Hire the best Roofing Expert

Valley Gutters

Results 1 to 16 of 16
  1. #1
    Misfit
    Join Date
    Dec 2005
    Location
    Perth, W.A
    Posts
    276

    Default Valley Gutters

    Excuse me if this is a dumb question. When you put a valley gutter on a iron roof what's stopping the water building backing up under the roofing iron? Like if it rains heavily or you get some kind of debris build up to stop the flow..

    Are you just relying on water good flow so it doesnt happen or do you use some kind of membrane under the iron for the worse case senario...

    On a flat roof line that is not a pitch...

  2. #2
    Tool Whore - 1K Club Member Vernonv's Avatar
    Join Date
    Oct 2006
    Location
    Armidale NSW
    Age
    50
    Posts
    1,181

    Default

    Quote Originally Posted by chromis View Post
    Excuse me if this is a dumb question. When you put a valley gutter on a iron roof what's stopping the water building backing up under the roofing iron? Like if it rains heavily or you get some kind of debris build up to stop the flow..
    Nothing other than the valleys pitch and a fold along each long side.

    Are you just relying on water good flow so it doesnt happen or do you use some kind of membrane under the iron for the worse case senario...
    Yep, generally valleys keep pretty clear (more so than gutters). But I guess the sarking under the roof may act as a backup of some sort.

    On a flat roof line that is not a pitch...
    You don't normally have valleys on a flat roof.
    Cheers.

    Vernon.
    __________________________________________________
    Bite off more than you can chew and then chew like crazy.

  3. #3
    3K Club Member
    Join Date
    Oct 2005
    Location
    Adelaide
    Posts
    3,585

    Default

    Valley gutters are an abomination.

    They install long term water hazards in a house because they eventually rust out, and in the meantime there are multiple flooding opportunities due to outlet blockage with leaves and other debris.

    woodbe.

  4. #4
    Misfit
    Join Date
    Dec 2005
    Location
    Perth, W.A
    Posts
    276

    Default

    In a situation where you wanted to put a gable patio against flat roof, what would you do?

    Something like this.

    http://www.kerdels.com.au/Pics/Custom/CUS05-lge.jpg

  5. #5
    3K Club Member
    Join Date
    Oct 2005
    Location
    Adelaide
    Posts
    3,585

    Default

    Quote Originally Posted by chromis View Post
    In a situation where you wanted to put a gable patio against flat roof, what would you do?
    Easy.

    I wouldn't

    Still, it takes all types, if we all liked the same things it'd be a boring place.

    If you really want to do that, you need to protect the inside of the house from flash flooding. For me, that would mean running the flashing well up under the tiles. Galv is ok, copper is better. Others here might have other ideas of different types of flashing.

    Think about the worst storm you can remember, then cater for it happening just after a hailstorm. The gutter will be full and clogged with hail and the stormwater has to go somewhere, make sure it's into the patio or off to the side.

    woodbe.

  6. #6
    Tool Whore - 1K Club Member Vernonv's Avatar
    Join Date
    Oct 2006
    Location
    Armidale NSW
    Age
    50
    Posts
    1,181

    Default

    Quote Originally Posted by chromis View Post
    In a situation where you wanted to put a gable patio against flat roof, what would you do?

    Something like this.

    http://www.kerdels.com.au/Pics/Custom/CUS05-lge.jpg
    I think maybe my understanding of a flat roof is different to others Do you have a pic of your "flat" roof?

    Anyway I'll remain blissfully ignorant for the moment - I would not touch the flat roof and build the cabled roof just overhanging the flat roof and then fill in the back triangle of the cable (to provide weather protection from that angle).
    Cheers.

    Vernon.
    __________________________________________________
    Bite off more than you can chew and then chew like crazy.

  7. #7
    Old Chippy 6K
    Join Date
    Mar 2007
    Location
    Canberra
    Age
    70
    Posts
    6,575

    Default

    Quote Originally Posted by woodbe View Post
    Valley gutters are an abomination.

