Fascias-style guttering leak internally

Fascia-style gutters causing water to run into the building

Guttering can be a hidden leaky building danger in many ‘low-risk’ homes

Fascia-style (hidden) guttering systems pose risks of causing leaks to come into building walls and cause rot and leaky building syndrome. Because of their design and construction, small defects of installation or blocked drainpipes can cause overflows into the building. For example the back edge of the internally-mounted plastic guttering system may be cut too low and this becomes the first overflow point. Similarly over time the plastic can warp, causing low points along the wall. Excess rainwater from a blockage during heavy rain will overflow at low-points first. Then it will track where the surrounding materials guide it. If the surrouning soffit has even a slight tilt towards the house, this directs substaitial amounts of roof water run-off into the walls and ceilings, causing leaks and encouraging rot. Unless the owner is aware of this happening, it could continue for years unnoticed.


An example where the fascia-style guttering has overflowed or leaked causing moisture to build up on the soffit liner. It is unclear whether water has entered the building walls. Mould can be seen growing on the soffit liner at the multiple locations where the gutters leak

Compare this design approach to traditional externally-mounted guttering systems. These are usually designed as ‘fail-safe’ in that if there is a blockage somewhere, water will overflow away from the building. This does no harm to the building, and will alert the owner to a problem.


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9 Responses to Fascias-style guttering leak internally

  1. Mark Thomson says:

    Great to see some facts about this flawed design that contributes so much to leaky buildings. It is a much bigger problem than the now banned pink Hardietex sacrificed as a scapegoat in the obfuscation & political arse-covering of the leaky building debacle. It is compounded by idiot builders who do not run the cladding up behind the soffit to provide a waterproof barrier to water overflows – a traditional requirement of this eave design that has been lost.

    I am just about to rip out the gutter/fascia from our fletchers built 90s house & put up proper gutter fascia. I will also Waterproof the back wall in-soffit and vent the soffit or maybe run it under the rafters at an angle & run another line of cladding up to cover the newly exposed wall. Thankfully our framing is all H3 and Boric & because I clear gutters every two weeks, leaks have been only in once every 30 year or more rainfall.

    Either way the message is clear – DO NOT buy a house with concealed fascia guttering. It is a serious flaw in waiting – not if but when.

  2. Eileen Smith says:

    Hi, I live in Auckland and have just had a building inspection on a small 2 bed unit, built around 1980, in Tauranga. The report stated
     Type: Internal concealed guttering.
     Condition: Defective Repairs & Maintenance Required
     Noted: There is heavy internal rusting.
     Recommendation: Replace as required
    I need to have a general idea as to what this might cost before I go unconditional. Not looking for quotes just ball park figure, so that I can decide whether to go back to vendors or not

  3. Phil A says:

    Power to the people. Nice to hear you guys sharing ideas to combat the ‘industry’ created by the leaky building disaster.

  4. Brendon says:

    I have the same problem, in a storm I had water pouring into the house above the windows in many places. I did have a little bit of debri in the gutter, so I installed gutter guard (mesh to stop leaves entering guttering). We had another storm a couple of weeks ago, gutters all clear and it happened again. Something not mentioned in the blogs above and something I am considering is to put many overflow drop down pipes straight down. They will allow water to drop down if a certain height is reached, under normal conditions water will still drain to downpipes. It may not look the best but it could be the cheapest option.

  5. Ant says:

    I’m surprised there are not more postings about this flawed design which appears to have been incorporated into NZ houses since the mid 80’s, all in a bid to hide gutters. The design fails at conception with the secondary stormwater flow path into the soffit cavity and commonly into the external walls.
    This is especially the case with aging (26 year old!) structures with soffit linings that may have slightly sagged. This then renders the designed secondary flow path to the soffit scuppers useless, with water heading towards the interior or even finding external soffit light fittings and filling them with water!
    We are spending a lot of money to extend the rafters, construct new fascias and fit conventional guttering to exterminate the hidden gutter system from our home, simply because they leak during storms, are difficult to monitor for debris build up and are difficult to clean.

    • Arne says:

      Like to hear the details of how this is being done, Ant…we are being forces into the same fix, with the problem compounded by the half-dozen pairs of starlings who annually squeeze into our gutters and build nests faster than I can tear them out!

      • sugadmin says:

        Yes these systems are defective in design and plagued by poor workmanship. Never trust them. All building products must be designed with an allowance for failure – so if they do fail, they don’t adversely affect other parts of the house in parts not easily discoverable like framing hidden inside walls.

        These fascia gutter systems are worst at valleys where the back of the gutter is lowered and when there is no soffit at all. Many are siphon systems so flow rates are slower and some don’t have enough outlets so overflow regularly even if built to specifications. My advice is to remove them. I know its expensive but repairing them is just a temporary delay to more leaks and they will be rusting away anyway, especially by the sea.

        Drill the rivets, pop off the outer shell, snip the brackets and release the gutter out. Bend what’s left of the brackets back and nog out the soffit to fix it and attach a new wooden fascia. You’ll need a slightly larger one (about 180mm) and only use H3.2. Check the roof overlap is around 70mm – if a bit less it will still work. Paint and fit new gutter on outside – when installing down pipes make sure you provide a relief – so if the main drains block it doesn’t back up and slow down the flow rates. If the fascias wrap around up the gable ends strip these off as well and continue the wooden fascia and install a flashing or cap tile.

        Or contact me and I’ll give you the name of a good plumber.

        • Monte says:

          Hi there I do have the same problem and very interested in your idea of total replacement with a external gutter system.Do you have any recommendation contact details for someone to talk to please. Regards Monte.

  6. I was very pleased to find this site. I definitely enjoyed reading every little bit of it.It feels so nice to find somebody with some original thoughts on this subject. Really thankful to you for starting this. Thanks for sharing.

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