Probes: Destructive Investigation

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PROBES

Destructive Investigation of Historic Fabricin the Built Environment

Prepared by: Ken Follett May, 2014

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Table of Contents:

PROBES

03 10 14 17 25page page page page page

Destructive Probes

The Long Talk Teamwork The Envelope RFP

There are 33 slides in this SlideDoc.

They include the title, this slide of contents and the end slide.


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Destructive Probes

Non-destructive Testing (NDT) is a technological phenomenon of great merit when it comes to non-interference in heritage fabric.

For good reason it has received a whole lot of attention and development. It is some really cool stuff with usually quite expensive equipment.

A lesser cousin, less exotic but a quite traditional approach to gaining information is to make a hole in the wall, to make a hole in the historic fabric.

To put a hole in the wall.

“He got mad because he could not figure out where the electric conduit was buried in the wall and in a rage he swore and kicked the sheetrock. His work boot put a nasty hole.

That is how we found what we had looked three days for.”

Compared with NDT a whole lot less attention in the preservation industry has been applied to improvements in how an investigation team goes about destructive probes.

It seems easy enough.


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Why?

Does all of the terra cotta at the cornice of this building need to be removed and replaced?

This as-built drawing from 1876 shows a beam here behind this chestnut panel, but that makes no sense when I look at the building.

We thought that all of the cast iron pieces were bolted together until we got up there and took a closer look. Forget about it!

We need to know how this beam is connected into that beam, and there is a whole lot of concrete fireproofing in the way.

Stop for a minute and hold this thought in your head: "I need to know something, and I am not really sure what to do about it."

Why do probes?

Because we have an idea about what we do not know.


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Why not?

With the well known preservation mantra "Do No Harm", it makes sense to do one's best to not interfere with or potentially cause damage to irreplaceable and often delicate heritage fabric.

Indiscriminate use of construction workers who are not experienced with traditional materials or building techniques, or who may not be informed or sensitive as to the importance of historic fabric, can do a whole lot of harm in a very short period of time.

Before taking anything apart it is important to have confidence in the craftspeople who will be using the tools to touch and play with the materials.

Not all workers will understand the importance and delicacy of the heritage fabric that they touch.

Why not do probes?

Delicate materials.

"It was not up to us but the owner hired a demolition contractor to do the probes. They thought it would be cheaper. You can see what sort of mess that made.

Can you fix this?"


silk wall covering

silver gate of St. Sophia of Kiev, Ukraine

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To Open a Hole in the Wall

Noise is not signals we desire to uncover and reveal, it is the clutter that hides and disguises what we look for.

It is the blue paint that we see that hides the plaster that covers the red brick that encases the rusted steel column buried in the masonry of the wall.

Noise is stuff that we do not want to hear. It is the chatter that envelopes the signal that we actually do want to hear, and we hope that we hear it clearly.

But if we do not engage with the environment, if we do not open ourselves up to all of the noise, then we may miss the very information that we need.

Information does not exist in a vacuum.

It is surrounded by an environment of noise, of a whole lot of distraction and stuff that doesn't particularly matter.

NOISE: “Hey, do you hear that orange bird up there in the

branch above the nuthatches?”


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Reality

Unknown information reveals itself over time, but time is short and expensive.

What you at first think may be going on may not be what is going on at all.

Discovery is the process of

revealing what is not known.


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Theory

An understanding of the structure, with the background of theory, needs to be adequately communicated to the project team in order for appropriate and optimized decisions to be obtained by the project team during the pre-construction design phase.

The tools that you have as a preservation engineer provide a conceptual framework within which the structure can be envisioned and modeled.

Theory needs to be applied

to an understanding of the existing historic structure, and to how materials behave over time in the natural environment.


“...the trouble about arguments is, they ain't nothing but theories, after all, and theories don't prove nothing, they only give you a place to rest on, a spell, when you are tuckered out butting around and around trying to find out something there ain't no way to find out...There's another trouble about theories: there's always a hole in them somewheres, sure, if you look close enough.”

- Tom Sawyer Abroad, Mark Twain

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B&PI: Bits and Pieces ofInformation

Bevan P. Sharpless (1904–1950) was an American astronomer. He concluded in 1944 that the orbit of Phobos was decaying and reported his observations at the US Naval Observatory in the Astronomical Journal in 1945. A crater on Phobos

is named after him.Do you remember Bevan?

I just now read that 50% of our awake consciousness is spent in daydreaming.

So how do we stay focused the rest of the time?


He travelled 7,300 miles to

the tiny island of

Niuafoʻou (the name

means “many coconuts”)

to observe and

photograph a total eclipse

of the sun which lasted

only one minute.

