Few obstacles will present as big a challenge as concrete bowls.  The immense amount of sheer physical exertion needed on a pour day should not be underestimated.  When it came time to pour the bowls, we contracted with a union concrete contractor to provide us with six concrete finishers for three days.  These individuals were paid by the hour, with insurance and taxes covered by the contractor.  Expect to pay around $50 an hour.  These individuals were in addition to a team of five others that had been involved in the construction (forming) up to that point, and a few other volunteers cleaned the concrete off tools and jigs.  Just cleaning equipment is a full-time job, but these volunteers can also assist in other ways throughout the day.  Overall, you will need a large team to pour the concrete bowls. 

We must mention a word or two about union workers who do concrete finishing.  First, they will arrive with their own hand tools.  Second, they will arrive on time and be ready for work at 8 a.m.  They will not care if you are ready for them or not, and their time clocks will be running.  You can generally send the union labor home within one hour without penalty (called on account of rain, etc) except for a transportation fee.  After one hour, they will be paid for the first four hours regardless of the time worked over that first hour.  Likewise, after five hours of work, they will be paid for eight hours.  They are paid by the hour for overtime by rounding up to the next hour.  Overtime is usually double (in our case $100 per hour).  They will quit promptly eight hours after start or expect overtime pay.  Do not expect them to stay around extra time without compensation.  They will not.  So you want to time things correctly so that they can complete all of the placement and finishing within the eight hour period.  Due to the nature of concrete work, they will not take lunch, rather they eat as they can throughout the day.

The upshot to this is that union finishers are, in our experience, extremely professional, especially if they come from a reputable contractor and want to remain working for the company.  It is our experience that they will remain on the job for the full day, no matter how difficult things get.  Avoid the tendency to just get a bunch of concrete workers together, even if they are finishers, because pouring the bowls for a skatepark is probably the most physically demanding work that any member of the team has done in quite a while.  It is not unforeseeable that if you get some loosely knit crew that you will have some walk-offs or no-shows the next day.  For the pouring of bowls, you want the best workers that you can find and the best may cost more than usual.  Do not scrimp on the labor needed to pour the bowls.

For the St. Helens skatepark, we planned to pour two bowls in three days.  The bowls were elongated ovals that were each 55 feet long and 38 feet wide.  One bowl was 6 feet deep, the other was 8 feet deep.  There was a saddle in the center and a saddle at the end where the small bowl connected to the street course.  Between the bowls and the surrounding deck, we needed 132 yards of concrete with a cost of over $5000 dollars a day including labor and materials, but the results were well worth it.

At six o’ clock a.m. on the days of the pours, the team responsible for forming and jigging should be at the site, making sure that the screeds are in place, the rebar is blocked into the center of the forms, and water hoses have been run and are ready.  All finishing tools should be gathered.  In addition, it is a good idea to have electric power available.  Be as prepared as possible for anything and everything.  The pump truck should be scheduled to arrive in time for set-up before the union finishers arrive at 8 a.m.  Contract with the pump truck company well in advance as they are in high demand during peak times.  Try to get a little of the bill for the pump truck donated.  Work this angle well in advance of the pour.  Expect to pay around $1000 to $1500 a day for the rental of the pump truck depending on the size of the truck.

So the pump truck is there, and the finishers and the rest of the crew are assembled.  The first load of concrete should arrive at that time and the driver should immediately begin preparations with the pump truck driver.  Specifically instruct the driver of the concrete truck not to add any additional water to the concrete mix without approval.

Now is the time to get everyone, including all of the workers, together to discuss how the bowl will be poured.  With the St. Helens project, none of the union finishers had ever done anything like this before, with the exception of two that had some experience with swimming pools.  Remember, the finishers are there to do whatever you tell them to do for the next eight hours.  You should be prepared to tell them when and where the pour will begin and end, explain how the system works and answer their questions.  Overall, this meeting should take no more than fifteen minutes.

The pour is then started by pumping concrete a minimum of two-thirds of the way up the bowl wall.  Start up high, concrete doesn’t have any trouble moving downward, but once placed it can only be moved higher with a shovel.   If the concrete is of the consistency specified, it will start to stack upon itself up the sides of the walls.  Yet, there will be a lot of hand shoveling of concrete to the top of the wall until it finally begins to stay in place.  When a section has been filled from top to bottom, the screed is dragged across (see previous sections).  When constructing a bowl this requires one worker at the top, one at the bottom and one working in the center of the screed.  At this point, some workers will remain to float that section while others working with the screed move ahead.  Eventually workers will begin to finish and trowel the area where the pour started and the crew will be dispersed among the various stations of placing, floating, finishing and troweling. 

One person will walk around the inside and outside of the bowl determining where high and low spots exist that must be refinished.  There must be someone that is responsible for saying “O.K. This is good enough, time to move on.”  For you to have the highest quality skatepark possible, this individual must understand the entire process from start to finish and be attentive to detail.  He or she must not be afraid to insist on perfection and demand that others insist upon it as well.  This person should be familiar with what makes and breaks it when building a skatepark.  Chances are this person will all ready have identified themselves by their dedication to the project up to this point.  Choose this person carefully.

The rate at which additional concrete trucks are ordered must be determined during the pour.  Do not get ahead of yourself with the concrete.  It is much better to get the concrete that is all ready placed finished properly than to place more concrete than you can finish just because it is there.  If you have to, send the truck with the concrete back.  If it is your fault you will still have to pay for it, but you will be able to maintain the quality of the park.

RETURN TO CONTENTS