(214) 807-0414Request an assessmentLayover or tear-off
Installing a new covering over the old one is legal in many circumstances and it is genuinely cheaper on the day. It is also a decision to leave several questions unanswered for the life of the new roof. The trade is a real one and worth making with the whole of it visible, which is not how it usually gets presented.
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What this covers
Residential codes generally cap the number of roof coverings and prohibit a layover over certain conditions — a wet, buckled or uneven substrate among them. The limit and the conditions belong to whichever jurisdiction issues the permit, and across this Metroplex those jurisdictions do not agree on much. Confirm the rule for the address rather than the rule for the region.
Tear-off is the only occasion on which anybody sees the sheathing. Choosing a layover is choosing not to look, which is fine on a deck that was sound last time it was exposed and is a gamble on a roof with a leak history or an unknown one.
The new covering follows the surface it is laid on. Curled tabs, buckled courses, a ridge in the old deck and any repair patch will read through the new roof, usually within the first hot season. On a prominent slope that alone answers the question.
What to know
Two layers of asphalt on the same framing is added dead load, and the second layer holds heat above the deck rather than releasing it. In this climate that shortens the life of the covering on top, which means the layover is also buying a roof that will not last as long as the same product laid on a stripped deck.
A second layer raises the roof plane by the thickness of the first. Step flashing, valley metal, pipe boots, drip edge and any wall junction are now short by that amount. They either get rebuilt to the new height, which is most of the labor a layover was meant to save, or they get buried, which is where the next leak comes from.
Tearing off two layers later is more labor and more disposal than tearing off one. Some of what a layover saves now is simply moved to the next replacement, and where the second layer shortens the life of the roof, that next replacement arrives sooner. Neither of those makes a layover wrong — they make it a decision that should be priced across both events.
Choose a starting point
A short, non-diagnostic guide for working out what kind of assessment conversation to prepare for.
Decision support
Four situations, and the sensible next move for each. It does not diagnose a roof, decide insurance coverage, or stand in for somebody looking at the property.
Questions
It depends on the city that issues the permit, and the rules across Dallas–Fort Worth differ enough that a contractor working several cities may be applying the wrong one. It is a question with a published answer, and the city pages here are built around exactly that kind of difference.
Their printed installation instructions define what the product may be installed over, and the warranty follows those instructions. So the answer exists in a document rather than in a conversation, and it is reasonable to ask to see the relevant page before agreeing to the method.
Look at the edge: the thickness at the eave and rake, how the covering sits relative to the gutter, and the height of the flashing at any wall. Permit history for the address can also show it. On a roof already carrying two, a layover is generally not an option anyway.
Not meaningfully. The covering follows the surface it was laid on, so unevenness reading through from the layer beneath is a shape rather than a defect in the top layer, and nothing applied over it changes that. Where the appearance matters, the answer is a tear-off. Where it does not, it is cosmetic and can be left. What it does tell you for certain is that there are at least two coverings up there.
Assessment request
Short, routing-only questions. Nothing here asks you to diagnose the roof yourself.