Tuesday, December 9, 2014

Lowest Bid Swimming Pool is not always the lowest cost

General Contractors who are bidding the development of a property often times solicit bids from aquascape consultants and swimming pool contractors.  Yet, in the end the lowest bidder often times ends up being more expensive that the most expensive bid.  How is that so?

Experience and knowledge

The highest bidder is usually the one with the most knowledge and experience.  They have the foresight to anticipate additional costs.  Those costs and "extras" are built into their bid, saving them the hassle of justifying future change orders.

Change Orders

You should be asking yourself, "Why is the high bidder so much more expensive than the lowest bidder?"

The low bidder is going to present you with multiple change orders during the project.  Those increases in cost are going to push your overall costs close to that of the more experienced builder.

So why not just hire the best to begin with?
Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com 
Visit his website at: 
© Aquatic Technology Pool & Spa, 2013. 
All rights reserved.

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Wednesday, November 19, 2014

Proper Compaction of pool deck sub-base

Base materials are not "self-compacting" merely by dumping them on the ground.  To ensure longevity of the concrete pool decks proper compaction procedures must be followed.

Soils Report

A thorough soils report will make minimum recommendations for the preparation of the pool deck sub-base.  This may include over excavation, removal and recompaction, or the importation of materials.

The most common method is the over excavation of the pool decks when the pool is being dug.  After back filling the plumbing and utility trenches, a base material is imported to build the site back up to the proper elevation.

The soils engineer will specify the materials to be used.  It may be sand, road base or crushed rock.  The thickness of this material is specified by the soils engineer.

Proper Compaction

The thickness of this material will determine the compaction equipment that is to be used.  The confinement of the site will also dictate is larger, more efficient equipment can be used.

Jumping jack tampers are reserved for compacting trenches and open pits.  Vibratory plates are used for thin layer of materials or final compacting.  Walk behind or ride on compactors are sued when the material is to be compacted in 4-6" lifts.

Rolling compactors are the most efficient, as the size of the roller quickly compacts a lot of terra firma.  

Using the improper equipment is not only a waste of time and money, it will not result in a stable base.  Spreading a foot or more of material, and expecting to compact it with a vibratory plate is a fool hardy endeavor.  

While the top may become compacted, the bottom will remain loose.  Over time that material will settle, resulting in deck movement and cracking.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

Monday, October 27, 2014

Waterproofing and drainage - retaining walls and basements

Providing drainage alone behind retaining walls and against basement walls is not sufficient to prevent water migration through the wall.

Different Purposes

Drainage and waterproofing behind walls serve two distinct purposes.  Drainage is installed to transport ground water away from the structure.  Removing the water reduces the hydrostatic surcharge (weight of wet soil on the structure) and helps the waterproofing resist water intrusion.

Given infinite time, water will eventually seep through any waterproofing system.  Reducing the water in the soil adjacent to the wall, increases the waterproofing system's chances for success.

A waterproofing membrane is installed on the concrete, to protect it from water that migrates through the drainage system.  The waterproofing system also prevents water from seeping into and through the wall.  

Water passing through a wall can cause a myriad of issues: corroded reinforcing steel, mold and mildew in the basement, dampness and cold, dry rot, corroded nails and fasteners, electrical shorts, efflorescence, decay and discoloration of surface finishes.  As reinforcing steel corrodes it expands.  The steel's expansion can cause the concrete to crack - allowing even more water to enter.

Drainage Systems

Drainage systems should consist of a crush proof perforated pipe, wrapped in filter fabric.  The pipe should be installed with the holes DOWN.  As the rising water level enters the perforations, it will flow away in the pipe (incorrectly placing the holes up, forces the water  level to rise to the height of the holes, before it can flow away).  The filter fabric around the pipe, prevents it from filling with dirt, sediment and fines from the gravel.

Though inexpensive and readily available, black corrugated drain pipe is subject to collapse and filling with sediment.  It should not be used and is frequently prohibited by structural engineers and geo-technical engineers.

Vertical drainage behind the wall can be provided by crushed gravel or drainage mats.  Drainage mats provide time and labor savings.  They should be installed with the fabric side towards the soil.  Drainage mats also provide another impermeable layer of protection behind the fabric layer.

