Sealing cast iron soil pipe joints

[Donto]

I need to install a 4 inch cast iron soil pipe down the outside of my house (listed building) to take waste from a new 1st floor bathroom. The whole thing is approx 18ft high as it's to go up to vent at roof level. There are several joints which need to be sealed (airtight?) - what should I use to do that?

 

[dan the man]

black silicone

 

[Alfredo]

I believe that for the traditionalist its tarred string/rope to fill the gap topped off with putty for the seal...But these days its bound to be the all conquering mastic gun

Alfredo

 

[kevplumb]

well you got the first half right anyway (tarred hemp )

then

try lead wool then poured lead caulking

 

[Nige F]

Un tarred hemp Yes I`ve actually done them .....if it`s listed then use 4 inch lead ...........because I`ve pulled a bend on that too

 

[ChrisR]

The places which sell the cast iron will also sell you the bits and goo to seal the joints. I've forgotten the names now, but do remember that the sealant is something like £40 a pot!

Traditional method with propane ring, crucible, ladles, rats tail, caulking irons... too much faffing about.