Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Before
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AfterFast, Reliable Roof Installation Across Simi Valley
A full roof installation in Simi Valley typically runs $14,000 to $34,000 depending on the roof size, the materials you choose, and whether the old roof is wood shake that needs code-upgrade work. Most re-roofing jobs here take four to seven days once materials are on site. If you’re in Simi Valley and wondering what a new roof will actually cost and who you can trust at your door, call (743) 200-8347 for a written line-item estimate.
We’ve worked on homes from Wood Ranch to the tracts north of the 118, and as a Roofing Company - Simi Valley, we know what a local roof has to survive: triple-digit summer heat that bakes shingles, Santa Ana winds that tear at edge metal, and a fire-code environment stricter than almost anywhere else in Ventura County. Local knowledge here isn’t a talking point. It’s the difference between a roof that passes inspection the first time and one that gets red-tagged.
Why Mercer Roofing Is Simi Valley’s Preferred Roof Installation Company
We solve the problem most roofers ignore: you don’t know who’s at the door. Every Mercer technician’s name and photo is sent to you before they arrive, and they badge in with a photo ID at your front door. No unmarked trucks. No mystery workers. That matters a lot to homeowners in Simi Valley, where people are often home alone, raising kids, or simply want proof of who’s on their property.
Mercer Roofing is part of the Threshold Group family, founded in 2000. Each location is independently owned and operated, and we’re contractually held to the Threshold Verified standard: background-checked, identity-verified, uniformed technicians on every visit. Grant Whitlock leads our team, and he holds every crew to that standard on every job.
Every Simi Valley project starts with a written price before any work starts. Not a verbal range. Not a “we’ll see how it goes.” A written price. Every installation includes our 365-Day Done Right Promise: if it’s not done right within a year, we make it right. And every repair includes a written guarantee with a free second visit if it fails.
Roof Flashing Installation in Simi Valley
Roof flashing installation in Simi Valley is the metal work that keeps water out of the joints where your roof meets a wall, chimney, skylight, or valley, and it’s the single most common source of leaks we fix on 1970s and 1980s tract homes. Flashing on a typical single-family home in Simi Valley runs $450 to $1,300 for a repair or replacement section, and $2,000 to $4,800 when we’re re-flashing the entire perimeter as part of a full Roof Installation. The valley heat and Santa Ana wind cycles take a real toll on this metal.
Why Galvanized Flashing Fails Faster Here
Standard galvanized flashing corrodes quickly in Simi Valley’s heat-and-wind cycle, especially where dust and debris from the Santa Susana foothills sit against the metal and hold moisture. The wind funnel through the Simi Hills then works the corroded sections loose. We spec stainless steel drip edge and flashing on rake edges and ridge lines in the VHFHSZ tiers, particularly in Wood Ranch and near Rocky Peak, because those are the exact failure points we see season after season.
What a Flashing Replacement Actually Involves
We pull the old metal, inspect the decking underneath for rot, replace any damaged sheathing, and reset the new flashing with proper overlap and fastening. On Simi Valley homes with original wood shake tear-offs, we often find the old flashing was nailed at the shake gauge, not the new shingle gauge. That’s why we re-deck before we flash. Skipping that step is how you get a brand-new roof that leaks at the chimney within three years.
TPO Roofing Installation in Simi Valley
TPO roofing installation in Simi Valley is a single-ply membrane system we install primarily on flat or low-slope roof sections, which show up on a surprising number of Simi Valley ranchers and two-story colonials with flat porch roofs or sunroom additions. TPO reflects heat well, which matters when your roof surface hits 150°F in July. A TPO installation on a typical Simi Valley flat roof section runs $7,500 to $14,000 depending on square footage, insulation thickness, and whether the old roofing underneath needs to be removed.
When TPO Makes Sense on a Simi Valley Home
If your flat roof is peeling, ponding water, or showing cracked seams, TPO is often the right call because it handles UV exposure and thermal expansion better than older modified bitumen roofs from the 1980s and 1990s. The heat-trapping geography of the valley means the surface temperature swings more than coastal Ventura County, and TPO’s white membrane reduces that thermal stress. We install TPO with heat-welded seams, not tape, so the joints don’t open up under Simi Valley’s wind loads.
What We Check Before Installing TPO
We check for moisture trapped in the existing insulation, which is common on older Simi Valley homes where a previous roofer installed membrane over wet decking. We also verify the roof’s drainage slope, because ponding water on a TPO roof degrades the membrane faster than UV. If the slope is deficient, we correct it with tapered insulation before laying the membrane. That’s the kind of detail that determines whether the TPO roof lasts 15 years or fails in five.
Trusted Brands We Service in Simi Valley
We install and repair shingle systems from GAF, CertainTeed, and Owens Corning, and we stock the common profiles and colors locally so Simi Valley homeowners aren’t waiting on a special order from a distribution center. GAF Timberline architectural shingles are our most common recommendation for Simi Valley’s tract ranchers and colonials because they handle the valley’s UV load well. CertainTeed’s Landmark line is a strong option when homeowners want a heavier, denser shingle, and Owens Corning Duration offers good wind performance for the rim neighborhoods that catch the Santa Ana funnel. We spec materials based on what the house actually needs, not what’s on a promotion.
Common Roof Installation Problems We See in Simi Valley Homes
- Corroded galvanized drip edge and ridge fasteners. The combination of intense heat, dust, and seasonal wind accelerates corrosion on standard galvanized hardware. By the time a re-roof happens, the edge metal is often loose and uplift-prone, especially on homes near the Simi Hills wind funnel.
