Roofing FAQ: Straight Answers for Los Gatos and San Jose Homeowners
Most homeowners arrive at a roofing question the same way — a stain on the ceiling, a bid that seems too high or too low, a letter from an insurance carrier, or a neighbor’s reroof that raised something nobody has answered yet. This roofing FAQ collects the questions our Roofing Consultants field most often across Los Gatos, San Jose, Saratoga, Campbell, Cupertino, and the rest of the South Bay.
Each answer is the short version, with a link to the longer guide where one exists. Nothing here is a quote. No honest price or diagnosis exists until somebody has physically walked the roof.
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Roof Replacement Cost in Los Gatos and San Jose
How much does it cost to replace a roof in the Bay Area?
Replacing a roof in the Bay Area generally lands between $20,000 and $60,000, and the width of that range has more to do with your roof than your house. Our numbers tend to fall near $1,000 per square for composition shingle, $1,400 to $1,600 for concrete tile, $1,600 to $1,800 for clay, and near $1,800 for standing seam metal.
A square is a 10-foot by 10-foot area, or 100 square feet, and the average Bay Area home carries 20 to 30 of them. That puts a typical composition reroof at roughly $20,000 to $30,000, and a tile roof anywhere from $28,000 to $54,000 depending on which material you choose.
Why do two houses on the same street get such different prices?
Because story count is not roof area. A 2,500 square foot two-story house has roughly half the roof of a 2,500 square foot single-story house, so a neighbor’s total price tells you almost nothing without the square count attached to it.
Complexity moves the number too. Hips, valleys — the internal corners where two roof planes meet and funnel water down — dormers, and wall transitions all add labor, and on standing seam metal a cut-up roof climbs from about $1,800 per square to $2,300 or $2,400. When you compare bids, ask each contractor for the square count and for what is specifically excluded.
How much does a standing seam metal roof cost compared to asphalt shingles?
Standing seam runs close to double asphalt shingles: about $1,800 per square for the metal system over a sound, prepared deck, against about $1,000 for composition. Across a whole house, that is roughly $20,000 to $30,000 for composition against $40,000 to $60,000 for standing seam metal once tear-off and any new plywood are included.
The cost-per-year math is closer than most people expect. Composition works out to roughly $33 to $40 per square per year across 25 to 30 years, and standing seam to $36 to $45 across 40 to 50. Metal wins on the things that arithmetic leaves out — paying tear-off and disposal once instead of twice, at today’s prices rather than 2050’s — not on the arithmetic itself.
Is concrete tile or clay tile more expensive?
Clay costs more. Concrete tile runs $1,400 to $1,600 per square, and clay runs $1,600 to $1,800, which puts a 20- to 30-square home at roughly $28,000 to $48,000 in concrete and $32,000 to $54,000 in clay.
If your home already has tile over sound plywood and a straightforward roof design, the number comes down considerably—closer to $1,100 or $1,200 per square —because much of that work is replacing the underlayment rather than rebuilding the whole system. Converting to tile from composition or old shake pushes it the other direction. Every wall flashing gets rebuilt, and a home framed for shingle wasn’t designed to carry roughly 900 to 1,000 pounds per square of tile, so that question belongs to a general contractor or engineer before anyone orders material.
Are synthetic roof shingles worth the money?
Synthetic shake and slate products from DaVinci, Brava, and Cedur are convincing lookalikes, light enough for almost any structure, and — importantly for South Bay homeowners under insurance pressure — not wood. They also cost more than standing seam metal in our estimates.
The honest caveat is that the category has been commercially available for only about 20 to 25 years, so it hasn’t yet run a full service life in the field. If these products deliver 40 or 50 years, the premium is money well spent. If they deliver 20 or 25, you paid considerably more for the lifespan of a mid-grade asphalt shingle.
Why is the lowest bid often the most expensive one?
Because the leverage disappears the moment the roof comes off. A bid that starts at $20,000 becomes $23,000 on day one when a second layer of roofing appears, then $28,000 when the plywood nobody mentioned goes on — and the bid you set aside for being $3,000 higher often included all of it from the start.
Once you have an open deck and a weather forecast, you cannot say stop. Ask every bidder, in writing, what happens if a second layer turns up, what plywood costs per sheet, and what the number excludes.
Repair or Replace: How to Read Your Own Roof
Should I repair my roof or replace it?
Replacement is the right call when the roof can no longer keep water out reliably. A roof repair is the right call when the problem is confined to one detail on a roof that still has years left. Two facts narrow the question faster than anything else — how old the roof is, and what it is made of.
