Need I use sealant on plumbing joints?

[zetland76]

Is it necessary to add sealing stuff to plumbing joints or is it just "belt and braces" for us amateurs.
I have used ptfe tape on screw fittings but do I need sealant on the cold water feed from the header tank and should I use anything extra on the olives of compression fittings?
Thanks

Mike

 

[Diyisfun]

sealant not required.
If using olives, DO NOT OVER TIGHT

 

[mogget]

should I use anything extra on the olives of compression fittings?

Quite often compression joints will seal without any assistance. It's not bad practice to use a bit of jointing compound on the olive though (Water Hawk or similar)

 

[Slugbabydotcom]

You shouldn't need any extra. Like you say its a belt and braces thing.
Most plumbers I find will only use an additional sealant on compression if its giving them problems.

 

[JohnD]

I heard of people running PTFE tape round the olive and pipe end before final fix, and it seems to work well for me. You have to trial-assemble first and tighten the nut enough that the olive stays in place on the pipe while you tape it.

I am a householder not a pro

 

[Whitespirit66]

You won't find professional plumbers using PTFE tape on olives. A light smear of joining compound (eg. Boss White) if you must.

PTFE tape is used where one fitting screws into another fitting (eg radiator tail into a radiator). The PTFE stops fluids running through the tiny gap between the threads.

With a compression joint, the olive forms the seal.