by Rob Cox, August 31 2012
Following up to our blog post last week on Gunite pool construction phases, we wanted to take a look at how inground vinyl liner pools are built.
The process for building a vinyl liner pool is very similar to a gunite pool, but is simplified by the fact that several specialized trades are eliminated. We won't need to set-up work from a gunite crew, a tile and coping crew, nor a plastering crew.
Many homeowners take on the task of installing their own inground pool kit by acting as general contractor, pulling their own permits, and working nights and weekends to get it done. If that is you, don't consider this blog post as all the help you'll need, but do some deeper research and planning before deciding to build your own pool.
In a nutshell, the process of building an inground vinyl liner pool looks like this:
- Design the Pool
- Excavate the Shape
- Install the Walls
- Install the Floor
- Plumbing and Electrical
- Install your Vinyl Liner
- Backfill your Pool Walls
- Install the Pool Decking
Your builder will pay a visit to your property, and make some sketches with you. He will have some idea of the property line set back that must be observed, but may have to dig further to find out about any existing easements, proffers, or resource protected areas that might come into play. Topography, soil type and access to the building area will also be considered. Assuming that the property is pretty "clear" of these restrictions to building a pool, a plan will emerge with your initial thoughts on the size and placement of the pool.
Once size, shape and placement are determined, then comes 1,000 questions, or options really. You will have many choices in shape of pool, and also in optional equipment. Slides or attached Spa? Fountains or Pool Cleaners? Planter areas or Water Features? Love seats or Swim outs? Then, there's the vinyl liner pattern, and the choice of material for the pool decking.
You may have a choice of filtration equipment, and the option of adding a pool heater. If the pool is rectangular, you may want to consider a built-in automatic pool cover. If you are in the snowbelt, your builder may offer a winter safety cover (a good purchase) or even their own winterization services.
In come the backhoes (or excavators, or skid-steer loaders)! The heavy equipment will come loaded on a trailer, and then make its way across your side yard, and through a removed section of fence - to access your pool build site. Sometimes trees or bushes (and always grass) will be sacrificed to make access possible. Don't worry about it, but be prepared for the "destruction" before the "construction" can begin. It is also possible that larger trees or bushes near the build site will sicken as a result of disturbing the nearby soil, and perhaps cutting off some root systems.
On "Dig Day", the crews will start in the cool morning to a staked out pattern and a drawn set of plans. An experienced operator can make quick work of a pool dig, sometimes in as little as 3-4 hours, for an average sized pool. They will usually make a separate pile of the topsoil, so that it can be reused on top of your backfill. Some of the fill dirt will be saved to fill in around the pool walls, but most will be hauled off, unless you have a suitable place on the property for several tons of dirt!
For inground vinyl pools, the dig will be in two stages. First the depth of the walls is overdug to a size that is 24-30 inches larger than the finished size of the pool. The walls are usually 42 inches long, so this will be a 42" hole, that is 2 feet wider than, but the same shape as, your finished pool. Then the second stage is to dig the deep end of the pool. The outline of a vinyl pool hopper bottom is painted or staked on the ground, for the operator to follow. Depending on the machine used and the operator skill, some hand digging may be required to firm up the corners.
After checking level of the areas around the pool where the wall sections will be connected, the panels are connected to each other with bolts and kicker legs as support. After assembly, a transit is used to check level of the pool on all corners, and then bolts are tightened up.
Beep, beep, beep! The concrete truck backs up (across your lawn) and dumps his load near the pool edge. Workers scurry to spread it out around the base of the walls, to fill up the overdug area with concrete about 10 inches deep.
The floor of your pool is another choice that was made. Depending on your soil type, rainfall, elevation, or budget - you chose either a sand bottom, vermiculite or concrete pool floor. Sand is cheapest, but needs work every time you change the liner, and could lose its shape if the vinyl liner leaks or from shifting soils. Also, heel divots and other floor irregularities will occur over time. A Vermiculite product known as Pool Base can instead be used. It's lightweight and is mixed with water to form a solid base of good durability. The third type of floor would be a poured concrete floor, which can be done the same day as the foundation is poured. Strongest and smoothest, but also the most expensive. Many builders like to pour a concrete hopper bottom (a 6'x8' pad on the deep end bottom), and use vermiculite for the other floor areas.
All 3 types of vinyl liner floor material are troweled into place, to a depth 1-3 inches thick, and all can be completed in one day.
A trench will be dug from the location of the pool pump and filter, to the pool. PVC pipes are laid in the trench and connected together with glued couplings. These pipes will be connected on your pool to the main drain in the pool floor deep end and the wall skimmer and wall returns. On the other end of the pipes will be glued valves to control the flow of water and then pipes will run into your pump, filter and maybe a pool heater. Automatic pool cleaner lines are installed, if applicable. After plumbing a loop to and from the pool, the pipes will be pressure tested to ensure that no leaks exist underground before backfilling the trench.
The electrician will also lay conduit in the trench before backfilling, to power underwater pool lights. Light niches, are installed in the pool wall, usually in the deep end wall, and from this a conduit is run to a junction box that will stick up behind the eventual pool deck. In this junction box, the wires from the pool light will meet the wires from the pool equipment electrical panel, which the electrician will also install. He will bring power from the home's main electrical panel, to provide power for the pool pump and pool light, and for an electrical outlet. A sub panel breaker box may be installed along with a pump timeclock, for more control, and the ability to add power to a heater, pool cleaner booster pump, or other future electrical needs.
Many builders like to fill the pool with water before they backfill the pool walls, and some do exactly the opposite. In either case, the installation of the vinyl liner is the same. The floor is cleaned one more time, and the seams between walls are taped with duct tape. The floor is swept clean and gone over with a close eye to smooth out any rough spots.
The new liner will be pulled from one side to the other and the top edge of the liner is popped into a track in a few areas. Then the liner bead, at the top edge is gradually put into the track all the way around the pool. Then a vac blower is installed, like our Mighty Vac, and all of the air is sucked out from behind and under the liner. This causes the liner to fit tightly like a glove to the walls and floor.
While the vac is keeping the liner tightly "set", the main drain ring and cover are installed and filling of the pool can begin. When the pool is halfway full, the vacuum is removed. When the pool is nearly full, the skimmer, returns and pool light faceplates and hardware can be installed (after the liner has stretched fully).
The topsoil or fill dirt is placed up against the walls of the pool, and tamped every foot of depth. Then, it should be watered very liberally, to help the dirt settle even more. On top of the dirt is usually placed 3-4 inches of bluestone gravel, in the areas where you will plan to have a pool deck installed.
Your pool deck should tie-in with any existing patio decks, where possible, and with your pool safety fencing. A 4-sided fence is the safest, or some combination of barrier walls, bushes and fencing can create adequate layers of protection.
For the decking material, you can choose from basic broom finished concrete, or jazz it up with brick trim and runners, or opt for exposed aggregate decking. A wood deck area of the pool deck, for lounge chairs or tables, is a nice touch. Interlocking brick pavers are a popular pool deck option, installed on a sand base.
Installing the pool deck can take 1-2 days - be there when they finish, so you can put your names in the concrete!
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