News and Opinion from Sisters, Oregon

Spalling is a Sisters fact of life

Walk anywhere in Sisters for more than three or four blocks and you are very likely to encounter spalling, the unsightly flaking on concrete sidewalks. It looks as if the surface is pitted or pocked. While it occasionally happens from putting sodium chloride (rock salt) based ice-melting products on sidewalks, its actual causes are several.

They include poor quality concrete or inferior finishing, improper curing, corrosion of the underlying rebar (reinforcing bars or screen), or, as is most likely the case in Sisters – wear and tear from the freeze-thaw cycle.

Spalling is generally an aesthetic issue since only the upper, finished portion of the concrete slab crumbles and exposes the rough stone aggregate beneath, whereas the inner core of the slab remains mostly intact.

Despite its hardness and seemingly solid, impervious appearance, concrete is quite porous and absorbs water, albeit slowly. Just as quickly it can dry itself out when the freezing rain or snow goes away. The ice-thaw cycle repeated dozens or hundreds of times every winter in Sisters can weaken and crack the top layer of your concrete.

The result is ugly, both in looks and the cost to repair. With all the new construction and homebuilding in Sisters, homeowners are often shocked that within weeks or a few months of taking delivery on their expensive new home, they note sidewalk spalling and want to take on the contractor or concrete supplier.

In few cases does the claimant prevail. Sidewalks don’t come with warranties like appliances, windows, or roofing materials. Then there is the repeated question: Whose sidewalk is it — yours or the City’s? It’s yours in nearly every case, and you must build it and maintain it to City standards.

If you care to know about it in detail, it’s in the Municipal Code, Chapter 12.25. It’s a three-minute, unambiguous read. So, now knowing the problem and who’s responsible for the repair, how to get it fixed?

There is no contractor in Sisters that specializes in such repairs or resurfacing. And the contractors we interviewed, like Jeremy at Ridgeline Contracting, are skeptical of “patch” jobs.

“The only real solution is to rip it up and start over,” he said.

He doesn’t see the problem in the Valley with its milder temperatures.

“It’s just a fact of life in Sisters with the day/night temperature swings,” he said.

That leaves you with do-it-yourself remedies. The most common method for repairing a spalled sidewalk is by applying cement stucco over the broken part of the sidewalk. Cement stucco is basically a mixture of Portland cement and sand that penetrates into the cracks and binds it together.

Since Portland cement is the main component of the mixture, it should be added in correct proportion so that the sidewalk can withstand bike and foot traffic. The sand to be used is available in three varieties — fine, medium, and coarse — but most contractors prefer the medium one since it gives a smooth and even look when the stucco dries.

There are a couple of locally available products known categorically as polymer-modified cement. Hoyt’s Hardware & Building Supply sells a 40-pound bag of Re-Cap which is mixed with water and troweled on. Sisters Ace Hardware has the same product, and a few other options by DAP. They also have the ingredients sold a la carte, such as the stabilizing primer, or bonding adhesive.

With any of these off-the-shelf products, the only color is gray and will not be an exact match to most of the sidewalks in Sisters. Thus patching may actually make the problem look worse cosmetically. Left unattended, the problem will continue to worsen. If you are a gambler you can add tints — and hope when cured that you called it correctly.

If you decide to tackle it, it’s best to plan on doing the entire slab or section to even out the color.

Home Depot carries Henry RestorePro — about three times the price of Re-Cap. Consumer reviews say that it is worth the extra price. Lowe’s sells Flo-Coat, comparable to local options.

After resurfacing, professionals recommend applying a liquified waterproof membrane. It is not inexpensive but may be necessary in worst-case or repetitive situations. Some are available in up to eight shades, giving you a greater likelihood of matching your existing tone. Expect to recoat every five years.


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