underbuilt

Verb

underbuild (third-person singular simple present underbuilds, present participle underbuilding, simple past and past participle underbuilt)

1. (transitive) To build beneath another structure; provide a foundation or support for; undergird.
   • The two eastern arches have been underbuilt for the sake of strengthening them.1900, Yorkshire Archaeological Society, Yorkshire archaeological journal: Volume 15
2. (transitive) To perform insufficient construction on a building or in an area; build below a specified requirement or standard.
   • Appellee was obliged to overbuild, rather than underbuild, the appellant's telephone line for the distance of these six spans for the following reason [...]1903, West Publishing Company, The Northeastern reporter: Volume 65