building permit question

[mullfitz]

In a bit of a problem

I am an owner builder but have a traddie at the moment giving me a hand with the roofing

The plans clearly state that I use 190 x 45 mgp 12 for rafters but the stuff is hard to get and i cant get the correct lengths.so I want to use LVL instead now

The building permit surveyour is on holidays so my question is do i have to notify him first before i install the different material and thats a drama due to the fact that the traddie helping me is booked out for another five weeks after this week

Any ideas

[ringtail]

As long as the replacement LVL's are designed to the same spec to equal or exceed the mgp 12 you will be fine. 190 x 45 lvl will slaughter mgp 12 in all performance criteria easily

[mullfitz]

i showed my plans direct to a lvl supplier and he said it would be fine

for roofing battens they have put 38x50 f8hw any ideas on that

[Pulse]

Other option is MGP10 and decrease the spacing of the rafters... needs to be checked on the span tables... or just stick to the LVL

Cheers
Pulse

[r3nov8or]

for roofing battens they have put 38x50 f8hw any ideas on that
what is the spacing of your rafters?

And what state are you in - may help advise on availability of various grades/sizes.

[mullfitz]

what is the spacing of your rafters?

And what state are you in - may help advise on availability of various grades/sizes.


i am in vic and the rafter spacing is 900 and the roof is 5 m wide

cheers

[r3nov8or]

from my span tables for battens -

with rafters at 900mm spacing and battens at 600mm spacing use F5 or MGP10 @ 35x90 or MGP12 @ 35x70.

Seasoned/KD Radiata Pine with most of the above specs should be available down here in Vic.
All spacings are measured at centres.

I used MGP12 35x70 at the above spacings on my extension.

[barney118]

Raftres @ 900mm
Batten spacing @ 900 0r 1200 for sheet roof 45x70 Mgp10 seasoned. I used MGP12 35x70 it was 20c l/m dearer and allowed me to span battens @1200mm. Dont forget to offset the top batten at the ridgeline to allow for screwing ridge capping.
I used 1x 75mm 14g bugles batten to rafter in an offset to centre of batten staggered from one rafter to next so when I screwed my sheeting to centre of batten I didnt hit the bugle screw.

[r3nov8or]

I mentioned 600 centres for battens, but re-checking I actually did 900 myself. I like to have a batten under my foot when I'm walking the roof (corri zincalum), and 1200 is just too far to step easily on a roof. I'm a biggish fella too and don't like to crunch my corri.

[Stan 101]

Raftres @ 900mm---
I used MGP12 35x70 it was 20c l/m dearer and allowed me to span battens @1200mm.

Hi Barney, did the rafters require a size change or grade change after they were checked with 1200mm top chord restraints instead of the original 900mm?

cheers,

[barney118]

Stan,
Looking at my pics of the roof battens It looks like I have used 900mm spacing 6 rows used. I am taking the measurements from 1684.4 Table A37 battens sheet roof supporting roof load only, where it says 35x70 MGP 12 is good for upto 1200mm spacing. My roof length sheets were 5.2m, So I put mine at 900mm cant remember why except needing a batten at the ridge and fascia and divided the rest up to give my a number.