The Problem with Undersized Box Gutters

Gutter replaced, overflow inserted to reduce likelihood of damage, but look at the quality of the workmanship with the overuse of silicone.

The hail storms in Melbourne and Whyalla have once again highlighted the problems of  box gutters, particularly where they are undersized or do not have an overflow mechanism.

With seemingly more intense storms and where hail is involved, many gutters are simply unable to cope and overflowing occurs.

With a gutter out over an eave, if the gutter overflows it tends to pour out harmlessly over the ground. Where there is a box gutter involved, any water that overflows finds it way inside the building.

Compounding this is that in far too many cases the gutters are undersized, or, equally as bad, there are insufficient and or undersized downpipes.

Where possible, the inclusion of overflows do stop internal damage. Another risk management measure to reduce the likelihood of damage is the regular cleaning and inspection of gutters and downpipes to remove leaves and other rubbish and detect lifting roof nails or screws and/or early signs of rust or the deterioration of any sealers.

I also question the craftsmanship of many of the roofers and plumbers. Silicon seems to be the cure all rather than doing the job properly. I think they should rename “No More Gaps”, “No More Skills”!  The other issue is that many gutters do not have sufficient fall or, worse, still fall the wrong way.

The issue of unwanted water entry from above (leaking roofs, overflowing gutters and downpipes) and below (flood or overflowing storm drains) needs to be considered from the design phase. Where possible, the gutters should be located so as to avoid damage and designed with plenty of spare capacity. It, of course, does not stop there but continues with the employment of quality trades personnel during the building phase and then regular cleaning and maintenance.

Councils also have to play their part. For more than one claim I attended to in Melbourne following the Christmas Day hail storms, the gutters became completely full of leaf litter as the hail, wind and rain stripped the leaves of huge overhanging trees. In each case, the Insured had asked permission to remove, or at least trim, the trees but had been refused for enviromental reasons. I strongly believe the energy wasted in replacing carpets, ceilings, furniture, computers, stock etc, more than outweighs the benefit of the trees.

2 responses to “The Problem with Undersized Box Gutters”

  1. Peter Gerrard says:

    We have had water ingress issues twice now because of having had a parapet roof section and box gutter installed as part of a renovation. The pitfalls of hidden box guttering were never explained to us at the time and we are still dealing with the consequences 12 years later. The solutions appear to be along the lines of installing deeper box gutters; adding more downpipes and rainheads etc….All of which might help, but won”t necessarily solve the problem if (or rather when, as they are getting more frequent) we get another deluge. Surely these types of designs should be outlawed unless they have significant overflow solutions built in, because as your article notes…the only place the build up of water can go is inside your roof space and eventually onto your floor as it has done for us!

  2. Allan says:

    Sorry to hear about your water inundations. It is more than a real pain.

    In principle, I agree that they should be banned particularly with what appears to be more intense storms coupled on occasion with hail, box gutters, butterfly style roofs etc do cause a problem. The cost of retro-fitting a box gutter is very expensive.

    Trouble is with buildings take up the full footprint of the land sometimes box gutters provide the most floor space. In these cases they need to be over-engineered and regularly cleaned and maintained to reduce the likelihood of overflowing.

    Thanks for your reply.


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