Suspended floor insulation

[BILLDIYNOT]

Hello, I have seen a few threads on this topic but some questions remain for me. I have a 1970's dormer with suspended wooden floorboards. The last EPC recommended floor insulation to improve the energy performance of the property. I've had other floorboards up and there is about 10" (250mm) below the floor joists to a concrete base, so no room for crawling. I would like to install 4" (100mm) Celotex/Kingspan on 1" (25mm) battens as been advised in this site. I will do this room by room over time. I'm doing the bathroom first as it is being refurb'ed soon, so I've started ripping things out so I can get to the floorboards. I expect to be able to remove ~ 6 and leave the next 6 in to be able to slide the insulation in, in sections.
1. Not sure what I'll see re pipes and cables when taking the bathroom floorboards up. Logically, would they be below the level of the joists, which would make installing insulation easier. Or would they be "in the way" and if so, how do you tackle this to avoid any risk of damage to them ?
2. I know the design I want of the bathroom refurb re shower, basin, toilet etc. What should I take into account when installing the insulation so that I don't make it difficult for the plumbers/bathroom fitters ?
3. I have several sheets of 2" celotex foil covered insulating board, already. Can I double pieces of this up to give me the 4" thickness I want or does it need to be 4" solid ?

Any additional advice on this topic is always appreciated. Thanks, in advance.

 

[JP_]

1. Not sure what I'll see re pipes and cables when taking the bathroom floorboards up. Logically, would they be below the level of the joists, which would make installing insulation easier. Or would they be "in the way" and if so, how do you tackle this to avoid any risk of damage to them ?
2. I know the design I want of the bathroom refurb re shower, basin, toilet etc. What should I take into account when installing the insulation so that I don't make it difficult for the plumbers/bathroom fitters ?
3. I have several sheets of 2" celotex foil covered insulating board, already. Can I double pieces of this up to give me the 4" thickness I want or does it need to be 4" solid ?

1. For pipes I just worked around them and used a bit of rockwool over them if need be.
2. Plumbers can cut through the insulation. For shower, just consider where the waste will need to go.
3. Yeah, double them up.

 

[BILLDIYNOT]

Thanks, JP_. Appreciated.