Box Gutter for Parapet Wall

[zacnelson]

Hello, I am converting a couple of walls that have standard eaves into parapet walls. The walls are brick veneer. The roof is not a truss roof, it is a traditional pitched roof. I will have to cut back the rafters to the point where they sit on the top plate of the load bearing walls. Because of this, I will not be able to notch the rafters in order to sit a square box gutter below the roof sheets. However, I was hoping to be able to utilise a box gutter with a slant that follows the rafters, to enable a large enough gutter capacity without compromising the rafters at all. The attached picture should illustrate everything quite clearly. My questions are; 1) are box gutters made to suit this application? I have searched all over the web and can't find catalogues or anything with different box gutter profiles. 2) Is this a common solution for box gutters next to a parapet wall?

Thanks,

Zac

[TermiMonster]

Hi Zac,


1) are box gutters made to suit this application?

Box gutters are custom made in all cases. Usually, your plumber (or you) will measure up, get them made up and install. A plumbers hardware like Reece, Tradelink, Swan etc will be able to help you.

2) Is this a common solution for box gutters next to a parapet wall?

Usually they are cut in, because the quantity of water is reduced by the angle. You must take in to consideration the worst case scenario, it's bucketing down, will your box gutter be able to remove all the water, or will the water lap over the upper edge of your flashings, costing you a bucket load of money, and giving you a very wet *ss.
Box gutters should be avoided if possible. (unfortunately, not always possible.)

TM

[TermiMonster]

Also, don't forget to allow for drop, so one end has to be higher than the other. On a long run, this can add considerable headache to the design of the gutter. One of the reasons we pay plumbers so much?!!! (Also because they have to clean out our blocked sewers
TM

[Brickie]

I wouldnt use a box gutter in a mad fit, they are designed to leak over time, or overflow back into the house in a downpour.

[zacnelson]

Fortunately, the length of wall with the box gutter is quite short, and there will be a rainhead at each end, so I hope that over-filling will not be a problem. Also, being a concealed box gutter, I guess I can go ahead and make it as big as possible, it doesn't matter if it looks oversized. I may even re-batten the roof with higher battens to enable the box gutter to have more of a vertical upturn on the roof side.

[Tools]

I have a box gutter exactly as you are planning .My house was built in 1912.I have been here over 30 years,and I have never had a leak from it.

Tools

[sports fan]

I wouldnt use a box gutter in a mad fit, they are designed to leak over time, or overflow back into the house in a downpour.

that is exactly what theyre designed not to do

[Brickie]

that is exactly what theyre designed not to do

Of course they are..

[billbeee]

Hi Zac,
I wasn't going to reply to this cos it's mostly all been said, with the last wry comment from brickie saying it all. Still here's my 2 bob's worth.

We need to know the reason why. If it's not broke don't fix it.
What you already have is a perfectly good design and you are proposing to change it for the worse. So presumably you are not doing it just on a whim.

* Like brickie I hate the bastards, seen too many problems. Out of sight out of mind, clogging up with leaves, overflowing into the house. Rusting away quietly for years without any cleaning and then leaking with silicone on top of silicone until finally a major and costly repair.
* I have seen heaps, but never one to a single skin wall like you show.
* At least keep clear off the brickwork with your rafters.
* A normal detail would be to turn a flashing say 15mm into a brick course, or if you have drawn it to scale then your capping flashing should lap over you box gutter.
* Make the gutter a bit higher than you have drawn it. I like a min of 150.

Having said that I am in Darwin and we tend to get a drop of rain now and again, whereas you guys don't get the same amounts.
Cheers
Bill

[zacnelson]

Hi Bill, thanks so much for your helpful suggestions. Let me just say I have for a long time enjoyed your website, it's one of the best ones around, so keep up the good work!

1) I didn't show it in the diagram, but yes I do intend of course to turn the flashing into a brick course. I intend to lay the bricks over the flashing turn, rather than just cut it in later. In fact, just on Saturday I was fixing some flashing for my mother in law and it's shocking how loosely it can be installed in some instances!
2) Thanks for the advice about keeping the brickwork clear of the rafters, that was something I was still unsure about.
3) I will definitely make the gutter a min of 150, it will be as high as possible.