Coping with Salt
In my work as a construction-defect expert witness, I’ve seen how damaging salty water can be to hardscape materials around pools and spas equipped with saltwater chlorination systems. It’s so common that, personally, I now try to avoid using those devices on the watershapes I design and build.
It’s not that I think saltwater chlorination is intrinsically evil; instead, it’s the fact I’ve seen so many different things go wrong with watershapes that have these systems that I decided some time ago that they weren’t for me.
It’s often said that water is the universal solvent. Salt, my friends, is the near-universal corroder.
The scenario: In my forensic cases, I’m often called to pools and spas with damaged stone or concrete coping and/or decks marred by pitting, pop-outs and discoloration. The common factor in all of the images seen with this article is the presence of salt chlorination systems.
| The damage seen in this and the other photos accompanying this text is caused when salt penetrates fissures and gaps in the surface. As water evaporates, salt crystals are left behind to grow and ultimately fracture the material, whether it is stone or concrete. The resulting delaminations and pop-offs are unsightly – not anything that makes a poolowner happy. |
Salt is a particular challenge to any form of sedimentary stone (including the slates, sandstones and flagstones that are so popular around pools and spas), but it’s also an issue with poured concrete: When water splashes or drips onto any of these materials, it penetrates their surfaces, evaporates and leaves behind salt crystals that grow and eventually infiltrate and break the bonds between the sedimentary layers of many types of stone and within fissures in a concrete surface. This causes flakes to slough off or small bits of material to separate from their surfaces.
In many instances, designers and builders are aware of or have observed these situations for themselves and will carefully discuss the issue with their clients. Most often, this involves advising the client to hose down surfaces around the pool or spa immediately after use to rinse away or at least dilute the saltwater. If the homeowner listens and follows through, that’s great – but unusual. And eventually the contractor may hear from an upset homeowner who is displeased by the deteriorating aesthetic appearance of what were once beautiful surfaces.
The fix: None of the remedies here is particularly pleasant. One approach might be to get rid of the salt system, empty the pool and start over with non-salted fill water, but that leaves the already-corroded coping and decking behind. You could power wash the surfaces to clear away compromised material and then apply a sealer, but that doesn’t take care of the corroded appearance and tends to make areas around the watershape quite slippery, which is obviously not desirable.
Finally, you can keep the salt system, remove the damaged surfaces and replace the coping and decks with other materials that are impervious and therefore resistant to salt damage. I know of one company – Artistic Pavers of North Miami Beach, Fla. – that offers attractive coping and paver materials warranted against salt-related damage, and there may be others.None of these is a particularly inexpensive solution, but something needs to be done because, left alone, the conditions that are already objectionable will only get worse.
Lesson Learned: As stated above, I now do what I can to avoid using salt chlorinators. If I have a client who insists on having a salt system, I can live with it – but this means that I’ll specify materials that I know won’t be harmed or corroded by frequent, repeated and extensive contact with salt.
This crosses whole classes of beautiful, much-in-demand decking materials off the list along with common metal fittings and components and anything else I can think of that might be damaged by steady salt contact.
My recommendation is simple: When homeowners (and contractors!) decide to install salt systems, they need to educate themselves on the special maintenance required, the potential for hardscape damage and possible problems with metal components – all of the pros and cons, and in detail. This way, homeowners are making informed decisions. And when they simply must have salt, contractors should protect themselves by presenting their clients with a detailed disclaimer – signature required!
Some people absolutely love their salt water systems. Although we don’t recommend them at my company, if it’s what a client really wants, we’ll do it.
Scott Cohen is a construction defect expert witness and president of The Green Scene, an outdoor design/construction firm in Chatsworth, Calif. Past articles in the Lessons Learned series have been compiled in his book, The Candid Contractor. He also provides consultation for clients nationwide and gives seminars on designing landscapes, swimming pools and outdoor kitchens. For more information, go to www.greenscenelandscape.com.