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While taking a walk in my neighborhood one day I noticed that water was spewing out from everywhere at a nearby home, or at least it seemed that way. Upon closer inspection it appeared that the valves that service the irrigation system were damaged, causing this mess.
If ever there was a reason for installing valves below ground in a valve box, this was surely one. Valve boxes are used to conceal and protect the valves, fittings, wires and manifolds -- in other words the components of an irrigation system.
So, what is an underground valve box, and why is it used?
As basic as this may sound, there are a number of contractors who really don't know. A valve box is an enclosure designed to provide a safe environment for the components that comprise an irrigation system. It protects them from vandalism, the elements and damage due to mowers, string trimmers, etc. Equally as important, what about its aesthetic value? For homeowners who have spent thousands of dollars for the design and installation of an irrigation system, the last thing they'd want to see are the components dotting the landscape.
Underground valve boxes have been gaining in popularity, especially in the residential market, due in part to the improved technology.
At one time, valve boxes were made of concrete and were used almost exclusively in the commercial market. These prefabricated boxes were expensive, heavy and costly to ship and install. With the advent of plastics, the price came down and they became more affordable and more commonplace.
It is a given that in commercial applications, underground valve boxes are almost always installed, so we will concentrate on the residential market, and the pros and cons of above ground versus below ground installations.
Some contractors still install valves above ground, believing this is a less costly way to go. When it comes to housing the valves, manifolds, wiring etc., you can choose to put them uncovered in a hole in the ground or use an underground valve box, unless you are installing anti-siphon valves. These have to be installed above ground.
"The valves above ground, although easy to install and easy to work on, require more pipes and are exposed to a myriad of problems," said Raleigh Ormerod, product manager at Rain Bird, Tucson, Arizona. "It's safer and better to have your manifolds and valves below ground."
No one wants to see a beautifully designed landscape marred by annoying, unsightly valves and pipes that could have easily been located underground. Above all others, this may be the number one reason for installing underground valve boxes. But valve boxes do so much more.
Above ground placement of the equipment leaves it vulnerable to vandals and thieves who might view them as an attractive target. Protruding pipes and valves can create a safety concern for those who would work or play around them. In their place could be a nice even patch of ground that won't be a hazard for someone to trip on or snag a piece of clothing on.
Also, in areas that see dramatic changes in temperature, housing the valves underground provides protection -- it takes dramatically lower temperatures for the equipment to freeze below ground than it does above.
That is why many contractors have adopted valve boxes as standard operating procedure. For safety reasons, aesthetic reasons, and practical reasons, this makes good sense.
Now that we've discussed some of the benefits of underground installations, it is important that the valve box is installed properly.
Because it appears so simple, when contractors first begin to install the box, some don?t bother to read the instructions. As easy as valve box installation sounds, and as obvious as it may seem, there are little intricacies to doing it correctly? subtle things to be aware of that make the difference between a properly functioning valve box and a potential nightmare.
Somewhere, somehow, somebody is installing a valve box incorrectly. "It happens all the time, in every market, both commercially and residentially," said John Burns, vice president of sales, Carson-Old Castle, Glendora, California. Here are a few tips to help in your next installation, and to avoid some of the more common mistakes that occur in the field. Minor oversights can lead to major problems and headaches in the future.
Perhaps the biggest blunder occurs before the valve box ever sees the ground. Contractors who haven?t installed a lot of valve boxes might have the tendency to use a smaller box than is called for.
Although it houses the valves and creates the protective environment, if at any point the valves need to be serviced, if the box is too small, it's nearly impossible to work on them in the space provided. "If you use a valve box that's large enough, you have the hand clearance," said Ormerod. "Otherwise, you have to dig the box out in order to work on the valves."
"Think about what's going in the box, and what's around the box, then choose the size in proportion to the job," said Burns. "Put it like this: if you had to come back and service that box, how would you like to find it? What would you like to see?" Provide adequate space to get in there and work on or around the valves when necessary.
