Frequently Asked Questions
“We have a lot of gently sloping ground here in Austin, Texas and the city permitting office is now requiring certain drainage criteria be met when doing a major renovation and new building. If I could use OPaver™ in this situation I would be concerned about:
How to tie the grid into the ground below. If I’m installing this over dirt (most situations this would be the case) how do I stop it from allowing water under it and creating a channel over time of water washing away whatever is in the grid (dirt or gravel)? Maybe I could use landscape staples or something similar? If so how many per square foot to ensure stabilization?”
This concern was thought through the design of the product. Where four of the circle cells meet you will find the diamond shape cell and at the base there’s a flange. This allows for a mechanical fasteners to go through secure the grid to the ground. The amount per square foot would be dependent upon the quality of the ground conditions.
“What volume of water will this product allow through from the side? I know you said it allows water to feed from one chamber to the next. I have an application where I’d like to install maybe 15′ x 45’ but my concern is that this is a low volume water path (mainly in rain but also from a neighboring lot). I’m worried about what will happen when the water starts pooling at along the short end and can’t get “into” the grid. I can think of a number of applications where this “wall” of the beginning of the product will create a barrier and divert water where the plans didn’t intend. Do you have any thoughts on this one?”
Where the common ground, weather it be be asphalt, concrete driveway, or grass begins just ensure that the OPaver™ MP sits at the height the ground cover just mentioned or slightly below. In other words, if the grid system is installed on a 45° slope where the grid begins install the panels beneath the earth so water coming down that slope will be forced to flow onto the grid itself and not collide with the side of the OPaver™ MP grid.
Do you have any data on the weight bearing limitations on the plastic grid itself? Will this material crack or crumble under the weight of a car when filled with dirt/grass?
USA EcoSystems’ OPaver™ permeable pavers are made from a high-strength copolymer polypropylene which has a compressive yield strength of over 5,500 psi, roughly twice that of typical high density polyethylene used in other permeable paving systems .* Measuring compressive strength of un-filled grid systems is highly subjective due to the fact that the pass/fail criteria is purposely left very vague to allow for permanent deformation and other evidence of compressive yield. Without the additional of fill aggregate, USA EcoSystems’ OPaver™ Grids will withstand forces in excess of 400 psi before plastic deformation begins to occur.
I’ve read that using gravel on a high traffic parking lot areas will cause the gravel itself to be crushed have a “sanding” effect and become imprevious. Is this true for The OPaver™ Grids?
The core purpose of the USA EcoSystem’s OPaver™ paving grids is to control and prevent the shifting of the aggregate fill, which serves to transmit the applied load directly into the base thus utilizing the full compressive strength of the natural aggregate stone. A major added benefit of this process is that the “sanding” effect is virtually eliminated when installed properly.
Commercial pea gravel varies in composition and may have a rated compressive strength in excess of 25,000 psi.* However, surfaces paved with pea gravel alone may be prone to a “sanding” effect, due to the grinding action that occurs as a load travels across the aggregate and the aggregate shifts to compensate.
This will not occur with the OPaver™ grid system.