Ground Penetrating Radar (GPR) – allows contractors to actually “see” inside pool structures. GPR systems are perfect for locating reinforcing steel and determining the thickness of the concrete. Another helpful aspect of GPR is its use in locating elements inside of framed buildings, pipes, and conduits. Though these systems typically are priced at over $12,000, once prorated across many jobs, the cost is minuscule, while the benefits can be monumental.

What is Ground Penetrating Radar?

Ground Penetrating Radar is a geophysical method that uses radar pulses to image the subsurface of the ground. It is a non-destructive and non-intrusive technique commonly employed in various fields, including archaeology, geology, environmental studies, civil engineering, and utility detection. The primary purpose of GPR is to identify and map subsurface features, anomalies, or objects without the need for excavation.

How Does It Work?

GPR works by emitting short pulses of electromagnetic waves into the ground. These radar pulses penetrate the subsurface and interact with different materials and structures. As the waves encounter boundaries between materials, some of the energy is reflected back to the surface. The GPR antenna receives these reflections, and the system processes the signals to create a detailed image of the subsurface. GPR is widely used for utility detection, subsurface mapping, and construction applications, providing valuable information without the need for excavation.

GPR For Pool Builders & Contractors

Today, construction technology is evolving. Ground Penetrating Radar (GPR) has become a valuable tool for pool builders and contractors in various aspects of their work. Here are some ways in which GPR can be beneficial for professionals in the pool construction industry:

1. Locating Utilities
2. Identifying Subsurface Anomalies
3. Mapping Soil Stratigraphy
4. Detecting Void Spaces
5. Quality Control and Inspection
6. Ensuring Compliance with Regulations
7. Time and Cost Savings

Using GPR for Non-Destructive Testing

Today, there are a number of intelligent reasons to be using a ground penetrating radar to scan your pool shells. GPR is a non-destructive method to determine what is actually occurring inside of the concrete, without having to drill cores or demolish concrete. Radar allows experts to see the rebar schedule and depth within concrete. Pool construction professionals have even used them to validate the presence of bonding clamps and wire, when inspections were missed (for other contractors).

Use of Ground Penetrating Radar in Remodeling Swimming Pools

For contractors, being able to precisely locate the placement of the reinforcing steel is invaluable. When planning for coring a shell for pool lighting, add plumbing or coring for samples, it is critical to know where the steel is located. Hitting a rebar while coring can easily damage a $500 core bit. Worse yet, a handheld drill binds and kicks back, breaking the user’s thumb.

After stripping the plaster, scanning the shell can definitively determine if there’s sufficient shotcrete coverage over the steel. If it’s insufficient, then the pool can be “flashed” with additional shotcrete (at an additional charge). This will require new coping and tile as well, as the interior dimensions will change. In my own personal firm’s pool remodeling contracts, we have a disclaimer about shotcrete thickness. We will scan the shell for free, but if there is an inadequate amount of coverage, there will be a change order to add shotcrete and adjust the coping, tile and fittings. Think of this as a potential profit center. You can actually show the owners the location and depth of the rebar.

GPR companies charge $500-600 for a 1-hour visit. You can see how quickly owning a GPR unit can pay for itself. After a while, it will actually start earning you money! A Proceq GP8800 can be had for around $12,000 plus the cost of an iPad.

Photo Credits: Proceq

Let’s face it… quality help is hard to find. You cannot have quality pool construction without quality people, either direct reports or sub-contractors.

More than having specialists, the correct employee must be assigned to the tasks at hand. The job site supervisor must understand the project expectations and make sure that the right talent is assigned to the proper task.

The supervisor must have the knowledge of how to perform the tasks. They must have the ability and authority to train subcontractors and employees on the company’s expectations and methodologies. On-the-job training cannot occur if the supervisor themselves does not possess the requisite knowledge. You must invest in your employee’s professional development, in order to create a better product.

Employees with specialized skills and interests should be encouraged to further develop those skills. Employers should embrace industry seminars and manufacturer training to further hone these skills. After all, you cannot deliver quality projects without quality people.

Communication

Nothing dovetails together more than effective communication and quality control. You must develop a consistent means for everyone on a project to communicate expectations, project specifics & details, project progress and scheduling, job site safety & compliance, policies and procedures. A lack of communication often results in costly change orders of corrective measures.

Instituting Quality Controls With Your Team

Quality control needs to be included in every team meeting with employees and sub-contractors, to ensure it remains on the forefront of everyone’s mind.