One lifted flashing on a 15-year-old roof is a repair. The same ceiling stain under a 29-year-old composition roof is usually the end of a service life. Our own rule is that if a repair will not keep you watertight for at least five more years, we would rather not do it. Our guide has a fuller walkthrough on when to repair your roof versus replace it.
How long should a roof actually last in this climate?
A properly installed, properly vented composition shingle roof lasts about 25 to 30 years in the South Bay. Standing seam metal legitimately lasts 40 to 50 years.
Tile is what confuses people. The tile itself will outlast the house, but the underlayment beneath it — the waterproof membrane the tile sits on top of — will not, so a tile roof’s real service life is the underlayment’s service life and nothing else. Ventilation moves all of these numbers: poor exhaust venting can turn what should have been a 28-year roof into one shedding shingles in 15 mph winds at year 18.
Why is my roof losing granules?
Because the shingles are wearing out, those granules are crushed stone pressed into the shingle’s surface, and they are the only thing shielding the asphalt underneath from ultraviolet light — asphalt has no UV rating of its own. Once granules leave, the asphalt degrades, the fiberglass mat is exposed, and water follows, in that order and only that order.
A handful of loose granules in the weeks after a new roof is normal manufacturing excess. A steady accumulation at the base of your downspouts on a 15- or 20-year-old roof tells you where it is in its life. Localized loss in one spot is often still a repair, and sometimes a gutter correction rather than a roofing one.
Is a sagging section of roof serious?
In most cases, no. What you are almost always looking at is deflection — the slow, permanent response of framing that has carried load for fifty or seventy years, and wood does not spring back. Homes built in the 1950s and 1960s were framed to the spans and lumber standards of their day, which were generous about how far a two-by-six could reach.
Two situations change the answer. A genuine structural deficiency is one. The other is going to a heavier product: asphalt loads a roof at roughly 300 to 400 pounds per square foot, and concrete tile at three times that, so a sag plus a tile conversion is an engineering question.
A sag often becomes visible only after a reroof—thick wood shake hid it with texture and shadow, and a flat modern shingle reads the plane exactly as it is. Roofing contractors specialize in roof coverings rather than roof structures, so a general contractor should handle structural correction before any roofer touches it.
Can a tile roof be reset instead of replaced?
It is a real method — the trade calls it a lift and relay — but on a concrete tile roof it rarely saves what homeowners expect, and a new tile roof often comes in at or below the cost of reusing the old one.
Plan on losing roughly 15 percent of the tile to cut pieces at hips and valleys before anyone touches it, and another 15 percent or so to breakage and handling. You also have nowhere to put it: old tile cannot be stacked more than five to seven pieces high without the bottom ones breaking. Clay is the exception worth taking seriously — it can be washed and come back looking new after sixty years, and it is genuinely worth saving.
Roof Leaks, Noises, and Warning Signs
Why does my roof leak only in heavy rain?
That pattern has three possible explanations, and the job is to figure out which one you have. Either the roof has been leaking the entire time and light rain never made it past the attic insulation, wind-driven rain is entering a detail that sheds vertical rain perfectly well, or the water isn’t coming from the roof at all.
Wind-driven water frequently enters ten or fifteen feet away from where it shows up inside, which is why inspecting only the shingles directly above the stain misses it. And in a real storm it is often not the roof — windows, siding, chimney caps, and door trim all leak under wind pressure.
Why is my roof making cracking and popping noises?
Nearly always metal or wood expanding and contracting with temperature. In South Bay homes, three causes account for most of the calls: seamless aluminum gutters, a newly installed plywood deck, and plain heat.
Aluminum expands about half again as much as steel, and in our experience a long uninterrupted run can grow on the order of a quarter inch across a hundred feet. On a 90-degree afternoon, a dark shingle surface commonly runs 140 to 170 degrees and sheds fifty or sixty of them after sundown. None of it means the roof is failing. Investigate when the noise has company — a water stain, a bowing ceiling, a lengthening drywall crack, or noise that started right after a windstorm.
A tree branch punctured my roof. What do I do first?
Leave the branch where it is. Pulling a limb back out almost always enlarges the opening and drags more covering loose, turning a contained hole into an open trench for the rain. Call a tree service and a roofer, and coordinate them so the limb comes out and the opening gets covered in the same window.