Click on image to see the lack of waterproofing and drainage
Waterproofing (aka: damp proofing)

For a basement redundant layers of protection are warranted.  These would entail an integral waterproofing agent mixed right into the concrete and an external membrane system.
Basement walls lacking waterproofing membrane (click image to enlarge)
There are a host of choices available to choose from, when selecting a surface applied membrane system.  There are spray on, roll on, peel and stick and panel systems.  What ever system is chosen, it must no have seams that allow the passage of water.  They should also extend below the perforated drain pipe and to the bottom of the structure.

Perimeter drainage around the foundation should be installed similar to that behind a retaining wall.  However, provisions will need to be incorporated for a sump pump to discharge any collected ground water, as the basement drainage system is usually below grade.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

Friday, October 24, 2014

Floor tile crack control waterproof membrane - Proper Application

To achieve the full benefit of a floor tile waterproofing and crack control membrane, it must be installed in adherence with the manufacturer's instructions.


The substrate needs to be clean and free of foreign matter: dirt, oil, grease, dust, moisture.  These create a layer between the substrate and the membrane that prevent complete adhesion.
Improperly applied TEC Hydraflex Membrane - click on image to enlarge


For the membrane to be effective, it must be installed to the thickness specified by the manufacturer.  To achieve these thicknesses oftentimes requires 3 to 4 coats.  One layer is usually insufficient.

Good rule of thumb: If the substrate can be seen through the membrane, the membrane is too thin.  Better yet, buy a tester and measure the membrane thickness to verify the minimum thickness has been achieved.


The membrane must be cleaned of dirt, dust and debris that collects on top of it.  Thinsets and mortars will not adhere to a dirty membrane.


Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

Wednesday, October 15, 2014

APSP NPC ANSI ICC ANSI/APSP-12 Pool Plaster Standard

ANSI/APSP-12 Swimming Pool Plaster Workmanship Standards

How bad can it get and still be defensible?

On July 28, 2014, the APSP and the NPC announced a “joint” committee to write a new plaster workmanship standard, under the guise of APSP/ANSI-12.  The alignment of APSP with ANSI, would in effect cause the resulting standards to become “statute” in many regions of the country.  Through ANSI's affiliation with the ICC (International Code Counsel, who ironically published the International Building Code, which has been adopted across the US), this may just become law in your state. 

You can see where this is going.  It is a end around run on consumer rights, forcing them to settle with inferior workmanship, just because it meets the industry's own minimum acceptable level.  

In other words, "how bad can it get and still be defensible?" 

Their proposals for this standard include defining acceptable "deviations" and explanations as to why pool plaster cannot achieve the levels of performance delivered by other plaster trades.  These deviations will be governed by "accepted trade practices" and not the BEST AVAILABLE PRACTICES.  Again, locate and identify the lowest common level of performance and make that acceptable.

Fox in the Hen House

Trade associations writing their own workmanship standards is self-serving and against the general interest of the American public.  Even if a standard is written with the absolute lack of personal biases and interests, the end result will still be a self-serving document.   

This is what I take offense with… putting the fox in charge of the hen house.

The pool builders association will continue to refuse to hold their members responsible for delivering properly constructed and prepared shells, watertight, trimmed and prepared to precise tolerances.  Due to the generous workmanship tolerances provided pool builders, plasters are relegated to dealing with the issues and variables you described.  Almost every one you describe is the result of a poorly constructed shell.

There is absolutely no reason why a plaster pool finish cannot be delivered with a smooth, even finish that is color consistent from batch to batch.  Many of these issues are a direct result of the human tendency to avoid conflict or extra effort:

·      Plastering in adverse conditions (e.g. high winds, extreme heat/cold)

·      Staffing difficulties (e.g. insufficient time allotted, inadequate staffing levels, poor training)

·      Improperly prepared shells (e.g. leaking, seeping, voids, dry, hot)

·      Shells with poor tolerances (e.g. wavy surfaces, penetrations trimmed at incorrect elevations, improper radii)

·      Poor quality control measures (e.g. failure to measure/weigh batch contents or water)

·      Failing to perform pre-site visits, preparations or inspections

·      Refusal to hold builders responsible for making shell corrections

No one wants to tell the pool owner that their pool will not be plastered due to any issue.  Nor is it cost effective to have to leave and return.  Most pools should never be plastered in their state of readiness, as delivered to a plaster company.  Yet the plaster company wants to satisfy their customer - not the pool owner, but the pool builder who brings them steady business. 

