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Gutter profile? HK gutter vs Quad Gutter and slotted vs non slotted?

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  1. #1
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    Default Gutter profile? HK gutter vs Quad Gutter and slotted vs non slotted?

    Hi

    I am trying to choose a gutter profile as part of a overall roofing job.

    My two options or choices come down to the below. I slightly prefer the quad style cosmetically but what is superior for overflow? it seems also to be the quad based on the cross sectional and carrying capacity below.

    I note that the non slotted carrying capacities are substantially larger than the slotted counterparts too which leads me to think that a properly designed gutter system with enough downpipes shouldnt need the slotted option?

    I am worried about reports that a roofer confirmed that staining can occur around the slots as water weeps out. Given the much smaller slotted capacity it would appear those slots would always have water draining out of them?

    Further whilst my DPs carry water to soakwells or the street away from the house, slots would cause water to weep down the gutter onto the fascia and then my rendered walls or the footings directly below the house would they not?

    Stratco HK Gutter - square gutter, Smoothline round and half round gutters, OG gutter, Quad gutters, eaves gutter, diy gutter

    with

    <TABLE style="bordercolor: black" border=0 cellSpacing=0 cellPadding=4 width="95%" align=center><TBODY><TR align=middle><TD class=InfoTable_top_left_curve width="15%">
    Tensile (MPa)
    </TD><TD class=InfoTable_top_right width="15%">BMT (mm)</TD><TD class=InfoTable_top_right width="10%">Type</TD><TD class=InfoTable_top_right width="20%">Capacity (mm˛)</TD><TD class=InfoTable_top_right width="40%">Total Cross Sect. Area (mm˛)</TD></TR><TR align=middle><TD class=InfoTable_content_left height=35 rowSpan=2>G550 <TD class=InfoTable_content_middle rowSpan=2>0.35</TD><TD class=InfoTable_content_middle>Standard</TD><TD class=InfoTable_content_right>5394</TD><TD class=InfoTable_content_right>6590</TD></TR><TR align=middle><TD class=InfoTable_content_middle>Slotted</TD><TD class=InfoTable_content_right>3717</TD><TD class=InfoTable_bottom_right_curve>4816</TD></TR></TBODY></TABLE>


    or

    Stratco Quad Gutter - square gutter, Smoothline round, half round gutters, OG gutter, Quad gutters, eaves gutter, gutter kits

    <TABLE style="bordercolor: black" border=0 cellSpacing=0 cellPadding=4 width="95%" align=center><TBODY><TR align=middle><TD class=InfoTable_top_left_curve width="14%">
    Size (mm)
    </TD><TD class=InfoTable_top_right width="14%">Available in </TD><TD class=InfoTable_top_right width="14%">Tensile (MPa)</TD><TD class=InfoTable_top_right width="12%">BMT (mm)</TD><TD class=InfoTable_top_right width="12%">Type</TD><TD class=InfoTable_top_right width="18%">Capacity (mm˛)</TD><TD class=InfoTable_top_right width="30%">Total Cross Sect. Area (mm˛)</TD></TR><TR align=middle><TD class=InfoTable_content_left height=35 rowSpan=2>115 <TD class=InfoTable_content_middle rowSpan=2>NSW, VIC, SA, WA, AS, NZ</TD><TD class=InfoTable_content_middle rowSpan=2>G550</TD><TD class=InfoTable_content_middle rowSpan=2>0.42</TD><TD class=InfoTable_content_right>Standard</TD><TD class=InfoTable_content_right>5621</TD><TD class=InfoTable_content_right>6760</TD></TR><TR align=middle><TD class=InfoTable_content_right>Slotted</TD><TD class=InfoTable_content_right>5057</TD><TD class=InfoTable_content_right>6192</TD></TR></TBODY></TABLE>

    the

  2. #2
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    Default

    Quote Originally Posted by DaleBlack View Post
    Hi

    I am worried about reports that a roofer confirmed that staining can occur around the slots as water weeps out. Given the much smaller slotted capacity it would appear those slots would always have water draining out of them?

    Further whilst my DPs carry water to soakwells or the street away from the house, slots would cause water to weep down the gutter onto the fascia and then my rendered walls or the footings directly below the house would they not?

    the

    There is a new BCA requirement towards gutters now regarding over flow as with recent downpours we have been seeing alot of water damage inside houses due to the ineffective of slotted and non slotted guttering actually is see link for more info

    Cheers
    TS
    Gutter Grip | Gutter Overflow Solution
    Cukuna Sales - Big River Group - For all your Timber and Formwork needs.

  3. #3
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    Quote Originally Posted by TimberSniper View Post
    There is a new BCA requirement towards gutters now regarding over flow as with recent downpours we have been seeing alot of water damage inside houses due to the ineffective of slotted and non slotted guttering actually is see link for more info
    Gutter Grip | Gutter Overflow Solution
    Your quote: "we have been seeing alot of water damage inside houses due to the ineffective of slotted and non slotted guttering" indicates that you work in the industry. Is this so and where did you get your information from regarding "There is a new BCA requirement towards gutters now regarding over flow"?

    Guttering is required to provide a continuous overflow provision as stated in AS/NZS 3500.3 (2003) "Eaves gutter systems, including downpipes, shall be designed and installed in accordance with clause 3.2 so that water will not flow back into the building".

