Roofs leak at interruptions
A composition shingle field sheds water extremely well. Overlapping courses, gravity and a slope are a robust system, and it is rare for water to get through the middle of an intact plane. What leaks is everything else: every hole, every edge, every change of plane, and every change of material. Each is a designed detail, and a designed detail can be built wrong, aged out, or repaired badly.
The word for those details is flashing — the sheet metal, membrane or moulded component that carries water from one surface onto another without letting it behind. Flashing is the roof's real engineering. Shingles are the easy part.
The Standards of Practice track this precisely. An inspector must report evidence of water penetration and evidence of previous repairs to the roof covering material, flashing details, skylights and other roof penetrations, and must report as deficient any deficiencies in fasteners, adhesion, roof covering materials, flashing details, skylights and other roof penetrations. The exterior wall section separately requires reporting deficiencies in flashing.
The leak points, in North Texas order
Plumbing vent pipe boots — the most common finding by a wide margin
A pipe boot is a base flashed into the shingle courses with a thermoplastic or elastomeric collar that seals against the vent pipe passing through it. The collar is the part that fails. Ultraviolet light and heat degrade it; it hardens, shrinks, and splits circumferentially around the pipe, opening a direct path into the attic.
In North Texas sun, the collar routinely fails before the shingles do, which produces the situation buyers find confusing: a roof in reasonable mid-life condition with failed boots on every stack. It is also a cheap, high-return repair.
We will not publish a service life for a pipe boot. There is no authoritative source for one — every figure available comes from contractor marketing — and the honest version is more useful: the mechanism is exposure-driven, not calendar-driven, so inspect the collars. The corollary is a workmanship finding: after a re-roof, look for original sun-chalked boots poking through brand-new shingles. Boots not replaced during a re-roof tell you what else was skipped.
The rest, roughly in order
Sidewall and headwall flashing where a sloped roof meets a wall, and chimney flashing, both have their own sections below.
- Valleys, which carry the most concentrated water on the roof. Open metal valleys fail through debris damming; closed-cut valleys fail where the cut shingle was nailed too close to the centreline, putting a fastener in the path of the water.
- Low-slope tie-ins and dead valleys. IRC R905.2.2 permits asphalt shingles only at slopes of 2:12 or greater, with double underlayment required between 2:12 and 4:12. DFW porch roofs, patio covers and additions are frequent offenders. A patio cover shingled at 1:12 will leak, and no amount of maintenance fixes it — that is a wrong-system problem.
- Sealant-dependent repairs generally. Roofing cement smeared on a flashing is a maintenance item with a short life, not a repair. Mastic at many details is a roof that has been managed rather than corrected.
Step flashing, counter flashing, and the kickout
Step flashing is a series of individual L-shaped pieces, one per shingle course, woven into the courses where a sloped roof meets a vertical wall. Each piece laps the one below, so water running down the wall is stepped out onto the shingle surface.
Counter flashing, or cap flashing, covers the upstanding top leg of the step or base flashing. It is embedded in a masonry reveal or set under the siding, and sheds water onto the step flashing so nothing runs down behind it.
Where this goes wrong in Dallas-Fort Worth is at brick veneer walls. Step flashing at a roof-to-brick intersection needs to be counter-flashed into the brick and coordinated with the veneer's own flashing and weeps. The cheap version — step flashing surface-caulked to the face of the brick — is everywhere here. Sealant is a maintenance product with a service life measured in a few years. It is not a flashing, and treating it as one produces a leak that arrives inside a wall.
The kickout, and why it matters more than anything else here
A kickout flashing, sometimes called a diverter, sits at the bottom end of a roof-to-wall intersection where the roof edge meets the wall plane. Its job is to kick the water running down that intersection out into the gutter rather than letting it continue into the wall cladding.
A missing kickout is one of the highest-consequence, lowest-visibility defects in residential construction. The water does not appear on a ceiling. It goes inside the wall, wets sheathing and framing every time it rains, and the visible damage may show up years later and several feet away — or not at all until the cladding comes off. If you look at one thing yourself: find every place a roof edge dies into a wall, and see whether something is turning the water outward at the bottom of it.
Chimneys, crickets and chase covers
A cricket, or saddle, is a small peaked structure built on the up-slope side of a chimney to divert water and debris around it rather than letting them pile against the masonry. Without one, the upslope face of a wide chimney is a dam: water and leaves collect, sit, and eventually find their way through the flashing. Model codes require a cricket above a defined chimney width; the threshold and the section number vary by code edition, so confirm both against the edition your city has adopted.
Three more chimney findings belong on a roof leak page. Chase covers on framed chimney chases are extremely common on 1980s through 2000s DFW houses: a flat galvanised cover ponds water, rusts through at the low point, and dumps water into the chase, where it runs down the inside of a wood-framed structure. Cross-broken or sloped covers in stainless or copper are the durable version. Cracked crowns on masonry chimneys admit water into the top of the masonry. And a missing storm collar, where a metal flue passes through a chase cover, leaves an open gap at the highest point on the roof.
The Standards separately require reporting deficiencies in the chimney structure, termination, coping, crown, caps and spark arrestor. What they do not cover is the flue interior, which is a chimney sweep's work.
Why flashing failures get missed
This is the most useful section on this page, and every reason in it is written into the rule or into the physics.
- The leak point and the damage location are different. Water enters at a flashing, travels along a rafter, a truss chord, or the back of the sheathing, and appears at a ceiling several feet away. Tracing that is an exploratory probe to determine the cause of a deficiency, which the Standards say an inspection is expressly not intended to be.
