who installed the insulation and plasterboard? if you have evidence of the materials used (ie receipts and/or proof of payments) details for the unreachable contractor, photos of the work and you complied with the Basix agreement and used the correct rated products it should be acceptable as i'm sure Covid has caused numerous other delays and problems ..i found the BASIX staff helpful and easy to deal with ...contact BASIX by phone and discuss options with them

I don't have any details I can provide about the contractor since it was back a couple of years ago and no receipts for work done. I lost that information unfortunately. I do have a paid invoice for the insulation that was used, complete with R value detailed.

Is plasterboard part of Basix requirements if you have insulation installed? I thought you only need insulation certificate.

Thanks regarding the BASIX hotline. I only today realised on the BAsix cert that I needed a certificate for the insulation. The extension is only tiny and I didn't expect there to be a need for it considering the rest of the house is ancient and has hardly any insulation at all. :D

i'm confused about why you needed a BASIX certificate that usually applies to energy conservation (insulation, water and power use etc) ...did you make a development application to the local council? i would start at the beginning by first asking if you needed a DA and a BASIX certificate for your project... if the answer is no.. then you shouldn't need to do anything else, if the answer is yes then you will need to explain what has happened to Basix and the council and take their advice

Are you selling? What is triggering your need for paperwork?

The extension is under a CDC already and has been going for a year and a bit (thanks Covid lockdowns :( ). The rest of the house that the new extension is attached to is from the 1950's. The old part of the house has got no insulation in the walls and 1990s gold bats (probably around R1.5 now) in the ceilings. :D .So it seems ridiculous that one room extension needs all these energy efficiency requirements when 90% of the house is way below their requirements.

I'm not selling the place, I just need the certification documents (I guess) that the BASIX certificate stipulates that I require.

Basix can only regulate what you planned to do not what was already in the old house but no reason why you can't improve insulation for the rest of the house

@bigreader I think you are correct. My overall cost of the build was only $25k. I tried to do my own BASIX application and I can't progress through it because the first question doesn't have a valid option for me to pick.

Now that I understand this myself, I'll contact my CDC certifier with this information and hopefully that's all that's required to do away with BASIX.

Thanks everyone.