How To Install A Pool Skimmer
Installing a new skimmer on your pool is a pretty big job regardless of whether you have a concrete pool or a vinyl liner pool. A concrete pool skimmer can be
replaced without affecting the interior surface of the pool in most cases. A vinyl liner pool however will need a new liner if you are installing a new skimmer. This
is why it is so important to inspect vinyl pools for deficiencies such as cracks in the skimmer and address these issues prior to installing the new liner. Vinyl shrinks over time and when you take the old faceplate off the vinyl will shift and you will not be able to line up the holes in the liner with the holes in the skimmer. If a liner were brand new it is at least possible that a very skilled person could change the skimmer as you can manipulate the liner to a small degree with boiling water, as well as the option for gluing in sections of new vinyl if the liner does shift out of place, however these would not be normal skimmer repair protocol. The conventional wisdom is that if you need to replace the skimmer on a vinyl pool then you will most likely need to replace the liner also.
The good news is that on a vinyl liner pool the skimmer is usually just buried adjacent to the pool and you can dig it up to replace it. A concrete pool is usually not so easy. Most concrete pool skimmers are (should be) attached to the pool wall, encased is a solid cube of concrete on all sides. Digging up a concrete pool skimmer involves mostly jackhammer work unfortunately.
In addition to installing the skimmer body itself, both concrete and vinyl liner pool skimmers have connection ports on the bottom that must be connected to your pool plumbing lines. These connections are about as tricky as they come in terms of pool plumbing connections as you will mostly be doing it blind and the height of the skimmer must be perfect to line up with the correct orientation on the pool wall. The skimmer is what sets the water level of your pool so having it sit too high or too low is a problem.
Vinyl pool skimmers - A vinyl pool skimmer must be attached to a templated section of the pool wall. This means that the plumbing connections will be made after the skimmer is already mounted to the wall. While you can connect the plumbing first, you must be absolutely sure that the skimmer will line up 100% exactly with the hole cut out in the pool wall such that the screws will all line up with the holes.
Concrete pool skimmers - A concrete pool skimmer will be connected to the plumbing lines first as there is no way to fully secure the skimmer to the wall prior to connecting the plumbing. Unlike a vinyl pool skimmer, a concrete pool skimmer has a very slight amount of play as to the orientation. Ideally you want the bottom of the skimmer throat to line up perfectly with the tile throat in the pool but this is not 100% essential. Since the skimmer will be getting encased in concrete on all sides you will still be able to have a leak free connection point even if the skimmer is offset or slightly crooked in comparison to the pool wall.
How To Install A Concrete Pool Skimmer
A concrete pool skimmer is encased in concrete on all sides to help anchor it to the pool. Without this concrete the ground around the pool will shift, move and settle
over time and take the skimmer with it. In order to replace the skimmer in your pool you will need to open the ground (cut the deck) all around the skimmer area and
dig up and expose the concrete on all sides. Once you have exposed the skimmer box you can begin the long process of chipping away (jackhammering) out the skimmer
box. This will take a significant effort and many hours of jackhammering. Unfortunately you can not just attack the skimmer box with the largest jackhammer you can
find - you will need a delicate touch at times to prevent from creating any further damage to the pool wall, the tiles around the skimmer mouth or the coping over top
of where the skimmer mouth is. If you damage any of these areas you will have an even larger repair job on your hands.
Once you have managed to remove the old skimmer you will want to expose the plumbing lines under the skimmer as much as possible to make the new connections easier for yourself. Be sure to put rags or caps on the pipes in your skimmer, and in your cut off skimmer pipes at all times to prevent debris from falling down into the lines and plugging your pipes. You will need to temporarily hold the skimmer in the correct finished orientation such that you can measure the pipes underneath for the best possible fit. This is going to be tricky on most pools. Worst of all it will be tricky in a way that is unique to your installation and not something that you can easily give general advice for how to get through. In most cases the solution will be to dig lower and expose the pipes further such that you can add a fitting or two that will connect to your skimmer ports as well as leave you with the skimmer at the correct finished height.
If you have old poly style fittings that use stainless steel clamps then you should try to switch over to PVC fittings that you prime and glue into place. To switch from poly to PVC you would use an inset barbed adapter like the one pictured here. Simply heat the old poly pipe slightly with a heat gun to make it more pliable and then inset this fitting. Add two stainless steel clamps that are facing in opposite directions to secure this fitting to the old pipe.
