you can do it either way but personally I would put the offer in first subject to a pest and build inspection.
Then u want the offer accepted subject to those conditions.
Only then would I outlay the expense of a pest/build report.
Then once completed, you can go back and negotiate the offer if the build/pset inspct finds and abnormalities or issues with the hosue.
ie: you put in the offer of say $330k subject to balh balh and blah.
You get it accepted.
You get the report completed.
It finds there are some issues, costs will be $5,500 to fix.
I would then negotiate the price down to reflect this cost.
Just FYI.....when the bank gets the valuation report done, you can ask them to order a build, pest inspction on your behalf......sometimes this works out to be much cheaper for you cost wise.
Then again, it will also provide the banks with faults that may mean they drop the LVR (loan to value ratio) ie: may lend u less than usual due to what they may percieve as risks with the house.
perhaps get it done yourself.
You want to get the offer signed off by the vendor first, this will mean noone can jump the queue and overide your offer.