Miscellaneous

Have you ever seen someone tapping a concrete wall with a hammer? Or dragging a chain along a concrete floor? These are a couple of the conventional methods for evaluating concrete- that is, identifying and locating unsound or “loose” concrete. These methods are known to be noisy and typically require close-up, physical access to the concrete surfaces. You might wonder is this the only efficient way to evaluate concrete?

While there are numerous contemporary alternatives for surveying and evaluating concrete, many of these methods have limitations in cost, accuracy, or both. One method that has proven its accuracy and is already a well-developed technology is thermal imaging. Infrared cameras have been used to depict thermal images since the 1960s. Over the history and development of these cameras, they have been effectively applied in many industries including medical (detection of fevers), military and law enforcement (surveillance), firefighting, and many others. Recently, the technology of thermal imaging has found success in yet another application: evaluation of concrete structures.

Infrared cameras detect thermal radiation, or heat, and translate the radiation into a thermal image that the human eye can see. We can then understand temperature differences by the colors depicted in the image. Unsound concrete typically traps air beneath its surface. Since air heats up and cools down much faster than many solid materials, including concrete, a temperature difference between sound and unsound (delaminated) concrete is created and can be detected by an infrared camera. The thermal image produced by the camera will show a hot spot in the morning as the ambient temperature is rising, and it will show a cool spot in the afternoon as the temperature begins to drop.

Although thermal imaging applied to concrete structural evaluations has its own limitations (e.g. training required for the thermographer, availability of equipment, ambient temperature differences), it can serve as an accurate alternative to the conventional hand-sounding methods. For more information on this topic from a certified infrared thermographer, feel free to email spenn@etc-web.com.

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Surrounded By Sounds & Smells

Getting The Most From Quality Assurance Inspections

No Need For A Hazmat Suit

Two recurring complaints of residents in multi-family buildings are related to sound transmission and odors emanating from neighboring units.  Generally, sound related complaints are most often logged in wood-framed buildings.  This is usually because the wood floor support system is lightweight and relatively thin, with air space within the floor-ceiling sandwich.  This configuration allows sound to travel more readily.  As opposed to buildings made from steel and concrete, which have thicker floors that are heavier and tend to dampen sound transmission.  Both types of buildings use thin, lightweight walls to divide units, which do not dampen sound very effectively.

Often condominium documents require that the floors be covered in carpet and limit the exposed hard floor surfaces such as tile or wood.  This can help absorb and dampen sound related to impacts, such as foot falls.  However, the noise related to a loud television or music tend to be less affected.

Sound is a wave of vibration.  Solutions to reduce sound transmission can be found in two categories.  One option is sound absorbing materials, such as mats or insulation.  The other is isolating solutions, which often involve adding another layer of drywall placed on spacers to reduce the contact and therefore, the locations in which vibrations can travel through a wall or floor.

When white noise machines and other relatively inexpensive approaches do not work, renovations to the living space are the next step to addressing the offending noise.  Since the annoyance of disturbing sounds are related to individual tolerances and perceptions, it can be nearly impossible to eliminate sound transmission.  It is also costly to address sound, as well.  Thus, just the sleeping rooms are usually modified with sound dampening strategies.

Odors from cigarette smoke and cooking are the most logged odor related issues.  Gaps in the floor or walls between units can allows odors to travel.  Hunting down these gaps can be difficult as the smallest of openings can be the culprit.  First look for the most likely locations; gaps around plumbing pipes and exhaust or ventilation ducts that extend between floors and gaps around electrical outlets in walls.

Another likely source is a poorly sealed or a dysfunctional exhaust system.  Multi-story buildings often have a common kitchen and bathroom exhaust system that links all the vertically stacked units.  Sometimes these ducts are clogged, unsealed, or the rooftop exhaust fan is not operational.  Sometimes renovations to units include the installation of kitchen exhaust hoods or bathroom exhaust fans, which were not part of the original system design.  Adding these fans can disrupt the operation of the common exhaust system.

If sealing gaps around pipes and ducts prove unsuccessful at stopping the odors, the next step would be to positively pressurize the living space.  Most older buildings are negatively pressurized.  By introducing positive pressure in the unit, air from neighboring units cannot enter the living space.  This usually requires the installation of HVAC-type equipment to bring outside air into the unit.  This effectively makes the air drafts associated with the unit exit rather than enter the living space.  Newer buildings typically are positively pressurized, so this may not be an option in all cases.

Addressing sound and odor related concerns can be more challenging than stopping water infiltration, as small defects can result in large concerns.  Interior walls usually need to be opened to seal the gaps, which can be quite disruptive, and the efforts may be less effective than desired.  However, all is not lost, solutions do exist, and improvements or corrections can make a big difference to keep those sounds and smells out of your living space.

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Buying a Condo – Part 2 / Document Review

Keeping Our Boatswain Chair Inspectors SAFE!

Pouring Concrete In The Summer

Words can have a number of meanings and can even change meanings with time. This is especially true of terms specific to a technology or industry. Following are definitions of a few roofing and paving terms that people outside those trades (such as board members) may hear and not fully understand.

Overlayment – Placement of a new roof over an older covering or placement of a new asphalt surface course over an existing pavement.

Resurface – Install a new layer of asphalt (overlay) onto an existing pavement. Should not be confused with seal coat.

Seal coat – Apply a coal tar or asphalt slurry over asphalt pavement.

Tar – Stuff that dinosaurs got stuck in; the nasty stuff in cigarettes. Should not be confused with asphalt used in paving and roofing.

Coal tar – A byproduct of steel smelting used for producing pavement seal coating and interply waterproofing in some roofing systems.

Fishmouth – What a fish eats with; distorted membrane lap in roofing, resulting in an opening.

Shark fin – A closed fishmouth in roofing.

Spud – Tool for removing aggregate surfacing from a roof; the act of removing the aggregate; tater.

PRMA roof – Protected Roof Membrane Assembly, wherein the membrane is adhered, applied or laid onto the roof deck and is covered with a layer of insulation and ballast.

Ballast – Heavy materials (typically stone, concrete pavers, etc.) placed on a roof to hold down insulation or loose-laid membranes that might otherwise be blown off by wind.

Loose-laid – Not fastened or adhered.

Mud – Roof cement.

#$%! Gooey %&*@ – Roof cement.

Alligatoring – Interconnected cracking in pavement; pattern characteristic of depleted asphalt flood coat in roofing.

Flood coat – Hot (liquid) asphalt applied over top ply in built-up roofing system, usually followed by small aggregate surfacing.

Stoning – Installing aggregate surfacing in a flood coat on a built-up roof.

Resaturant – Material intended to rejuvenate asphalt in pavement or roofing by replacing depleted volatile constituents; waste of money.

Consultant – Someone who knows a hundred ways to make love, but doesn’t know any women.

Pitch pocket – Roof flashing consisting of a receptacle for sealant (or pitch), placed around an opening through which utility lines or other items penetrate a roof.

This is not a radioactive fluid spill! We just used a fluorescent green biodegradable dye to see if water was flowing under, rather then through the culvert. It turned out that water was flowing under the pipe through the gravel setting bed.  We have more dye left if you need to know where water is coming from or going to.