Does Your House Need Eavestroughs? What Happens Without Gutters

Yes, most houses in Ontario need eavestroughs. Without them, every roof delivers its rain and melt in a single line beside the wall, which soaks the soil at the foundation, splashes siding, rots fascia and ices over steps and walks. A few roofs with deep overhangs and well-drained ground can go without, but they are the exception.

Do you need eavestroughs? The short answer

If your roof edge sits above a wall, a door, a walkway or a foundation, you need a way to control the water. For most houses that means eavestroughs, also called gutters, and downspouts that carry water away from the building.

The volume is bigger than most people expect. One millimetre of rain on one square metre is one litre. So a roof with 100 square metres (about 1,076 square feet) of footprint receives roughly 1,000 litres from a 10 mm rain. Without eavestroughs, that water runs off the edge and lands in a strip a short distance from your wall. Add a spring thaw, or a storm that drops rain for hours, and the same ground takes it again and again.

The Government of Canada says that, when properly installed and maintained, eavestroughs and downspouts can reduce water damage by capturing roof water and directing it away from your exterior walls and foundation. That is the job, and the rest of this post looks at what fails when nothing does it.

What happens to your foundation and basement without eavestroughs

Roof runoff that falls at the base of the wall saturates the soil right where the foundation needs it dry. That water can then:

• Push through cracks, cold joints and window wells into the basement.
• Raise damp conditions that lead to musty smells and mould.
• Freeze in the soil beside the wall. Freeze-thaw cycles heave and settle the ground, and frost reaches about 1.2 m (4 feet) deep in this region.
• Wash away soil from the drip line, which leaves a dip beside the wall. That dip then collects more water.

Spring is the hard test. Snow melting off the roof, frozen ground that cannot absorb water and a heavy rain can arrive together. If water is going to find a way into a basement, it often does so then.

Eavestroughs are one part of a system, not the whole fix. The ground also has to slope away from the house. The City of Waterloo describes this as positive slope: soil that rises away from the foundation so that water drains away from it.

Siding, fascia, soffit, windows and doors take the splash

Water that drops from the roof edge hits the ground and splashes back up the wall. Over time that shows up as:

• Dirty, stained lower siding and a green film of algae where the wall stays damp.
• Wet window sills and basement window wells, which are a common leak point.
• Rotting wood trim, fascia and door frames. Rot usually starts where roof water sits against the board.
• Water running down the face of the wall in wind, which can get behind the cladding at corners and trim.
• Wet thresholds at doors that sit under the drip line.

In winter, a roof with no eavestrough drips meltwater straight onto steps and walkways, where it freezes into sheets. Icicles form along the edge and fall over doorways. One note matters here: eavestroughs do not cause ice dams. Heat escaping into the attic does. A house without eavestroughs still gets ice dams, and the water they back up goes behind the roofing and down the wall instead of into a trough.

Landscaping, walkways and the drip line

Look along the edge of a roof with no eavestroughs. You will usually see a trench or bare strip in the soil, flower beds that are washed out, and mulch or stone thrown onto the lawn. Roof water also pounds on decks, stair treads and concrete steps beneath the eaves. In winter that water freezes into slippery patches at the places people walk.

A roof with eavestroughs sends the water to a few downspouts instead, where you can plan where it goes. Extensions can carry it onto a lawn, garden or other area that drains. The Government of Canada recommends discharging at least 2 m (6 ft.) away from the foundation of surrounding homes where possible. Our post on downspout management explains how to choose a discharge point.

Can you go without eavestroughs? When it can work

Some roofs and lots can manage without a conventional system, but only when the water has somewhere safe to go. Use this as a checklist, not a permission slip.

Municipal rules matter here. The City of Waterloo asks that downspouts and sump pump outlets drain onto your own property, not a neighbour's. The City of Guelph lists discharging roof, foundation or yard water directly onto walkways, stairs or adjacent properties as something to avoid. Check with your municipality's building department or bylaw office before relying on a no-gutter design, especially on a lot with a grading plan.

