Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Before
After
Before
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Before
AfterFast, Reliable Roof Installation Across Los Altos
A full roof installation in Los Altos typically runs $14,000 – $28,000 for a standard single-story ranch home, with material choice, roof pitch, and the condition of what’s underneath driving most of that spread. We schedule Los Altos jobs within 7 – 14 days of your written estimate, and every project starts with a detailed inspection of not just the shingle field but the flat garage sections, valleys, and flashing that cause most post-installation failures here. If you’re weighing a re-roof on a 1950s – 70s ranch, call (743) 200-8347 for a free estimate that puts the full scope in writing before any nail goes down.
Why Mercer Roofing Is Los Altos’s Preferred Roof Installation Company
Los Altos homeowners call us because we treat the job the way the house actually is: a collection of connected roof systems that all need to work together. The main pitched field, the 3:12 garage slope, the rear-addition flat section, the valleys where they meet. That’s the reality of 1950s – 70s ranch stock, and a crew that only looks at the shingles will miss what fails first. Our Roof Installation team walks every plane of the roof before quoting, so the price you see is the roof that gets built.
Every technician who comes to your Los Altos home is background-checked, identity-verified, and arrives in a clean, marked uniform with a photo ID badge. We send you their name and photo before they pull up. That’s the Threshold Verified standard, and it matters in a city where homeowners want to know exactly who’s walking their property. Grant Whitlock leads our Los Altos projects personally, and he’ll be the one reviewing your written estimate with you line by line.
The 365-Day Done Right Promise applies to every installation we complete. If something isn’t right within a year, we make it right, in writing. No phone tag, no “we’ll get to it.” That guarantee is part of every contract we write in Los Altos.
Roof Flashing Installation in Los Altos
Roof flashing installation in Los Altos is the difference between a roof that sheds water and one that leaks through every penetration, valley, and wall intersection. Flashing is the metal material that seals the joints where roof planes meet chimneys, skylights, vents, and sidewalls. On Los Altos ranch homes, the valleys where a low-slope garage roof ties into the main house are the single most common flashing failure point we see. A properly flashed valley moves water off the roof. A poorly flashed one sends it into the decking and, eventually, your ceiling.
Flashing installation as part of a full roof job in Los Altos typically adds $1,200 – $3,800 depending on how many penetrations exist and whether original galvanized metal needs full replacement. We price this as a line item, not a vague “miscellaneous materials” charge, so you know exactly what you’re paying for before work starts.
Valley Flashing on Low-Slope Ranch Roofs
Valleys on 3:12 – 5:12 pitches move water slowly, which means debris sits and moisture lingers. We use ice and water shield beneath valley metal on every Los Altos installation, even when code doesn’t strictly require it in your zone. The winters here, with marine-layer moisture pushing up against the foothills, punish any valley that isn’t layered properly.
Replacing Original Galvanized Flashing
A 1960s Los Altos home almost always has original galvanized flashing that’s corroded through at the bends. We replace it with powder-coated aluminum or copper, depending on the roofline and budget. If your flashing is original, it’s done. We’ve never pulled a 60-year-old galvanized valley that was still sound.
TPO Roofing Installation in Los Altos
TPO roofing installation in Los Altos is the fix for the flat and low-slope garage and addition roofs that standard re-roof bids ignore. TPO is a heat-welded, single-ply membrane that handles standing water and UV exposure far better than the original tar-and-gravel systems found on 1950s – 70s ranch garage sections. We recommend TPO on any flat or near-flat section of a Los Altos home where water needs to move across a shallow plane to a drain or edge.
TPO installation on a typical Los Altos garage or rear addition runs $3,500 – $8,500 depending on square footage, the condition of the existing substrate, and whether edge metal and tapered insulation are needed. When we tie a TPO garage roof into a new pitched shingle field, the connection detail is where the work either holds or leaks. That’s why we write it into the contract as its own scope item.
Replacing Tar-and-Gravel Flat Sections
The original tar-and-gravel membrane on a Los Altos garage roof has a 20 – 30 year service life, and most are well past that. They fail at the perimeter first, where the membrane lifts and water tracks underneath. We remove the old system entirely, inspect and replace decking as needed, and install TPO with proper termination bar and edge metal, so the replacement actually lasts.
Tying TPO Into the Main Roof Field
Where the flat garage roof meets the main house’s pitched roof is the transition that decides whether you get leaks. We flash that junction with the same ice and water shield used in the valleys, then extend the TPO up the wall and counter-flash it. This single detail accounts for a large share of Los Altos callback disputes when other contractors skip it. We don’t.
Trusted Brands We Service in Los Altos
We install and repair shingle systems from GAF, Atlas, and Tamko, and we stock the accessory components those systems require: ridge caps, underlayment, starter strips, and flashing matched to the manufacturer’s specs. For Los Altos homeowners in or near a California Fire Hazard Severity Zone, we walk you through Class A fire-rated material options from these manufacturers, so your material choice satisfies both your insurance carrier and the local code enforcement officer. No upselling, just the brands we’d put on our own roofs.
