Off to the Race(way)s!

During many of our volunteer gigs we end up doing projects that were not anticipated when we arrived. This is either because the staff didn't know what we could do, or because we didn't know what needed to be done.

The subject of concrete repair had never been brought up during our interview or during the first several weeks we were at the hatchery. But while power-washing some of the outdoor concrete pools we noticed that concrete in some of the drainage sumps had eroded away, leaving rough holes that caught old food and feces. Can you say STINKY??

Missing concrete in drainage sump

We brought the holes to the attention of the staff, and were told that they wanted them fixed but had to wait a year or two until a contract could be put together. We mentioned that we thought it was a pretty minor repair, and something that we could handle, so off we went to buy some patching material. 

Patching the hole with repair material

The next morning we made the repairs, and found ourselves with quite a bit of leftover material. It turns out that there is eroded concrete in many of the outdoor pools and indoor raceways, so we did a little more patching here and there to use up the remaining material. 

At this point the staff got the idea that perhaps we could fix the biggest of their concrete problems, which is a set of indoor raceways. Water running through the raceways over the decades has made the sides so rough that they couldn't be cleaned thoroughly and were no longer safe to use.

Existing raceway surface

It is hard to tell in the picture above, but the concrete below the waterline (the brown area) has eroded as much as 1/2 inch back, leaving a very sharp, rough surface. Now, instead of a 1 square foot concrete repair like the sump, Teri and I were looking at about 100 square feet!  We were a little hesitant to take it on, but agreed to give the first raceway a try, and then decide how to proceed. 

Cleaning the sides. 

The first step was to power-wash, brush and vacuum the raceways. There was a lot of loose dirt, sand, and rock on the walls and it all needed to be removed before repairs started. In some places the more we brushed the more the walls eroded, but we finally got them clean. 

The next step was to apply the skim coat material, which is a special mortar mix for thin, smooth repairs. This is a quick-setting, time-sensitive material, so no time for pictures!!  While Teri was up top mixing and providing me the material, I was down in the trench skimming it onto the sides. We were able to mix a couple of bags of material and get it spread before having to completely wash all of the mixing and troweling equipment down. Then we'd do it all again. We did one wall on a Saturday, and the other on the following Saturday. We find it easiest to do this kind of big, specialty project with fewer folks around to, umm... help!

Finished skimcoat repair

The picture above shows the finished repair. We returned the lower portion of the wall to a smooth, even surface. The next step was to paint the inside of the raceway with a special, fish-safe coating. It took over two months for the staff to decide on the appropriate coating, check the budget, get it ordered, etc. We really didn't think that we'd get a chance to finish this project before leaving at the end of September, but the coating finally arrived about mid-month. 

 Applying prime coat 

The first step was application of the primer coat. This was an odd material with the consistency of skim milk. It was finicky to apply, but we got it on and let it dry overnight. 

Applying top coat

The top coat was a much thicker rubber material. The coating manufacturer required three coats of the top coat over the primer. So it took us a couple of more days to finish the coating. 

The finished product turned out great, with nice flat walls and a thick durable coating. 

Here is a look at an "original" raceway next to the refinished raceway. The hatchery staff is really pleased and is hoping that we can refinish three additional raceways next summer. 

We have to let the coating cure for a full week before adding water and fish, so we won't be around for the filling. Hopefully everything works out as expected!

Mark