Editing Openai/6928dffa-2c40-800e-b585-2520d50a2cbb (section)

=== When foam is appropriate ===
* Small, non-structural posts: fences, mailboxes, signs, light ornamental posts — especially when you want a quick install and instant set. Manufacturers market foam specifically for these. Sika USA<ref>{{cite web|title=Sika USA|url=https://usa.sika.com/retail/en/products-catalog/post-setting/sika-postfix.html|publisher=Sika USA|access-date=2025-11-28}}</ref>
* Fast installs / single-person jobs: foam sets in minutes (some products initial set in 3–30 minutes and are buildable in under an hour), so it’s excellent when you don’t want mixing, wheelbarrows or long curing waits. Sika USA<ref>{{cite web|title=Sika USA|url=https://usa.sika.com/retail/en/products-catalog/post-setting/sika-postfix.html|publisher=Sika USA|access-date=2025-11-28}}</ref>
* Where you want a lightweight, waterproof backfill that protects the buried post base from soil contact (closed-cell formulations). Fast 2K<ref>{{cite web|title=Fast 2K|url=https://fast2k.com/|publisher=Fast 2K|access-date=2025-11-28}}</ref>
* Not appropriate for main structural supports: tall deck posts, load-bearing columns, flagpoles or anything the building code treats as a footing unless the product specifically has code/ICC approvals that permit that use. (Note: some foam deck anchors claim IBC/IRC compliance — check the product data sheet carefully.) Sika USA<ref>{{cite web|title=Sika USA|url=https://usa.sika.com/retail/en/products-catalog/post-setting/sika-postfix.html|publisher=Sika USA|access-date=2025-11-28}}</ref>