Communications should occur on a regular schedule via a digital platform that records the messages, tasks and assignments. These construction messaging platforms ensure that there are no misinterpretations and that the collaboration is smooth and efficient.

These platforms standardize the communications channels, document the decisions and approvals, and ensure that the follow-through occurs.

Planning & Documentation

Inadequate planning almost always results in poor quality, delays, defects, re-work, and cost overruns. On a fixed-price contract, these will affect the bottom line. Each year, billions of dollars are spent by US construction firms, simply because of inadequate project documentation.

I could drone on for months about the importance of detailed plans, sections, scaled drawings, written specifications, MEP schematics and material lists.

Failing To Plan = Planning To Fail

One of the most common causes of errors and losses beyond having inadequate plans, are the slow response to RFI’s and change orders. Work often must cease or efforts shifted, while the approvals or clarifications are received. Sometimes the work proceeds without approvals or clarification, which may not eventually be a correct decision.

Even the simplest project will incur deviations from the original project plans or intent. Short delays in change order approvals or RFI responses often result in scheduling delays, deficient quality, or remediation.

Implementing a document management program is critical for the success of any construction project:

1. The centralized document database must be word-searchable. It should identify each document in which a word/phrase appears.

2. Hierarchical access should be provided to all stakeholders.

3. All project documents should be archived (proposals, plans, revisions, RFI’s, change orders, shop drawings, punch lists, etc.).

4. Archive access should remain available throughout the project.

Document management through a digital archive will result in better quality control, swifter communication, fewer miscommunications and improved project quality.

Swimming Pool Expert Witness

Pool industry professionals certainly came away excited about all of the new and innovative products and materials they saw at the recent Coverings event in Orlando, Fl. However, when selecting which pool tile materials to use it is vital to learn the differences between the US ANSI standards and the EU ISO standards which are not the same. Consequently, ANSI standards are more stringent.

It’s important not to buy into the sales presentation and perform your due diligence before choosing a product. Using materials that are not suitable for the application could potentially expose you to liability should there be a failure.

ANSI A137-2017 are the standards for tile performance (A137.1 Ceramic Tiles & A137.2 Glass Tiles). Below are the minimum performance characteristics for ceramic tiles for submerged aquatic applications, the applicable test methods, and the minimum standards required.

One important factor to consider, porcelain tiles are 50% feldspar and are fired at much higher temperatures than regular ceramic tiles. This makes them much harder and denser than regular ceramic tiles. Porcelain tiles are a sub-group of the broader ceramic tile group, to which these standards apply.

10 Important Factors To Consider When Choosing Pool Tile Materials

1. COEFFICIENT OF FRICTION (COF – TCNA: DCOF Acutest test method).

There are two types: Static (SCOF) and Dynamic (DCOF). COF is the ratio of forces necessary to initiate sliding between two surfaces. The outdated ASTM C1028 static test measured the SCOF.

DCOF is the ratio of the force necessary to maintain sliding between two surfaces. The higher the DCOF, the more slip resistant the surface. This may not be of any concern underwater, but of grave concern on a pool deck or locker room floor. Industry standards generally accept ≥0.42 DCOF for commercial floor applications. Wet/dry locations, like aquatic locker rooms or moveable pool floors, may require ≥0.60 DCOF.

2. WATER ABSORPTION (ASTM C373-88 test method)

Tiles are weighed dry and again after soaking in water. The weight gain determines the percentage of absorption. Tiles are rated as follows:

Impervious: Tiles exhibiting 0.5% or less.

Vitreous: Tiles exhibiting more than 0.5%, but not more than 3.0%.

Semi-Vitreous: Tiles exhibiting more than 3.0%, but not more than 7.0%.

Non-Vitreous: Tiles exhibiting more than 7.0%.

3. FROST RESISTANCE (ASTM C1026 test method)

Directly related to water absorption. You can see that any absorbed water will be detrimental in a freeze condition – the expansion of freezing water will crack the tiles. Porcelain tile, by definition has a water absorption of less than 0.5%, making it frost proof as well. For aquatic applications we want impervious pool tile materials.

4. SCRATCH HARDNESS (MOH’S SCALE RATINGS)

The hardness of a tile’s surface will determine how it wears. The surface is scratched and a MOH’s hardness rating assigned. MOH’s scale 1- Talc (softest) to 10 Diamond (hardest). A hardness of 5 is suitable for residential flooring. A hardness of 7 or greater is usually recommended for commercial or outdoor applications.

