Swimming Pool Blog
by Mark Garcia August 6, 2013
Concrete Pool Skimmer Replacement
We had a customer who emailed recently asking about skimmer replacement on an old style Sylvan pool. 40 years old, with a metal skimmer (probably pitted with holes). I pointed him to an earlier blog post we did that showed different skimmer plumbing arrangements.
He emailed back asking about which replacement skimmer he should buy, and the big question - I suggested the Hayward SP1070 model, for inground pools.
Then he emailed back and very politely asked ... 'How do I remove and replace my skimmer?'
'The hard part', I told him, is getting the old one out! On gunite pools, the skimmer is often encased in concrete - it has to be, to hold the skimmer in place, up against the outside of the pool wall.
He later told me he planned to remove the pool deck, which will make the job a little easier 'Not much easier' I told him. Easier maybe, than cutting a 3'x3' section of deck open, and working in a little pit. I said that his question deserved a lengthy answer, and if he could wait a day, I'd write a blog post about the entire process.
Replacing an Inground Pool Skimmer
After the deck is removed over the skimmer area, dig down to unearth the pipe running to the skimmer, and cut it off, several feet back behind the skimmer. Plug or cap the line, to keep dirt out. Dig around the skimmer to remove dirt from around the concrete mass surrounding the skimmer.
Hammer Time! With a medium to large jackhammer, go to town on the mass of concrete around the skimmer. You may find rebar curved around the skimmer and pegged into the back of the pool wall. If so, keep blasting away at it with the jackhammer, sledge hammers and pry bars - until you finally can pull the skimmer off of the pool wall.
Clean up the hole, to get it ready for the new skimmer. Chip and chisel away the old concrete on the back of the wall, and carefully clean the three edges where the new skimmer will line up with the tiled skimmer throat.
Skimmer Placement. Line up the skimmer so that the height and width of the skimmer lines up with the skimmer throat. Install the plumbing beneath, and the 90 fitting to act as a support on the ground.
This is a common spot for pool leaks, so you'll want to be able to pack in a lot of fresh concrete around the front, underneath and on the sides of the skimmer. To really lock it in place, you need several inches of concrete on each side of the skimmer.
Building Forms. Usually, the area around the skimmer is too large, and you need to build a form, or find a way to contain the concrete, so that you can encase the skimmer in concrete - once again. This is known as 'boxing out the skimmer'.
You can build wooden forms, which most people do, or if you're like my grandpa, you use a burlap bag wrapped around the skimmer, with the pipe sticking out of the bottom, and then fill up the bag with concrete.
Adding Steel. Before pouring the concrete, place 4 - 2 ft long pieces of rebar into 2 inch deep holes that you drilled into the back side of the pool walls, 2 holes on each side of the skimmer.
The steel rebar adds strength to the mass of concrete, and it also helps keep it attached to the pool wall. Adding a few vertical pieces of steel rebar, tied to the horizontal, will also increase the strength of your skimmer installation.
Pouring Concrete. You won't need to have the concrete delivered for this little job, and you don't want to pour this at the same time as a new pool deck - it has to be part of the pool, not part of the deck.
Tamp dirt under and around the bottom of the skimmer, so that the pipes and the bottom few inches of skimmer are covered. Use duct tape over the top of the skimmer and unconnected pipe openings to keep concrete mix out.
Mix up bags of concrete in a mixing tub or wheelbarrow with a hoe or rake, to a thick, not too wet mix. With a helper tip the tub into the form and pour in the concrete. Mix up another few bags, until the concrete has filled up all of the front side, and most of the back side. My grand father would do it differently, he'd mix it in a burlap bag, and roll it around until its just right, then pour the bag - into the bag!
There's no need to trowel the concrete, but tamping and shaking the mix with a 2x4 for several minutes will help increase it's strength and bring up any trapped air bubbles.
No concerns for light rain, but if heavy rain is expected, cover the concrete with a tarp or plastic bags. After 48 hours or so, you can backfill the hole, tamping layers of dirt as you go. Fill the top 4 inches with gravel and then a replacement concrete pad can be poured.
My new friend has quite a job ahead of him, replacing a skimmer on an inground pool is no easy job, which is why companies charge $1500 or more to replace a $75 skimmer.
It's not something that's done for routine maintenance, but if your skimmer is very damaged, or is 40 yrs old and literally falling apart, to where even pool putty and pool skimmer parts no longer fixes the problems, then maybe a skimmer replacement is in your future.
Thanks for Reading!