I find the lack of a quantifiable maximum water to cement ratio for a cementitious finish audacious.  Pre-packaged materials should contain maximum allowances for water or approved admixes.  Yet the loose NPC standards allow the crews to add water to extend its workability due to weather, short staffing or mere laziness or refusal to measure the water (they just add water from a hose until it looks good ).

Too much water is bad

It has been scientifically proven that excess water in cementitious products compromises it’s strength, causes discolorations, increases porosity, encourages shrinkage and promotes check cracking.  The NPC should not be allowing carte blanche with the water to cement ratio and then attempt to justify the errant results. 

To advocate the unfettered use of water by untrained personnel is irresponsible, especially when there are inexpensive and viable alternatives and techniques.  Instead, the NPC should be promoting improved quality through the use of various admixes – additional water, not being one of them.  Set accelerators, retarders and plasticizers should be the norm, instead of the exception.  The workability and plasticity of the product would improve, as would the durability and quality.  Archaic practices, such as the addition of calcium chloride and the re-tempering of finishes would no longer be required or acceptable. 

Acceptable Alternatives

These advanced methodologies and admix practices should be advocated and promoted.  Calcium chloride alternatives and set timing admixes are utilized in every other plaster trade, in compliance with the requirements of the pigment manufacturers.  Steel troweled plaster finishes are applied multi-stories in the air, delivered by the bucket, on scaffolding, in the hot sun and in windy conditions.  Their substrates are wavy and irregular.  These trades even lack the luxury of flood curing their finishes.  Yet the results are often far superior to the results seen in the pool plaster industry – even without remedial work. 

Cement chemistry is nothing new.  It dates back centuries to the Roman’s use of volcanic ash as pozzolans and animal fats and milks as plasticizers.  Yet, the swimming pool industry is always the last to embrace decades old and proven methodologies and technologies that are utilized in other related construction trades.  When these practices are “discovered” by our industry, their revelations appear as a sudden rapture (recent case in point – penetrating sodium silicate curing compounds for shotcrete & concrete).

Virtually flawless pool plaster finishes are achievable.  I consider myself very lucky to have plaster sub-contractors who understand the idiosyncrasies of their trade.  I take pride in delivering a high tolerance and quality watertight shell upon which they can ply their trade.  Pre-site inspections with my sub-contractors identify concerns that can be addressed prior to plaster day (pressure washing & surface prep, local water quality, staffing requirements, weather forecasts, access, etc.). 

My favorite sub-contractor (Adams Pool Specialties) brings their own water supply, which is measured as it is metered into the batch.  This is not rocket science – just an expressed concern with craftsmanship.  The end results are that my clients receive a virtually flawless hand troweled plaster finish, free of the issues that plague the industry.

Through this new joint APSP/ANSI-12 standards committee, the NPC has the opportunity to establish shell tolerances and standards, which will allow their members to execute higher quality finishes.  NPC members should no longer accept shells that fail to meet defensible workmanship standards and design tolerances, which affect their end product.  The American public needs to be given cosmetically acceptable standards, not minimums that are barely acceptable.  The need to defend the resultant questionable workmanship and cosmetic blemishes will become a thing of the past.

Let's see who takes the high road...

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

Saturday, September 27, 2014

Swimming Pool Expert Witness - How Structural Engineers Compromise themselves

Swimming pools can be designed utilizing 2,500 PSI concrete.  
However, the American Concrete Institute - Standard 318 (ACI-318), the International Building Code (IBC), and the California Building Codes (CBC) all specify and require 4,500 PSI as the minimum, with 5,000 PSI required, for most swimming pools.  This standard actually applies to all concrete structures in constant contact with water (fountains, pools spas, watershapes, dams, storage tanks, docks, pilings, breakwaters, etc.).

Expert Witness - Structural Engineer ?

So, if the codes and LAWS require higher PSI concrete, then why do many structural engineers specify 2,500 PSI for swimming pools?

