Originally Posted by Wet_Boots
You can stack two extensions and get the depth of a standard foot-deep valve box (don't build eight-valve-manifolds without them!) ~ Even though shallow boxes have become far too common (punk kids can't dig a hole?) that doesn't mean you have to follow suit.
The extensions we get sit directly ontop of the box and don't nest like stacking two boxes does.
Which is irritating, because you have to tamp the ground very tight to keep the riser from pulling off the box when you remove the lid. Especially when some landscaper adds 6" of mulch to a bed, so you have to add a riser,and the mulch won't hold the riser on.