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The Long Talk

At the Federal Reserve lobby that night there was the project architect, the senior architect, the structural engineer, the architectural conservator, the graduate student “specialist”, the probe contractor, the lead trade mechanic, and the recent preservation trade school graduate who looked like any other NYC laborer.

The first two hours were spent talking about the Guastavino Tile vaulted ceiling that we all looked at. The question was, “Where do we put the hole?”

Only fifteen minutes were spent to set up and for the lead trade mechanic to drill a 1/8” diameter hole in a mortar joint.

Communications: Plan, Execute, Monitor and Control

A vital element of the success of any project is the quality of the communications process.

An RFP with a focus on the information to be obtained does not necessarily outline expectations that the investigation team will need all members to be able to effectively communicate with each other.

But in any investigation there will be a need for long talks and less action.


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The Long Talk:Plan

Imagination builds castles in the air and then we see the television advertisement for the fantastic pick-up truck that shows children looking out windows in the very best ever tree-house in the grand old basswood tree that suddenly, very suddenly reverses in the short-short movie and is rapidly un-built before our astounded eyes into a pile of boards delivered in the dirt.

When we approach an understanding of how the built environment was built, then we need to imagine it in our mind ten times. We may or may not have seen this particular detail before. Was the carpenter left or right handed? We could have seen it diagrammed in a book, or we could have once seen this pattern when we had a hammer in hand after busting through a hole in a sheet-rock wall.

Or this could make absolutely no sense to us at all. Maybe we had better sleep on it. Better yet, you stay awake while I go sit in the truck and watch that it is parked legal.

“Build ten times in your mind. Build three times on paper. Build once in the real world.”

John Leeke’s Dad


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The Long Talk:Execute

“After we had that long talk at the old house along the Neversink they went out to their truck and in a few minutes they came back with an assortment of tools.

They also brought in protection for the floors and they took care of a few things I had never even thought about.

One of them handed me a dust mask and ear plugs.

They went to work and did not bump into each other, despite the space being very close and tight. It was like they knew what they were doing.”

It can be very easy to move quickly in the wrong direction.

The longer the talk the shorter the work... if we know what we are doing.


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The Long Talk:Monitor and Control

How will we get the best results from our efforts?

Everyone needs to be prepared to stop the motion and talk about what it is that is going on.

Otherwise things can get squirrelly in a hurry.


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Teamwork:Working Together

Bring experienced people together in a shared adventure of curiosity and then see what happens.

When I was first hired to be a foreman on a project and sent out to lead in the field my mentor said to me, “ I am sending you out to work with people that will know a whole lot more about what they are doing than you. Will you be able to deal with that?”

There needs to be people brought together as a team, to work together, in order to have a Long Talk.

That is, unless we are going to only talk to ourselves.


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Teamwork: to LearnFrom Each Other

When we work together as a team, then we all gather together in a shared environment and learn from each other.

"Like other men, he gathered his education as he lived. He was the creature of his environment and inheritance, and his ideas matured gradually as he learned from other men and from his own experience."


Be curious.

Ask stupid questions.

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Team Building In the midst of January it was bitterly cold in the masonry tower.

We had spent the better portion of the morning pulling and carrying up containers of equipment to the top for the Non-Destructive Testing team. There were cracks in the stone wall that needed to be mapped out. We also moved and held ladders for the architect.

The kerosene heater was way less than perfect. We made a few holes here and there to confirm findings. What do you think this squiggle here means? Everyone was cold. We ate lunch together up there where we could see our breath as a white vapor in the chill air. The report was due the following Wednesday.

When all was said and done at the end of three days the engineer turned and said, "We usually use XYZ for this work, they have a good crew, but you folks seem to actually care if we find what we are looking for."

Who would be best to have on our team, who has experience and can share their knowledge to help us?

.

Do not think in terms of, "Oh, anybody can put a hole in the wall.”

Think about who you want to spend your time at work with.


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The Envelope

The envelope is all of the activity in the environment that surrounds the process of the investigation.

Access, permits, insurance, movement of tools and materials, parking, weather, toilets, food, shelter, dust masks, eye protection, lunch, the public, temporary barricades, traffic cones, and signals and signs. Safety harnesses, eyewear and hard hats. All are elements of the envelope and they all need to be managed.

Time, Space, Cost and Politics

It was a very hot day and the consultant who had been for several hours out on the stone plaza, which radiated heat into the air, came over and sat down with the team where the ongoing Long Talk was about next steps.

Suddenly the consultant noticed that we were all drinking water and he said, “Where is the water?”

He was sitting on the water jug.


