On Jun 2, 10:23 am, Kurt Ullman wrote:
. . .when we built the house, we put in sprinklers
right after the final grading. So, due to settling and other reasons
over the years, some of the heads even at full extension are spraying
much of the water into the ground nearby. . .
Are there any extensions of an inch or two that I could screw in or
other method of bringing the heads up a little? . . . . .. These are Rain
Birds.

Standard NPT pipe threads. Go to a Big Box store and figure out
what you need using either plastic couplings and/or nipples. My
Lowes has box after box of anything anybody might conceivably need to
extend heads.

There's a cheap and very, very useful doo-dad in the same part of the
store which allows you to unscrew a stuck nipple/coupling.

Make certain the pipes are free of dirt and debris when you do the
final installation. You don't want to clog the filter or nozzle in
the sprinkler head.

jason