Roofs and water collection query.

So, I will need to buy some garden storage for new home and I'm thinking of which type of shed. But, now I'm wondering: which roof style harnesses the most water?

Apex vs pent?

Any and all advice appreciated

 

I'd say an apex roof would be better for collecting rainwater.

Rarely does rain actually come down vertically, it usually falls at an angle, driven by whichever way the wind is blowing at the time.

So if you have a pent roof, little water will be collected on the occasions when the roof slope is facing away from the wind. Whereas an apex roof will always have one side facing into the wind, (or both on occasions), so more water will be collected overall.

 

Good thinking Trunky Thank you

 

On the other hand you need only one set of guttering on a pent roof whereas on an apex one you you need guttering on both sides.
Actually the roof with the greatest area will generally collect the most water.

 

Are you digging a pit for an underground rainwater storage tank?

 

No - but I'm taking 6 large water butts with me and they'll have to earn their space.

 

That's what I thought, hence the question

 

And that will be an A Pent. It is an apex or pent style roof with the apex off centre, this gives much more headroom and a greater surface area than a normal apex roof.
Try Kirton Buildings where I got mine from, they do have stockists around the country. Be warned though, these are serious well made sheds, not the thin B&Q type, and the prices reflect that.

 

Sorry, should read "it is an apex style roof"

"greater surface area than a normal apex or pent roof"
Apart from my mistakes they are a great roof and a great shed

 

I don't think the roof type matters, the amount of rainfall falling on it will be dependant on the floor-area, not the roof area. Pent-roof only needs one gutter. Might help if the pent slow is facing the prevailing wind, but I doubt it makes any difference (if the rain is coming in at 45 degrees the rain near the high-edge will miss the roof - but conversely the rain falling just-off the low-edge will hit it, surely?

You'll get far more water collection off your roof / garage though - can you water-butt them too?

My water butts for house / shed / greenhouse are pretty much level, and joined with a hose (as a syphon, but attaching to the taps would be fine), so they are all self levelling (I mostly use the water butt by the greenhouse, but the most rain falls on the house roof, and I rarely use that water butt).

I would also attach a cattle trough, or similar, so you can dunk a watering can rather than having to wait for it to fill from the poxy tap on the butt.

 

How does that work Kirsten? My A Pent shed is 10' x 8' and if it had a Pent roof would give me 80sq foot of roof. The roof on my A Pent is 10' x 5'6" on one side and 10' x 6'6" on the other giving a total area of 122sq foot of roof.

 

Can you not just connect them to your house? @"M"

 

clinedFor rain at 45 degrees



For vertical rain no difference. All you need to do is find out the mean angle of rainfall in your area, weight it for the amount of rain at each angle, re-weight for wind/rain directions, adjust the average rainfall for your area x the area on plan of your shed roof and you'll get the difference between the 2 roofs.

Or just buy a pent roof shed which are easier (in larger sizes) to assemble and re-roof, less inclined to suffer from roof sag, can provide above head storage space and give you more choice of water butt location.

 

Rain falls per sq.m. of ground area, not per sq.m. of roof area. At the extreme if you have a roof angle of 89 degrees - i.e. hugely tall and steep - that would not collect more rain than a flat roof (if rain falling vertically)

If I am answering the right question?

 

Kristen is correct.........................

As you can see from my rubbish drawing, the side facing away from the rain gets less water.

However, the mono roof design may collect more water depending upon it being inclined in a favourable direction ( the prevailing wind direction I would have thought).