Frequently Asked Questions

Choose the product tab to answer you question.

Beachrings2

What is Beachrings2?

Pronounced “beach rings two.” Beachrings2 is a portable, reusable boardwalk (mat) system, for comfortable, stable, and slip-resistant access over sand and mud.

Why Beachrings2 instead of a Beach Wheelchair?

Beach wheelchairs are great and provide great access for the disabled. However, Beach wheelchairs are large and hard to store. Beachrings2 are light, portable, easy to store and provide access to an unlimited amount of people – wheelchair bound, pedestrians, strollers, and even light automobiles. Beach wheelchairs are very expensive and provide access to only one person at a time.

What is the difference between Beachrings2 and the competitors?

Beachrings2 can be re-rolled after use. Beachrings2 is extremely lightweight compared to modular systems. Beachrings2 comes in 3 colors, blue, tan, and gray. Beachrigns2 can support the weight of cars and golf carts.

What are the product dimensions?

An individual Beachrings2 tile is 40 cm by 40 cm (15.75 inch by 15.75 inch). Please visit the pre-assembled roll sizes page for convenient shipping rolls.

How wide should a Beachrings2 mat be to fit a wheelchair?

We recommend at least three tiles wide (3.9ft or 1.2 m) or wider. Beachrings2 mats that are two tiles wide (2.6 ft or 0.8m) can accommodate pedestrians and strollers.

What is the product cost of Beachrings2?

ISI can’t give an exact price, that has to be done by our manufacture’s representative. Draincore2’s superior performance and initial quality place it on he high end of composite drainage layers.

Draincore2

What is Draincore2?

Pronounced “drain core two.” Draincore2 is a high volume drainage layer capable of withstanding heavy loads in direct contact.

What is the difference between Draincore2 and the competitors?

Draincore2 can move water at 42 gallons per minute per foot-width. Draincore2 is flexible and can be shaped without expensive connectors, T-joints, or clamps.

What are the product dimensions?

The individual Draincore2 rings are one inch deep and two inches in diameter. The product itself comes in nine different roll sizes ranging from 108 sq. ft. to 538 sq. ft.

What is the product cost of Draincore2?

ISI can’t give an exact price, that has to be done by our manufacture’s representative. Draincore2’s superior performance and initial quality place it on he high end of composite drainage layers.

What is the installed cost of Draincore2?

The installing cost varies a lot depending on the size of the installation and geographic location.

Grasspave2

What is Grasspave2?

Pronounced “grass pave two.” 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 manufacturer’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.

 

Gravelpave2

What is Gravelpave2 Porous Pavement?

Pronounced “gravel pave two.” Gravelpave2 is a plastic sub-surface reinforcement structure, with fabric added to the back, that creates a dust, weed, and pot hole free porous gravel parking/walking/riding area.

What is the difference between GV2 and the competitors?

Gravelpave2 is the only product on the market that comes in rolls, which makes it easy to cut and install. All the other Permeable Paver 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. Gravelpave2 is also the only product on the market with a fabric backing that is attached to the product that acts as a weed and dust barrier

What are the products dimensions?

The individual Gravelpave2 rings are one inch deep and two inches in diameter. The product itself comes in five different 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 Gravelpave2 installed?

Gravelpave2 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 installed and compacted the Gravelpave2 is rolled out and nailed into place at the rate of four pins per square meter. Finally the product is back filled with a small, clean, and angular gravel a quarter inch above the rings and compacted into place. After compaction the fill stone should be flush with the top of the rings to prevent migration.

What size and type stone should I use as fill material.

The important characteristics of the stone are that it is small (3/16″), washed, angular and hard. Small angular stone will lock together in the rings while large or rounded stone will migrate out of the rings into the surrounding area. The fill material must be a hard stone – any soft stones, such as dolimite, will break down into a dirt/mud mixture and will not remain porous. Please view our fill page for more information.

How do I lock Gravelpave2 together in the field?

There is a clip system along the edges of the Gravelpave2 product. When rolling the product into place align the male and female connectors from each roll next to one another and snap together. The product is shipped with eight inch pins and washers that are nailed inside the rings at a rate of four per square yard with special attention being paid to the seams. Additional pins are available at a cost of $.20 per pin.

What depth of base course does the product require?