    They install long term water hazards in a house because they eventually rust out, and in the meantime there are multiple flooding opportunities due to outlet blockage with leaves and other debris.

    woodbe.
    Huh? Not sure what the alternative is - only roofs that have gables and not allow houses with angles sections that meet? In any case they are one of the least troublesome part of roofs IMO - unless poorly maintained (ie: debris is allowed to accumulate in gutters and/or or valleys and so on). I have seen an occasional rusty valley on coastal houses, but even on 90 yr old rusted gal roofs it is unusual to see the valley itself rust through. As valleys are raked well water flows down and off them quickly so it is rare to have valley overflow up and over the turned up edges - and the height of that turn up is generally increased in high rainfall areas.

    As with all water management systems they work only if they are open - so if an owner occupier does not clean out leaves and other debris from valleys, gutters and pipes then that can hardly be sheeted home to the valley design. Now if you want to talk about more common poor designs in water management start on box gutters especially blind box gutters - where even the simplest of calculations would tell the designer that the gutter or usually its outlet(s) will be unable to handle water flow from those sections of roof it is supposed to funnel water.

  8. #8
    3K Club Member
    Join Date
    Oct 2005
    Location
    Adelaide
    Posts
    3,585

    Default

    Quote Originally Posted by oldbloss View Post
    As with all water management systems they work only if they are open - so if an owner occupier does not clean out leaves and other debris from valleys, gutters and pipes then that can hardly be sheeted home to the valley design.
    There by the donkey hangs it's tail.

    It's not that they can't be designed and built to withstand blockage without flooding the house, the problem is that they generally aren't. And yes, box gutters are usually even worse. The hailstorm example is a classic condition that often shows design shortcomings based on minimum cost building practices.

    woodbe.

  9. #9
    Old Chippy 6K
    Join Date
    Mar 2007
    Location
    Canberra
    Age
    70
    Posts
    6,575

    Default

    Quote Originally Posted by woodbe View Post
    There by the donkey hangs it's tail.

    It's not that they can't be designed and built to withstand blockage without flooding the house, the problem is that they generally aren't. And yes, box gutters are usually even worse. The hailstorm example is a classic condition that often shows design shortcomings based on minimum cost building practices.

    woodbe.
    Seems we are vociferous agreement!

    But I guess my emphasis was on getting owners/ renters to take responsibility for the basics - as failures occur mostly not just in a 25, 50 or 100 year event, but in the regular storms that happen several times a year, because the simple jobs have not been done. Few of us would happily pay for design that would manage the extreme, but too many are quick to blame design or build when basic maintenance is the issue. Which is not to say there aren't some way below standard designs & builds out there!

  10. #10
    Misfit
    Join Date
    Dec 2005
    Location
    Perth, W.A
    Posts
    276

    Default

    Quote Originally Posted by Vernonv View Post
    I think maybe my understanding of a flat roof is different to others Do you have a pic of your "flat" roof?

    Anyway I'll remain blissfully ignorant for the moment - I would not touch the flat roof and build the cabled roof just overhanging the flat roof and then fill in the back triangle of the cable (to provide weather protection from that angle).
    Ok so maybe it isnt totally flat but there's not much of a pitch on it. The roof/extension was put on after the house was built. However it's pretty flat.

    Anyway! There's steel stirrups you can get that can be inserted into the roof and fit onto the rafters, then you bolt your beams on those. Would that be a better way to do it? Is that what you mean when you talk about overhanging the gable?

  11. #11
    Tool Whore - 1K Club Member Vernonv's Avatar
    Join Date
    Oct 2006
    Location
    Armidale NSW
    Age
    50
    Posts
    1,181

    Default

    Yep, that's pretty much the idea.
    If you can leave the old roof in place and maintain it's integrity, then there will be no need for valleys.
    Cheers.

    Vernon.
    __________________________________________________
    Bite off more than you can chew and then chew like crazy.

