Saturday, February 21, 2015

Natural Stone around Swimming Pools

Natural stone is beautiful adjacent to water.  But not all natural stones are suitable for use around swimming pools.

Chose the Right Stone

The density of a stone will help determine it's durability outdoors.  Soft stones will wear from traffic, spall, crack and stain easily.  Many people like the softer appearance of these stones, such as flagstone, limestone, shale and sandstone.  These stones are known as sedimentary rocks.

The porous nature of these rocks also makes them susceptible to  cracking from freeze - thaw cycles.  They are suitable for use in warmer climates, however they will experience issues in colder climates.  Irrigation overspray and chlorinated pool water can also cause damage to the stones.

These stones stain easily.  Stains easily penetrate the matrix of the stone due to their porous nature.  They will quickly degrade in oceanfront applications, due to the salt exposure.

Igneous rocks such as granite and basalt are much denser.  As such, they are more suitable for use outdoors and around swimming pools.  Like any stone, they are susceptible to damage and staining.  But their density prevents deep penetration of the stain.  This density also helps resist free - thaw damage.  Splash out from salt water pools also seem to cause less damage to these  stones.

Metamorphic rock, such as marble may not be the best stone around swimming pools.  They tend to be soft and contain minerals that are easily dissolved by salts.  Chlorinated pool water can wreak havoc on these stones.  Common pool chemicals, acids, food and drink stains if not attended to swiftly can lead to permanent stains and damage.

Get it in WRITING

Who ever specifies and recommends stones for use around a swimming pool should be asked these questions.  They should respond to them in writing, so that the owner has documentation as to the performance of the materials.

If there is any doubt, inquiries should be made of the rock quarry.  They know the exact properties of their products, the densities, compressive strengths, permeability and resistance to freeze - thaw issues.

When in doubt - get it in WRITING.

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

Sunday, February 15, 2015

Water loss in wintertime heated Pools & Spas

Your in-ground concrete spa or above ground portable spa seems to lose water in the winter months, even though you have a cover on it.  You suspect a leak... But I doubt that it is even leaking.

Wintertime Water Loss

How is it that your pool or spa loses water in the wintertime?  Let's think about this... 

Do you see that stuff floating in the air above your pool or spa?  That's called steam.  
Newsflash - that steam is water!

Even with an insulated cover, your pool or spa will lose water, just like it loses heat.  The greater the temperature differential between the air and the spa water temperatures, the greater the amount of steam that will be produced - (more water and heat that will be lost).

Bucket Test

The best way to satisfy your curiosity, is to perform a bucket test.
Uncover the spa and place a bucket of warm water into the spa.  The rim of the bucket must rise slightly above the spa water level.  
Weight the bucket down with a brick if needed to keep it from moving around.

Mark the water level on the outside of the bucket.

In 24 hours, check the levels of the level in the spa and inside the bucket.  If you do not have a leak, the levels should be close to each other.  

If there is a great difference then proceed to a static test.  Basically, repeat the same test, this time with the equipment off for 24 hours.

Warning: You assume the risk of frozen, cracked or damaged pipes/equipment if you chose to perform the static test when your spa may freeze up.

Typical Water Loss

Spas and pools that are heated during the wintertime may even experience greater water loss that during the summertime.  
How's that even possible?

The temperature difference is a lot less during the summer months, so the water and heat loss is less.

Depending on the temperature differences, wintertime heated pools and spas can lose 2 - 3 inches of water in a 24 hour period.  
If this is not acceptable to you, then consider draining and winterizing your vessel.  That steam you see is MONEY - water, heat and chemicals floating off into space.

Otherwise, crank up the heat, open a bottle of wine and start adding water.  Enjoy it, because we cannot turn off physics.

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

Saturday, February 14, 2015

Aquatic Consultant and Professional design Collaboration

Design Collaboration is a team of professionals working together in the client's best interest.

Going it Alone

Many design firms, whether they be interior designers, landscape architects, architects or self-proclaimed "designers," attempt to go it alone - for the glory.  Their egos do not allow them to ask for assistance on complex structural, hydraulic or design matters.

Instead they conceive of concepts, sell the client on the notion, then proceed to invest a lot of time and money into the plans.

Just not THAT way

Instead of hiring a watershape consultant to advise them during the conceptual development stage, they wait until the project design has been completed.  

At that point the errors of their ways, results in concepts needing to be modified to comply with various building codes, workmanship standards and industry standards.

Of course there is a lot of resistance in modifying the design.  The egos had already pitched and sold the concepts to the clients.  To now back pedal would only disgrace them and force them to admit their errors.

Conflicts arise, the client develops distrust and apprehension, egos are shattered and the plans are reworked.

Wouldn't it have been easier to collaborate as a team at the beginning of the project?  Doing it right the first time?  Developing client trust and future referrals?

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

Sunday, February 1, 2015

Why you need a swimming pool expert witness inspection of aqua international design or construction workmanship disputes.

Workmanship disputes

Most swimming pool construction disputes begin with a disagreement over a few minor workmanship issues.  

Why you need an expert opinion

Since most disputes are initiated over minor issues of workmanship, imagine what larger issues were overlooked?  

How can you be sure that there are not more serious issues?

Were the aqua designs internationally correct?

Did the plans even comply with acceptable industry standards for care and workmanship? 

Was the structural engineering even sufficient for your site and soil conditions?

If you are not an expert on the subject of international aqua design, construction, building codes or workmanship standards, then how can you possibly be aware of all of the relevant issues?

An expert witness will perform a visual evaluation of the project, and review the photographic documentation, project plans and specifications.  From a review of these items, opinions can be made about most items.  

If questions remain to be answered that cannot be resolved by visual inspections, sample and material testing may be warranted.

You didn't know how to build your own pool to begin with - how can you sure that everything was built correctly from the ground up?

An expert witness can help you determine if there are larger issues than the minor issues you are disputing.

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

Wednesday, January 14, 2015

Swimming Pool Reinforcing Steel Non-Contact Lap Splices

Pool Expert Witness discusses the importance of non-contact lap splices in reinforcing steel (rebar) for shotcrete (gunite) pool structures.

Since most concrete swimming pools are constructed out of shotcrete (sprayed concrete, sometimes also incorrectly called "gunite"), the placement of the reinforcing steel is critical.

Placing bars adjacent to each other (contact lap splice) is permissible for poured or cast concrete structures.  It is easy and efficient.

Contact Lap Splices

In sprayed concrete applications, contact lap splices can cause shadowing, honeycombs and voids within the structure.  

If the contact lap splices are stacked & orientated towards the direction of the sprayed concrete, shadowing will be minimized.  

However, this will also cause the reinforcing steel to be thicker, resulting in the use of additional concrete (equal to the thickness of the stacked bars).  On a large project that additional concrete cost could be substantial.

Non-Contact Lap Splices

A simpler and more economical method is the non-contact lap splice method.  Bars from opposing directions are staggered and separated by two to three inches.  This allows the concrete to encase and encapsulate each bar and virtually guarantees no voids behind groupings of bars.

 Both Contact Lap Splices and Non-Contact Lap Splices can be seen in the above image.  It is not particularly important on this project, as the floor will be cast in place concrete.

Contact the author, Paolo Benedetti of Aquatic Technology Pool and Spa at: or 408-776-8220. 
Visit his website at: 
All Contents © Aquatic Technology Pool & Spa, 2013. 
All rights reserved.
Aquatic Consultant, International Pool Designer, Pool Construction, Watershape Engineering

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: 
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: or 408-776-8220. Visit his website at: All Contents © Aquatic Technology Pool & Spa, 2013. All rights reserved.