Photograph everything from the ground, from the attic, and from the room below, and keep every receipt from the first 48 hours. If the limb stopped at the decking — the plywood your shingles or tile are fastened to — this is roofing work. If it cracked a rafter, a framing contractor must resolve the structure before finished roofing goes back over it.
My tile roof is leaking, but the tile looks fine. What is going on?
The tile is a rain screen; the underlayment beneath it is the actual roof, and that is nearly always what has failed. Two patterns dominate in Santa Clara Valley.
Homes built in the late 1960s and early-to-mid 1970s sometimes had tile set directly on one-by-six spaced sheathing with no underlayment at all. From the 1960s to the 1980s, builders commonly laid a single layer of 30-pound felt, stacked tile pallets on it, and left it exposed for 90 to 120 days while they finished the interior — 30-pound felt has no UV rating, so those roofs were compromised before they were finished. Our tile roof guide covers both.
Does a tile roof need maintenance?
Yes, and tree debris is the single most common reason homeowners call us about a tile roof leak. Leaves, needles, and small branches collect in the water channels between tiles and in valleys, damming the flow, and pushing water sideways into places the system was never designed to send it.
On a property with mature trees and a complex roofline, annual or biannual tile maintenance is a real cost of ownership — and it is not something you can do with a leaf blower from the ground. Clearing debris is inexpensive. The five-figure repair it prevents is not.
Roofing Materials, Decking, and Ventilation
Can you just roof over the old roof instead of tearing it off?
The California Residential Code caps a home at two layers of roof covering, so an overlay is sometimes legal. Los Gatos Roofing tears off every time, and the reason has nothing to do with selling a larger job.
An overlay leaves you unable to inspect the deck, correct dry rot you cannot see, or do anything about the flashings—the sheet metal that seals every transition where a roof meets a wall, a chimney, a skylight, or a valley. Roofs usually don’t leak in the middle of a shingle field; they leak at transitions. On an overlay, the new roof goes down over the existing metal, which stays exactly as old and as corroded as it was the day before. The savings are real, and they are deferred with interest.
The other issue is weight. Most homes weren’t engineered for multiple layers of roofing.
What are asphalt shingles actually made of?
Four things, in order. A fiberglass mat forms the skeleton — it holds out no water at all; it provides strength and dimensional stability. A fiberglass mat is pulled through a bath of hot asphalt that saturates and coats both sides, and the asphalt does the waterproofing.
On architectural or dimensional shingles, additional laminated layers create shadow lines and texture. Finally, crushed stone granules are pressed into the still-hot top surface, giving the shingle its color and forming the opaque shield that blocks ultraviolet light from ever reaching the asphalt.
Plywood or OSB for roof decking — which should I use?
For most South Bay reroofs, this is no longer a close call. Our standard spec is 7/16-inch radiant barrier OSB installed over the existing skip sheathing — the one-by-six boards run across the rafters on roughly ten-inch centers that older Bay Area homes were built with.
The reason is the nail gun, not the price. A sheet of CDX plywood has knots and voids in it, and hitting a knot overdrives the nail — a small thing on any single fastener and a real thing across 30 squares of deck. OSB’s advantage is density consistency.
Plywood is roughly 10 percent stiffer sheet for sheet, and we still specify it for repair tie-ins, exposed eave details, and applications that call for 5/8-inch material. There is a full comparison in our plywood versus OSB guide.
How much attic ventilation does my roof need?
Code requires one square foot of ventilation for every 150 square feet of attic floor space — or one square foot per 300 if the system is balanced, with roughly half the venting at the eaves as intake and half at the ridge as exhaust. Balanced is the benchmark to aim for.
Homes built here in the 1950s through the 1970s were roofed in wood over spaced sheathing and literally breathed. When the industry moved to asphalt composition, the roofs became vapor barriers, and the houses did not change to match. Powered attic fans are the intuitive answer and usually the wrong one, since a thermostat set to 110 degrees rarely, if ever, runs in winter, which is exactly when the moisture problem is worst. Our roof venting guide explains the whole system, and the roof ventilation page covers what we install.
What does a lifetime shingle warranty actually cover?
Not what most people assume. “Lifetime” means the warranty applies for as long as the original owner owns the property — it is not a prediction of service life.
The first ten years of most major manufacturer warranties include full labor and material replacement for genuine manufacturing defects. After year ten, the coverage shifts to prorated and materials-only, and by year fifteen the payout is often a small fraction of the cost. Labor is never covered past that initial window, and real asphalt shingle performance in this climate is 25 to 30 years, regardless of the number on the wrapper. Our shingle warranty guide breaks down the CertainTeed, Owens Corning, and Malarkey programs individually.