They think that they are doing everyone a favor.
Specifications above 2,500 PSI require special inspections, quality assurance lab testing, and many other minor additional expenses and double checks.  Something most budget conscience swimming pool contractors would rather not deal with.

Though these structural engineers can show on paper that 2,500 PSI is sufficient, they cannot justify their non-compliance with the laws, codes and statutes.

Compromised as an Expert Witness

If a structural engineer has delivered thousands of plans in violation of these laws, codes and standards, does that compromise their integrity as an Expert Witness?

If they continue to deliver plans in violation of these regulations, even after they have been made aware that they are not compliant, do they even have any value as an Expert Witness?

How do they justify such behavior and blatant disregard for the laws and building codes?

Do you really want one of these clowns as your Expert Witnesses?

Wait until the opposing attorney gets them on the stand and asks them under oath !

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

Monday, September 22, 2014

East Hamptons - Preventing Swimming Pool Deck Frost Heave Damage

What is Frost Heave?

More precisely it should be called "freeze heave."  When the wet soils become frozen, they expand.  These expansive forces usually go horizontally and vertically.

If the soils are constrained (surrounded by immovable objects) by a building foundation, retaining wall or swimming pool, they will push against those structures.  The weakest structure loses, and may experience structural distress.

Usually these forces  push upward, causing the concrete pool decks to heave or buckle.

An Ounce of Prevention

Proper preparation of the materials that underlie the concrete is key in preventing frost heave.

Preventing the underlying soils from becoming saturated, prior to a hard freeze is key.  Replacing the soils with drain rock, to a depth below the frost zone will greatly reduce soil saturation.

However, the water must be given a way to escape.  Perforated drain pipes, sump wells and daylight drains can assist as well.

Preventing water from running off of the decks and into the surrounding planters or lawns will also eliminate a lot of the ground water.  An 18-24 inch deep (or deeper) footing around the perimeter of the deck will also prevent irrigation water from seeping back under the pool decks.

Keep it Dry & Warm

Basically, the key is to keep the soils under the pool decks from becoming saturated.  Dry soils will freeze, but will expand minimally.  

Saturated soils will expand exponentially, causing cracked concrete (allowing water to seep under the slab), loose stone work and heaved pavement.  Well drained soils or gravel will not retain water & thereby not expanding sufficiently to cause damage.

Some success has been achieved with the heating of slabs and insulating the underside of the slabs.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. 

All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.

Sunday, September 7, 2014

International Aqua Design and Watershapes Consulting

With a background in swimming pool construction, design and operations, we deliver thoughtful designs with an emphasis on reducing reoccurring maintenance, operating and labor expenses.  A focus on the ROI drives our design decisions.... the REAL definition of VALUE ENGINEERING.

A few extra dollars spent upfront can bring a significant savings in maintenance, operating expenses, labor, downtime and ease future expansion.


Combining 20+ years of actual construction experience, watershape consulting, owner's representation, quality assurance, construction defects expert witness, a formal business degree and graduate courses in watershape and aquatic design - our background is unparalleled in the swimming pool design industry. 

We are not "self-trained," but are rather one of a few firms uniquely educated trained and qualified to design and engineer complex hydraulic systems and concrete pool structures. With a background in international consulting and as the owner's representative, makes us uniquely qualified in the entire world.

Educator and Published Author

Our founder has authored 100+ articles on such topics as swimming pool design, watershape consulting and construction defects.

He has taught courses on pool construction, waterproofing and aqua design to international audiences.

Uniquely qualified in all of the world - personal enough to be yours.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. 
All rights reserved.

Saturday, September 6, 2014

Aqua International Swimming Pool Design Consultants and Engineering

Whether your project is in Arizona, New York, Florida or California, the National Electric Code applies to your project.  And service disconnects are the most frequently omitted item on swimming pool projects and plan specifications.

NEC 680

Most people involved with the design or construction of swimming pools, merely focus on NEC Section 680, because it deals specifically with swimming pools and spas.  However by law, they are equally responsible for the entire contents of the NEC.

NEC 430.109(B)-(D)

The NEC requires a permanent means of disconnecting equipment for service purposes. 
The disconnect must be located on the equipment itself or within the line of sight of the equipment. 