- Most flashing is concealed by design. Step flashing is under the shingles and behind the cladding. Counter flashing hides the top leg. Veneer flashing is inside the wall. This is a system whose failure surfaces are, by construction, buried, hidden, latent or concealed — which the Standards exclude from the required inspection.
- It only leaks under specific conditions. Wind-driven rain from one direction, sustained rain that saturates before it penetrates, or an overflowing gutter. A dry-day inspection cannot reproduce any of those, and the Standards do not require water testing a roof.
- The vantage-point problem. If the roof was inspected from the ground or from a ladder at the eave, the flashing details at upper intersections were not seen at all. The Standards require the report to state the vantage point. Read that line before anything else in the roof section.
None of this is an excuse. It describes what a limited visual survey is and is not, and it is why a flashing finding — or a report that could not see the flashings — belongs with a specialist inside the option period rather than on a someday list.
Code requirement versus reportable deficiency
This distinction confuses buyers, agents and quite a few contractors, and flashing is the cleanest way to explain it.
The code has specifications: IRC R905.2.8.5 provides that a drip edge shall be provided at eaves and rake edges, with 2-inch minimum overlap between segments and fasteners at a maximum 12-inch spacing. The Standards of Practice are not that. TREC has answered the drip edge question directly: drip and rake edge flashing materials are recommended by most shingle manufacturers but are not required. If installed and if visible, the installation described in your question is required to be reported as a deficiency.
Read those together and the answer appears. A missing drip edge on an older roof is not automatically a reportable deficiency under the Standards, but a wrongly installed one, if visible, is. The code requires a drip edge; the Standards do not adopt the code.
TREC has stated the underlying principle in its own words elsewhere: the standards of practice are not based on a specific requirement such as those promulgated by model building codes. That single sentence resolves most arguments about whether a house is up to code after an inspection. A home inspection reports observed condition against the Standards; older houses built lawfully under earlier codes are legal nonconforming; and an inspector grading a 1968 roof against the 2021 IRC is generating a list of things that were never wrong. (TREC FAQ on drip edge; TREC FAQ on standards versus model codes.)
What to do about it
Sort the findings by consequence, not by cost. The two are inversely related here, which is what makes this page necessary. A roofing contractor reconstructs flashing; a building envelope or water-intrusion consultant is the right specialist where the leak is inside a wall and the source is not obvious; a chimney sweep handles the flue interior, largely outside a home inspection's scope.
- Cracked or deteriorated pipe boot collars: budget for it, and do it before the next storm. Routine, inexpensive, and among the highest-return repairs on any North Texas roof. Remedies run from a slip-over repair collar to full boot replacement, with lead and no-caulk designs as common upgrades.
- A missing kickout flashing: get it evaluated before closing. The concern is not the metal. It is what may already be inside the wall.
- Mastic at multiple flashing details: get it evaluated before closing. That is a patch history, not a maintenance finding.
- An active ceiling stain, a damp meter reading, or wet decking on the attic side: get it evaluated before closing — and rule out the mechanical causes at the same time. In a DFW house the attic air handler's condensate system produces ceiling stains that look exactly like roof leaks and appear in July.
Common questions
What is the most common roof leak in a North Texas house?
The plumbing vent pipe boot, by a wide margin. The boot's thermoplastic collar seals against the vent pipe and is degraded by ultraviolet light and heat until it hardens, shrinks and splits around the pipe. In Texas sun the collar frequently fails well before the shingles do, so a roof in reasonable mid-life condition can have failed boots on every stack. It is also an inexpensive repair, which makes it a good example of a finding that buyers over-worry and owners under-fix.
How long does a pipe boot last?
We will not publish a figure, because there is no authoritative source for one — every number in circulation comes from roofing contractor marketing rather than manufacturer or laboratory data. What is defensible is the mechanism: the collar fails through ultraviolet and heat exposure, so the driver is exposure and orientation rather than the calendar. Inspect the collars for hardening, shrinkage and circumferential splitting, and treat a boot's condition as an observation rather than an age.
Why did my inspector miss the roof leak?
Usually because a leak is not visible on a dry day and its entry point is not where the damage shows. Water enters at a flashing, travels along framing or the back of the sheathing, and stains a ceiling several feet away — and tracing that is an exploratory probe to determine cause, which a Texas real estate inspection is expressly not intended to be. Most flashing is concealed by design, water testing is not required, and a roof inspected from the ground was never seen up close. Check the vantage-point line in the report.
Is a missing drip edge a defect?
Not automatically under the Standards of Practice. TREC's published answer is that drip and rake edge flashing materials are recommended by most shingle manufacturers but are not required, and that a visibly incorrect installation is required to be reported as a deficiency. The IRC separately does require a drip edge at eaves and rakes. So an older roof without one is not out of compliance with the Standards, while a badly installed one is reportable — a good illustration that the Standards are not a code checklist.
What is a kickout flashing and do I need one?
It is a small piece of metal at the bottom of a roof-to-wall intersection that diverts the water running down that intersection into the gutter instead of into the wall cladding. Yes, you want one at every such location. A missing kickout is one of the highest-consequence, lowest-visibility defects in residential construction, because the water goes inside the wall and the visible damage can appear years later and several feet away. It is a cheap part protecting an expensive repair.
My patio cover keeps leaking even after repairs. Why?
Check the slope. IRC R905.2.2 permits asphalt shingles only on roof slopes of 2:12 or greater, and requires double underlayment between 2:12 and 4:12. Dallas-Fort Worth porch roofs, patio covers and room additions are frequently shingled below that limit, and at a shallow slope water moves slowly enough to work backwards under the courses. That is a wrong-system condition rather than a maintenance failure, and repeated sealing will not resolve it — the assembly has to change to a low-slope material.