Tag Archive: Spa Repair


To: Multi-Tech Products

I have attached a photo of a hot tub installed in a hotel. It is a plastered spa, and large chips are coming off of the surface. Can it be salvaged using your FRL System?
Thanks,

Jim
untitled5

To: Jim

The quick, simple answer is yes, it can be used to renew the hot tub surface. However, before I give the complete answer on FRL resurfacing of a plaster finished hot tub, I want to address common issues with the practice of using fiberglass coatings over plastered swimming pools. Even though they are the same application, using a fiberglass coating on a plastered swimming pool brings much greater risks for failure than using fiberglass over plastered hot tubs.

There have been companies that specialize in a total refinish of pools by applying a fiberglass composite on top of the plaster. Therefore, there are a lot of these swimming pools in service today that have experienced a high rate of failure. Repairing these failed jobs have great appeal to repair technicians. Even complete pool resurfacing can be achieved with our FRL system. The larger the pool, the bigger the job, and bigger the pay check, right?  Our advice is don’t be quick to jump for that big pool job. Even though it might appear to be a great business opportunity, it is very risky to re-surface plastered swimming pools. Applying fiberglass resin systems over plaster does not always provide for resolution of the underlying issue, deteriorating plaster. These overlays of FRP usually fail as the plaster continues to deteriorate.

The explanation is that although advanced resins are utilized, and the top layer bond is great, adhesion between the different layers of fiberglass, plaster, and concrete base will decline. This leads to complete failure of the composite structure application. Some resurfacing will lose adhesion in big sections, and some will just have small areas that come loose. It is best to refer the major failures to a contractor that will completely re-plaster the pool. On the same note, the smaller failures provide the opportunity for repair professionals.

The following photos show one example of a swimming pool that had been completely over laid with fiberglass, and a partial repair was made, successfully. So, if the plaster has not become too brittle and chalky, a pool with small area(s) of failure can be repaired with the FRL System. It can provide a worthwhile extension to the life of the pool before a complete re-plastering is necessary. However, we would not recommend providing a warranty on these partial repairs.

2013-05-09 10.51.50 Before

2013-05-27 11.43.35After

Your hot tub can be refinished with our FRL system. It would require a complete resurfacing of the entire surface (nothing partial). Therefore, you should not commit without a prior inspection of the empty spa. Based on my analysis of your pictures, the glaze layer of the plaster is peeling. This layer is comprised of about .125″ thickness of the total original plaster finish. The glaze was created as part of the total installation process when the plaster was applied during the original construction.

The primary issue in resurfacing with any fiberglass product including our FRL system will be the ability to achieve prolonged adhesion to whatever you are applying it to – in this case the aged glaze or exposed plaster. But, if you re-surface the entire plastered hot tub, the FRL resin layer acts as a cap over the plaster, although it does rely on achieving a strong, long-term bond to the substrate. Hot tubs are smaller than pools so as the plaster layers deteriorate, the smaller bonding surface areas stay in place for the long-term. Ideally, the smaller volume allows for sufficient structural strength without the need for the strongest substrate composite integrity. Thus, it will stay in place and function correctly as a capped surface.

An inspection would be necessary to determine the condition of the plaster. Plaster fails by becoming brittle and chalky. The core plaster layer is under the glaze and on top of the concrete structure providing the shape of the hot tub. The primary cause for plaster becoming chalky, soft and brittle is from over-use of pool chemicals. So, you should remove the glaze in a few areas, and assess the condition of the plaster underneath, as well.

The FRL resurfacing procedure includes grinding and filling the substrate to assure smoothness, and provide a surface that allows the best possible bond with the FRL resin. That process will expose the core while leaving some of the glaze in place. If inspection confirms that the plaster is hard and shows little evidence of brittleness or chalkiness, then a re-surfacing with the FRL system would be advisable. One advantage of the FRL finish compared to a plaster surface is the ease of cleaning. The surface is much smoother, less porous and will be more durable.

Important Note: Resurfacing over peeling plaster is risky, and should be attempted only with everyone understanding the issues and potential for success or failure.

My experience is that plastered Hot Tub resurfacing with the FRL system has yielded long term adhesion and less call-backs when good judgment has been used during inspection and preparation for the refinishing stages. The same judgment should be used when establishing a warranty.

Rob Clos

TO; Multi-Tech Products

Wow, the before and after pictures of this hot tub are incredible. I’m amazed at how well it was repaired. Is an FRL system pretty common? Or do they use that on the newer hot tubs only? I’m just curious because I’ve got a pretty old hot tub that I need to get repaired.

Thanks Mia

To: Mia

If your hot tub is very old, 30 years or more, it is probably gel coat with a FRP backing, and installed in a cabinet or outside deck.  This type of product is suited well for resurfacing with the FRL system.  Refinishing a gel coat spa will give a permanent finish that will last 10 to 20 years.  The same applies to a spa made with an acrylic surface.  Acrylic spas were introduced in the early 1980’s, and quickly replaced gel coat products, due to superior performance.  These were offered as portable spas, but in-ground models were available.  Older plastered spas, which are frequently built with swimming pools, can also be resurfaced with the FRL system.

