I would look at OpenLCA which is free excluding needs for inventory databases

OpenLCA is the way to go, the challenge is the database, you can look on their site for free datasets and then adapt them to the Malaysian context. https://nexus.openlca.org/searchds. If you are on an academic institution you can get special rates on Ecoinvent.org as well.

I would also recommend OpenLCA for calculations (or GaBi if you are a PhD student - you can get a free license).

For the database: ecoinvent would be a good start (free for educational use in non-OECD countries, global coverage), or ELCD (free, European context) and NREL-USLCI (free, US context).

BUT: you will probably have to adjust the datasets to the Malaysian context, which could be quite a task. As a first step for the electricity grid, simply combine US-LCI or ELCD data to create the Malaysian electricity mix, including network for transmission losses. This would assume, that electricity producing units in Malaysia operate in the same manner as they do in US or EU. This would have to be reasoned for! Maybe you need to do soe adjustments (especially for the upstream processes of fuel imports, for the efficiency of operation, etc)

Actually, maybe Malaysia electricity mix and network migh be covered by econinvent, I have not checked this.

you can go for OPEN LCA. if you are a student, you can try GaBI 

i have tried OpenLCA & GABI as well.

but i found its really hard to create flows for a building since it involved massive of data.

& most of the case studies available on the website are just products which involve lesser flows.

so, does anyone can provide a case study of building?

or show me how to conduct a whole building LCA in detail?