When renovating or building a new home, your eaves, and the design of hoods or awnings over your glass windows and doors, can be one of the most impactful passive solar tools available to you.

And it can be one of the easiest to get wrong.

Learn more about how to size them for your climate and orientation, what your team should be showing you, and where they can also protect the health and durability of your home.

Listen to the episode now.

Hello! This is Episode 425. This is Way #25 of the 44 Ways to Create Your Sustainable Home series, and it’s the last episode in Section Five: The Building Envelope.

Over this section we’ve worked through airtightness, windows, building wraps, and insulation.

This episode pulls together two concepts: the information about designing for the orientation of your site that I shared back in Way #1, Episode 401, our first episode of the ‘44 Ways’ series, and the discussions we’ve been having in this section about the building envelope.

Because once you understand how the sun moves across your site, the next question is about how your building envelope is designed to provide the protection you need from the elements on your site.

And that’s what eaves, hoods and awnings can provide.

Way #25 is: Include Eaves and Window Hoods in Your Finished Home.

If you’ve ever lived in a house that overheats in summer, where the sun blazes through the windows on a hot afternoon and it feels like the only solution, and it’s one that doesn’t work very well, is to close every blind in the place, you’ve felt what happens when shading hasn’t been designed properly in a home.

Eaves are the overhang that extends beyond the external wall of the building at roof level. Usually created by the extension of the roof line, the underside of the eave is called the soffit. Soffits can be flat, or raked.

The eave overhangs are commonly created by the continuation of the roof structure itself, or sometimes additional structure can be bolted on to create them.

Depending on the roof design and structure itself, and the direction the sun is coming from, you can often achieve quite a sufficient unsupported or cantilevered eave overhang to shelter and shade the wall below.

Hoods and awnings over glass windows and doors perform the same function as an eave, but in a more localised way. They’re a projection over an individual window or door opening that provides cover and shade over the opening below it.

Functionally, eaves, hoods and awnings do two important jobs.

Firstly, they manage how much of the sun’s heat can penetrate the glass of your windows and doors at different times of year. They can provide shade before that heat enters the home, or allow it in during colder months, and they do this based on the sun angles and the design and size of the eave, hood or awning. They can also shade the walls of your home, so the building envelope isn’t overloaded with heat in the warmer times of the year.

Secondly, they assist with longevity and durability of your home’s facade, by keeping rain and weather off the external walls, windows, doors and cladding.

The sun is in a different position in the sky depending on the season, and where you’re geographically located, and with that knowledge for your site, you can size your eaves, hoods and awnings to allow sun into your home in the colder months, whilst shading your home in the warmer months.

In the warmer parts of the year, the sun is higher in the sky as it moves through its arc. This enables you to create shade through horizontal elements, such as eaves, overhangs and awnings. 

Then, when it’s lower in the sky in its arc of movement in the colder times of the year, the angle of sunlight means it can shine in under your eave, hood or awning projection, to penetrate through the glass windows and doors, into the interior of your home.

I see a lot of homeowners assume because their home has eaves, that their windows and doors will be shaded.

However, when you look at the distance the eave is above the window opening, its overall depth, and then the angle of the sun, the eave’s shade gets nowhere near the opening because there’s too much wall above, or the eave is too short.

Equally, I see people add oversized eaves or hoods and awnings, that then provide shade for too much of the year, and as a result, don’t let the sunlight into the home in the cooler parts of the year.

So, work with your team, especially your energy efficiency assessor, to determine whether the shade that’s being provided by the elements included in your design is sufficient for your climate, is helping your home stay cool in Summer, without detrimentally impacting the comfort of the home in Winter.

The second job of eaves and window hoods is to help with the long-term durability and health of your building.

As water hits your facade, and doors and window openings, it accelerates the weathering of paint finishes and sealants, and also potentially works its way into the wall assembly and interior of your home. 

In Episode 422, I talked about the building wrap as the primary system managing moisture in the wall assembly. The eave reduces the moisture load on that system. Less rain reaching the wall means less work for the wrap to do, and lower risk of water finding its way in.

A lot of contemporary residential design incorporates flat or low profile roofs with no overhangs, and this has meant that eaves have been removed or significantly reduced on a large proportion of new homes over recent times.

If your designer proposes shallow or no eaves for aesthetic reasons, I’d encourage you to ask a direct question: how are we shading the building and its window and door openings? And what is protecting my external cladding from rain?

If the answers are specific and considered, great. If the answer is ‘internal blinds’ or ‘we’ll address that with window treatments,’ note the red flag, and catch it whilst your home is lines on a page.

In this Episode, I cover:

• What eaves and window hoods actually are, and the different forms they take, from Queenslander bullnose hoods to contemporary horizontal blades and motorised awnings
• The two important jobs eaves, hoods and awnings do
• How the sun’s altitude changes across the seasons, with specific angles to demonstrate how much this changes based on your location
• How to think geometrically about sizing an eave, hood or awning so it shades in Summer and lets Winter sunlight in
• Why I don’t recommend using AI to work out your eave sizing, and what I found when I tested it myself
• Why your existing eaves may not actually be shading the windows and doors you think they are
• How to shade east and west orientations, where horizontal projections don’t work
• How eaves and window hoods reduce the moisture load on your building wrap, and support the long-term durability of your facade
• What to do when eaves disappear for design reasons, and why property developers push walls out to the boundary at the cost of shade and weather protection
• Alternatives when sufficient eaves can’t be included
• The questions to ask your designer, and what a good design team should be able to show you in section drawings or 3D modelling

Plus a whole lot more.

LISTEN TO THE EPISODE NOW.

RESOURCES:

Episode 401, on designing your future home for the orientation of your site >>> 44 Ways #01

Episode 415, on using energy modelling during the design phase >>> 44 Ways #15

Episode 416, on other options to model your design before you build >>> 44 Ways #16

Episode 422, on reviewing building wraps to manage moisture for climate >>> 44 Ways #22

Australian Government’s sustainable design guide on shading >>> Your Home: Shading

A free guide to simplifying sustainability across research, planning, design, materials, and building, from Amelia Lee’s 30+ years in residential design and construction >>> 44 Ways to Create a Sustainable Home

Access the support and guidance you need to be confident and empowered when renovating and building your family home inside my signature online program >>> HOME Method