Is the foundation of the Salt Lake Temple composed of granite or sandstone?

DOES the famous and historic Salt Lake Temple actually sit on a base of all granite?

There’s no doubt that a sandstone base, taken from Red Butte Canyon, was the Temple’s original base. But is any of the sandstone still there?

The vast majority of all Internet searches find sources that imply the sandstone base was entirely removed – it is all granite now.

The most authoritative of these sources is from the BYU Religious Studies Center at:

https://rsc.byu.edu/archived/salt-lake-city/4-design-construction-and-role-salt-lake-temple

This report states that the Temple’s foundation was covered as the U.S. Army approached Salt Lake in the summer of 1857.

Then, as the Army threat disappeared, the foundation was uncovered as Temple work was ready to resume.

The BYU Religious Studies history of the Salt Lake Temple then states:

“At this time, President Young examined the newly uncovered foundation and became aware that it was defective. He and his associates noticed large cracks and concluded that its small stones held together with mortar could not carry the massive weight of the temple. On January 1, 1862, he announced that the inadequate foundation would be removed and replaced by one made entirely of granite. The footings would be sixteen feet thick. “I want to see the Temple built in a manner that it will endure through the Millennium,” he later declared. The work of rebuilding the foundation moved slowly, and the walls did not reach ground level until the end of the construction season in 1867, fourteen years after the original cornerstones had been laid.”

However, this report can be supplemented by several Deseret News stories, including a photograph from the early 1960s.

The Deseret News of March 30, 1963 published a photograph of when extensive excavations were made around the base of the Salt Lake Temple. This photograph lists the granite foundation as 14 feet deep (two feet less than the BYU article stated).

It also clearly shows a sandstone sub-foundation still there, underneath the granite foundation.

So, technically both statements of a granite or sandstone base are true.

An earlier Deseret News story on Sept. 8, 1962, stated:

“The story of the foundation and the back-breaking labors of the pioneers who toiled with oxen to haul giant pieces of granite from Cottonwood Canyon quarries to replace an original foundation of sandstone has been told.”

Thus, if there ever was a full foundation of sandstone up to the ground level, then the upper 14 feet of that base had to have been removed and replaced with granite. However, the BYU story stated that the temple structure didn’t rise to ground level until 1867, or 10 years after the threat from the U.S. Army. So, this casts some doubt on a full underground base of sandstone ever existing.

Notwithstanding, it is a fact that some 14 feet to 16 feet of lower sandstone sub-base still remain below ground.

The 1963 Deseret News story stated that the sandstone sub-foundation was 30 feet down. Amazingly, only hand tools, horse and oxen power created that foundation.

This sandstone sub-foundation covers an area of 4,850 square feet.

The photograph also reveals how layered in blocks and even partially eroded the sandstone sub-foundation appears to have been in 1963.

During the 1963 renovation, cement wells and footings were added to replace the previous rocky subsoil. At the same time of the 1963 underground improvements, underground passages were also added.

-“Facts about the Temple” was an Oct. 22, 1891 story on the S.L. Temple in the Salt Lake Herald newspaper. This article accurately mentions the deepest foundations as being sandstone.

“The Salt Lake Temple foundation is not laid of granite from Cottonwood canon (sic), as has been stated, but is of the same kind of sandstone as the temple block wall foundation – we call it firestone – and has never been disturbed or taken up and relayed as has been stated …” the Herald story stated.

The Herald also explained that oxen hauled the sandstone from a spur in the mountain a little south of the mouth of Red Butte Canon (sic), in blocks about three feet thick.

Back to the Deseret News’ 1963 photograph, it does appear to show the three-foot thick sandstone blocks in the sub-foundation.

-One other interesting excerpt from the BYU Religious Studies article on the history of the S.L. Temple is this:

“Because the builders recalled President Young’s desire for this temple to stand through time, the structure was very solid. Even at their tops, the walls were six feet thick, and the granite blocks were individually and skillfully shaped to fit snugly together. Nearly a century later, Elder Mark E. Petersen attested to the soundness of the temple’s construction. He was in the temple when a rather severe earthquake hit, damaging several buildings around the Salt Lake Valley. “As I sat there in that temple I could feel the sway of the quake and that the whole building groaned.” Afterward, he recalled, the engineers “could not find one semblance of damage” anywhere in the temple.”

So, the finished Salt Lake Temple may be more earthquake resistant than some may believe – notwithstanding that sandstone sub-foundation.

-Still one more interesting fact from the BYU Religious Studies article is this:

“Some have suggested that in the Salt Lake Temple, shafts were provided for elevators and spaces left throughout the building for electric conduits and heating ducts even before these technologies were known. Angell Sr., (the temple’s architect) however, certainly would have learned about elevators, which were just coming into use at the time of his 1856 visit to Europe. By the early 1860s, electricity was already being used in Utah for the Deseret Telegraph system. Hence, most of the temple’s interior was designed and built long after these technologies emerged. Although the west center tower proved to be a convenient location for the two main elevators, there is no evidence to suggest that their shafts were planned when there was no knowledge of this technology.”

NOTE 1: The term "granite" is a layman's term in this article. Geologists probably have their own different scientific terms.

NOTE 2: It was announced in April of 2019 that the Salt Lake Temple will close at the end of 2019 for approximately 4 years for extensive remodeling. This will be the first remodeling of that temple since 1963, when some of the photos on this blog were taken. Extensive seismic upgrades will be made -- and the sandstone sub-foundation will surely be exposed again.

-Originally published in the Deseret News.

NOTE 2: Temples can be vulnerable to earthquakes. Example: The Logan Temple's main structural beam was found to be cracked in two when extensive remodeling work began in 1976. It was surmised that a past earthquake (possibly from the March 27, 1975 Pocatello Valley Idaho quake that was near the Utah-Idaho border and equaled 6.3 in strength), damaged it.
Thus, if the temple had simply been renovated, the roof could have eventually collapsed. Fortunately, a total rebuilding inside the walls and roof was done.