Swimming Pool Structural Engineering - Custom Vs Generic

 Defective Infinity or Vanishing Edge Swimming Pool Expert Witness Paolo Benedetti discusses the importance of using project specific structural engineering and geotechnical reports.

Generic or Project Specific Engineering?

Generic structural engineering fills a void in the concrete swimming pool construction market by providing cost effective "ready made" and "off the shelf" engineering.  These plans are sufficient for most tract home pools with a flat yard and no surcharges.

Project specific engineering is structural engineering that has been designed FOR YOUR SPECIFIC PROJECT.  This means that the experts have consulted with each other and have designed something that will economically function on your site.

The Dangers of using Generic Engineering

The publishers of generic structural engineering provide a catalog or on-line listing of their various plans and construction details.  This allows the pool builder to select the products that they need & rapidly receive the plans.  Therein lies the whole problem...  the pool builder SELECTS  the engineering, the strengths and what is required.

Soil Conditions

Though the plans are engineered, each is contains details unique to the soil conditions.  Standard plans are designed to accommodate various types of expansive soils.  Many contain three to four various steel schedules, based upon the soil condition on the construction site.  Who determines the soils conditions on the site and the resulting strength of shell to use?   The pool builder, of course.

Without obtaining a soils report (aka: geotechnical report) prior to construction, then your pool builder will select the appropriate (or inappropriate) engineering.  There is ABSOLUTELY NO WAY to determine the soil conditions without a soils report.   

Site Conditions

Generic mail order plans also do not take into consideration the "site conditions" on a construction project.  The structural engineer has not reviewed the topography of the site to determine if any surcharges are present.  A surcharge is something that can potentially place stress upon the pool structure.  Surcharges can be nearby up slopes, down slopes, buildings, structures, lakes, retaining walls, surf, snow, wind or even seismic events.

Without a structural engineering review of the project plan, soils report, topographical map and site images, the responsibility of identifying these surcharges is left to the pool builder.  Even if they do identify potential surcharges, do you really want them determining the amount of surcharge?  Are you confident that they identified ALL of the potential surcharges?

Catch-All

Generic engineering is designed to be a catch-all for all geographic regions where the mail order engineering firm is licensed.  This means that the plans may include structural elements that are not required in your local.  This all translates to unneeded additional cost for the buyer.  The plans may also omit items that may be required by local code or ordinance.

Additionally, these plans are only designed to meet the MINIMUM standards.  Though industry standards often utilize 4,500 or even 5,000 PSI concrete, these generic plans oftentimes only specify 2,500 PSI concrete.  

Why?  Because most pool builders who are utilizing mail order plans are cost conscience.  5000 PSI concrete costs more.  Concrete exceeding 2500 PSI also requires that the placement of the concrete be inspected by a special deputy inspector, and in some regions, a quality assurance testing laboratory.  Again, additional costs.  But why wouldn't you want these workmanship guarantees and quality assurances?

Correctly Utilizing Generic Engineering

If you plan on utilizing generic mail order engineering, then there are some things that must occur:

1.  A soils report for the construction site must be provided to the structural engineer.  Test borings must occur in the proposed locations of construction.
2.  The structural engineer must be provided site images, a topographical map and proposed project layout.
3.  The structural engineer must provide a letter or notations on the plans that they actually reviewed the soils report & make reference to the Soils Engineering Report, date and author.
4.  The soils engineer, then must review the generic mail order structural engineering and write a letter stating that they have reviewed the structural engineering and that they agree that the plans meet or exceed the requirements for the site.
5.  The structural steel should be inspected by the structural engineer to verify that the plans were followed.  This can be an in person inspection or through digital photographs.   An "inspection letter" should be obtained, stating that the structural engineer has reviewed and approved the steel placement.
6.  Minimum concrete strengths should be 4,500 PSI.
7.  An inspector should be present during all gunite/shotcrete placement.  Samples should be sent to a testing lab to verify that you're getting what you paid for.

