Water Leaking Behind Your Gutter? Here's What's Probably Wrong

Water running down the wall behind your gutter is a warning sign that something isn't draining properly. It might be a blocked gutter, loose brackets or a gap between the roof edge and the guttering. Whatever the cause, you want to find it before water starts damaging the wall underneath.

If you've noticed water leaking behind your gutter during heavy rain, here's how to work out what's happening and what needs fixing.

Why Is Water Running Between My Gutter and the Wall?

Your guttering has one job. Collect rainwater from the roof and direct it safely into the drainage system.

When it's working properly, you should barely notice it.

But if water starts running behind the gutter rather than into it, one of several things has gone wrong.

1. Your gutter is blocked

This is the first thing worth checking.

Leaves, moss, twigs and general debris build up over time. Once the gutter fills, rainwater has nowhere to go.

It starts overflowing, sometimes down the front of the gutter and sometimes behind it.

The problem becomes especially obvious during heavy rainfall.

If you've got trees close to your property, debris can build up faster than you expect. A professional gutter cleaning service can clear the obstruction and check that water is flowing properly again.

2. Your gutter brackets have come loose

Gutters need to sit in the correct position to catch water running from the roof.

When the supporting brackets become loose or damaged, sections of guttering can sag or pull away from the fascia board.

That creates a gap.

Instead of flowing into the gutter, rainwater drops behind it and runs down the exterior wall.

You might also notice one section hanging lower than the rest.

3. The gutter isn't positioned correctly

Even brand-new guttering can cause problems if it's fitted badly.

If the gutter sits too far from the roof edge, water can miss it entirely. If it doesn't have the correct fall towards the outlet, water can collect instead of draining away.

The solution depends on the installation.

Sometimes adjusting the brackets is enough. In other cases, the guttering needs refitting.

4. There's a problem at the roof edge

The problem isn't always the gutter itself.

Damaged roof felt, poorly fitted eaves trays or deteriorating materials at the edge of the roof can allow water to run behind the fascia rather than into the gutter.

This is worth investigating if the gutters appear clear and properly aligned.

Cleaning them repeatedly won't solve a roofing defect.

A roof inspection can help identify whether the water is coming from the roof edge or the guttering.

Can Leaking Gutters Cause Damp Inside Your House?

Yes.

Water running down the same external wall every time it rains can eventually cause damage, particularly where the masonry, pointing or other parts of the building are already vulnerable.

You might notice:

• Dark patches appearing on exterior brickwork.

• Peeling paint near the top of an internal wall.

• Damp patches around windows or ceilings.

• Green staining or algae below the gutter.

• Soft or rotting fascia boards.

One rainy afternoon won't necessarily cause serious damage.

Repeated water exposure over months is a different story.

Historic England's advice on looking after your home is a useful starting point for understanding why routine building maintenance matters, particularly on older properties.

How to Check Your Gutters Without Climbing a Ladder

Wait until it's raining, then look at the guttering from a safe position on the ground.

Watch where the water goes.

Is it spilling over the front? Running behind the gutter? Coming through a joint? Or pouring over one end?

Those details can tell a guttering specialist a lot about the likely cause.

Take a short video if you can.

Don't lean out of an upstairs window or climb onto the roof to investigate. Guttering is awkward to access, and wet ladders introduce a completely unnecessary risk.

Does the Gutter Need Repairing or Replacing?

That depends on its condition.

A single damaged bracket, leaking joint or minor alignment issue can often be repaired.

But if the guttering is cracked in several places, repeatedly pulling away from the property or badly deteriorated, replacement could be the more sensible option.

The important thing is to fix the reason water is escaping.

There's little point replacing one joint if the entire gutter is sagging towards the wrong end.

For blocked gutters, Precise Roofing & Guttering also provides blocked gutter repair in Morden and surrounding areas.

Need Your Gutters Checked in Morden or South West London?

Precise Roofing & Guttering is a family-run roofing and guttering company based in Morden, with over 20 years of experience.

We cover Wimbledon, Sutton, Mitcham, Worcester Park, Tooting and surrounding parts of London and Surrey.

Whether you've got overflowing gutters, a loose section or water running down your outside wall, we can assess the problem and explain your repair options.

Get a free same-day quote.

Call +44 330 133 4111 or request your quote online.

Get the water going where it belongs.