Circuit breakers are referred to in the NEC as a branch circuit over-current protection device
According to the NEC 430.109(B),
branch circuit over-current protection devices shall not be used as the disconnection means for motors greater than ½ horsepower. 

For motors between ½ and 2 horsepower you cannot rely on the breaker.  Per NEC 430.109(C) you need a separate means to disconnect the power.

Variable speed pumps are a perfect example why we need service disconnects - they are wired so that they constantly have live power running to them - 24/7.
They are signaled to turned on and off via a data cable and not by way of switching the power on or off.  As is, the only way to turn off the power to the pump is at the circuit breaker.   But their nameplate rating is greater than 1/2 horsepower.
Therefore, that would be in violation of NEC 430.109(C).

The solution is to install an approved means of disconnection between the circuit breaker panel and the equipment.    

Section 680 of the NEC is not the only section that applies to swimming pools....  

Time to break out the NEC code and do some reading, isn't it ?!

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. 
All rights reserved.

Thursday, September 4, 2014

Miami, Florida Watershape Aquatic Consultant Swimming Pool Designer and Expert Witness

Smooth dowels should be utilized to transfer loads between adjacent concrete slabs.  This typically occurs where a pool deck abuts a building's foundation.

Required by Codes and Standards

The standards set forth by the American Concrete Institute (ACI) are incorporated in and adopted by almost every building code in the United States.

ACI 302.1R goes into great detail about the proper installation and requirements for doweling adjacent concrete slabs and foundations.

Freedom of Movement

Allowing the dowels to move freely within the slabs is one key requirement.  This is why greasing, smooth bars and sleeving are key elements.

Smooth dowels are similar in dimensions to typical deformed reinforcement steel (rebar), except that smooth bars do not have any ridges (deformations) along their length.  They are smooth...

Sleeving and greasing are two common methods to ensure that the dowels can slip freely within their cavities (when installed after one slab has hardened).

Dowel chairs (dowels supported on wire baskets) are commonly used when foresight allows their installation prior to the first concrete pour.


The improper installation of dowels can lead to transfer cracking of either slab.

These are usually caused by the use of deformed bars, whose ridges grab within the drilled holes.
The transfer of stress, causes the bars to crack one or both slabs.  Not a serious problem on a patio, but it can be a problem with building foundations, slab floors, highways and bridge decks. Cracks allow water intrusion and possible corrosion of the reinforcement steel.  This is why most smooth bar dowels are epoxy coated.

Following the standard industry accepted methods and practices will prevent a lot of repair expenses later.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. 
All rights reserved.

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Wednesday, September 3, 2014

Hamptons Swimming Pool Aquatic Consultant

Expert witness and construction defects consultant Paolo Benedetti of Aquatic technology Pool and Spa (www.aquatictechnology.com) discusses the importance of isolating the pool decks from the pool structure.


Independent movement is critical for the proper performance and protection of the swimming pool structure.

A 1/2 inch layer of closed cell foam should isolate the pool structure from the concrete deck and any stone or tile overlay.

Tying the pool structure to the pool deck with a few pieces of rebar or resting the pool deck on a ledge of the pool structure, will subject the coping and/or tile to horizontal stress when the decks move. 

A hinge effect is created where the pool deck is tied to the pool structure.  A few measly pieces of rebar will not prevent this hinging effect. Expansive soils can easily bend these bars and crack the pool structure.

This transferred stress will also result in cracked tiles, loose coping stones and a cracked pool shell.  This is usually evidenced by horizontal cracking within the top 6-8 inches of the pool, usually through the tile.  Loose and dislodged tiles soon follow.

Frost Heave and Expansive Soils

Deck movement can occur from expansive soils or frost heave.  The forces generated by these movements are enormous.

Cheap Protection

To protect the decks and any outdoor structure from such damage, it is a wise idea to place isolation foam everywhere the decks abut an immoveable object (planters, foundations, retaining walls, columns, pool structure, bbq, etc.).

To prevent water from getting into the joints, they should be sealed with an appropriate elastomeric sealer.  This help will prevent the soils under the concrete from becoming saturated from bather splash or rain water.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: info@aquatictechnology.com or 408-776-8220. Visit his website at: www.aquatictechnology.com. All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.