Leak that is driving me crazy

[Woodbear]

I purchased a 1964 designed house about six years ago. The architect when designing the roof in his wisdom put fall from both ends of the house into the centre of the dwelling. The runoff flows into a box gutter (6m x 200x 150) that runs smack bang through the centre of the house. The problem is that the bloody thing is always leaking as it deteriorates. Over the years I have had several occasions where water damage occurred

There are two issues. I will be putting another story on in three years so I don’t want to go to the expense of a new roof. Also due to certain issues it is extremely difficult to replace the box gutter. I have tried two different sealing compounds but after short time they crack and cause leaking.

<O</O
My question is there any suggestions on what I can do to seal this gutter before they have to put me away.

[Gumby]

I know how annoying leaks can be and that design is one I've seen a few times but is just asking fro trouble.

It's just a suggestion but would fibreglass work maybe ? The trouble could be getting it to stick which means removing all dirt etc.

[journeyman Mick]

You might get away with painting it with a waterproof membrane. It would need to be one that's okay outside (as opposed to one that's designed to go under tiles)

Mick

PS Bloody architects! (well silly ones that use box gutters where they don't really need to)

[Skew ChiDAMN!!]

'64... I imagine it's gal and not aluminium? Maybe good, old fashioned lead solder? Not recommended if it's running to a tank, though...

[joe greiner]

Oddball geometry suggests the gutter has insufficient slope. Street gutters are usually 1/2% minimum but still get birdbaths due to construction tolerances; 1% better, 2% better yet (minimum cross-slope on roads and bridges).

For only a few years protection, might be easiest to build up a mortar trough with proper slope, and slather with sealant as if it was free, at least at the boundary with existing roof surface.

Joe

[silentC]

That's called a butterfly roof. People are still building them despite all the problems they have with leaking gutters.

Maybe you could have a new box gutter folded up that is small enough to slip in over the old one without removing it?

[mat]

You could try getting a roll of malleable aluminium flashing that is wide enough to shape to the inside of the gutter and long enough to run the full length.

[Bob Willson]

You could try getting a roll of malleable aluminium flashing that is wide enough to shape to the inside of the gutter and long enough to run the full length.

That's a good idea.

[HappyHammer]

The cheapest solution if the holes are small and identifiable might be Selleys Marine sealer. I used this on my tinny when I drilled holes for the sounder below water level and it withstands salt water very well so should handle rain water. It's also flexible (rubbery) when dry so wouldn't crack.

HH.

[journeyman Mick]

Trust me, no sealant will last in this application for three years. You can make up new trays or overflashings if you want to go to the trouble, but a waterproof membrane will be the easiest option and probably the cheapest.

Mick

[bitingmidge]

Mick knows best!

If you could knock the ends out so there was no chance of overflow, that'd help too!

Cheers,

P

[savage]

Trust me, no sealant will last in this application for three years. You can make up new trays or overflashings if you want to go to the trouble, but a waterproof membrane will be the easiest option and probably the cheapest.

Mick

Hey Mick,
Do you think that product called "Pondtite" would work, it is the stuff for painting the inside of cement/concrete fish ponds. It's safe for fish so should be good for rain tanks, it seals porous materials so the water does not leak out nor the lime and other things leech into the pond water and it's meant for outside use, what do you think.

[Woodbear]

Thanks for all your great suggestions. Yes it is a gal guttering and yes the fall is incorrect and pools of water stay in the gutter. Tank water is only used on the garden. My concern is if I make it any smaller the volume of water cannot get away. Twice we had a rainstorm where the water could not get away quick enough and like most box gutters it flowed up and under the roof sheeting into the house flooding three rooms.
<O</O

I tried bit coat but that was no good. I then tried a product called Emer-clad but it seems to crack in places after a couple of months.
<O</O

I wonder if fibre glass would work. Also the malleable aluminium sounds like a good idea. Is that sold through plumbing supplies?

[journeyman Mick]

The pondtite might work, but being for underwater use may not be UV resistant. The stuff I'm thinking of is used to flash parapets and roofs and there's even trafficable grades for flat rooftops. Sorry but I don't know any names. If possible I'd enlarge the downpipes and outlets and fit overflows or knock the ends out like Midge suggests.

Mick

[mat]

Aluminium flashing is available at plumbing suppliers, roofing suppliers, builders suppliers and even Bunnings (small selection)

It sounds like you have two problems though. Not enough capacity to remove water quickly ? blockages further down ie down pipes or even pipes in the ground. Are the pipes earthenware in the ground? Unlike traditional gutters that overflow to the ground when the pipes don't cope your overflow will always go straight in the house. This sounds like you biggest problem. Agree with midge - look to create an overflow out the end or ends.

The second problem is the waterproofness of the gutter.