Every year I am invited to give quotes on resurfacing concrete, usually stairs, landings and walkways.
Here’s the basic fact to hold on to. The original concrete, aged as it is, has been getting stronger, and it is a single coherent mass. A new layer, even using the best cement, is still a new layer and so it’s only fair to accept that it won’t do as well as the original.
However, if your surface has pits or low spots that are collecting water then these spots are going to get worse, as the concentrate water entry and their roughness creates more surface area for the water to enter. So a resurfacing job can protect these spots and make water run off better.
Usually there’s a cause for rough spots, and so look for the cause to see if you can do something about it. Can you use sand instead of cement? Can you sweep or shovel away snow so that it doesn’t collect in a spot?
Given that resurfacing isn’t cheap, take care with the new layer, try to avoid using force on it like a shovel picking at ice, and avoid salt.
And to give the resurface layer its best chance to succeed insist on getting the old surface pressure washed first so that it really is cement that the new layer is trying to bond to. Make sure the cement is saturated without any standing water before the new layer is put on.
You can pick your season, so I’d avoid having it put on during the peak of summer. I never resurface when the temperature is predicted to go above 25 degrees just it can cure better. Cooler is better, without being cold. early June, late August, and September are often great times for such masonry.
Finally, there is special cement meant for resurfacing and the best stuff isn’t found at Home Depot or any of the big chains. Go to Merkely Supplies and get T1 or T2 from W. R. Meadows, or Sika Top, these small bags cost about $75 each. They have special adhesives and polymers in the mix and they’ve been purpose designed, even to avoid spoiling from rust showing through from imbedded rebar. It’s important too that your mason use the whole bag when they’re doing the job because some of the special contents may have settled – if they’re showing up with half an open bag, which half are you getting? These products are hard to work with so it’s in your interest to find someone who has done more than a few. In any case, I’d get the statement of work itemized to include the cleaning and saturating and the specific type of cement.