The pictures you referred to are actually a pool that was fiber glassed over plaster.  Fiber-glassing plastered pools and hot tubs is pretty common.  Companies that specialize in this service have come and gone over the years.  The business failures have been due to the liabilities from deterioration of plaster as described above.  Resins have improved over the years, which have made a difference in how long the new surface lasts.  But the main issue is that the plaster fails.  The FRL system is unique, and is designed for surface renewal.  It has proven performance in the right application.   See the above article for recommendations and limitations.  FRP is the acronym for Fiber Glass Reinforced Polyester.  This description encompasses a broad range of products with varying levels of quality.  The FRL system is designed to be used with numerous surfaces including acrylic, gel coat, ABS, and other spa surfaces.  We can refer you to a contractor that has been qualified to perform these applications.

Thanks,

Rob

To: Multi-Tech Products

I am a spa surface repair contractor, and I perform manufacturer warranty work and non-warranty repairs. I have a customer with an acrylic spa containing a crack at the rim. What causes these type of problems, and what is correct method to repair?
Thanks,
Carlos
To: Carlos

Carlos, thanks for your inquiry. The information I am about to share will be very valuable to you, and other repair technicians. It will enhance your overall knowledge on troubleshooting spa problems, and improve your repair results. It will minimize the potential of returning at a later date to fix the same or additional cracks. This will make you a more valuable resource to your manufacturer clients for warranty repairs. We also recommend that you know your manufacturers well. That includes the basics of their designs, and the terms of their warranty.  Understand the manufacturer’s guidelines for installation.

If it is possible, make a visit to the manufacturer’s plant. During a complete tour, pay attention to what they use for shell support, and where it is placed. Ask about the use of insulating and structural polyurethane foam. Check the thickness of the shell in various locations. Observe if there are any unique materials or devices used to add reinforcement. One manufacturer uses large diameter PVC pipe to provide support under the key portions of the spa (picture below). Understand that a spa is a reinforced composite structure, and the details of the reinforcement are extremely important Some manufacturers even have specifications on how much deformation along the rim is allowable under normal loads.
Also, know what the shell material is. Is it monolithic acrylic, or is it co-extruded acrylic over ABS? Is it reinforced with FRP (polyester resin with chopped glass fibers), or is it polyurethane? Is a vinyl ester used in the reinforcement composite?

spa support

Your question is a very complex one. First, you did not mention whether it is a portable spa, or if it is an in-ground or in-deck installation. You also did not mention whether it is under warranty.  Also, if it is a portable spa, does it have an ABS plastic pan for a bottom?

Before repairing a cracked spa, a repair professional should investigate the circumstances enough to try to determine the root cause of the crack. This may not be easy, but you should strive to define the most logical cause. First, cracks occur when the material is subjected to a stress that exceeds its strength. The material strength will decline as temperature is increased. Certain types of chemicals will also accelerate crack formation. See other blog entries that discuss chemical attack. Acrylic is known as a fairly brittle polymer, and will crack under excessive stress. Obviously, a large impact from another object will cause a crack.

In the absence of an impact, most spa cracks occur due to inadequate structural reinforcement. An 8-ft. spa may contain 400 gallons of water, which results in about 3200 pounds of weight. Add a few people, and the total weight can exceed 4000 pounds. Unless the stress ( pounds per sq. ft.) from this weight is spread over the entire surface area, it can cause a crack(s) at the high-stress points. This is typically at the rim.

So, manufacturers of portable spas must incorporate enough support beams or other devices under the rim, seats, and floor to accomplish this stress reduction. Sometimes, manufacturers fail to accomplish it 100% of the time. The following picture shows one example where the weight actually caused the vertical support boards to bow under the weight. This magnitude of deflection is very likely to cause sagging and cracking of the rim.

IMG_0088

If you look behind the skirt of a portable spa, and see any evidence of deflection, you can conclude that additional support might be needed. Sometimes, you can determine this by checking how straight and level the top edge is. Portable spas should be placed on a concrete or other strong pad to facilitate the function of the supporting structure. If the spa has a strong ABS base, it enhances the overall performance, providing it has the required design.

In troubleshooting root causes, it is helpful to know that if the crack is separated, the area was in tension. If it is pushed together with a ridge, it was in compression.

Now, if the spa is in-ground or installed into a wooden deck, it falls to the installer to assure that ample support is included under the frame, rim, seats, and foot-well of the shell to distribute the weight around those load-bearing surface areas. A commonly used technique is to wash sand into the cavity between the shell and the excavated dirt.  It is important to provide support that limits deflection in all critical areas similar to the photo above showing the use of PVC pipe.  The rim area also needs to be supported.   The information above will apply to analyzing the cause of cracks in these type installations.

