How to Clear Blocked Box Gutters and Avoid Serious Roof Damage

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Your gutters are blocked, and you’re stressed. Water keeps overflowing, and it’s starting to look like a big problem. What do you do?

Box gutters protect your foundation and exterior cladding and allow water to be directed to specific areas. This means it won’t pool and leak back into your foundation. You don’t want substantial rain in front of your door or window, or you’ll have a waterfall!

This article will detail what a box gutter is, why it’s important to maintain water flow, the minimal installation requirements by law, and how you can avoid water damage in the future.

Box Gutters: Why Do We Need Them?

Pour water on a kitchen counter edge. Some water spills on the ground, but more of it will track along the bottom of the counter (and into the cabinets). Roofing is similar to the constant moving of water and will end up eroding and damaging the building.

Box gutters also stop water from cascading down the roof at locations you’d walk through, such as doors or garages. Preventing erosion and overly-saturated soil prevents flooding in heavy rain, and when water drips off the roof and splashes onto dirt, this can discolour the bottom layer of painted houses. Plants that are under your roofline also won’t be destroyed by falling water.

What Causes Gutters to Block?

Debris is accumulating over time. Twigs, leaves, pine needles, seed pods, or even trash that’s been blown by the wind can block up the gutters. If you have trees that overhang your roof, you might notice this happening more frequently.

Weather conditions. Strong winds move around debris from trees and other properties, which can get stuck in box gutters. Heavy rain can overwhelm your gutters if they’re partially blocked, and nearby construction sites generate dust, debris, and building materials.

Seasons change. In spring, flowering trees and seed pods can blow into your gutters, autumn brings in a lot of leaves, and in winter, cold temperatures can turn trapped water into ice dams.

Poor gutter positioning. If your gutters haven’t been installed to standard (even if they’re slightly slanted), they are more likely to block up. A professional roofing contractor can check to ensure these things are correct.

How do you know if your box gutters are blocked?

According to the Victorian Building Authority, the design of a box gutter must:

Demonstrate compliance with all relevant Performance Requirements of the National Construction Code, or:
Demonstrate that the solution used is at least equivalent to the Deemed-to-Satisfy provisions

Both building and plumbing practitioners must comply with the AS/NZS 3500.3 for the Deemed-to-Satisfy box gutter system.

Box gutter width, grade, and flow rate are required to chart the minimum depth of a box gutter that discharges to a rainhead.
The design flow rate can be plotted between 3 and 16 litres per second (L/s), or sole widths of 200mm cannot accommodate flow rates exceeding 10.5 L/s.
Larger buildings might require internal sumps to stop box gutter flows exceeding 16 L/s.
Grades for box gutters can be charted at 1:200, 1:150, 1:100, and 1:40.

What about box gutters discharging to a rainhead?

The minimum depth, length of a rainhead are dependent on:

The design flow rate
The size and shape of the downpipe selected (round/square/rectangular)
The box gutter sole width
The width of the rainhead must be at least equal to the width of the box gutter.

Let’s look at a deemed-to-satisfy rainhead overflow:

The weir of the rainhead overflow must be 25mm below the sole of the box gutter
The width of the overflow is equal to the width of the rainhead
The rainhead must be left open above the overflow weir
Ned Kelly slots, round holes and vertical chute/ducts are not deemed to satisfy designs

For box gutters discharging to a rainhead:

The size and shape of the downpipe are selected when sizing the downpipe
Round downpipes must be fitted so that the centre of the downpipe is no further than the diameter of the downpipe from the nearest vertical side of the rainhead
A square or rectangular downpipe must be fitted so it is not further than the average of the two side dimensions of the downpipe from the nearest vertical side of the rainhead
Downpipes must discharge vertically from the sole of the rainhead

For more information, refer to this educational resource by the VBA or read this blog on how to choose the right material for your gutters, advantages and disadvantages.

What Happens if You Ignore Blocked Gutters?

Let’s explore some of the issues that arise if box gutters aren’t designed, installed, or maintained correctly.

Water can overflow and seep into your home’s structure, and this includes your soffits, siding, and fascia boards.
It can infiltrate the roofline, which damages ceilings, walls, and insulation.
Moisture being trapped creates ideal conditions for wood rot, damaging roof structures, eaves, and fascia.
When water pools, it exerts pressure and causes shifts, cracks, and instability.
Damp conditions are breeding grounds for mildew and mould, which is risky for occupants who have respiratory problems or allergies. Mould discolours ceilings, surfaces, and walls, as well as being horrible to look at.
If clogged gutters are filled with stagnant water, it attracts flies, mosquitoes and cockroaches.
They provide nesting places for rodents, which can invade your home.

Read: Top 5 Reasons Rusted Gutters Can Lead to Major Roof Issues.

DIY Gutter Cleaning: A Guide

How can you begin cleaning your box gutters? It can feel like a chore, but it’s well worth getting it done! The tools you will need are:

Bucket
Garden hose with a spray attachment
Gutter scoop
Ladder
Ladder safety clamp

Set up your ladder safely

Set the ladder on a stable surface and make sure it is the right height for you to reach your gutters without overstretching or balancing. You want to maintain three points of contact with the ladder, such as two hands on one foot or two feet and one hand. It’s a good idea to take your time setting up the ladder to avoid any accidents.

Scoop out the debris

Once safely positioned, use a gutter scoop or garden trowel to get rid of twigs, leaves, and any other debris into a bucket.

Wear gloves to protect your hands from sharp edges, dirt, and insects. Also, double-check for signs of damage, rust, cracks, or loose areas.

Spray with water

Starting at the end of the downpipe, flush the box gutters with water with your garden hose to rinse out any leftover dirt. Professionals recommend maintaining your gutters at least twice a year to keep them in excellent condition.

When checking your own gutters with a ladder, make sure to follow the ladder safety rules on the WorkSafe website. Xclusive Roofing is suitably registered and licensed.

Whether you require maintenance for box gutters in Frankston, Carrum Downs, Seaford, Cranbourne, Dandenong, Chelsea, Berwick, Beaconsfield, Mornington, Officer, Pakenham, Hallam, Brighton, or Caulfield, we can help you with roof repairs!

Reliable Roof Repairs for Melbourne Homes: Call Us!

If you need extensions and roof replacements, gutter replacements, Colorbond steel roofing, downpipes, custom made flashings, or have specific questions about your gutters, Xclusive Roofing is reliable and dedicated to any roof problem.

Revitalise your home, discover the benefits of Colorbond gutters, or talk to us about how fascia and gutter systems safeguard your property. As a family-owned business, we aim to meet your roofing needs with precision and care.

Contact us today for obligation-free quotes and after-hours emergency assistance. Many homeowners choose us for roofing needs. Request to view more of our work by calling 03 5978 6473, emailing quotes@xclusiveroofing.com.au, or visiting us in Clyde North!