Gravelpave2 requires the same depth of subbase 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″ minus sandy gravel compacted to 95% modified proctor. The base should allow enough void space for water to percolate. 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.

How are parking spaces delineated on a Gravelpave2 lot?

The most effective way to delineate parking spaces on a Gravelpave2 installation is through the use of concrete tire stops. Other methods, such as pouring concrete striping, are possibilities but the tire stops remain the easiest and most effective.

How heavy of a load can Gravelpave2 support?

With a pounds per square inch (psi) capacity of 5,720 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. Gravelpave2 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?

Gravelpave2 is designed to withstand high frequency traffic on a daily basis.

What is the installed cost for Gravelpave2 vs. Asphalt/Concrete?

Gravelpave2 is generally 10-15% higher than hard paving surfaces. However, using Gravelpave2 can eliminate the need for stormwater drainage and collection systems which could provide a significant savings over asphalt or concrete. The maintenance of Gravelpave2 over a 15-20 year life span is so minimal that it can produce an additional savings of 40% over traditional hard surface paving materials that require constant resurfacing.

Can we plow Gravelpave2?

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 gravel and potentially tearing the product out of the ground. Many plows already have skids or a flexible plastic/rubber strip on the bottom of the blade that protects the blade while plowing asphalt streets and can be used very easily on the Gravelpave2 system.

How is Gravelpave2 maintained?

The product requires very little maintenance when installed correctly. The areas of the installation that are the most frequently trafficked may require attention as gravel works its way out of the rings. Maintenance can be done easily by brooming the gravel back into place or adding a small amount of stone if necessary and should only require attention once or twice a year.

What is the product cost of Gravelpave2?

ISI can’t give an exact price, that has to be done by our manufacture’s representative.

What is the installed cost of Gravelpave2?

The installing cost varies a lot depending on the size of the installation and geographic location.

Rainstore3

What is Rainstore3?

Pronounced “rain store three.” Rainstore3 is a plastic structure used to store water underground. It is commonly used under parking lots as an “underground pond” to hold rainwater during and after a storm.

What are the common applications of Rainstore3?

The water either percolates into the ground (retention) or is allowed to leave Rainstore3 at a controlled rate (detention). It may also be used to hold rainwater for use at a later time for such uses as irrigation (water harvesting).

What are the product dimensions?

The basic Rainstore3 part is a square 40 inches (1 meter) x 40 inches (1 meter) x 4 inches (0.1 meter). These basic units may be stacked to form cells at any depth between 4 inches (0.1 meters) and 7.9 feet (2.4 meters). These cells are placed side by side to create storage volumes any length or width (in 1 meter increments).

How strong is Rainstore3?

Rainstore3 has been laboratory and field tested to H-20 loading (bridge loading).

How much water does Rainstore3 hold?

Rainstore3 is 94% void area so each cubic meter of Rainstore3 holds 250 gallons. One unit holds nearly 25 gallons.

Why is Rainstore3 better than competitive products such as pipe or arched chambers?

Rainstore3 has the advantages of being virtually any depth, holding more water, using less stone, and having a lower overall installed cost.

What keeps the soil from entering the Rainstore3 cells?

The entire Rainstore3 system is wrapped in a geotextile fabric or a PVC liner to keep soil from entering.

What goes below the Rainstore3 system?

A layer of geogrid goes on top of the existing, leveled soils and below the Rainstore3 System.

What goes above the Rainstore3 cells?

A layer of Geogrid and a minimum of 12 inches of compacted roadbase.

How are inlet/outlet pipes attached to Rainstore3?

They are attached by forming a “boot” with the fabric or liner and securing with a hose clamp.

How are the Rainstore3 cells installed?

They are installed by lifting by hand (1 meter or smaller) or using a lifting tool and a back-hoe.

Can Rainstore3 be inspected after it is installed?

Yes, by installing maintenance ports during installation. Download RS3 Maintenance Guide in pdf.

What about silt build-up in Rainstore3?

Silt is prevented from building up in Rainstore3 by using proper pre-filtration, such as catch basins or sediment filters.

What is the product cost of Rainstore3?

ISI can’t give an exact price, that has to be done by our manufacture’s representative.

What is the installed cost of Rainstore3?

The installing cost varies a lot depending on the size of the installation and geographic location.

Slopetame2

What is Slopetame2?

