Heavier rain, older gutters: is it time for deep flow?

The Met Office says rainfall totals on the UK's wettest days have increased, and links that to climate change: warmer air holds around 7% more moisture for every degree of warming, so when it rains hard, it rains harder.

Gutters are sized for a rate of rainfall, not a yearly total. A system that coped comfortably when it was fitted can be overwhelmed by the short, intense downpours that are now more common.

Most older houses have standard half-round gutters. Deep-flow gutters have a deeper, wider profile, so each run holds and moves more water before it reaches the edge, and they usually pair with larger downpipes and outlets.

From the ground they look much the same. The difference shows in a cloudburst: the water goes down the pipe instead of over the front.

Rule out a blockage first: a clear is cheaper than a new system. If the gutters are clean and these still happen, capacity is the likely cause.

If you're replacing the roofline anyway, it's the natural time to go deep flow, because the gutters come off either way. If your gutters are sound and only struggle in the worst storms, an extra downpipe can sometimes solve it for less.

Water that overflows ends up in the walls, the fascias and eventually the house, which is the kind of slow damage insurers often won't cover. Our guide to home insurance and maintenance explains why.

?To confirm with Blue Shield: Which deep-flow systems Blue Shield fits, and whether it can add downpipes or outlets to an existing system.