Gutter drop

[Peter Percival]

By how much per metre length should a gutter drop?

[Tim Watts]

On Thursday 22 August 2013 14:14 Peter Percival wrote in uk.d-i-y:

1:600 or better - usually.

You *can* lay level, but that typically halves the max flow.

So 1cm in 6m.

I researched this when installing mine.

[Baz]

As Tim said, it can be Level. By doing calculations and depending on the application.

You use bigger or smaller or flatter or sloppier.

Baz

[Tim Watts]

On Thursday 22 August 2013 15:24 Baz wrote in uk.d-i-y:

Some good info there. I used a mix of resources for mine - it is frightening how much worst case peak flow you have to cope with in the SE of England!

I needed to re-engineer mine to have 2 downpipes round the back instead of the 4 even spaced it had before. So I switched to deep flow ogee style and with a >1:600 fall it was within spec.

Tip for getting the slopes:

First mark a level datum line around the house. Use a laser level (if bright enough/dusk/convenient) or a classic tube filled with water to get datum points at the corners.

Mark these.

Then after calculating the falls, noting an constaints ("too high"/"too low"

- eg hip tiles, windows that open close to the gutterboard etc), mark the desired gutter heights at the corners relative to the level datum.

Then find out what you are going to line the gutter fixings to. Mine (Brett Martin) had a moulding on the couplers (these need screws) that lined up with another moulding on the clips. Essentially, those act as tell tales so you need to correct the gutter alighnment datums to suit those telltales (eg find the offset and mark again for those).

Then it's screw in the mark at each end and classic chalk-line time.

Afte rthat it's easy going, unless you are hanging cast iron up a 2+ storey building, in which case you have my sympathy!

[newshound]

Also, don't be tempted to economise on bracket spacing. If the fittings for one "give" for any reason you end up with a sag which then collects moss, grit, or whatever and soon you have a permanent puddle there. And personally I would avoid "level".