What is a Dormer Roof?

What is a Dormer Roof?

Dormer roofs are small architectural additions that pack a big punch.

If you want to brighten up your attic with natural light, a dormer roof may be the perfect solution for you. A dormer roof is a little room that projects from the top of a roof with the purpose of letting light into your attic.

Some other benefits include added headspace, improved ventilation and architectural detail.

There are a few different kinds of dormer roofs to choose from if you’re considering one for your home:

Flat Roof

A flat roof dormer protrudes from your roof with 90-degree angles and straight lines. This boxy appearance makes for an excess of space added onto your attic. This simple style accounts for its lower average costs for installation. Exactly as it sounds, flat roof dormers have flat tops, making it undesirable for locations that get a lot of rain or snow. A good alternative to this is a shed roof, which is the same as a flat roof dormer, except its roof is sloped to allow for better rainfall drainage.


A gable dormer roof is one of the most common types of dormer roofs. Almost looking like a mini house, a flared gable dormer is structured similarly to a flat roof, with a two-sided slanted roof atop of it. This creates an abundance of added space to your attic and provides shade for your window. These added benefits contribute toward a flared gable dormer’s higher average cost.

Arched Top

An arched top (also known as a barrel roof) dormer is the most recognizable form of a dormer roof. This style usually has a smaller amount of living space and is intended solely for added natural light. The tops of these dormers are sloped making it easier for them to distribute rain and snow.


Appropriately named, an eyebrow dormer roof’s shape is similar to a squinted eye. A small hill protrudes from the shingles of your roof to create a seamless opening for a window. The continuity of the roof’s structure makes for a leak-proof and stable addition to your home’s roof. This rounded roof blends right into the roof of your home, which is perfect if you’re looking for a subtle addition and a little extra natural light. Since they need to be installed in direct accordance with your roof, the installation costs are typically a bit higher than styles like a flat roof.

Inset/ Recessed

An inset roof dormer is different from most styles because it recedes into the structure of the roof as opposed to protruding outward. The walls of this dormer sit beneath the slope of the roof, which may make is susceptible to water infiltration. This style can either be built with a gabled roof or a rounded one, making it easily customizable to your home’s style.

Finding a New Window for Your Home

Dormer roofs are an excellent addition to add light, ventilation and increased usage square footage to your home. With any dormer style it’s just as important to make sure you have a quality window.

Whether you’ve just installed a window on your dormer roof, or are needing to get your current one replaced, Thompson Creek experts can help you with any of your home’s needs. Visit our site to get a free estimate on your next home improvement project or browse our products at thompsoncreek.wpenginepowered.com.