Slopetame2 is unique erosion control system with integrated rings, grid, bars and injection molded fabric. Slopetame

What is the difference between ST2 and the competitors?

Slopetame2 is the only combination product available – a three dimensional containment system with fabric backing for immediate and permanent protection.

What are the product dimensions?

The individual Slopetame2 rings are one inch deep and two inches in diameter. The product itself comes in nine different roll sizes ranging from 108 sq. ft. to 538 sq. ft.

What is the product cost of Slopetame2?

ISI can’t give an exact price, that has to be done by our manufacture’s representative. Slopetame2 is usually more expensive than a simple mat and less expensive than a gabion or retaining system.

What is the installed cost of Slopetame2?

The installing cost varies a lot depending on the size of the installation and geographic location.

Terratame2

What is Terratame2?

Pronounced “terra tame two.” Terratame2 is a thick plastic mesh supplied in a roll that is installed directly onto existing grass or soil. Terratame2 is designed to protect the ground from water, erosion, and vehicular traffic/parking.

What is the difference between TT2 and the competitors?

Terratame2 is the only product with TRU GRIP™ slip protection. TRU GRIP™ adds traction for pedestrians, wheelchairs, and strollers. Terratame2 is also the only product on the market with dual colors (green and brown) to blend in with grass, vegetation, and soil.

What are the product dimensions?

Terratame2 is .56 inches high / 14mm by 6.6 ft (2meters) by 65.6 ft (20 meters. One roll covers 431 sq ft / 40 sq meters. Terratame2 can be easily cut to conform to your site plan.

What is the product cost of Terratame2?

ISI can’t give an exact price, that has to be done by our manufacturer’s representative.

What is the installed cost of Terratame2?

The installing cost varies a lot depending on the size of the installation and geographic location. Please contact your local reseller.

How heavy of a load can Terratame2 support?

Terratame2 is designed for light vehicles (pedestrians, golf carts, cars, and pickup trucks). Terratame2 is not designed to support heavy vehicles such as fire trucks or semi-tractor trailers. If you need to support heavier vehicles please use Grasspave2 or Gravelpave2.

How much traffic can the product withstand?

Since the Terratame2 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. Traffic should be limited to 5-6 passes per day on Terratame2. Higher frequency traffic areas that require Permeable Paver should use Gravelpave2.

Can Terratame2 be used for Fire lanes?

No, Invisible Structures recommends Grasspave2 or Gravelpave2 for fire lanes.

Can Terratame2 be installed on existing turf or grass?

Yes, Terratame2 can be installed on existing turf. Please see our installation guide and our technical specifications. The grass will need time to grow through and camouflage the area.

Can Terratame2 be installed on newly prepared surfaces or directly on the soil?

Yes, Terratame2 can be installed directly on newly prepared soil and then planted with seed. Please see our installation guide and our technical specifications.

How is Terratame2 Different than Grasspave2 for grass parking?

While Terratame2 and Grasspave2 have some overlapping uses in parking applications, Terratame2 is quite different from Grasspave2. Terratame2 is thinner, can be used on both existing grass surfaces and exposed soil, does not require a base course, and is less expensive than Grasspave2. Grasspave2 is more robust, stronger, needs a prepared base course, needs to be new installation, and cannot go directly on existing grass.

How is Terratame2 Different than Slopetame2 for erosion control?

Terratame2 is quite different from Slopetame2 both structurally.. Slopetame2 has a geotextile fabric backing attached to its three-dimensional ring and grid structure at 1 inch (2.4 cm) high. Terratame2 a rhomboidal mesh at .56 inches (13mm) high. Slopetame2 is more robust and is generally used in situations that require a higher level of erosion control.

How is Terratame2 held down?

Terratame2 should be anchored down to the ground using 8 inch by 2 inch, 8 gauge landscape pins. Grass and vegetation will supply additional anchoring support. See our design details for anchoring patterns.

About ISI

Why the name “Invisible Structures” Inc.?

In the case of most of our products, when they are properly installed they will not be seen.

How do you say….?

Our product names are pronounced with the numbers said as words.  For example, Grasspave2 is pronounced “grass pave two” and Rainstore3 is pronounced “rain store three.”

Then why do your logos look like they should be pronounced “squared” or “cubed”?

Yes, our logos have superscript numbers next to the names.  This is just because…, well…, we like it that way.