Retaining wall geogrid reinforcement and when an engineer is required

Above ~3–4 ft a wall needs geogrid: layers between courses reach back into the backfill (≥ 0.6 × H) to tie the soil into one reinforced mass. Get a permit + engineer when the wall is over 48″, carries a surcharge, has a slope above, or is tiered (IRC R404.4).

A taller segmental retaining wall reinforced with geogrid. Layers of geogrid laid between the block courses extend back into the compacted backfill a length of at least 0.6 times the wall height (NCMA), tying the blocks and the soil into one heavy reinforced mass — which a simple gravity wall above about 3 to 4 feet cannot do on its own. Code (IRC R404.4) also requires a permit and a licensed engineer when the total height exceeds 48 inches, any surcharge sits above the wall, the ground slopes up above it, or the walls are tiered. — Source: NCMA SRW design (geogrid 0.6×H); IRC R404.4 (permit/engineer)

Use this diagram free on your site — grab the embed codeGet the code

What this diagram shows

A taller segmental retaining wall reinforced with geogrid. Layers of geogrid laid between the block courses extend back into the compacted backfill a length of at least 0.6 times the wall height (NCMA), tying the blocks and the soil into one heavy reinforced mass — which a simple gravity wall above about 3 to 4 feet cannot do on its own. Code (IRC R404.4) also requires a permit and a licensed engineer when the total height exceeds 48 inches, any surcharge sits above the wall, the ground slopes up above it, or the walls are tiered.

Use this diagram — free

You're welcome to use this diagram on your own site, blog, handout, or lesson at no cost. The only condition is a visible credit link back to the source page. Copy the snippet below and paste it into your page — the credit is already included.

Embed code (HTML)

<figure style="margin:0;max-width:800px">
  <a href="https://remodelcalculators.com/construction-diagrams/retaining-wall-geogrid" target="_blank" rel="noopener">
    <img src="https://remodelcalculators.com/api/figure-embed/retaining-wall-geogrid" alt="A taller segmental retaining wall reinforced with geogrid. Layers of geogrid laid between the block courses extend back into the compacted backfill a length of at least 0.6 times the wall height (NCMA), tying the blocks and the soil into one heavy reinforced mass — which a simple gravity wall above about 3 to 4 feet cannot do on its own. Code (IRC R404.4) also requires a permit and a licensed engineer when the total height exceeds 48 inches, any surcharge sits above the wall, the ground slopes up above it, or the walls are tiered." width="800" height="480" style="width:100%;height:auto;border:0" loading="lazy">
  </a>
  <figcaption style="font:14px/1.4 -apple-system,sans-serif;margin-top:6px;color:#555">
    Diagram: <a href="https://remodelcalculators.com/construction-diagrams/retaining-wall-geogrid" target="_blank" rel="noopener">Retaining wall geogrid reinforcement and when an engineer is required</a> — courtesy of <a href="https://remodelcalculators.com" target="_blank" rel="noopener">RemodelCalculators.com</a>
  </figcaption>
</figure>

Please keep the credit link intact and don't alter the diagram itself. Redistribution as part of a competing diagram library or template pack isn't permitted. Questions? Reach us via the site.

Was this diagram helpful?