- Original cedar shake tear-offs with under-decking gaps. Simi Valley’s 1970s and 1980s tract homes were often roofed with wood shake at a specific nailing gauge and the sheathing underneath shows the old nail holes and gaps. Re-shingling over that decking without re-decking is a recipe for premature failure at the field.
- Non-listed ridge vents that fail Simi Valley’s ember-resistant venting inspection. In the highest VHFHSZ tiers, California Building Code Section R902.2.1 requires listed ember-resistant roof venting. A roofer who specs a standard ridge vent will fail the permit inspection and delay the job.
- Valley flashing that was never upgraded when the shake came off. We regularly find valley metal that’s too narrow or too thin for modern architectural shingles. The valley is the highest-volume water channel on a Simi Valley roof, and undersized metal there is the fastest path to a leak.
Pricing for Roof Installation in Simi Valley, CA
Here’s what homeowners in Simi Valley should expect on a roof installation. A standard single-story rancher with a 1,800 to 2,400 square foot roof and Class A architectural shingles runs $14,000 to $22,000. Two-story colonials in tracts like those near Wood Ranch or east of Tapo Canyon run $18,000 to $34,000 because they have more square footage, steeper pitches, and taller wall flashing. If the original wood shake has to come off and the decking has to be re-sheeted, add $2,500 to $5,500. TPO sections on flat or low-slope roofs run $7,500 to $14,000. Flashing work runs $450 to $1,300 for isolated sections, $2,000 to $4,800 for a full perimeter re-flash. These are the real numbers. Call (743) 200-8347 for a written line-item estimate specific to your house, free of charge.
We Also Serve Cities Near Simi Valley
Mercer Roofing serves homeowners across the surrounding area, including Moorpark, Oak Park, Thousand Oaks, and Westlake Village. If you’re in one of those communities, we’ll bring the same Threshold Verified standard to your door. Our crews are dispatched locally for Simi Valley and the nearby cities, so you’re not waiting on a crew from across the county.
Serving Simi Valley, CA - Our Local Coverage Area
We’re based in the Simi Valley 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 Simi Valley
Simi Valley is largely mapped as a Very High Fire Hazard Severity Zone by the state, which makes Class A fire-rated roofing materials a legal requirement on every permitted re-roofing job. Moorpark has large areas outside the VHFHSZ mapping, so an identical house there can legally use a lower fire rating. Your brother’s roof isn’t the standard your house has to meet. The city and the state set different rules for different fire-risk zones, and Simi Valley sits in the stricter tier. Call (743) 200-8347 and we’ll tell you exactly what your specific property’s mapping tier requires.
The inspector checks fire-rated material compliance, underlayment type, nailing patterns, and in the highest VHFHSZ tiers, ember-resistant roof venting under California Building Code Section R902.2.1. That vent requirement is specific to the highest fire-hazard zones. If the roofer installed a standard ridge vent instead of a listed ember-resistant product, the inspection fails. We spec listed ember-resistant vents on every Simi Valley re-roof in the affected zones, which is why our inspections pass on the first visit. Call (743) 200-8347 for an estimate that accounts for these local requirements from the start.
Pay more for stainless. The heat, dust, and Santa Ana wind cycle in Simi Valley corrodes standard galvanized drip edge and ridge fasteners far faster than the coastal-spec stainless steel we use on VHFHSZ rim homes. The galvanized edge metal that’s common on cheaper bids will be loose and lifting within a decade. The price difference on a typical roof is $300 to $800. Replacing failed drip edge later costs far more once the shingles have to be pulled. Call (743) 200-8347 and we’ll put the stainless spec in your written estimate so you can compare bids honestly.
On a 1979 two-story colonial in Wood Ranch we tore off the original cedar shake and found the sheathing had been nailed at the original shake gauge, so we re-decked and re-sheeted the field before laying GAF Timberline architectural shingles over a high-temp ice and water shield in the valleys. The Santa Susana wind funnel had blown the old drip edge loose at the rake, so we reset stainless drip edge and re-secured the ridge per the enhanced fastening pattern the VHFHSZ mapping calls for. The inspector signed off on the ember-resistant ridge vent on the first pass because we spec’d a listed product, not the standard vent the same house would get a few miles east. Expect old nail holes, possible gaps in decking, and old flashing that needs full replacement. Call (743) 200-8347 for a written estimate that includes the re-decking work up front, not as a surprise after the tear-off.
Put the two bids side by side and check four things: whether the shingle is Class A fire-rated, whether the drip edge and fasteners are stainless or galvanized, whether the venting is a listed ember-resistant product if your home sits in a VHFHSZ tier, and whether the bid includes re-decking if the tear-off uncovers old shake-gauge sheathing. The cheaper bid usually specs galvanized edge metal, a standard ridge vent, and no stated allowance for re-decking. That’s not a real savings. That’s a future inspection failure and a leak waiting to happen. We give you a written line-item estimate so you can compare against other bids line by line, not just total price. Call (743) 200-8347 for yours.
Get Your Free Simi Valley Roof Installation Estimate
You’ll know your price before any work starts. You’ll know the name and face of the person coming to your door. And you’ll have a written guarantee for every repair we make. That’s how Mercer Roofing does roof installation in Roof Installation in Simi Valley. Call (743) 200-8347 to schedule your free estimate.
Written by Grant Whitlock, Owner at Mercer Roofing, serving Simi Valley since 2000.