This is Why Your Shed Needs Guttering
Maths isn’t my strong point. Countdown calculations give me headaches. Carol Vorderman doesn’t. When asked to find ‘x’ in an equation, I invariably point to said letter and say, ‘There it is.’ 7 x 8 always gets me counting on my fingers and if you move a negative number to the other side of the ‘=’ sign when fumbling around with algebra it either becomes a positive or you divide something. Or is it multiply? I struggle. To the nth degree.
I do, however, understand 6x8 when it comes to a shed (see what I worked up to there - nice!) and just as vital, the importance of guttering.
Your shed roof is large. It catches a lot of rainwater. I tried to find out how much water actually runs off an average sized shed roof in an average year in an average part of the UK. An average task you would think, but it proved to be a difficult one. I did unearth a formula and you are welcome to squirt some Mr Sheen on your dusty old abacus and work out your own figure. It goes like this:
Roof area (in square metres) x Annual rainfall (in mm) x System efficiency x Run-off coefficient of roof (a pitched, tiled roof is 0.75, but a flat roof 0.5 or less) = Annual collection in litres (1000 litres = 1 cubic metre, or m3)
And for me, as a simple soul with my own 6x8, that’s enough to quickly fill a water butt, but only if you get the water from the roof into the water butt, and that requires guttering. Run guttering down both sides of your shed and into water butts. And after a heavy rainstorm check the volume of water in the water butts. After a week of rain, I reckon a water butt will be full. And that’s full of water that’s ideal for your plants.
Using water from a water butt is better for your plants as it is at a milder temperature, doesn’t contain any of the chemicals that are added to tap water and doesn’t put a strain on water meters/bills.
Guttering also stops all that water (Remember: Roof area (in square metres) x Annual rainfall (in mm) x System efficiency x Run-off coefficient of roof (a pitched, tiled roof is 0.75, but a flat roof 0.5 or less) = Annual collection in litres (1000 litres = 1 cubic metre, or m3) from sheeting down the sides of your shed or dripping to form pools and puddles at the base of your shed. Your shed build isn’t complete without guttering.
When thinking about collecting rainwater from your shed roof, remember:
- Guttering needs to slope slightly towards your water butt (I might be weak at maths but physics and gravity are my specialities!).
- The guttering needs to be cleared of leaves and general debris.
- A water butt is heavy when even half full so get things in their final positions from the start.
- Use a rolled-up ball of chicken wire or similar at the top of the downpipe to stop any errant leaves getting into your butt and causing problems (stop sniggering - we’ve gone through most of this blog without any childish smirking at the word butt, so let’s keep going).
- Get your butt high enough so a watering can can comfortably fit beneath the tap (I said stop it).
- Connect two or more butts together as things can quickly overflow (OK, that’s enough).
But guttering is the key to make it all happen. There’s always a bit of tricky overhang on sheds that makes some guttering hard to fit. The rounded part of the gutter tends to tilt towards you and can result in poor water collection. You can bodge it with blocks of wood, gaffer tape and on one shed of mine, a few years ago, a piece of roof tile wedged between shed and guttering.
A Hall's gutter kit makes fitting guttering easy. It may look like a Mediaeval torture implement but that clamp and screw system will ensure the guttering is perfect - and that means more water in your water butt and less flooding down your shed walls. And that equates to healthier plants and less water use from the tap. It’s that simple.
Unlike that devilishly difficult calculation. Right, back to the calculator remembering to convert feet and inches to metres and litres into gallons. I think. Run-off coefficient of what? I’ll try Google again.