Over the last half century, we’ve become experts in the installation of wood athletic sport flooring. That means we’re an industry leader when it comes to installing wood floors. We have advice on how to avoid problems as you prepare for installation.
Here are three conditions critical to optimal wood athletic sport flooring installation:
1. Flatness of the concrete slab
The level of the concrete slab is critical for correct wood sport floor installation. Slabs for all types of athletic performance floors must be within a tolerance of +/- ⅛” in a ten foot radius. Some concrete pourers may use Ff/Fl numbers to measure the slab flatness. This is not acceptable because there must be tolerance of +/- ⅛” in a ten foot radius.
Often, general contractors approach maple athletic sport floor installations as they would any other flooring installation. The concrete slab is poured. The concrete contractor is paid. That’s when the sport floor installer is brought in to find an out-of-spec slab that needs to be corrected. The concrete contractor then has to come back to correct the problem. The project is delayed. The costs add up.
The question is, “Who pays for the concrete slab correction?” Usually, there is no allowance built into the project budget for concrete corrections. General contractors don’t have a budget for this issue, and so the athletic sport flooring contractor is told he or she is responsible. However, the Maple Flooring Manufacturers Association (MFMA) specifications state that the general contractor is responsible for turning over a slab that matches specs. Concrete slab correction is not inexpensive.
Avoid costly arguments over concrete slabs by following these steps:
- If possible, pour the slab at least six (6) months before wood flooring arrives.
- Put an allowance in the budget to correct concrete slab flatness.
- Require the concrete contractor to put in writing that the slab meets the +/- ⅛” in a ten foot radius tolerance.
- Ask your athletic sport flooring contractor to approve the slab by taking readings with a laser.
- Do not store anything on the slab prior to wood athletic sport floor installation.
2. Moisture content of the concrete slab
Moisture content of the concrete slab is another major consideration, and MFMA has specific guidelines regarding allowable moisture content of concrete slabs upon which maple flooring is installed. MFMA recommends the relative humidity level of a concrete slab for a non-glue-down maple athletic sport floor system be 85% or lower. The relative humidity level of a concrete slab for a glue down maple athletic sport floor system should be 75% or lower.
Here are five tips to help you establish the best concrete slab moisture content:
- Concrete must be poured with the proper water/cement ratio. The higher the ratio, the longer the dry time. If concrete is poured with a .4 water/cement ratio, it takes about 60 days to get to the 85% relative humidity. If cement is poured with .5 or .6 water/cement ratio, it will take longer to establish ideal relative humidity.
- The concrete slab should never be poured and left uncovered or open to the elements. If rain or snow get on the slab, the moisture will settle into the concert and it will become difficult to get it out. Always have a roof over the concrete slab.
- Ask your flooring contractor to test the slab before he or she starts installing the floor.
- The environmental conditions in the building will have a direct effect on the time it takes for a slab to dry. The most important strategy is to keep the relative humidity in the room as low as possible. MFMA has some helpful suggestions.
- If you can not wait for the moisture to meet specifications, there are chemical, topical materials that might solve the problem. These solutions will be expensive. While these chemicals are available, they should be used only as a last resort.
3. Environmental conditions of the room
The environmental conditions of the room are just as important as concrete slab flatness and moisture content. MFMA has specific recommendations for the temperature and humidity conditions of a room in which the sport flooring is installed.
Before the flooring contractor delivers materials, aim to complete the following preparations:
- All overhead work is complete.
- Painting is complete.
- Basketball backstops and other athletic equipment are installed.
- The HVAC system is installed and has been operating.
- All windows and doors are installed and functioning.
The environmental conditions of the room are important because wood is hygroscopic material, meaning it absorbs and releases moisture according to the room conditions. If relative humidity of the room is higher than the wood’s moisture content, wood absorbs moisture and expands. If relative humidity is lower, wood releases moisture and shrinks.
For example: during summer when humidity is high, the room may not be climate controlled to keep wood from picking up extra moisture and cupping or buckling. During winter when heat is turned on, relative humidity in the room can become low and, as a result, the wood releases moisture and shrinks. That is why wood floors are generally very tight in the summer and show gaps between the boards in the winter. It is as simple as that.
Avoid problems of swelling and shrinking floors by following these simple steps:
Take steps to prevent problems if the room cannot be climate controlled:
- Install the wood in the spring or the fall when the humidity is acceptable.
- Make sure that the wood comes off the truck with the proper moisture content for your region. In the tri-state area, moisture content should be about 8%.
- Install wood when moisture content is 8%. Moisture content of the wood is more important that the acclimation period. For example, if the wood comes to the job at 8% and you allow it to acclimate for 7-10 days, if the humidity is 90%, the moisture content of the wood could jump to 10% by the time you are ready to install. At that point, you would have to wait for the moisture to drop back down. That might not happen quickly in every case.
- Complete all doors, windows and wet trades prior to arrival of the wood.
- Keep a log of the daily moisture readings of the wood.
By taking extra care of concrete flatness, moisture content and environmental conditions of the room before maple athletic sport floor installation, you’re more likely to complete your floor installation without unnecessary delays or budget-bursting setbacks.
We invite you to see what wood flooring looks like when it’s installed correctly and explore our wood athletic sport floor products at mathusek.com.
For more information about the ILS Financing Program, contact Kim White by email, or phone 800-438-1470, ext. 109.
Visit Mathusek’s Financing Page to learn more about this offer.