Do gutters help with foundation issues, and what they cannot fix

Eavestroughs help prevent water-related foundation problems, but they do not cure existing ones. They will not seal a cracked wall, fix a failed window well or lower a high water table. They work only if three other things are also true:

1. The troughs are clear. The Government of Canada advises checking eavestroughs and downspouts at least twice a year, in fall and spring, and after storms. A clogged trough overflows in the same spots as having none.
2. The downspouts end in the right place. Extensions carry water away from the foundation onto ground that slopes away from the house. Connecting downspouts to a municipal sewer can be illegal in some municipalities, so confirm local rules before changing a buried connection.
3. The ground slopes away from the wall. Low spots and settled soil can send water back toward the house.

If you already have eavestroughs and still see water at the base of the wall, our guide to where roof water ends up is a good next step.

Should I get eavestroughs? What a proper installation involves

If you have decided to add or replace them, here is what a sound installation looks like:

• Material and length. Aluminum troughs formed on site from coil to the length of each run, so joints fall only at corners, outlets and end caps. See eavestrough materials compared for other options.
• Size. Five-inch K-style suits most houses. Six-inch carries more water and suits long or steep roof faces, valleys and metal roofs. Downspouts are 2x3 inch as standard, and 3x4 inch for bigger roofs and six-inch systems. See five-inch versus six-inch eavestroughs.
• Support. Hidden hangers screwed through the fascia into solid wood, typically every 60 cm (24 inches), closer where snow and ice load is heavy.
• Pitch. About 2 mm per metre (roughly 1/4 inch per 10 feet) toward each outlet.
• Fascia first. Rotted fascia is replaced or wrapped before new troughs go up.
• Extensions. Downspouts finish with extensions onto ground that slopes away.

Gutter guards are optional and still need inspection. On cost, nobody can price your house without seeing it, but our eavestrough replacement cost guide explains what moves a quote.

Do gutters add value? There is no reliable figure to quote. Missing or failing eavestroughs are the kind of thing buyers and inspectors notice, and a working system protects the parts of the house that do carry value: foundation, siding, fascia and landscaping. D&D Exterior Finishing installs and repairs eavestroughs across Waterloo Region, and the free written estimate lists scope, materials, colours and warranty terms. See the eavestrough installation and repair service for details.

Eavestrough questions homeowners ask

Are gutters necessary on a house?

On most Ontario houses, yes. They collect roof water and direct it away from the foundation, siding and walkways. A few roofs with deep overhangs, sloping ground and no doors or paths below may manage without, but they need a planned drip strip and good drainage to avoid damage.

Do gutters help with foundation issues?

They help prevent water-related ones by keeping roof runoff from saturating the soil beside the foundation. They only work with clear troughs, downspout extensions and ground that slopes away from the house. They will not repair existing cracks or leaks, which need their own assessment.

Do gutters increase home value?

There is no reliable number to quote. A sound system is expected, and missing or failing eavestroughs are something buyers and inspectors notice. The real value is protection of the foundation, siding, fascia and landscaping, which are costly to repair when roof water has done damage.

Should I get gutters if my house has none?

Usually yes, especially if the roof edge sits above a door, steps, walkway or the foundation, or near a property line. Have the roof size, pitch and ground slope assessed so the troughs and downspouts are sized correctly and the water has a safe place to go.

Why are eavestroughs important in winter?

They keep meltwater from dripping onto steps and walks, where it freezes into ice. They do not stop ice dams, which are caused by heat escaping into the attic. Ice and snow load can pull on hangers, so secure fastening matters. Check and clear them in fall and spring.

Devon Moore, Operations Lead Co-Founder & Operations Lead — D&D Exterior Finishing

Devon Moore is the co-founder and Operations Lead at D&D Exterior Finishing, specializing in siding, roofing, windows, and exterior renovations across Waterloo Region.