HI Emily Carpeting bedrooms is only dictated by your budget. The only variable is the price of the carpet, all other costs (installation, smoothedge, underlay) will be the same no matter what you choose. When you say remove wooden floors....do you know what is already installed? If you are only wanting to take the wood from the bedrooms but leave it in hallways etc, then the cost to remove wood planks (laminate?) may be around $20 per m2... A lot depends on how the timber was installed, so I think it's best to get in a professional and get a free quote. Good luck.

Do you want to keep the wood floor? It is rare to see wood floors as garage floors. I've seen homes like this moved onto pour basement slabs (same concept as pile foundation...but with a basement instead of dirt. If you want to keep the wood, then there has to be a way to keep the wood off of the concrete. An 18" crawl space (dirt covered with 6mil poly sheeting or cement) is always an option. The 18" crawl space would have to be cross vented/heated properly. This is for "keeping" the wood. Flooring. I'm not sure what has to be done to remove the wood floor and have the building sit (joists and all) on concrete. Remove the joists and you have plenty of stability problems. You would need to speak with a local architect/building engineer who has some knowledge of what you are trying to do, soil conditions, etc. to get this right. In theory it can be done (we've just landed a small car on a comet...we should be able to put an old building on a cement slab)...I'm wondering about the expense to get it there (excavation + soil stabilization + concrete + piles, etc).

If you are seeking a truly open feel to the floor plan you have shared, then using one material in the mail living area is the best approach to making this space feel truly open. Using a variety of materials on flooring chops up the space and decreases the visual footprint. I would suggest using wood, tile, or if you are on a tight budget laminated flooring for the living/dining/kitchen. Then use carpet in the more intimate spaces; bedrooms and possibly hallway. Save the tile for the bathrooms.

I cant imagine that tiles on concrete will be any colder than concrete alone. But the choice of colour may make a difference to the heat absorption qualities; dark tiles will absorb heat better than light coloured ones.