How do I keep rodents from getting under my roof tile?
Start with a rodent professional, not a roofer. This is mostly not a roofing problem, and Los Gatos Roofing does not perform pest control or rodent exclusion.
That said, the roof decides how bad it gets. High-profile S-tile creates a continuous open channel running from eave to ridge; thus, switching to a low-profile or flat tile removes that channel entirely. A granulated underlayment is the single most useful thing a roofer can contribute, because the mineral surface is unpleasant to chew — it raises the cost of entry substantially without closing the door. Trimming branches back off the roofline is the least expensive measure on the list.
Permits, Inspections, and the Reroof Timeline
Do I need a permit to replace my roof in California?
Yes, in effectively every jurisdiction, and every South Bay city is included. The only real gray area is partial work: San Jose treats anything under 25 percent of the roof area in twelve months as a repair rather than a reroof, and the Town of Los Gatos sets its threshold at 100 square feet of roofing material.
The one exception we know of is the City of Santa Clara, where the distinction has historically turned on whether new plywood is going on. That is our field understanding rather than a published rule, so if you are in Santa Clara and a contractor tells you no permit is needed, call the Building Division and confirm it for your specific scope. California sets a Class C fire rating as the statewide minimum on new and replacement roofs; the Town of Los Gatos raises that to Class A for every roof in town.
Who is supposed to pull the permit — me or the contractor?
The contractor. Their license number goes on the application, their name goes on the permit, and they schedule the inspections.
If a contractor asks you to pull it yourself, that is one of the strongest signals to walk away. It usually means either that they don’t hold a business license in that city or that they don’t know the jurisdiction’s requirements well enough to want their name on the document. It also makes you the legal owner-builder, responsible for code compliance and for workers’ compensation for anyone on the project. If the permit is in your name, the inspection problems are yours.
What happens if the work is done without a permit?
Three consequences follow the property, not the contractor. An insurance claim connected to wind, water, or fire damage can be denied because the work was unpermitted. At resale, a buyer’s inspector will flag a recently replaced roof and the buyer’s agent will ask for the permit.
City enforcement is the third: fines, retroactive permitting, or in some cases mandatory tear-off and reinstallation. Most Bay Area cities do not actively patrol for unpermitted work, which is exactly why the problem tends to surface years later at the worst possible moment.
How long should a roof replacement take?
Two to four working days for a typical 20- to 30-square composition reroof, measured from the start of tear-off to the final city inspection. Tile and standing seam typically add a day or two, and a complex hillside home in Saratoga or Los Gatos with steep pitches can run five or six days.
A bid timeline of two weeks or more usually tells you something about the company rather than your roof. When tear-off, plywooding, sheet metal and roofing are separate subcontractors, the work happens sequentially instead of in parallel, which roughly doubles the elapsed time. Faster is not automatically better; quality matters more than speed.
What actually happens on tear-off day?
The crew arrives around 7 a.m. behind a dump truck, and tear-off on a typical 20- to 25-square-foot tract home takes four to six hours. What happens next is the part nobody can see once the new roof is on: the deck gets inspected, dry rot gets cut out and patched, and skip sheathing gets covered with new decking.
Then underlayment goes down, and the day should end with the deck completely covered and weather-tight. Move anything within ten feet of the house perimeter beforehand, and know that until the old roofing comes off, even the most thorough estimate is partly an educated guess on whether dry rot or damaged sheathing exists.
What order should I do exterior home projects in?
Top down, every time, because gravity rather than aesthetics dictates the order. Fumigation first if needed, then the roof, then wall coverings, dry rot, and windows, then paint, then gutters, then the attic, then hardscape, then landscaping.
The physical reason roof precedes paint is that properly installed flashings tuck behind the wall covering, so stucco or siding sometimes has to be pulled back and patched — and fresh paint in those areas is coming off. Gutters are the exception: they come off before the roof and go back on after the paint. Our guide to the right order for exterior home projects includes a full walkthrough.
Insurance and Solar
My insurance company is not renewing my policy because of my roof. What now?
Read the notice before you call anyone, because “roof age” and “roof condition” are different stated reasons, and only one is arguable. Age is a number, and there is nothing to dispute. Condition is an assessment, and an assessment can be documented — which is the only one of the two a roofer can help with.