I have included some pictures showing some examples of cracks from over stress.

Crack 1Crack 2

photo 1

 

The cracks can be repaired by following Multi-Tech Products’ standard crack repair procedures as shown at the following link.

http://www.multitechproducts.com/content/Procedures/SPA-REPAIR-Quick-Glaze%20_revised-10252011.pdf

The spa shown in the next photo developed cracks at the rim.

photo 2

Please note the brick blocks it sits on.  Unless the spa has an ABS pan base or other type of rigid platform between the bricks and the spa bottom and constructed as a self-supporting unit, it would not comply with normal installation specifications from a manufacturer  Therefore, cracks would not be covered by a warranty.  Most portable spas are designed to set on a strong, steel reinforced concrete pad or a wood deck with correct spacing of deck joists, correct beam span, and proportionate post pillar spacing for strong deck construction.  A weak  or improperly supported deck would cause the same type of crack shown in these pictures.  This spa’s crack was at the center of one rim edge.  This suggests the spa is suspended at the rim with little support in the critical areas mentioned above.  Large spas (> 7ft.) are more likely to crack in this manner.  The following diagram shows one example of a well-designed deck.

Pad

A technician should inform the customer of these issues, and make a recommendation to correct the support issues.  If the customer chooses to ignore the advice but still wants the contractor to perform the repair, a warranty should not be provided.  Also, this example of a crack edge would require structure repair at the back of the shell before the cosmetic repair was performed.  Otherwise, new cracks would likely form in the future.  The best service is to fix all of the problem sources to prevent future call-backs, and an unhappy customer.

Thanks,
Ken Wolfe
Consulting Chemical Engineer

Effects of Hard Water in Spas

TO:  MULTI-TECH PRODUCTS CORP.

ACRYLIC SPA REPAIR CONSULTANTS AND MATERIAL SUPPLIERS

I am the manager of warranty service for a major manufacturer.  One of my customers has provided these pictures, and asked for our opinion of the cause of the white deposits around the surface.  Can you help?

Thanks,

John

image (1)image (2)image

To: John

The pictures indicate a common problem associated with hard water that is prevalent in many areas of the country.  You probably have experienced the same hard water problems in coffee makers, bathtubs and shower devices.  They are found frequently on household faucets, drains and bathroom grout.  When appliances are not regularly cleaned with products formulated to remove calcium (e.g. Lime Away®), they develop deposits of the chemical salts present in hard water.  These deposits are basic, and need a weak acid to dissolve them.   When commercial products do not do a complete removal, a stronger acid solution is required.  An economical and readily available product, muriatic acid,  can be used.  Muriatic acid is actually hydrochloric acid, and is commonly used for swimming pool water chlorine maintenance.  However, it must be diluted with water before use in removing hard deposits.  Muriatic acid is a strong oxidizer, and should be used very cautiously.  It is also recommended to use heavy kitchen-type latex gloves, goggles, and a chemical cartridge respirator with cartridge(s) when using strong acid solutions.  You can also refer to the safe handling recommendations of the manufacturer of the chemicals.  A fan can be used to blow harmful vapors away from the work location.  Pure acid is likely to do damage to some surfaces, so it should be diluted using equal amounts of acid and  distilled water.  You may even want to test a small area to confirm that it does not attack the surface.  Be especially careful using it on vinyl covers, electronic devices and other plastic components within the spa.   Apply the solution with a clean towel, scrub with a nylon bristle brush, and rinse with clean water.  You may need to repeat the process to remove 100% of the deposit.  A wet/dry vacuum can be used to remove the acid solution and rinse water.

In order to prevent a new build-up of calcium, the owner should use calcium deposit removal products in a regular maintenance program.  The frequency will depend on the hardness level of the water, and the frequency of total water replacement in the spa.  It is also imperative to maintain overall water chemistry.  Improper use of water chemicals can also lead to deposits.

Total hardness is one measure that is used to maintain water chemistry.  It is a measure of all the dissolved minerals such as calcium, magnesium and sodium. For practical purposes, calcium hardness is the common reference used in pool and spa water chemistry.  The recommended level for calcium hardness is 200 – 400 parts per million, and both high and low levels can result in problems.  It should be closely monitored.

High calcium hardness results in scale formation on surfaces as well as scaling in the pipes, plumbing and filter. In extreme cases the water becomes dull and cloudy with the calcium precipitating out into the water rather than onto a surface.  High calcium levels will also irritate users, causing sore eyes as an example.

If high calcium level is a result of spa chemicals, draining some or all of the water and replacing it with fresh water will lower calcium hardness.  If the cause is the fill water, commercial hardness reducers or chelating agents will bond with the calcium to keep it trapped in solution.  If the user is uncomfortable using the home kits for water maintenance, a professional can provide the service at most spa/pool dealerships.

I hope this helps.

Ken Wolfe

Consulting Chemical Engineer