Common Roof Installation Problems We See in Los Altos Homes
- Original tar-and-gravel garage sections left untouched. A main pitched re-roof gets quoted, the flat garage roof gets skipped, and the first rainy season brings a leak the homeowner thought they’d paid to prevent. We scope every plane of the roof on day one.
- Low 3:12 – 5:12 pitches trapping debris in valleys. Los Altos ranch roofs drain slowly by design, and leaves, needles, and dirt pile up where panels meet. That debris holds moisture against flashing and underlayment until they fail. We spec valley protection and ventilation built for slow drainage.
- Open-deck inspection reveals damage the original bid never covered. Once a permit is pulled for a Los Altos roof installation, the inspector looks at what’s under the shingles. Undersized framing, dry-rotted fascia, failed waterproofing. If you’re working with a contractor who doesn’t walk you through that possibility before starting, the contract changes mid-job. We write allowances into the bid so surprises are priced and approved in writing before we continue.
- Debris and moisture accelerating wear at eaves and fascia. The wet winters and dry summers in Los Altos mean the roof edge takes abuse year-round. We inspect eaves and fascia on every installation and replace damaged sections as part of the written scope, not as a surprise add-on.
Pricing for Roof Installation in Los Altos, CA
Here’s what roof installation actually costs in Los Altos. A full architectural shingle re-roof on a standard 2,000 – 2,600 square foot ranch home runs $14,000 – $28,000. That includes tear-off, decking repair where needed, new underlayment, ice and water shield in valleys and at eaves, new flashing, and manufacturer-spec shingles from GAF, Atlas, or Tamko. TPO flat sections add $3,500 – $8,500 depending on size. Flashing-only scope items run $1,200 – $3,800. What moves the number: how many roof planes you have, how many penetrations, whether the decking is sound, and whether you’re in a Fire Hazard Severity Zone requiring Class A materials. We write every dollar into a line-item estimate before work starts. Call (743) 200-8347 and we’ll walk your roof with you, in person, and explain what you actually need.
We Also Serve Cities Near Los Altos
Our crews handle Roof Installation in Los Altos and the surrounding communities along the Peninsula foothills. We regularly work in Mountain View, Stanford, Palo Alto, and Menlo Park, where the same aging ranch stock and low-slope roof systems present the same installation challenges we solve every week. If you’re a few minutes down El Camino or across the border in any of those cities, the estimate process is the same: inspection first, written price before any work.
Serving Los Altos, CA - Our Local Coverage Area
We’re based in the Los Altos area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Roof Installation in Los Altos
Yes, often. Once a permit is pulled for a full re-roof in Los Altos, the open-deck inspection can expose undersized or damaged framing, outdated electrical clearances, and failed waterproofing that the original bid never included. We handle this by writing allowances into your contract upfront, so if the inspector flags something, the price and scope get approved in writing before we do the work. No change orders you didn’t sign off on. Call (743) 200-8347 to get a bid that accounts for this from the start.
Because the original tar-and-gravel or early modified-bitumen membrane on those garage and rear-addition flat sections is 50 – 70 years old and well past its service life. If you re-roof the main pitched field and leave the flat section, you’ll be back within one rainy season with a leak. We scope both as one project and write them into the same contract, so the entire roof system gets replaced at once. The free estimate includes a walk of every plane, including the garage.
Class A fire-rated composition shingles from GAF, Atlas, or Tamko are the most practical choice for Los Altos homes in or adjacent to the foothill fire zones. California requires Class A materials on any full re-roof where the zone applies, and these manufacturers produce Class A systems that also handle the moisture and UV exposure we get here. We’ll check your zone and spec the material that passes both code and insurance review. Call (743) 200-8347 and we’ll tell you exactly what your zone requires before you spend a dollar.
We install underlayment, valley protection, and flashing built for slow drainage. Low-slope roofs move water off more slowly than steep roofs, which means the materials at the valleys, eaves, and penetrations take more sustained moisture exposure. We use ice and water shield in valleys and at eaves on every Los Altos job, even where code doesn’t require it, because the marine-layer winters here will find any weak point in a shallow-pitch system. The estimate reflects that protection upfront.
Yes, but only as a back-of-the-envelope number. In Los Altos, you can expect roughly $650 – $1,100 per square, which is 100 square feet, for a full tear-off and architectural shingle installation on a typical ranch. What that per-square number won’t tell you is the condition of the decking, the number of valleys and penetrations, or whether your flat garage section needs TPO replacement. We quote by the line item, not by the square, so you know exactly what you’re paying for. The estimate is free. Call (743) 200-8347 to get one for your specific roof.
Written by Grant Whitlock, Owner at Mercer Roofing, serving Los Altos since 2000.