Now that you have transitioned to PVC fittings you can easily connect to a new skimmer. Start by priming and gluing a pipe or fitting into the skimmer and building downwards towards the existing pipes. Every connection needs to be done perfectly to avoid leaks so take your time and work carefully. Use 90 degree elbows and slip PVC couplings primarily for these connections. For more info on PVC pool fittings, glue and primer you can read the pool equipment installation tips which has information on all of these subjects.
Once you have removed the old skimmer and you have figured out how you will attach the plumbing connections you will need to tackle the technical challenge of attaching the new skimmer to the pool wall so you can pour a new structural concrete skimmer box. If you do this step wrong it is certain that your new skimmer will also need to be replaced one day.
Use mechanics tie wire to hold the skimmer in place as you work. Drilling and installing screws and concrete anchors on the pool wall will help give you something to tie the wire to and hold the skimmer firmly in place. In order for your new concrete skimmer box to become attached to the pool wall you will need to install rebar dowels into the pool wall. You need to drill holes on a slightly downward angle into the pool wall and insert 10mm rebar into these holes. The rebar needs to be secured with epoxy or a non-shrink grout product. Epoxy works very well provided that the holes you drilled have been blown out and are free of dust or moisture. You can also sleeve a few strands of tie wire into the holes and use a hammer to wedge the rebar into the holes. This will help to hold the bars nice and securely until the epoxy has had a chance to set.
You then need to add more rebar and build a cage around the skimmer. Places where you attach one piece of rebar to another need to have significant overlap, more than 6" at bare minimum and should be tied with mechanics tie wire. Once you have built a rebar cage around the new skimmer and securely fastened your rebar dowels to the pool wall you can begin the process of building a concrete form around the skimmer. You will need to fill the skimmer box completely with concrete and this usually equals more than a few bags so do not build the skimmer box unnecessarily large.
The new concrete will need to be poured at minimum above the waterline of the pool in order to prevent the new skimmer from leaking.
When you pour the new concrete skimmer box it will be incredibly important to bond the new concrete to the old concrete on the pool wall. This means that you will need to acid wash this area as well as rinse thoroughly. You will also need to bond the new concrete to the old concrete. If your concrete mixing, placing and bonding skills for a project like this need some updating then be sure to read the concrete basics section of this website that explains everything you need to know about mixing and bonding concrete for a job like this.
The new concrete in the skimmer box will need to be agitated as you place it to make sure that is envelops the skimmer on all sides. This is especially important for the area where the skimmer mouth meets the pool wall. In this area you will need to tape or stuff the gap between the new skimmer and the existing wall skimmer throat. When you vibrate the new concrete skimmer box the concrete will want to overflow in this area. Pay attention to the details here and be sure that you have this gap completely sealed and also that you vibrate or manually agitate the concrete inside the skimmer box thoroughly.
Setting the deck lid of the skimmer as well as cleaning or re-tiling the skimmer mouth are all that remains in order to install the skimmer. You will need to re-pour the pool deck if you had to break it out to expose the skimmer, or reset the stones if you have interlocking stones around your pool. The area where the skimmer meets the pool wall (the area you stuffed / taped to prevent concrete from overflowing) will be a potential leak point once you have replaced the skimmer. Use a hydraulic cement product to finish this area once your skimmer concrete has set completely. This hydraulic cement is heavily modified to bond to any surface. It also expands slightly as it cures to create a water tight seal. This would be a great choice to finish your skimmer installation with where the pool wall meets the new skimmer mouth. Try to drop as little of this into your pool as possible as it will cure even underwater and stick to the floor of the pool.
How To Install A Vinyl Pool Skimmer
Installing a vinyl pool skimmer is a much easier job than installing a concrete pool skimmer. The trick for how to install a vinyl pool skimmer is to dig up
and expose the skimmer on all sides and really give yourself a lot of room to work. The same is true for the pipe connections below the skimmer - dig extra deep and
expose the pipes as much as possible to make the reconnection with the new skimmer much easier.