California Insurance Code Section 678 requires at least 75 days’ written notice before a carrier non-renews a residential property policy. That notice has to state the specific reason and include a phone number for the insurer’s consumer inquiry representatives. A condition letter from a roofer sometimes moves a carrier and sometimes doesn’t, and no contractor can promise an outcome. Anything about your actual coverage belongs with your broker or the California Department of Insurance.
Will a new roof help with fire insurance in a hillside neighborhood?
It can, and the mechanism is specific. In designated Wildland-Urban Interface areas and Very High Fire Hazard Severity Zones, California Building Code Chapter 7A requires a Class A roof assembly, and the Department of Insurance identifies asphalt shingle, concrete and clay tile, and metal shingles or panels as Class A coverings. Wood shake is not among them.
Under the Safer from Wildfires regulation, insurers must offer discounts for listed mitigation actions, including a Class A fire-rated roof, and proof of completion triggers them. Confirm the specifics with your broker before you spend thirty thousand dollars solving what may not be a roofing problem.
Do I need a new roof before installing solar panels?
If your roof has fewer than 10 years of service life left, almost certainly yes. Between 10 and 20 years, it comes down to condition rather than age — a sound covering with tight flashings can carry an array, and a worn one cannot. Solar panels have a service life of roughly 20 to 25 years, so the roof underneath ideally has that much life left.
Note that the 10-to-15 year threshold most solar companies use is their number, not a roofing number. It clears their warranty exposure without getting you to the end of the panels’ useful life, which is the outcome you actually want. Have an independent roofer walk the roof, and don’t mention solar — you will get a cleaner answer.
Choosing a Roofing Company in the Bay Area
How do I choose a roofing company?
Five things you can actually verify: how close the contractor is to your house, how long they have been in business, what the reviews say once you read past the star average, whether they operate from a real place of business, and whether their own employees do the work.
None of the five is about the shingle, which is the part most homeowners get backward — a skilled roofer installing the least expensive product on the shelf will get you twenty-five years. Ask each bidder to describe the permit and inspection sequence in your specific city. A company that does it weekly will be specific; one that doesn’t will be vague.
What are the red flags in a roofing contract?
Start with the deposit. California caps it at the lesser of $1,000 or 10 percent of the contract value—a hard statutory limit —so a $5,000 deposit on a $30,000 roof is not a negotiating position; it is a violation. A large progress payment when material is delivered usually means the contractor has no credit line with their supplier and is operating on cash.
Beyond that, the contract should name products by manufacturer, line, and color rather than saying “architectural shingles,” identify the contractor as the permit-puller, and include the California mechanic’s lien warning and the three-day right to cancel. Five to seven pages of plain language is about right.
Does it matter whether the roofer is local?
It matters most at the moments you cannot see from the bid sheet — when a permit needs pulling, when a warranty call needs an answer, when a storm needs someone on your roof tomorrow. Some of the most aggressive marketing in this market comes from companies based in Modesto, Stockton, Tracy, Hollister, or Los Angeles.
One screening question almost nobody asks: what percentage of the company’s revenue comes from repair and warranty service rather than new installations? A roofer with long tenure has a real repair department, because their customer base is the homeowners they sold to decades ago. Local is not always the lowest line on the bid sheet, and it is worth being honest about that.
What types of roofing companies bid my roof?
Broadly three. The paper contractor holds a license, insurance, and a website but has no crews, no trucks, no sheet metal shop, and no permit-puller on staff — the office is often an apartment or a PO box, and every part of your job gets subcontracted.
The national franchise or private-equity rollup can do quality work, particularly early in a market, but tends to standardize the install regardless of what is actually on your roof, and the crew that installed your roof in 2024 may not exist in 2027. The local family-owned company is the one still reachable in your neighborhood ten years later. The install takes two to four days; the roof should perform for decades.
What should I ask about who is physically doing the work?
Ask specifically about four phases: tear-off, install, gutters, and flashings. Any of them can be subcontracted, and a contractor who owns the first three and subs the fourth carries a different schedule risk than one who owns all four.
Los Gatos Roofing runs its own tear-off crews, its own install crews, an in-house gutter crew, and an on-site sheet metal shop where flashings are fabricated to the dimensions of each specific roof—which is what makes a parallel two-to-four day schedule possible in the first place. It is a fair test to run on every bidder, this company included.
If something on this page describes what you are seeing at home, the useful next step is usually the least expensive one: get the roof looked at before the question gets more expensive to answer. A free roof inspection and estimate takes about an hour, and the Radonich family has been making that assessment for Bay Area homeowners since 1978.