Why not use Project Specific Engineering?

Since project specific engineering requires that the same steps be followed as using generic engineering correctly, why not just obtain project specific engineering?

GOOD QUESTION !

Paolo Benedetti Aquatic Artist, Consultant & Construction Defect Expert Witness
"Creating water as art."™
Aquatic Technology Pool and Spa
©www.aquatictechnology.com

Consumer Mistakes when Buying a Swimming Pool

Many consumers approach construction projects like they are buying a consumer commodity.... which is the furthest from the truth.

 

You're not buying a TV at Walmart

A swimming pool is a personal item - one that should be designed around the buyer, their lifestyle, how they entertain and the intricacies of the building site.  Unlike consumer commodities like tv's, the quality, design and performance varies by the designer or contractor.  In construction, it is the buried components that determine the long term performance of your project - and the cost of operation.

Not getting educated

Picking companies from the Internet or yellow pages based upon a pretty website or large ad is absolutely wrong.  Most pool construction companies employ a team of salesmen, who's job it is to "sell you a pool."  They are not interested in educating you as to the correct way to build a pool.

They are only interested in signing that contract.

Do your research BEFORE you talk to the first company.  The Internet is full of information, but don't believe everything on the Internet.  Create a list of criteria that you'll use to select your contractor.

Over reaching

It is foolish to call swimming pool contractors and request a "free quote."  You cannot make rational comparisons between different designs and specifications.  Since most swimming pools are built utilizing the lowest quality workmanship & materials without any written criteria or construction specifications, how can you possibly compare bids?

Since the salesman is out to SELL you a pool he is interested in "churning out" a plan or project scheme as fast as possible.  The quality of the design and project specifications are going to be reflect in the "FREE" effort they expended!  You get what you pay for!

Lack of Due Diligence

Everyone is willing to provide you with a list of references.  They are NEVER going to give you the list of people that they pissed off.  But how do you find these people???  Through due diligence and legwork.

Check the local Better Business Bureau.  They will not be able to give you references, but their records may represent a trend.  Where there is smoke there is fire.

Check the local court records.  Many are available for review on-line.  The builder may have been a plaintiff (suing to get paid) or a defendant (sued by an upset customer).  Contact the other party, learn what went wrong, why there was a dispute, why it ended up in court, and if the issues were resolved.  TAKE THE COMMENTS WITH A GRAIN OF SALT.  Remember, you cannot always please everyone.  Some consumers are unreasonable.  What you are looking for is a PATTERN of upset consumers in their wake.

Check the Contractors Licensing Board - Not every state requires that contractors be licensed.  Those that do, usually have records visible on-line.  Search other licensed states, as some builders that had licenses revoked in other states merely move to another state.  If a contractor has had any complaints or actions against their license - again, it illustrates that they cannot resolve issues before they get out of hand.

Check out on-line reference websites: The Franklin Report, Yelp, Angie's List and others.  Again, take what you read with a grain of salt.  Remember, you are looking for a pattern of happy or unhappy customers.

Review building permits issued in surrounding communities.  Most building departments have searchable on-line databases.  Search for the last 4-5 years of permits.  Contact these owners.  Most will be happy to provide a candid review of the contractor.

Price Point Decision Making

Warning: The prices are going to be all over the map.  Trying to compare apples, to oranges, to grapes, to lemons will only result in a brain full of fruit salad.  How do you make sense of it all?

It is best to obtain a design package (sometimes called a "bid package").  The entire project will be defined with schematics of the plumbing, high & low voltage electrical and lighting.  It will include illustrations of the minute details that are unique to your project.  It will also include construction and workmanship specifications.

Utilizing a "bid package" allows all possible contenders to provide a quote based upon the same exact set of criteria.  Stand your ground - ensure that they realize that substitutions are NOT ALLOWED.  This will ensure that the design does not get altered and that the performance is not degraded.  It also ensures that you are comparing APPLES TO APPLES !