    Problems with roof water drainage regulations exist because the regulatory bodies allow manufacturers recommendations to overrule sections of the (varying) codes. This was the reason for the high fronted gutter fiasco a few years ago that saw manufacturers supply fixing clips and fitting instructions that did not allow for a continuous overflow provision as required by the code. This allowed water to flow back into the building during storm events. Because the manufacturers recommendations were (wrongly) accepted as been permitted to override regulations; architects, builders, plumbers, inspectors and the regulatory bodies all followed suit and allowed the non compliant fitting of guttering that had no continuous overflow provision. If you have "been seeing alot of water damage inside houses due to the ineffective of slotted and non slotted guttering", then what you have been seeing is actually the effect of the non compliant fitting of those gutters.

    DaleBlack has queried slotted guttering and astutely posted:
    I note that the non slotted carrying capacities are substantially larger than the slotted counterparts too which leads me to think that a properly designed gutter system with enough downpipes shouldnt need the slotted option?
    This leads me to the link you posted and a statement at Q8 on the FACT SHEET (NOTE not the FAQ page) which (approximately) stated: Due to slotted gutters having less capacity than unslotted gutters, more downpipes are required for compliance. Note that I have changed the wording slightly for copyright reasons.

    I recently had discussions with major industry bodies regarding this very issue and the sometimes non commital and often conflicting but majority information I was given was that there is no such regulatory provision to differentiate slotted from non slotted guttering as they follow the various manufacturers recommendations. I think this is clearly wrong as slotted guttering has a reduced mitigation capacity. Also, as slotted gutters provide a non continuous overflow, they are not recognised in the Australian Standard which only recognises provisions for continuous overflow. The BCA 2007 also advises: "In heavy downpours, a slotted gutter may be inadequate". As an aside, I think that the phrases: "non continuous & continuous overflow provision" is misleading and needs substituting with wording that is more appropiate.

    While I strongly believe that slotted gutters SHOULD NOT be regulated the same as non slotted guttering, my information is contrary to the information you have provided as per the link you posted but I will happily accept different if you can prove different by providing details as to where in the regulations it states that slotted guttering needs more downpipes for compliance. If the regulations are as I believe them to be, then the site should change the wording to more accurately address what is a very important issue. Aside from the link's advice that I have questioned and to which I await your referenced clarification, the site's information is very good.

    The O.P. has previously opened another thread: http://www.renovateforum.com/f76/gut...-window-98773/ to which I posted but then deleted information about slotted guttering but then posted the comment: "EDITED reference to slotted gutter compliance, too much conflicting advice from different regulatory bodies and manufacturers".

  4. #4
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    DaleBlack,

    Gutter choice, as you have stated, is influenced by aesthetics but have you considered half round gutters? These drain and self clean much more efficiently than other gutter profiles.

    If you have a well designed system, you should not have any overflows. Eaves gutters are regulated to provide adequate drainage for a 1:20 ARI. This does not mean that you have to accept this limitation, designing for a 1:50 or even a 1:100 ARI may be as simple as having only 1 additional downpipe. The 1:20 ARI calculations are (supposedly) based on worst case design scenarios and so a well designed system will have a 'drainage reserve' in any case.

    The critical factor is having the most appropiate position and distance (maximum 12 metres) between the downpipes and having the more critical downpipes a little closer will also allow for a greater but not visually obvious fall. It must also be understood that many houses still have overflowing gutters during a 1:20 event even though their installations comply with the standards and this is because of the poor positioning of downpipes which is not addressed in the standards. Poor positioning is mainly due to draftsmen and builders opting for aesthetics over function. The most common examples are house frontages where downpipes are often positioned at the far corners. Compliant? Often YES. Efficient? NO!

    In the case of your house as per the diagram you posted on another thread, you also have issues with overflows on the frontage that is most probably the result of poor downpipe positioning as the distance between two of the downpipes appears to be non compliant and the diagram shows that there are 4 corner sections between the two downpipes that appear to be fed from the larger area of roofing. Photo 4 also shows a valley and a large roof area and a notation that maybe there should be another downpipe at this location. The BCA would require this and I agree that another downpipe is needed as the roof will be delivering a concentrated amount of water to this area.

    You also need to establish the current high points along all of the guttering and determine how the flow patterns relate to the roof areas drained and the current downpipe locations. If you get contractors in, then London to a brick they will replace the guttering with the same fall and retain the same downpipe positions unless you advise them differently.

    You need to:
    Determine if the guttering at the roof valleys are high points and also measure the distance between downpipes. Always have a high point at the valley.

    Look at the frontage and determine where the largest roof area draining to each sq m of guttering is. You may need to relocate the high and low points and the downpipes in this area.

    The size of the gutter pop/drop is what determines the drainage rate. If you decide to change over to 90 mm round downpipes, have a look at the new Rainharvesting 90 mm pop. It has an enlarged and tapered orifice that is very efficient. Don't pay attention to the various manufacturers claims about the flow rates of their 90 mm round downpipes. The claims vary from 4.2 lpm, 4.5 lpm and 5.0 lpm but the reality is that the pop and proper downpipe positioning is what determines flow rates and manufacturers should not override or misrepresent compliance by advertising optimum flow rates under optimum conditions at any rate.

    For efficiency, do not position a downpipe too close to a corner, particularly if you have rectangular downpipes.

    If the guttering is fitted compliant with the regulations re continuous overflow provisions, you will not need slotted guttering that WILL overflow more often than needed due to the smaller mitigation capacity (which is not addressed in the standards).

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