systems-obscure/posts/replacing-garage-guttering.md

---
title: "Replacing garage guttering"
slug: /replacing-garage-guttering/
date: 2025-12-06
tags: ["projects", "DIY"]
---

![](./img/new-main-guttering.jpg)

I faced the following problems with the guttering on my garage:

- It had been bent out of shape by the wind
- The seals on the joins had worn away causing leaks
- There was sitting water that wasn't making it to the downpipe
- It was old and gross

Whenever it rained heavily, these problems would compound and lead to water
pouring over onto the garage brickwork.

![The old guttering. I didn't save any un-annotated pics
unfortunately.](./img/old-main-guttering.jpg)

The sitting water was caused by the lack of a sufficient drop from the union
join with my neighbour's gutter to the downpipe. A further impediment was that
the water had to turn a 90 degree angle, around the side of the garage, before
reaching the downpipe. As a result, water was only making it to the downpipe
when there was very heavy rain and/or high winds. During normal drip-drainage of
the daily dew condensation on the roof, the water was just pooling in the
gutter.

![The old corner bend](./img/old-corner-bend.jpg)

![The old downpipe](./img/old-down-pipe.jpg)

I decided to redesign the passage to the downpipe. Instead of trying to make the
water turn a bend I thought it would be better to work _with_ gravity and have
the drop start at the end of the guttering, not around the corner. This way, the
water would have increased velocity at the beginning of its descent into the
downpipe.

![The new downpipe design](./img/new-downpipe-rotate.jpg)

By fashioning a "swans neck" sequence of joins, the downpipe now turns the
corner _during_ descent and is fed downwards along the wall to the water butt.

![The "swans neck" join to get arong the corner](./img/swans-neck-downpipe-rotate.jpg)

This has been working very well and the water no longer pools. I've noticed
however that condensation forms on the underside of the downpipe. This doesn't
look great and I worry about it wearing away the sealant I have applied at the
joins.

![The new guttering](./img/closeup-of-new-main-guttering.jpg)

Overall, however I think it looks much neater as well as being more satisfying
from an engineering perspective. The white half-round gutters blend in nicely
with the neighbours' and look a lot cleaner.

I didn't keep track of costs for this project. I think in total it cost around
£80. This included the cost of the Floplast guttering and fixtures, the downpipe
and the protective mesh I applied to the top of the gutters to prevent blockages
from leaves and roof moss.