, because the result will look poor and we will be the ones the homeowner calls about it. We would rather lose the job than do that one.
What each path costs
Residential roof replacements in our market generally run $15,000 to $40,000, with larger or more complex homes at $40,000 to $70,000. A recover lands below the tear off figure for the same house because removal and disposal come out, but the gap is smaller than most homeowners expect once flashing, ventilation correction and the underlayment package are specified properly. We quote both against the same house when a recover is legitimately on the table, so the saving is a number you can see rather than a claim.
Ask us for both numbers
If someone has quoted you a roof over, get a tear off number on the same scope before you decide. We will give you both, tell you which one we would choose on your house and why, and we will say so plainly when the recover is the better value. We work across Cook, DuPage and Lake counties on residential and commercial property.