Saturday, 28 July 2007

[Jargon.002] Sarking and Anti Ponding Board

Our builder told us that, because we are using "Terracotta" roof tile, we need to install "Sarking" and "Anti Ponding Board". This post is to talk about what I found about these 2 Jargons...

What is Sarking?
I found this definition of "Sarking" from the internet: "Sarking is a reflective foil laminate that is installed inside roofs. It has many benefits including weather proofing, insulation and reduction of dust and sound". The image below shows what it looks like:

The drawing below is from this page on, it clearly shows how the sarking are installed under the roof tiles. "RFL" stands for "reflective foil laminate".

The next image shows how sarking been installed: start from the bottom, with some overlapping when installing the second one. This is to ensure that if there's any water, it flows down to the gutter.

What is Anti Ponding Board?
So "sarking" is not that hard to understand, it took me a while to work out what is "Anti Ponding Board" used for.

The most simple and easy to understand explanation I found is from "The boards are installed to support sarking and ensure that any water collected by the sarking is correctly discharged into the eaves gutters."

The drawing below is also from the same page mentioned above from

The drawing below is from this page on

So this "Anti-Ponding Board" thing is installed at the edge of the roof, and under the sarking to allow waters collected by the sarking to discharge into the gutter.

I remembered one of the Clarendon sales strongly recommend not to install sarking. Her reason is, if there's a crack somewhere in the tiles, it will be very difficult to work out which is the cracked tile. Because the water will run all the way to the gutter because of the sarking... Hang on, what are you talking about? That's one of the main reasons for installing sarking: to prevent leaking water from damaging my roof/ceiling! I would certainly prefer to have this extra protection than water damaged roof/ceiling!


Michael said...

Great definition, I work in the construction industry and got it explained by sub-contractors. Your definition was waaay better, thanks.

Anonymous said...

Now I understand why the salesperson doesn’t recommend to have sarking installed, because there is no way to check broken roof tiles for upstairs, unless you have a very long ladder.
I have a broken roof tile on the lower level, and I can’t detect it even with a ladder from below, I can only see from upper level window.
Without sarking, you can detect broken roof tiles in the roof cavity very easily.
Now I am worried about the roof tiles for the upper level, so far, I haven’t seen the leaks yet, fingers crossed.

Allan said...

What you said is sort of correct.
We were told if you have the terracotta roof tiles you need sarking as those terracotta roof tiles won't 100% join perfectly and might have chance of some minor leaking in the joint area under heavy rain. With the extra sarking layer under the roof tiles, it will allow water to flow all the way down to the gutter instead of damaging your ceiling. And yes, it's difficult to check for broken tiles with sarking on.

But let's say you do have broken tiles somewhere due to whatever reason. Unless you climb into the man hole weekly/monthly to check, otherwise how do you detect that??

If worried about broken roof tiles for upper level, only way is to spend some money to get someone climb on top of the roof to check. But don't forget that this might actually cause more broken roof tiles if the trades person is not careful...

Anonymous said...

if I had my time again, I would use colorbond roof, not tiled roof.
The last thing I want is leaking....

Allan said...

Yes, colorbond roof would have less chance of leaking, and it's personal choice.

Value wise normally would consider that to be cheaper and might not look as good??