5. BREAKING STRENGTH CERAMIC TILE (ASTM C648-04 test method)

Ceramic floor tiles must be able to support the loads exerted upon them. The test applies a force in pounds, to an unsupported tile until it breaks. Your selection should be based upon the anticipated maximum loads. Properly installed tiles, with a supporting setting bed that is free of voids, will be able to support significantly greater loads. These breaking values are for comparison purposes.

6. CHEMICAL RESISTANCE (ASTM C650-04 test method)

In this test, sample tiles are placed in various chemical baths for 24 hours, rinsed and examined for surface damage. For aquatic venues, it is desired to have the greatest level of chemical resistance.

7. SHADE VARIATIONS

This is a purely a cosmetic evaluation as to the consistency of the tile shades within a production lot.

Monochromatic (V0) – Very uniform, monochromatic color.

Low (V1) – Consistent color within each tile and from tile to tile.

Medium (V2) – Color variation within each tile.

High (V3) – Variation from tile to tile & within each tile.

Random (V4) – Considerable variation from tile to tile.

8. ABRASION RESISTANCE (ASTM C1027-99 test method)

The durability of the glazed surface is examined following the abrasion testing. The performance classifications and recommended uses are listed below:

CLASS 0 – Not recommended for use on floors.

CLASS 1 – (Light Residential) Light Traffic – Residential floor coverings in areas subject to soft-soled footwear or normal footwear traffic, without scratching dirt (i.e. domestic bathrooms and bedrooms without exterior access).

CLASS 2 (Residential) Medium to Light Traffic – Residential floor coverings in areas subject to soft-soled footwear or normal footwear traffic with small amounts of scratching dirt (i.e. rooms in the living areas of homes except kitchens, entrances and other areas that may be subjected to high usage).

CLASS 3 (Heavy Residential or Light Commercial) Medium to Heavy Traffic – Residential or light commercial may withstand normal footwear and regular traffic, with some dirt and/or other abrasives present in limited quantities. Tile in this class may be used in light commercial installations with limited foot traffic and with no direct access to the outside. Examples may include residential kitchens and hallways with limited traffic from the outside.

CLASS 4 (Commercial) Heavy Traffic – Residential and commercial floor coverings subjected to considerable traffic and scratching dirt (i.e. entrances, workrooms, inns, exhibition halls, and sales rooms, as well as other rooms in public and private buildings). Floors should be adequately protected against scratching dirt at the entrances to buildings by either floor mats or some other footwear cleaning device.

CLASS 5 (Heavy Commercial) Heavy Traffic – Heavy commercial floor coverings subject to heavy traffic with very abrasive soil.

9. STAIN RESISTANCE (ASTM 1378 test method)

This test is intended to determine the resistance to staining of tile surfaces. Class A – provides maximum stain resistance

10. MOUNTING METHOD

While not a part of the ANSI A137.1 standard, in submerged applications, the TCNA standards require that 95% of the back of the tile be in contact with the thinset. Care must be taken when choosing a porcelain tile for an aquatic environment, to ensure that the combination of the mesh and glue to not occupy more than 5% of the contact surface. It’s easy to evaluate the mesh, but not the glue. Worse yet, is if the glues soften in water.

Selecting The Best Pool Tile Materials

To summarize when selecting the best pool tile materials for aquatic applications we would desire the following minimum characteristics:

1. DCOF – not critical in submerged applications, but values of ≥0.42 for flooring, ≥0.60 wet/dry floors.

2. Water Absorption – Impervious, Tiles exhibiting 0.5% or less.

3. FROST RESISTANT – Yes.

4. SCRATCH HARDNESS – MOH’s 6-7.

5. BREAKING STRENGTH – Exceed PSI loads.

6. CHEMICAL RESISTANCE – Chemical resistant.

7. SHADE VARIATIONS – purely cosmetic.

8. ABRASION RESISTANCE – Class 3-5.

9. STAIN RESISTANCE – Class A.

10. MOUNTING METHOD – free of glue and mesh backing.

Below are the equivalent US / ISO European standards:

• Slip Resistance: TCNA DCOF Acutest / ISO NONE
• Abrasion Resistance Glazed ASTM C1027/ISO 10545-7
• Frost Resistance ASTM C1026 / ISO 10543-12
• Water Absorption ASTM C373 / ISO 10545-3
• Chemical Resistance ASTM C650 / ISO 10545-13
• Break Strength ASTM C648 / ISO 10545-4
• Stain Resistance ASTM C1378 / ISO 10545-14
• Scratch Hardness MOHS Scale / ISO MOH Scale