Update: How I was tyrannized by the obvious during an engineering investigation

Who would have known that condensation was the real cause of the flooding in a furnace room – or so it seems now.  But don’t hold your breath at the rate this saga is unfolding.  Also note that forensic investigations can go off the rails like this too.

I blogged earlier (see below) on how I investigated the cause of flood water on a furnace room floor in a vet clinic and how I concluded it was obviously due to a high water table beneath the building.  Also how I was told later that it was really due to a burst water pipe in the washroom adjacent the furnace room after staff went there and saw water on the washroom floor.

The story could have ended there with me learning a valuable lesson, that if it seems obvious keep on investigating.  But it didn’t; my lesson continued a few days later.

Vet clinic staff called a plumber about the ‘burst pipe’, he came and investigated, saw the water on the washroom floor, looked for a burst pipe but found none.  He then looked in the washroom on the floor above.  Still no burst pipe but he did find water on the surface of the cold water pipes in the washroom.  The water was dripping on the floor and in turn on the washroom floor below next to the furnace room.

Water vapor in the moist washroom air had condensed on the cold water pipes.  This would be the same as vapor condensing on the inside of a window in the winter and water running down the window.  We’ve all seen that I’m sure.

So, the flood water in the furnace room was caused by condensation on cold water pipes, not by a burst pipe and not by a high water table.

To take inspiration from a quote by Hunter S. Thompson, “Wow! What a lesson!”. (Ref. 1)  I’ll keep you posted in the event there are more chapters in the saga.

You might ask, what’s this got to do with forensic engineering investigation?  It’s a reminder, that if being thorough in the investigation of water on a floor in a small room in an old building is important, it’s light years more important for the simplest of forensic investigations.


  1. Thompson, Hunter S., “Life is not a journey to the grave with the intention to arrive safely in a pretty and well preserved body: but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming “Wow! What a ride!”. (As cited recently at the celebration of a friend’s life)


Earlier Blog: How I was tyrannized by the obvious during an engineering investigation

It can happen to any of us, and it finally did to me.  I was tyrannized by the obvious when investigating the cause of flooding in a large, three story building.

A building renovator called me after water was seen on the furnace room floor by staff of a veterinary practice.  They had gone to the room where materials were stored and saw a few millimetres of water on the floor.  Not a lot but still.

The renovator said the building, which was erected in the 1960s, was on a concrete, ground-floor slab, on low land and near a lake.  The furnace room was enclosed by concrete block walls.  The flood water had pooled on the slab.  He estimated that the concrete floor slab was about five feet above the nearby lake surface.

When i went to examine the site I saw that the five feet was about right and that the furnace room was an estimated 50 feet from the lake shore.  I was also told that the lake level was higher than normal due to a lot of rain this spring.

The grounds around the building sloped down slightly to the lake shore.  The front and right side of the building were paved.  There was a lawn at the back and an old paved boat ramp on the left.  The surface of the boat ramp was bumpy after many years.

The corners of the furnace room were still wet where the concrete block walls rested on the concrete floor.

I had a good look around then walked across the floors of the different rooms in the practice.  They were a little uneven which wasn’t so unusual for an old building.  But my look around wasn’t as good as it might have been and I neglected to look in the small room adjacent the furnace room.

My examination complete I met with the owner and the renovator.  I noted how the water rises in a lake during frequent rain storms.  It also rises in dug wells.  The water in a well is the water table. The surface of the water table in the ground near a lake shore is usually higher than the lake.  There is also water in the soil above the water table due to capillary action – this is when water rises in the small voids in the soil above the water table (Check high school physics)

This higher water table plus some surface water runoff across the asphalt at the side of the building could explain the presence of the water in the furnace room.  It was obvious.  I mean, the building was so close to the lake with high water levels not seen in recent years and the furnace room floor was near the lake surface and the water table.

The irregular boat ramp was typical of frost heave due to water in the ground – a high water table and capillary action during wet springs over the years – and would back up this obvious conclusion further.

I talked about different ways of preventing water getting into the furnace room.  These included the obvious – terrible word – better perimeter footing drains and/or a sump pump.in the furnace room.  A sump pump is a pump in a depression or hole in the ground – a sump.

The sump pump was decided on as the least expensive and one that could be constructed several feet below the water table to draw it down below the furnace floor.  That decision was left with the building renovator.

I left the site after about an hour – an efficient examination and consultation, or a  hurried one?

A few hours later the renovator called to explain that a staff member had gone in the wash room – the one room I hadn’t gone in – adjacent the furnace room and found a burst water pipe, the real cause of the flood in the furnace room.

I was tyrannized by the obvious and guilty of expectation bias.  The moral of the story?  If it’s obvious, keep on truckin’ and do more investigation.