Reference
Twelve reference articles on the parts of the job people actually argue about: how many nails go in a shingle and where, what underlayment belongs under a metal panel, whether a valley should be open or cut, what a Class 4 rating really measures, and what the code says when a roof is too flat for shingles.
These are written for a working roofer first and a homeowner second. That means real dimensions, real failure modes, and a section in every article on where the standard answer stops being the right one — because on a roof, it usually does.
The details that get installed a hundred times a year and argued about every time — fastener counts, edge metal, valleys and panel layout. Every one of these is a place where the manufacturer instruction, the adopted code and the way the crew actually works can point in three different directions.
Eave-first or underlayment-first, the difference between a D-style drip edge and a gutter apron, hem orientation, lap direction, fastener spacing, and the rake detail that lets wind pull the whole run off.
Panel layout from the ridge back, floating vs fixed clips, why thermal movement decides your fastening scheme, eave and rake terminations, seaming, and where panel overlap rules actually apply.
Four versus six, where the nail line actually is on a modern laminate, what high-nailing does to wind performance, penetration depth, and why the warranty and the code can require different counts on the same roof.
The three valley methods compared on watertightness, labor, and where each one fails — plus valley lining, the dead-nail zone, cut geometry, and what to do when two different pitches meet.
What the material actually does on a roof, as opposed to what the sell sheet says. Underlayment chemistry, impact ratings, single-ply membranes and the shingle brands homeowners ask about by name.
Why felt is the wrong answer under a metal panel, what high-temperature self-adhered membrane actually buys you, condensation and the vented vs unvented decision, and how underlayment choice changes with panel type.
What the Class 4 rating measures and what it does not, SBS-modified versus mesh-backed construction, how insurers actually apply the discount, and why a Class 4 roof can still be totalled by hail.
Heat-welded seams against tape and adhesive, reflectivity against flexibility, puncture and grease resistance, attachment methods, and a straight account of how TPO is installed and where it goes wrong.
An even-handed comparison of the three laminate shingles homeowners name most: nailing-zone engineering, wind and impact ratings, warranty structure, contractor certification programs, and what actually differs on the roof.
Finding the actual source of water, which is almost never where the stain is. These are the walkthroughs for the call that starts with "it only leaks in a driving rain."
Working backwards from the stain: interior mapping, the attic inspection, the penetration checklist, the water test done in the right order, and how a flat-roof leak differs from a steep-slope one.
Where the roof edge dies into a sidewall, why the last piece of step flashing has to be a diverter, sizing and angle, sequencing with the water-resistive barrier, and how to retrofit one without tearing off the wall.
Slope limits, airflow math and the code sections that decide whether an assembly is legal before it is a good idea. Where the model code and the manufacturer disagree, we say so.
Cutting the slot to the right width, the ridge board problem, end terminations, nail length, balancing exhaust against intake — and an honest comparison with turbines, box vents and powered fans.
The 2:12 floor and the 4:12 line, what low-slope underlayment application actually requires, and the real options below the threshold — rolled roofing, single-ply, metal, or reframing the roof.
Specifics, or nothing
“Use a quality underlayment” is not information. Which product class, at what temperature rating, fastened how, and what happens when you get it wrong — that is information. Where we do not know a number, we say the number varies rather than inventing a plausible one.
Code cited carefully, or described plainly
Section numbers refer to the model International Residential Code. Jurisdictions adopt different editions and amend them freely, so we flag where a requirement is genuinely variable instead of pretending there is one national answer.
The manufacturer instruction usually wins
Nearly every roofing warranty is conditioned on installing to printed instructions, and those are frequently stricter than code. When the two disagree, the printed instruction is what a warranty claim will be measured against.
Brands compared, not ranked
Where manufacturers genuinely differ we describe the difference and let you weigh it. Where they are effectively the same product with different marketing, we say that too.
Several of these articles hinge on arithmetic you can do in the browser — the pitch multiplier that turns a footprint into roof area, the square and bundle count behind a materials order, and the net free area math that decides how much vent a roof needs.
Roof Pitch Calculator
Rise and run to degrees, percent slope and the pitch multiplier, with the full multiplier chart.
Roofing Squares Calculator
Footprint and pitch to roof area, squares, waste allowance and a bundle count.
Roof Ventilation Calculator
Attic floor area to required net free ventilating area, split into balanced intake and exhaust.
The encyclopedia covers how the work is done. If you are pricing a job, comparing materials or working an insurance claim, the homeowner guides cover repair and replacement costs, storm damage documentation, metal roofing and flat roof systems.
Browse the roofing guidesSearch roofing companies by city or state, compare Google reviews, and request quotes directly. Listings are compiled from public records — confirm any contractor’s license and insurance with your state licensing board before work begins.