Some contractors tend to disregard the value of valve boxes and will install a cheaply made or inferior product. The box is specifically designed to create a safe and secure environment for the valves. To protect them, it needs to be well-made and durable. It's nice to walk away from an installation knowing that the box will do its job.
If an inferior valve box is used, it can collapse laterally or vertically. If something heavy goes over the top of it, such as a mower or someone stepping on it, or if someone puts a heavy piece of equipment next to a valve box, the pressure on the ground can cause a shift in the soil. The result is an influx in lateral weight that pushes against the walls of the housing, potentially caving in the side of the box.
This can cause something seemingly simple, like the lid popping off, or something more severe, like having to replace the entire box.
Say the lid pops off. It seems like an easy fix, right? Not quite. The lid won't just snap back on because the pressure of the earth forced the walls to cave in, which means the lid doesn't fit anymore. In this case, you?d have to dig around the box, remove the excess earth, and put the walls back to their normal positions to allow the lid to fit again.
To shave a few pennies off the price, some contractors might use a lesser product. Using a quality box and spending the few extra dollars can ensure that you won't be going back to replace a faulty valve box.
"People tend to discount the importance of quality valve boxes, saying, 'Oh, a valve box is a valve box'," said Burns. "But a cheap valve box just does not perform the way a quality valve box does. A valve box is something that needs to be of high quality." Be aware of the situations and consequences of using an inferior box.
Also, because the instructions are so seldom followed, another mistake that is made before the box ever goes into the ground is that the ground is not properly prepared.
Prior to installation, you should prepare a crushed rock base. "You need to measure, and get the level of the crushed rock, not gravel -- gravel is fluid, and it moves," said Burns, "Crushed rock locks into itself."
You need to establish a good firm foundation rock base that's installed a number of inches below the grade level -- the expected finished grade level of the valve box.
This is an important step in installation and should be taken into consideration for two reasons: first of all, you won't have drainage. Without the rock base, the box has a propensity to fill up with water and will not drain properly. "If you have a problem that requires service," added Burns, "you would have to go clean out the muck and bail out the water, or pump it out before you could service it."
Using a crushed rock base provides a place for the water to go without causing a backup in water flow, or by causing the box to sink further into the ground due to the added weight of the water.
Also, the base provides just that, a base to prevent sinking. With the rock base, the valve will not heave or tilt or sink or settle. It will stay precisely where you installed it, at grade level, nice and smooth, the way you want to see it.
If you don't have the time or want to take the time to dig a deeper, bigger hole to prepare a rock base, there are alternatives. To alleviate the necessity of the rock base, and because manufacturers are aware of the added installation time that is required with the rock base, some are now making models that have a rim or a lip around the top. This rim sits on top of the ground to prevent sinking or listing. It's more stable and eliminates the need for rock beneath the box. The lip guarantees that the box will stay right where you installed it.
It's always advantageous to install the box so that the lip is just above ground. The reason for this is that generally the grade is going to creep up -- the soil will settle and the grass will grow around it. The growth will vary from location to location, so use your best judgment. In some cases, you might install the box a few inches above ground to make way for the inevitable growth.
However, if you install the valve box too low, the box has a tendency to get covered over or washed over, making it extremely difficult to find, no less access the valves. If you install it too high, it becomes a safety hazard. A protruding box that is not out of the way or next to a structure tends to be in an area of play or high traffic. It becomes a tripping and falling hazard for kids and adults alike. Not to mention that a box which sticks too far above the ground is unsightly.
Think about the lifetime of the box and the quality of the material. Install a properly sized, well-made, durable valve box. Prepare a crushed-rock base. Have it properly installed, relative to the height and grade, and you'll have a safe, protected environment for the valves to operate -- free from vandalism, from the elements, free from the kids, and the sighs of people who find their appearance unpleasant.
After spending all that money for an irrigation system, doesn't it make sense to protect that investment with something as simple and effective as a valve box?