February 5, 2020
As an owner or manager of a parking garage facility you are well aware that it is costly to maintain and up keep your structure. If one aspect is not taking into consideration, it can become even more costly and sometimes detrimental for your parking structure. In today’s blog I would like to focus on an important aspect which is traffic coatings systems.
If you do not currently have a traffic coating system on your parking garage, it would be a smart investment to do so, at least on the top deck or over occupied spaces. I have had multiple owners and managers ask why and my response is always “If you don’t it is the same as installing a roof on your house without shingles”. It is just simply mistaking activity for achievement. The coating helps protect the concrete from harsh environments just like the shingles do the wood. I think that coating decks is even more important when these parking structures are along the coast where salt is present. With that being said let’s talk about the proper steps to take when you as an owner or manager decide to have a traffic coating system installed.
The first step is to hire a consultant and engineer to help assess your parking deck and write a report and create drawings/specifications for the contractor to go by. The main purpose for the consultant and engineer is that they make sure that there are no structural problems such as column repairs, girder repairs, bearing pad replacement, crack injection, failed connection plates, etc. All these things should be assessed first before applying a traffic coating systems. Don’t put the cart before the horse.
Next, the consultant and engineer need to assess the concrete slab that the traffic coating is being applied to. Some engineers and consultants do not specify to have the concrete slab tested before the install, though I would highly recommend that the engineer require it. There could be unforeseen issues going on with the slab such as early stages of ASR. If the ASR is covered with a deck coating system, the moisture in the slab would then be trapped accelerating the ASR reaction. All the coating that you would have installed would have failed and most likely a ¼” to 1’’ of concrete would have to be removed and re-poured. A major cost that could have been avoided by simple core testing. If the parking structure is made out of precast tees, it is important that the joints in the topping slab are directly above where the two jointing precast tees meet. Also make sure that the joints in the topping slab are cut to a specified width to allow enough movement. Make sure that there is no rebar showing or concrete repairs needed throughout the deck. Last but not least is making sure that the slab is sloped correctly to drains or some type of outlet. The sloping should be researched by the engineer before the project starts which allows the owner opportunity to re-slope the deck if needed. The coating system is not designed to hold water and most manufacturer’s state how long water can be on a deck without considered being ponding which is usually 24-48 hours. If your slope is not correct, then ponding will occur which can have an adverse effect on the coating which could possibly void your warranty. This issue has caused major problems over the years which is why it is good to get it resolved on the front end of the project.
Now it is time to pick the product. Based on the testing stated in previous paragraphs, the engineer should specify three equivalent traffic coating systems manufacturers. Make sure out of these three manufacturers that each one screens their aggregates and if the manufacturer recommends a third party aggregate supplier be sure that they screen their aggregates as well for any metals such as iron ore. There has been problems in the past with rust stains surfacing due to iron ore being in the aggregate. Most manufacturers supply aggregate migrated into their top coat which is great because it is one less step in the application process which is major cost savings for the owner, less likely for failure due to weather impact, and one less manufacturer in the mix. Sole sourced!
Once the product has been chosen it is important that your contractor takes moisture readings of the deck to make sure that the moisture is below manufacturer’s recommendation. Make sure that the surface preparation meets an ICRI 3 profile and they do a pull test per manufactures recommendations.
After all these proper steps have been taken it is now time to install the deck coating and is up to Mother Nature to provide good weather to do so. The contractor needs at least 3-6 days to properly install a standard traffic coating system depending on which system is used. I know some people out there say it can be done quicker which I would not argue. Like I said, depends on what system being used. So it is important not to rush the process and know that it can become a lengthy one depending on the amount needed to be done. When your project is complete be sure that the contractor provides you with a cleaning recommendation data sheet from the manufacture so that you as owner are maintaining your investment.
I hope your future projects are a success and good luck!
Mark D. West