The words that stop people asking a second question.
Somebody tells you the decking needs replacing, the valley metal is shot and you should think about a ridge vent. Asking what a valley is feels like admitting you should not be in the conversation — so it does not get asked, and the estimate gets signed. Here is all of it, in the order it appears on a roof.
A valley — the internal angle carrying water off two planes at once, and the first line on a roof to be described to you in words you did not choose.
The assembly
The structure and the named lines on it. Most of these are places rather than products, and an estimate that is vague about a place is usually vague about the work there too.
10 terms
DeckSheathing · Roof deckThe panel surface beneath the roof covering; OSB is shown here.
The structural surface the whole roof is built on — usually plywood or OSB sheets nailed across the rafters or trusses.
Decking replacement is the most common allowance on a replacement estimate, because nobody can see the condition of it until the old covering is off. A quote with no position on decking at all is incomplete, not cheap.
The horizontal line at the very top of the roof where two planes meet.
The highest and most wind-exposed line on the roof. It is the first place a shingle lifts and the first thing worth photographing along its whole run rather than at one end.
The internal angle where two roof planes meet, carrying water from both of them into one channel.
Valleys move more water than anywhere else on the roof, so they fail first and cheap repairs there fail fastest. If an estimate is vague about valley treatment, that is worth a question.
Everything whose only job is to send water somewhere. More leaks begin at these details than anywhere in the open field of a roof.
8 terms
UnderlaymentFelt · Tar paper · Synthetic underlaymentThe sheet layer over the deck, before the finished roof covering.
The water-resisting layer between the deck and the covering. Traditionally asphalt-saturated felt; now more commonly a synthetic sheet.
This is the layer actually keeping water out once wind has driven rain under a shingle. It is also invisible once the roof is on, which is why it is a common place to economise quietly.
Sheet metal shaped to seal a junction — where the roof meets a wall, a chimney, a vent, or another plane.
More leaks begin at a flashing than in the middle of a roof plane. Reusing old flashing on a new roof is a real cost saving and a real risk, and it should be a stated decision rather than a silent one.
Individual L-shaped pieces of metal woven into the shingle courses where a roof plane runs up against a vertical wall.
Correct step flashing is one piece per course. A single long strip of bent metal in that position — sometimes called a shiner — is a shortcut that will leak.
Kick-out flashingThe small angled wing projects away from the wall at the gutter. This is not an installation specification.
A small diverter at the bottom of a roof-to-wall junction that throws water clear of the wall and into the gutter.
Frequently omitted. When it is missing, water runs down inside the wall cladding instead, and the damage shows up as a stain nobody connects to the roof.
The collar sealing around a plumbing vent pipe where it passes through the roof.
The rubber ones perish in North Texas sun, often well before the roof around them fails. A cracked boot is a small, cheap, extremely common leak source.
The airflow through the attic, which ages the roof from underneath. Almost always fails on the intake half, because that is the half nobody can see from the driveway.
4 terms
Intake ventilationThe openings in the soffit are one common intake location.
The low openings — usually soffit vents — that let cool air into the attic.
Exhaust without intake does not ventilate anything; it just pulls conditioned air out of the house. Intake is the half that gets forgotten.
Three-tab shingleA flat profile with repeating slots, unlike the layered architectural example.
A single-layer asphalt shingle with a flat, repeating profile. Largely superseded on new work by laminated products.
Still common on North Texas roofs from the 1990s and earlier. Its failure pattern is different from a laminate, which matters when hail damage is being assessed.
The top classification in the UL 2218 impact test, in which a steel ball is dropped onto the product from a set height without cracking it.
A laboratory test with a steel ball, not a guarantee against hail. It is genuinely more resistant, and many Texas carriers offer a premium credit for it, but a Class 4 roof can still take documented hail damage.
A tested wind speed a product withstands under defined laboratory conditions, commonly to ASTM D3161 or ASTM D7158.
The rating describes the product under test conditions. Installation — nail placement, count, and starter course — decides whether the roof gets anywhere near it.
The trade's unit of roof area: one square equals one hundred square feet.
Estimates are commonly priced per square. Two quotes with different square counts for the same roof is a question worth asking — one of them has measured the planes differently.
A written variation to the agreed scope, priced and authorised before the additional work proceeds.
The word to look for in a contract is 'before'. Work discovered, documented, priced and approved is a change order; work discovered and invoiced is a surprise.
Tear-offStrip · Full tear-offExposed decking beside the remaining covering illustrates what removal reveals.
Removing the existing roof covering down to the deck before installing the new one.
The alternative, laying new shingles over old, is cheaper and hides the deck. It also adds weight, shortens the new roof's life and makes the next assessment harder.
OverlayRoof-over · Second layerA sample showing two shingle layers, not a recommendation to overlay an existing roof.
Installing a new layer of shingles directly over the existing one, without tearing off.
Permitted in some circumstances and limited in most jurisdictions. If a property already has two layers, that changes the scope, the disposal and sometimes the permit path.
The portion of a covered loss the policyholder pays, either a fixed sum or a percentage of the dwelling coverage.
In Texas it is unlawful for a contractor to pay, waive, absorb or rebate it. An offer to do so is not a discount — it tells you what else the company is willing to do.
A request to a carrier for additional funds when the agreed scope proves incomplete once work is under way.
Legitimate when it documents genuinely discovered conditions. It is also the mechanism most open to abuse in this trade, which is why the documentation behind one matters more than the number on it.
Someone who represents a policyholder in a claim, negotiating the settlement on their behalf.
A different job from a roofing contractor, and a useful one to know exists. A contractor documents the construction condition; if you want somebody negotiating coverage for you, this is the role that does it.
A definition settles a word. A guide settles the decision.
Every guide these definitions point at, in one place. Each one covers a whole detail rather than a single term — what it does, how it fails, and what an estimate should say about it.
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