Question 2

I'm not yet aware of all of the specific requirements when it comes to insulating a building but I suppose I would consult an insulation handbook to make sure I meet all the minimum requirements.

After taking note of this, I would probably try to find the best material. To do this I might:

• Compare the R values and try to find the materials with the highest resistance.
• Check if it blocks heat transfer by radiation or convention as well since the R value would only tell me how well it blocks heat transfer by conduction. My knowledge on this topic is quite limited. Although I am aware that reflective insulation helps block radiation and the air pockets in bulk insulation help prevent heat transfer by convection, I suppose that there is more left to be learnt.
• Make an analysis of it's carbon footprint and try to make sure I choose a material with low embodied carbon.
• I might also look out for opportunities to be innovative with my insulation and try to use local materials to insulate the building. I've observed a wide range of insulating materials from recycled jeans to industrialized polystyrene but I might need to know a bit more about the various types of insulation before I could experiment with new materials.
• Think about how I would need to install the insulation. For example, if I'm installing it for a house that has already been built, I might have to stick to blow in insulation/ external cladding. 
• Compare the prices of the various options. 

There are a few external factors I might have to consider as well

• The climate. If it's a very humid area, I would have to make sure that it has a vapor barrier installed on it. If the insulation gets wet, it might turn moldy and it's performance would reduce drastically.
• The shading. If the walls aren't well shaded, it might heat up the building and create an 'oven effect' where heat would be trapped inside the building.
• Thermal Bridges. Even if the house is well insulated, thermal bridges could offset the effort by allowing heat to be transferred through it. Although I have a basic understanding of what a thermal bridge is, I know that there is more to be learnt about this topic.