REMEMBER: 
YOU GET WHAT YOU PAY FOR!  
IF SOMETHING IS TOO GOOD TO BE TRUE - IT IS!

On-line Quotation or Consulting Services

You cannot design a pool or provide a quotation on-line.  Just like I cannot paint your house or change your car's oil over the phone.

It is impossible for anyone to validate any assumptions that they make over wires.  They must visit your site, sit down with you, understand your budget and needs.  They have to get to know YOU!

Prices are lower in a down economy or in the off season

 Labor expenses, overhead, insurances, fuel, concrete, steel and everything else that goes into the construction of a pool is constantly increasing in price.  

There is no better time than RIGHT NOW to build a pool.  Why?  Because next year those items are going to cost even more!

The best pool designers and contractors are still busy, even in a down economy.  They are not going to "work for wages."  It ends up becoming a losing proposition in the long run, and the smart ones know that.  And you don't want to hire the dumb ones that will work for wages.  They just won't have the resources to perform system tweaks later on or perform warranty repairs.

Failing to Review and Understand the Contracts

A contract is a two-way street.  It should clearly define everything that you are to receive.  It should outline the contractor's obligations.  Anything that was promised during a sales presentation should be included in writing.

Ensure that a dispute resolution process is included.  Know what your obligations are: paying invoices within XX days of receipt; providing a soils/geotechnical report; marking property lines, boundaries and easements; obtaining planning department or HOA approval; providing trash disposal, dumpsters, electricity or toilet facilities; repairing fences, sprinklers, sidewalks and driveways, upgrading the electrical or gas meter... the list goes on and on.

Not obtaining proper structural or mechanical designs

Most swimming pools are design and specified by the salesman.  They have little or no knowledge of structural engineering, proper filtration, circulation or hydraulic designs, mechanical systems, water chemistry management, state of the art controls and automation or alternative energies.

Most select plumbing sized based upon a guess and not sound hydraulic design calculations.  When properly sized, the response from most potential bidders is "the pipes are way too big," "who specified these huge pipes?," "way overkill."  In reality the plumbing should be specified based upon the science of hydraulics (physics), which these contractors and salesmen apparently do not understand.  When you hear these responses, you should have one reaction... cross them off of your list.

Do they require a soils report?
Where do they obtain their structural engineering?  
Does the structural engineer actually review YOUR project plans, site/topographical map AND the soils report, prior to defining the strength of the pool shell and placement of the steel?  
 Will the engineer sign on the plans that they have reviewed those documents?  

This is very important because:
a) it ensures the consumer that the contractor forwarded those documents for review
b) you'll know that the document were actually read by the engineer
c) many contractors just buy random structural engineering on-line or mail-order (based on their best guess)
d) you are guaranteed that your pool is going to be built to withstand the forces from your soil and your site conditions.

Thorough plans prevent surprises

Having a thoroughly thought out set of plans with defined specifications ensures that there are not future surprises.

The plans should also include any infrastructure required for future projects.  Getting water, gas, sewer & electrical routed under the hardscapes & plantings now, will be less expensive than tearing it all up to install them at a later time when that outdoor kitchen, shower, cabana, guesthouse, garage or barn is built.  Maybe incorporating future connections for alternative energies may be something of interest. 

The safety components of the project, from fencing & gates, door alarms, pool covers or an integrated anti-drowning alarm system should be a part of the plans and contract.  You don't want to miss the final inspection because those items were left off for you to handle.

Best Advice

1) Hire a well respected designer or consultant to design your dream backyard, before you start construction.  
2) Hire the best contractor that you can afford.  
3) And if you are not hiring the BEST AVAILABLE, then come to the realization NOW that everything will not be PERFECT.  Nor should you expect or demand perfection from those lesser contractors.


Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool and Spa
©www.aquatictechnology.com