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Time Envelope

The theater site required that we do our probes between performances and public use of the building.

We were required to work three days, then take four off, then return and work four, then take five off.

It went on like that, and at the end of each session we had to be all closed up, cleaned up, and demobilized from the site.

All this and the design phase required that we be done with everything by the last day of the month.

To put a cost on this was a headache and three-quarters.

It would all be so much easier if we could reliabily use Remote Viewing. That would be the ultimate in non-destructive.

The time envelope begins when the investigation team arrives on the site and ends when the last person leaves at the end of the information collection process.

The preservation engineer will generally enter into the time envelope at a point after the start and prior to the end of the allotted site time.


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Space EnvelopeOne space is not like another.

The RFP says that the walls and walkways need to be protected but only includes a photo of a portion of the ceiling with a rectangular box drawn on it. Caption: ‘Make hole here.’

When the president of the United States shows up then you had better expect that you are now in a different sort of space.

When the structural engineer says that they want to poke their head up through the ceiling we look at their head and determine how large of a hole needs to be made in order for them not to get poked or stuck.

We also ask them if they need a flashlight. We hold the ladder until they come back down.

Space is the area of the physical activity.

Maintenance of logistics and safety, and supply lines are primary concerns within the space envelope.

A smoothly functioning team provides the structural engineer or architect with the support needed for a focus on the specifics of the information collection process.


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Space: Before You Visit the Structure

Know where you are going, how you are going to get there and what you need to take with you, or for others to be prepared to bring along.

Review the existing documentation.

Drawings: study them if they are available. Often they are not.

Photos: study them closely.

Previous Reports: share them.

Do not forget Personal Safety Gear: hard hat, eyewear, appropriate work boots, ear protection and gloves.

Do you need a harness?

Where is your tape measure?

Camera?

Paper, pen or pencil?


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Space: When You Visit the Structure

Walk About.

Observation.

The reality may not match the documentation. You need to discover the reality.

Ask questions; interview those who are familiar with the structure.

If you take photographs include the surrounding conditions. Step back a ways and capture the entire envelope.

Observation of Details: Learn the Value of Sitting and the Art of Doing Nothing in Particular.

Look for the unexpected.


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Space: Site Logistics


Very often a high proportion of the cost of an investigation is in

getting people, tools, material and equipment to where the probes need to be completed.

In some work environments a critical element to the success of the investigation is knowing where to park the truck full of tools.

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Cost Envelope

There are all sorts of ways to play with cost numbers, but one habit that architects seem to be very good at is making the boxes on bid forms too small to fit very much of any numbers in them at all.

Worse than that, often the way the numbers are broken out into boxes makes no sense at all and goes a long way to scaring the probe contractor away from placing a bid.

Everyone in the construction industry knows, particularly on the supply side, that rarely does anyone read the document: they look at the $ number.

General conditions, mobilization, demobilization, site logistics, protection -- they should be broken out from the unit cost of probes as separate line items.

It can be amazing just how much has to be completed, and at what cost, in order to collect a few sentences worth of valuable information.

The cost envelope is an overlay generally based on time, labor and materials to be expended.


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Political Envelope

Project Politics: Though not directly related to the doing of probes, often there are interrelationships of various levels of misunderstanding and stress involved within the investigative team.


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RFP: Request for Proposal

When you provide photographs with an RFP take the in-shot -- say, the area where you want the hole in the ceiling, and then the out-shot -- step way back and capture the entire space envelope.

If your investigation is out on the street, take photos of the street. Look at the signs -- when can the investigation team park here?

Are there any really difficult conditions that will make reaching the work a more than usual problem?

The header probes were on the exterior 19th floor of a high-security building and there was no access for anyone on the pre-bid walkabout to get to see them up closely. Nobody seemed to know if they were terra cotta or brownstone or cast iron. The RFP said, make holes and repair in kind.

Do not focus on how you think someone should go about enabling you to get the information, think in terms of the result that you want. What are you looking for?

Do not draw a bunch of 2’ x 2’ boxes and then not explain what it is that you need to know.


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De-Construction Logic

With heritage construction there is something to be said for being able to ask the craftsperson what it is that they think they are looking at, “Why do you think they would have built this like this?”

In doing probes there is always the question, “How do we get from here to there with the least waste of time, energy or resources?”

Simply said, start with the end in mind.

The probe contractor should be able to provide a flexibility to make changes as the investigation progresses, but to also be able to keep in mind the steps needed to close the project at the end.

A probe gig is a staged event with beginning, middle and end.

Real-time flexibility of management of the time and space envelopes optimizes the ratio between resources expended and value of the information collected.