With a vinyl liner pool it is very important to replace your skimmer with the exact same size, shape and model of skimmer. If you want to switch from one brand, or one size of skimmer to another then the replacement job just got quite a bit bigger and a lot more technical. Ideally you want to replace your skimmer with an identical model such that all the holes line up perfectly and you simply take the old one off and put the new one on. The exception to this would be if you have significant rust damage to the pool wall around the skimmer. This is common when long withstanding leaks have been present. You must have a secure and stable wall with which to attach the new skimmer. In this case it is not uncommon to buy a larger skimmer and cut the wall to fit the new one.
If you find the wall of your pool to be too rotten to install the new skimmer securely then you will need to do a repair that involves riveting a new piece of galvanized steel over the old skimmer mouth opening. The new piece will need to have the hole cut and screw locations pre-drilled to exact likeness of the old one. This is not something the average pool owner will be able to do, but not impossible if you have no other recourse to try.
There are usually four screws that hold the skimmer to the pool wall as well as 8 to 12 screws that will hold the faceplate on. As shown in these pictures you will need to drill out both of these holes for the new steel piece to be able to attach flat over the existing wall.
Skimmer gasket orientation - Where to put the gaskets when installing a new skimmer can be confusing. Some skimmers need 2 gaskets however most need 3 in total. One between the skimmer and the pool wall, one between the pool wall and the vinyl liner and then a final, third gasket installed over the vinyl liner and under the new faceplate being installed.
It gets even more confusing when many skimmer manufacturers are including rubber butterfly gaskets that sleeve on both sides of the pool wall (in between the skimmer and the wall as well as in between the wall and the liner. These rubber butterfly gaskets are very tricky to work with and very easy to have a problem. If you are doing this yourself and want to avoid potential problems with the install then consider picking up standard cork gaskets, or even standard rubber gaskets...anything other than the butterfly gaskets. The skimmer should be installed securely on the pool wall before you connect the plumbing lines on the bottom. This is because the skimmer must fit precisely in the correct location and it can be tough to get the plumbing to line up correctly. Once the skimmer is firmly installed on the pool wall then you will have a stable platform to build outward from. Similar to concrete pools you should be sure to switch to prime and glue PVC connections if you still have old poly pipes that use clamps.
Once you have made the plumbing connections and attached the skimmer to the wall, that is it. Unlike a concrete pool skimmer that must be attached to the pool wall with concrete you can simply carefully backfill your new skimmer area with dirt. use water to help compress the fill as you add it around the skimmer to prevent sinking in this area in the future. Before you install the liner be sure that you have a gasket on the pool wall as pictured here:
The new liner is then installed and then another gasket is installed along with the faceplate. This series of gaskets is how you prevent leaks in the skimmer and any screws on the skimmer which do not tighten fully will certainly cause another leak. This is often the way that skimmers fail and need to be replaced - they are not installed correctly in the first place and leak from the day they get installed. The results from this kind of leak can be fairly disastrous.
When you install the skimmer faceplate you must be absolutely certain that each screw is compression tight. Compression tight means tight enough that the flange squishes together hard enough that no water can leak by. If any of the screws in your skimmer faceplate will not tighten all the way or are spinning in the holes then you will need to repair this is order to prevent a leak in this location. You can try to oversize the screw if you have a Hayward style skimmer (coarse thread screws) but if you have a Jacuzzi style skimmer with fine, machine thread screws this will not work. As a final option on any vinyl liner skimmer you can drill new holes on either side of the failed hole and install two new stainless steel screws being sure that the flange pulls tight against the wall (as opposed to pushing away as you tighten the screw).
If you have an aboveground pool or a straightforward vinyl liner skimmer to replace this is not all that hard. The job only becomes more technically difficult if you have deficiencies such as rust, a different sized skimmer, or screws that area stripped - otherwise replacing a vinyl liner skimmer can be accomplished in only a few hours.
Tips For Installing Pool Skimmers
Before you attempt to install any swimming pool equipment you should take a look at the video series from Swimming Pool Steve that reviews installations of pool
equipment for deficiencies. Additionally there are sections on pipe materials, plumbing fittings, glue, primer, unions and valves commonly used for installing pool
and spa equipment. If you would like to learn more about how to install a pool skimmer correctly as part of a pool system check out the Installation Tips from Steve.