  12. #12
    Old Chippy 6K
    Join Date
    Mar 2007
    Location
    Canberra
    Age
    70
    Posts
    6,575

    Default


  13. #13
    Senior Member
    Join Date
    May 2007
    Location
    Darwin NT
    Posts
    116

    Default

    Valley gutters rarely give problems in roofs with pitches over say 15 deg. Provided they are maintained as already mentioned. They are a fact of life. Nobody would design a house plan based on the fact that the roof has to be without valleys.

    I have noticed a good trend recently, that is better and possibly cheaper than the old method of fixing 25mm timber boards to support the zincalume gutter. This gives a drop of say 20 from the say 45mm roof batten. (iron roofs).
    The newer alternative is to make the valley out of say 2.mm thick material that is stiff enough to support it’self without the timber board under. This way you get say a 40 difference between roof sheet and valley. The main thing though is that the thicker material only comes in galvanised, not Zincalume, so it should have a lot longer lifespan.

    On the other hand box gutters are indeed an abomination as Woodbe points out.

    We have been known to get fairly heavy rain here in Darwin, but luckily never with hailstones.
    Cheers
    Bill.

  14. #14
    Misfit
    Join Date
    Dec 2005
    Location
    Perth, W.A
    Posts
    276

    Default

    Thanks I appreciate your advice.

  15. #15
    Apprentice (new member)
    Join Date
    Jun 2011
    Location
    Perth
    Posts
    2

    Default

    In relation to gutters where two roofs join - A few years ago we bought our house and with it a nice looking gabled patio attached to the side of the house. Now of course, whoever installed it didn't install a gutter to the patio so all that water flows into the houses gutter. When it rains, and when it does acutally rain in Perth it rains hard, the gutter naturally can't handle it. Fortunately the gutters do have an overflow mechanism but I'm sure even that's not entirely effective.

    I can't believe the previous owners put up with it because the whole back paving floods - it's like my own little wading pool which I'll give credit does dry up pretty quickly once the rain stops. We've installed an extra downpipe, a rain chain in an area of guttering where water always seemed to pool (and where we weren't able to put a downpipe), I've drilled holes in the soakwell pipes to make sure the water goes out there if the soakwells/downpipes fill up and I'm going to get another downpipe installed.

    Other than installing this extra downpipe to get the water to flow out quicker (which hopefully will be the final piece of the puzzle), is there any other solution? The patio butts up against the houses gutter so it doesn't seem like it would be easy to put in bigger gutters.

    Thanks.

  16. #16
    Banned
    Join Date
    Jan 2010
    Location
    Melbourne
    Posts
    459

    Default

    Quote Originally Posted by wimpy View Post

    I'm going to get another downpipe installed.

    Other than installing this extra downpipe to get the water to flow out quicker (which hopefully will be the final piece of the puzzle), is there any other solution? The patio butts up against the houses gutter so it doesn't seem like it would be easy to put in bigger gutters.

    Thanks.
    I have a (very) soon to be released product that is three quarters the size of a D battery, weighs 11 grams and is easily and quickly fitted DIY at a fraction of the cost of fitting an additional downpipe. Once released, it will be announced on this forum. Its development was inspired by the numerous threads in this forum about overflowing gutters.

    Packaging & distribution is not yet finalised.


Similar Threads

  1. Zincalume roof, battens and valley
    By leeton in forum Structural Renovation
    Replies: 7
    Last Post: 5th May 2008, 10:09 PM
  2. Hip in a Valley
    By rod1949 in forum Roofing
    Replies: 5
    Last Post: 25th Oct 2007, 10:54 AM
  3. Roof sheets secured in the valley
    By spartan in forum Roofing
    Replies: 19
    Last Post: 18th Feb 2007, 12:23 AM
  4. Replies: 2
    Last Post: 15th Jul 2005, 12:03 PM
  5. Valley Gutters
    By micko in forum Plumbing
    Replies: 6
    Last Post: 5th Dec 2003, 05:22 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •