Top Questions of Newcomers to Geofoam

By Nick Harvill, Sales Representative – Architectural Products

I have been working in the EPS industry for over 35 years, starting right out of College in 1977.  My experience has involved Sales, Tapered Roofing, Packaging Design, and Manufacturing.  Before joining ACH Foam Technologies at the beginning of this year, my Geofoam experience was limited to floor fill.  Geofoam is used as floor fill when a concrete floor needs to be raised for leveling purposes or for Stadium Seating.  The raised area beneath the concrete is filled with Geofoam. Since joining ACH, I have been exposed to a few other uses: Foundation Walls, Retaining Walls, Floor Slab Fill, Roadbed Fill, and more.

Quite often Contractors and Designers have been tasked with using Geofoam in their project but have had no previous experience with it.  I appreciate their questions and have learned much from them.  Here are a few common questions that frequently come up:

1) Is there any special preparation for the foundation or base layer? 

The foundation is always important.  You will need a drainage material to carry away water, in addition to a flat, level base.  Geofoam will lighten the load on subsoils but the base has to be substantial enough to carry the load that is placed on it.  This is determined by your Soils Engineer.

2) Do I need aggregate between the wall and the Geofoam for drainage?

No.  Don’t place the Geofoam tightly against the wall.   You can hold it off the wall several inches to allow water to flow freely for drainage.  Only the top layer needs to be against the wall to prevent materials from falling into the drainage gap.

3) Do I need to cover the Geofoam before backfilling?

A filter fabric will help prevent loose debris from settling between the cracks.

4) Will the Geofoam eliminate the lateral load on the wall?

Soil places a lateral load at an angle of about 60 degrees.  By stepping the Geofoam out at this angle on each layer, the lateral load is virtually eliminated.

5) I have calculated the volume of Geofoam I need, can you give me a cost?

Geofoam comes in a variety densities with compressive strengths ranging from 5.8 to 50.0 psi at 10% deformation for different load requirements.  Your Engineer will have to determine what density is needed for your project based on the load it will have to carry.  Once we have this information, we will be able to provide you with accurate material costs.

6) How do we keep the Geofoam from moving after placement?

We have optional Gripper Plates available that are placed between the layers to keep them from slipping.

7) How do we fabricate or cut the material?

While you can cut EPS with just about anything (any kind of saw or knife), Geofoam is typically thick, 36”or more.  It is best to cut it with a Hot Wire.  The best is a paddle cutter.  Two insulated handles (like electric fence handles) a power supply (frequently called a rheostat), and some cutting wire.  You can acquire a complete assembly from a number of companies or contact your ACH Foam Technologies’ Rep for more info.

I hope you find these answers beneficial in designing your project using GeofoamThe ACH Foam Technologies Rep in your area will be glad to assist you with any additional questions you may have.

About Nick Harvill

Bachelor in Civil Engineering Technology 1982 and Associate in Architectural Technology from Southern Technical Institute 1977. Thirty Seven years experience selling Roof Insulation, EIFS Insulation and shapes, Packaging, OEM, and Manufacturing. Wife Robin, Daughter Samantha 25, Sons Nick, Jr. 23 and Ben 13.
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