Grasspave2 Porous Pavement Frequently Asked Questions
What is Grasspave2?
Grasspave2 is a plastic sub-surface reinforcement structure for trafficked areas that supports grass and prevents rutting, mud, and root zone compaction.
What is the difference between GP2 and the competitors?
Grasspave2 is the only product on the market that comes in rolls, which makes it easy to cut and install. All the other grass paving products are rigid and must be laid down one at a time on a bed of sand, in a process much like laying paving stones, and cut with a saw. Having the ability to install a flexible product in roll sizes up to 1,350 sq. ft. vastly decreases the time and expense of installation
What are the products dimensions?
The individual Grasspave2 rings are one inch deep and two inches in diameter. The product itself comes in five standard roll sizes ranging from 108 sq. ft. to 538 sq. ft. Don't be too concerned with the size, think of it like carpeting - you will be covering the whole area by placing rolls next to adjacent rolls.
How is Grasspave2 installed?
Grasspave2 is installed over a subbase of stone at a similar depth to what would be put under two inches of asphalt. Once the subbase is down and compacted the Hydrogrow mixture is spread out with a broadcast spreader/seeder. The Grasspave2 is then rolled into place and back filled with one inch of sand. Finally the area is either hydroseeded or sodded. Unless there is an emergency, wait two mowings before driving on the grass.
What is Hydrogrow and what purpose does it serve?
Hydrogrow is a fertilizer and soil amendment combination that is spread out on the base course at a rate of one pound per 108 square feet before the Grasspave2 is rolled into place. When Hydrogrow comes into contact with water it absorbs and holds a great deal of water and nutrients for the maturing grass roots until they can grow down into the subbase. This reservoir effect is necessary because sand is the growing medium and while it allows water to quickly drain from the surface it also deprives the grass of the substantial moisture it needs to germinate.
How do I lock Grasspave2 together in the field?
Unlike Gravelpave2, you do not have to nail Grasspave2 in place or snap the product together. There are male and female connectors along the edges of the product but it is not necessary to snap the rolls together as the grass will lock the product in place once the roots are established.
What depth of base course does the product require?
Grasspave2 requires approximately the same depth of base course as two inches of asphalt.
What type of base course does the product require?
The composition of the base course is outlined in our specifications as a 3/4 inch minus sandy gravel compacted to 95% modified proctor. The base should allow enough void space for water to percolate and grass roots to grow. If you intend on using a material that will seal tight once compacted (such as limestone) you must add a 30% mixture of sand to create the required void space. Download the base course information.
What types of grass should I use in the product?
Use a species that is both deep rooting and hardy. Generally a Blue/Rye/Fescue mix in northern climates and Zoysia, Fescue, or Bermuda types in southern climates.
Can I seed or sod over the product?
A very good stand of grass may be achieved through hydroseeding with wood or paper. Mulches such as straw or pine needle should not be used when seeding because of their low moisture holding content. Sod can be used as long as it contains very little soil which may compact and kill the grass with use. A sod that has been washed, cut thin (1/2 inch), or grown in sand or sandy loam is acceptable.
What material is the Grasspave2 filled with and why?
Grasspave2 is filled with only one inch of clean sharp sand (soil is never used), overfilling the rings can lead to ruts and product failure. Sand is used as the growing medium because it allows water to percolate very quickly and will never compact and become muddy with use, like soil. Our Hydrogrow mixture is used to provide a water reservoir to the grass roots while they are getting established.
How heavy of a load can Grasspave2 support?
With a pounds per square inch (psi) capacity of 15,940 psi. Graspave2 can support any load that is legal to drive on the street. The highest truck tire pressure allowed to drive on the roads is 120psi, fire truck outriggers are only around 81psi. Grasspave2 is designed to transfer the surface load to the subbase which should be designed to a depth that will support the anticipated loads.
How much traffic can the product withstand?
Since the Grasspave2 has an organic wearing surface it can take limited traffic without dying or becoming stressed. The product is ideal in areas that will receive little regular traffic, but can be used in situations like employee parking that may see three turnovers a day. Higher frequency traffic areas that require Permeable Paver should use Gravelpave2.
Can Grasspave2 be used for Firelanes?
Yes, Invisible Structures has installed numerous firelanes around the country. We have letters of acceptance from municipalities and testing data available to help in gaining the acceptance of Grasspave2 for firelanes in your area.
What is the installed cost for Grasspave2 vs. Asphalt/Concrete?
Grasspave2 is generally 10-15% higher than hard paving surfaces. However, using Grasspave2 can eliminate the need for stormwater drainage and collection systems which could provide a significant savings over asphalt or concrete. The maintenance of the Grasspave2 over a 15-20 year life span is so minimal that it can also produce a savings of 40% of asphalt and concrete.
Can we plow Grasspave2?
Yes, we have numerous installations across the country that are plowed on a regular basis. We recommend using skids on the corner of the plow blades to raise the blade and keep it from coming into contact with the grass and potentially tearing the product out of the ground. Many plows already have skids or a flexible plastic/rubber piece on the bottom of the blade that protects the blade while plowing asphalt streets and can be used very easily on the Grasspave2 system.
How is Grasspave2 Maintained?
Irrigate and feed as a normal lawn, but DO NOT aerate. A good rule of thumb is if golf courses in your area use irrigation, you will need irrigation for a Grasspave2.
What is the product cost of Grasspave2?
ISI can't give an exact price, that has to be done by our manufacture's representative.
What is the installed cost of Grasspave2?
The installing cost varies a lot depending on the size of the installation and geographic location.