Roof sarking anyone?

vpande · May 22, 2007 2:02 pm

I would like to consider roof sarking for my new home (plans-permit stage) and have a few questions for those who have taken that path
1.cost.. ball park figures for a 2 storey home (approx 40 squares)
2. I am considering putting downlights - (upper storey later on) would the sarking limit any access to roof cavity? Or do the builders leave some kind of an opening from the top level to access the roof cavity. (I'm not sure what that opening is called)
3. is it really worth it? Or shall I stick to standard?
cheers
VP

Michelle · May 22, 2007 2:11 pm

I’m not a builder…..and I may have this wrong.

But I’m pretty sure the sarking lines the roof trusses??? (anyone?)
Leaving you ample room for movement in the roof cavity, if you have a normal or high pitch to the roof.

jamiet · May 22, 2007 2:28 pm

I would expect a cost between $2K and $7K depending on the builder, roof area and the quality of the sarking.

The sarking goes between the tiles/colorbond and their supporting trusses. Tradies can use either the manhole to get into the ceiling space or alternatively they can take off a couple of roof-tiles and cut a hole in the sarking. The sarking is then usually taped back together with electrical tape.

Hennig · May 22, 2007 10:52 pm

Hi Vpande,

Spoke to good ol' dad.
He thinks about $5m2, roof area not floor area. So you'll need to know what the pitch is and something else, he did say what but I've lost it.
Something to do with a factor!! to calculate the roof m2 from floor m2.
I'm sure if you use the net you can get the calculations.

See how you go.

northlakes · May 23, 2007 10:19 am

Hi Vpande,

When you say sarking are you talking about sissalation or a full anticon blanket??

Sissalation is relatively cheap reflective foil that insulates against dust and drafts. It's the same stuff you see nailed to the wall frames.

An anticon blanket also has glass insulation wool adhered to the foil to add extra sound and heat insulation.(Typically used under a steel roof)

We've gone the anticon blanket option with our builder. $3k on a 30sq 2 storey home.
It doesn't block access to the ceiling as it's nailed between the roof and frame.

Cheers,
Mark

Yak_Chat · May 29, 2007 10:55 am

Typically sarking/sisalation in a pitched roof is put on top of the trusses, under the battens and under the roof, ie a 1 to 2 inch gap.

It stops some heat, but mainly stops condensation under the roof occuring, and it can also can help if you have a minor leak. You should also use ceiling insulation which sits on top of your plaster ceiling, gives you the majority of the thermal insulation. and yes the sarking is only cut if you need to access the ceiling via the roof, not via the manhole.

In a raked to roof house (catherderal ceilings) they often use the foil backed sarking with 1inch thickness of fibreglass adhered to it to give insulation which is not as good thermally as a dropped ceiling with R3 to4 batts.

Ideally,
If you have an accessible ceiling with a manhole, you should be putting sisalation under the roof, as well as R3 or better ceiling insualation to get the best performance.
Cost wise this is not prohibitive.
Steve

ahuang · May 29, 2007 8:11 pm

According to my builder AllCastle, sarking is recommended only if you use Terracotta Roof tiles.

But one of the sales from Clarendon told us if you have sarking and one of the tiles cracked and starts leaking, it will flow down to the edge of the roof and it's very hard to work out where the cracked tile is located. So they don't recommend installing sarking...

Personally, the main reason we use it is for better insulation.

Also, sarking is under the roof tiles, but above the roof imber frames. Your down lights should be installed on the ceiling, which is far below from the roof, therefore it shouldn't matter.

Hope this helps.

Cheers
Allan
http://building-our-first-house.blogspot.com/

vpande · May 29, 2007 8:13 pm

Thank you all.
The builder has quoted 2,500 for the sarking.They will also be providing ceiling batts- R4 type as standard. we will go for it provided site costs do not blow up.
Thanks,
VP