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Processthe vacuum cleaner

The paper we were handed described the probes that were intended. The descriptions, though, it turned out once we started to make the holes, left a whole lot to be desired.

Turns out the paper was meant to convince someone to allocate the funding for the probes and thus the thinking on the part of the person who put the paper together never went as far as to consider what the person standing there with tools in hand would need to know.

The process was not fully thought or communicated through to the end.

Every single government agency that we work with has a different process.

Most of the time we have no clue what that process is until we are already in the thick of engagement with the project.

For us it seems like the rules are constantly changing to make life more difficult.

Though you may know what is going on, you need to keep in mind that nobody else around you may have any clue as to your process.


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Insurance

A contractor who specializes in probe work is not running a large capital operation and may not be able to provide the levels and types of insurance that a General Contractor is able to provide.

At the same time a GC may not have the specialized knowledge, experience or management focus required for engagement in a team based investigation.

A GC can provide labor to make holes in a wall but maybe not a level of knowledge that needs to be applied to make informed and flexible decisions in the field.

For two days of work we were once asked for $17 million in General Liability insurance. We told them to go away.

Five weeks later they came back and said OK to our existing insurance coverage.

The probe contractor needs to know before they

provide a work proposal what may be expected for insurance requirements.

It does no good for any project for a probe contractor to provide a proposal and then find out that there are insurance requirements that they were not aware of and that they may not be able to meet.

As well, organizations need to understand that they may not be able to get the insurance that their legal team has outlined.

Rule: It never gets easier for anyone.


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Who is Hiring?

Situations vary from project to project but the general industry tendency is that the end-client, whomever is the owner of the property, or represents the owner, contracts directly with the probe contractor.

The activity of the investigation is then directed by the structural engineer or architect in coordination with the probe contractor who has responsibility for means and methods.

The insurance industry makes clear distinction between the liabilities of design work and those of physical activity with labor, tools and materials.

When the question comes up, “Who are we working for?” what is actually being asked is, “Who writes the check, who pays for this, and to whom are the insurance certificates addressed?”

Probe contracts are fulfilled on credit. That is, credit extended by the probe contractor to the party that is obligated to pay.

Will the probe contractor be hired directly as a subcontractor on your design team, or will they be contracted to work for someone else?


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Notice to Proceed(or Not)

Communications are always vital to the success of a project, but one of the most important pieces of information to clearly communicate to a probe contractor is that they have been chosen for the work, that they will be paid, and that someone actually wants them to get started.

A phone call is not sufficient... there needs to be a paper trail.

The next vital communication, at least as a courtesy, is to let the probe contractor know they have not been chosen, so that they know they are free to go about their business elsewhere.

An RFP should be structured in such a manner that the probe contractor will understand the process by which they will be provided with written documentation to confirm that a contract relationship exists.

What? You wanted us to start yesterday?

But, we won’t be able to be there for another week.

We sent in our bid three months ago.

This is the first we have heard back from you!


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Optimal Approach The engineer in their RFP asked that the contractor include in their proposal to drill sixty 1/2" diameter holes into the concrete foundation wall.

The RFP was not clear as to why the holes were needed.

When the crew went to the site with the engineer they drilled three holes and it was agreed by everyone on the team that there was no more information to be derived from the remaining fifty-seven holes.

Regardless, the engineer was flustered that the end-client would think that money was being wasted because work was not being done..

The engineer insisted that the remaining holes be drilled, looked in and then patched up. This was a waste of resources.

Drilling stupid holes, the crew felt used and disrespected for their experience.

The optimal approach is about how to get to the needed information with the least waste of anyone's resources.

The optimal approach is not about how to make better faster holes in a wall.

It is not about counting how many bricks are moved.

It is not about a 2’ x 2’ square mapped on a drawing.

It is not about how many hours that it took to do this task.

Sometimes the optimal approach is not so much what you do on the site as that you are awake and alert and able to think on your feet.


HOW WE GET HERE

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Closure

Closing up of probes, particularly where heritage fabric is involved, can be more time consuming and costly than the resources expended to do the probes and obtain the information.

The RFP should specify at which point in the investigation and closure process the final end ‘period’ is placed and all is done and completed.

Generally the people who need and want the information are long gone from the scene when it comes to clean-up and closure.

When poorly dealt with, the poor closing of probes and clean up of an investigation session can leave a lasting negative impression with the end-client.

When the focus is on the collection of information, very often what is neglected is consideration of how probes will be closed and finished up.


|Prepared by: Ken Follett May, 2014

The End

Probes: Destructive Investigation

Engineering

ken follett

wall noise

environment of noise

importance of historic

delicate heritage fabric

lot of harm

lot of attention

silk wall