Home » Services » Flat Roofing

Flat Roofing

Flat Roofing in the Seattle Area, WA.

A flat roof is not a roof with less pitch. It is a different system that has to hold water out rather than shed it away, and almost nothing that works on a shingle roof works here.

Why Low Slope Is a Different Problem

Shingles Shed Water. A Flat Roof Has to Resist It.

A pitched roof works because water leaves it quickly and gravity does the sealing. Overlapping courses are enough. On a flat or low-slope roof water moves slowly, stands after every storm, and sits against the covering for hours or days. Nothing overlapping will hold that. The roof has to be a continuous membrane with every seam and every penetration sealed as part of the surface itself.

In the Pacific Northwest this is tested hard. Months of standing water, debris that blocks the drains, moss establishing on any surface that stays damp, and freeze-thaw working at every seam. The failures are correspondingly specific: ponding where the slope was never right, split seams, failed flashing at parapets and curbs, blocked or undersized drains and scuppers, and membrane punctured by foot traffic to rooftop equipment.

Flat roofs appear on more Seattle-area homes than people expect: additions, dormers, carports, garage roofs, deck surfaces over living space, and mid-century homes built that way throughout. We assess, repair and replace them, and the first question is always the same one. Where does the water actually go, and how long does it take to get there?

How We Work

How We Work on Flat Roofs

Drainage first, membrane second. A perfect membrane over a roof that ponds is a countdown.

Full system inspection

We establish where water stands and why: slope, drain and scupper placement and condition, blockages, and whether the deck below has already been affected.

01

Define the Scope

The scope separates the drainage correction from the membrane work, states the system being used and why it suits your roof, and identifies every penetration and curb to be detailed.

02

Execute the Repair

Drainage corrected where it can be, then repair or full membrane replacement with every seam, parapet, curb and penetration detailed as part of the surface rather than sealed afterwards.

03

Verify & Document

We flood or flow test where practical, confirm water reaches the drains and leaves, and photograph the seams and penetrations, which are the only places it will ever fail.

04

Our Projects

Real WORK. REAL Results.

Standing Seam Metal Roof Replacement & Structural Integration in Seattle, WA

Seattle, WA

Structural Chimney Rebuild & Masonry Restoration in Sammamish, WA

Sammamish, WA

Freestanding Gas Fireplace Installation in Mercer Island, WA

Mercer Island, WA

Why Chimneyz

We Treat It as a Water System

Our entire practice is water leaving buildings: roofs, flashings, gutters, grade, foundations. A flat roof is the purest version of that problem, because it offers water nowhere to go unless someone designed somewhere. We look at the drainage before the covering, which is the opposite order from most quotes you will get.

GAF Certified Contractor

Factory-certified roofing installer with access to enhanced warranty coverage and proven materials.

BBB Accredited

Better Business Bureau accreditation with a commitment to ethical practices and customer satisfaction.

READY TO SOLVE THE FULL PROBLEM?

Get a Clear Inspection and the Right Repair Plan.

From chimney leaks and failing masonry to roofline issues and interior damage, Chimneyz helps homeowners identify the real source of the problem and fix it with one coordinated solution.

CLIENT REVIEWS

Trusted by Homeowners the Pacific Northwest.

See how Chimneyz solves complex chimney, roofline, masonry, and restoration issues with clear scopes and high-quality execution.

FAQ

Flat Roofing FAQ

Flat roofs are the least understood roof on a house. These are the questions worth asking.

Are flat roofs a bad idea in Seattle?

Not inherently. They are unforgiving of poor drainage and poor detailing, both of which our climate exposes quickly. Built and drained correctly, they perform; built carelessly, they fail fast.

Why is water standing on my flat roof?

Either the slope was never adequate, the structure has deflected, or the drains and scuppers are blocked or badly placed. Ponding is the single best predictor of a membrane failure, so it gets diagnosed first.

Can a flat roof be repaired or does it need replacing?

Seams, flashings and punctures are repairable when the membrane still has life. Once it has gone brittle, or ponding has worked it for years, patching becomes an annual subscription.

What systems do you install?

Single-ply membranes including TPO, and modified bitumen, chosen on exposure, foot traffic, roof geometry and budget rather than on whatever we happen to buy cheapest.

How long does a flat roof last here?

It depends far more on drainage and detailing than on the product. The same membrane that lasts decades on a well-drained roof will fail early on one that holds water after every storm.