Roof leak - question about the black paper

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Batman

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#119484 3-Jun-2013 00:31

My roof (70s with iron roof) has sprung a small leak.

It is raining moderately (not drizzle, not storm) and it is dripping slowly about once every few seconds (maybe around 10 seconds or more).

There is a bit of black paper not sitting flush against the higher one, but reflected down where the water is dripping.

Here is the dumb question - is the black paper thing supposed to let the water run off? I'm guessing there should be zero leak regardless of whether the black paper runs it off or not. Glad to have found it anyhow. There is a bucket to catch it while the roofer has a look

*sigh

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#829889 3-Jun-2013 02:19

Yes, the black bituminous paper is supposed to catch water that gets through the roof sheets and drain it into the gutter at the sheet bottom. The building paper should be just visible from the gutter edge, but not actually sitting in the gutter (otherwise it will drag water back in via capillary uplift).

The catching leaks and draining them to the gutter theory does not often work in practice. Too many nogs, netting, nails etc in the way there is never a straight path.

Also - it really only works if the building paper is laid horizontally starting from the gutter. That way the higher paper laps over the one below and the water can't drain under. In practice most roofers prefer to lay building paper vertically, because they can just walk to the peak, drop the roll and it lays itself. The problem is that if water goes sideways as well as down, it will go under the next sheet at some point and you get a leak.

Good luck finding it. Often it is old roof fixings (nails/screws) that have walked loose with time.

mattwnz

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#831887 6-Jun-2013 22:13

The other thing to note is that many corrugated roofs do leak, but it is that building paper that stops the water coming through. So if there is a problem with the building paper, it is a good idea to get it fixed, which isn't easy when the roof is on. Removing the corrugated steel, and re laying the building paper in that area can sometimes be the best solution.

Ramjet007

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#831939 7-Jun-2013 05:59

My roof was in the 70's era and wanted to get it checked. Got the Kowhai people and they “coated” it.

The next big rain I had water pouring in. They came back 5 times and finally stopped it (my guess is they just siliconed it)

Decided to get the roof replaced. Much happier now.

Batman

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#831946 7-Jun-2013 07:18

How many sqm and how much was new roof

timmmay

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#831957 7-Jun-2013 07:48

My house is about 140 square meters, the roof quote from memory was around $14K.

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#831961 7-Jun-2013 08:05

Had the same problem, but our roof was original from 50s or 60s.. More silicone and tar tape than roof. Haven't had any leaks since.

We had our 90sqm home reroofed last year in long run colour steel (corrugated). It cost is just over $7k.

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gamet

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#833465 10-Jun-2013 11:42

Hi I had a similar problem trying to find a leak. Finally decided to set up a bright light in the roof space and got up on the roof at night to find out where the light was leaking. The light came out in the approximate area of the leak. I sealed it up with silicon and have had no further problems.

Best of Luck

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Batman

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#833466 10-Jun-2013 11:44

What a darn good idea!

ubergeeknz

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#833470 10-Jun-2013 11:48

gamet: Hi I had a similar problem trying to find a leak. Finally decided to set up a bright light in the roof space and got up on the roof at night to find out where the light was leaking. The light came out in the approximate area of the leak. I sealed it up with silicon and have had no further problems.

Best of Luck

That is damn smart.

Although with tin roofs there's a lot to be said for just getting up there and having a look, and tapping down any loose nails

pctek

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#840067 20-Jun-2013 09:18

You want to get up there and check all the nails, probably rusted. Also the holes where the nails go through.
Fix that first then worry about the paper.

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#840120 20-Jun-2013 10:28

I was going to update but with all this rain haven't been up there didn't want to risk a fall. My roof is quite complex looking it is iron that has a tile look ie many pieces to over lap each other and covered with what looks like artificial grass

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#840150 20-Jun-2013 11:11

joker97: iron that has a tile look ie many pieces to over lap each other and covered with what looks like artificial grass

Decramastic tiles or similar. The chip coating can get lichen growing on it that encourages rust. You've probably got a hole rather than a nail problem.

Handle9

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#840160 20-Jun-2013 11:20

Bung:
joker97: iron that has a tile look ie many pieces to over lap each other and covered with what looks like artificial grass

Decramastic tiles or similar. The chip coating can get lichen growing on it that encourages rust. You've probably got a hole rather than a nail problem.

Yep, sounds like that exact problem.

The good news is that it is probably heaps easier to fix than a corrugated iron roof. You can still buy most tile profiles and if it's just one tile then it's under $100 for the part. If it's old, have a look on the gerard roofing site, it's probably one of theirs.

http://www.gerardroofs.co.nz/products/tiles-and-shingles/

The bad news is if it's really bad you may need to get the tiles re coated, which obviously will cost you some cash. You should get the tiles cleaned, either professionally or do it your self. Whatever you do don't water blast the roof, you will peel the chip off the tiles. If you do it yourself use wet and forget or 30 seconds and leave it for a couple of months. You will be amazed at the difference.

We got our roof cleaned professionally because i don't like heights, it cost us about $300 for 160m2

In the short term you'll still need to locate the leak, but get the maintainence done asap.

ubergeeknz

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#840290 20-Jun-2013 14:18

Bung:
joker97: iron that has a tile look ie many pieces to over lap each other and covered with what looks like artificial grass

Decramastic tiles or similar. The chip coating can get lichen growing on it that encourages rust. You've probably got a hole rather than a nail problem.

Yep just patched up one of these on my Mum's roof, although in her case it'd been nailed down wrong at some time it seems, and they'd patched up the hole, the coating had cracked and viola, water ingress. Bunged some all clear into it until she gets the roof re-done. Seems like unless you have a heck of a pitch, these tiles just collect water and it'll find a way in sooner or later...

Batman

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#840291 20-Jun-2013 14:20

Who do i ask to clean the roof our what to search in yellow pages cheers

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