Insulating pipework questions

[mike]

Just adding a new rad in a new location downstairs (suspended timber floors) and wondering whether to use plastic or copper pipe and how to insulate.

1. Is it necessary/desirable to add insulation to plastic pipework or is it only necessary for copper?

1. Wickes have two different types of pipe lagging - one which is by-law compliant and another called "economy" insulation at a quarter of the price. Is the economy one an inefficient, token gesture at insulation or is the by-law compliant one an overpriced, unnecessary expense?

2. Hardly dare ask this but does anyone know any pros and cons re: copper vs plastic? Current plumbing is copper, but I have a hacksaw so cutting plastic pipe holds no fear for me;-)

1. Finally, is it good practice to lag first floor pipework or is it unnecessary?

Thanks for any advice.

[John]

I thought a hacksaw was a real no - no on plastic

[Keith2.0]

Yes insulate with the best insulation.

The 1st floor is inside the living area so no real point. Maybe insulate from the boiler to the valves/hot cylinder so as not to waste heat during the summer.