Tap fitting

[bbb]

When fitting a set of taps I was always taught (many moons ago) that the rubber washer went topside i.e the tap sat on the rubber washer and then the backnut was tightened up. I come across alot of sets of taps where the taps are not sat on anything and the washer is underneath, with the backnut tightened in to the washer. I have also read fitting instructions where it tells you to put the washer underneath. I cannot see the point of this as when the washer is underneath it prevents you from tightnening the backnut tight enough and can also split the washer.

So the question is when fitting taps should the washer go on the top or bottom??

 

[uug197h]

I agree the tap should sit on the washer but a lot of the new taps just have 1 washer to go on the nut, I have a box of O rings and some times use them for the tap to sit on but that’s a personal choice. I know plumbers that say if you don’t get it with it, it doesn’t need it

 

[ProffesorPlumb]

Washer under the tap and then the back nut under the sanitary ware etc.

Like uug197h, I carry a boxful of washers just in case.

 

[2true]

you could always use a fix a tap seating kit. work well all the time

 

[Bernie2]

Metal sink unit top, tap washer on top to form seal between two metals, nylon top hat washer underneath (use some old 28mm or 22mm compression fitting backnuts, for top hat washers if you can't get metal top hats, that is if you want to have a good tighten up) to allow for tightening space.
On some pattern sink unit taps, the thread doesn't go all the way up to underneath the tap, so you can't tighten them enough to stop them from moving.
In the old days most taps where called pillar taps, because they had a square pillar underneath and the hole in the unit was square as where the top hat washers. So they couldn't turn very far if they came loose. Now they can spin right around and loosen the tap adaptor causing a flood in the unit base.

In a washbasin depending on what sort of washer it is they can go on either the top or bottom. Incidentally basin taps had a pillar on like the sink unit taps and the basin holes where square as well to stop them from turning beyond a certain point. Today you can also get anti turn washer sets for them.
In the old days we bedded them in with plaster, white cement or either white or red lead putty eek!. They sure never moved. If you got a real mover then putty with a bit of knotting in it went hard as a rock. Usually though todays stuff is okay with one of those flimsy anti turn washers on top, a plastic washer underneath and just tighten it up. I suppose you could bed it in with the likes of Dow Corning if you wanted. Putty tends to go a bit funny especially on the hot tap with the heat.