CAUTION! Flooring Penetrations May Result in Structural Changes

Many of our multi-story condominium communities are wood framed with wood flooring. Most high-rise communities are concrete structures with concrete flooring. Whether wood or concrete, flooring is an integral part of the structural integrity of the building.
The unfinished floors (i.e., slabs) provide lateral and vertical support, and are intended to be load bearing. A floor may also provide sound attenuation and may even prevent smoke and fumes from entering units.
Over the years, many associations have unwittingly approved penetrations through the structural flooring without requiring an analysis of how such penetrations will affect the structural integrity of the building as a whole. When these issues are subsequently raised at meetings, I often hear comments from boards such as, “we have always allowed owners to…” cut into the floors to install wiring, add ventilation ducts or install plumbing.
I reached out to Professional Structural Engineer, Carl Josephson, on this topic and he offered the following insight:

“When a wood floor or beam is cut improperly, usually a sag will occur, if not immediately, then over time. The sag may be very noticeable or only slightly noticeable. There may be cracking in wall or ceiling finishes to alert someone that there is a problem. However, when a concrete floor slab is improperly cut or notched, there may be some cracking or floor sag, but many times there will not be any noticeable distress. Concrete can fail quickly and abruptly. The best thing to do is to avoid the problem in the first place by checking with a qualified engineer before cutting or notching any concrete slabs, beams, columns, or other component parts.  If you suspect you could have a problem it may be necessary to carefully examine the area in question, review the original drawings and calculations (if they are available), test the concrete using ground-penetrating radar or other non-destructive techniques, in the worst-case scenario, core the concrete and chip out and expose some of the reinforcing steel.”

The tragedy in Surfside, Florida is a grim reminder of the need for constant vigilance over building modifications which may impact the structure. Rumors abound as to the cause of the Champlain Tower failure. It is likely that there were multiple factors that came together to cause the collapse.
While we will allow the courts to weigh in on liability, one issue that has been a source of speculation is whether penetrations in the concrete floors caused by an owner’s improvements was one of the contributing causes to the disaster. We have seen occasions where owners have requested floor penetrations and the retained structural engineer has responded, “no penetrations should be allowed, or the size of the penetrations should be modified.” On occasion, the risk of accidently cutting into the slab and damaging the post tension cables was a risk the board was unwilling to take.

So, what is the take away?

When an architectural application is received or when floor penetrations are noted, the affected area should be evaluated to determine whether any floor penetrations could affect the structural integrity of the building. Spending a few dollars now with licensed engineers may prevent a serious problem down the road.