by Dennis Buirge
There are times during specification editing when the following question comes to mind: How many contractors truly know the meaning of that sentence I just wrote? Language in some specification software packages incorporate terms not normally used by the general public. Does the following sentence, which incorporates terms found in some construction related project manuals, make sense to you? "Use laitance to verify that the deleterious substrate is acceptable to code required dunnage."
This blog identifies and defines three of these not so commonly used specification related terms.
LAITANCE: This is a result of the improper placement and finishing of concrete. When concrete is placed containing excessive water, when the concrete mixture is overworked, when improper or excessive finishing is performed, or when any combination of the aforementioned occurs, a wear layer of cement and aggregate fines can accumulate on the concrete wear layer. A milky white substance, which we call laitance, is the accumulation of fine particles on the surface of fresh concrete and is caused by the upward movement of water. The root word of laitance, lait, is French based and means milk. What happens if the laitance is not removed? The base concrete without any subsequent finish covering can cause dusting. If any type of coating or paint is to be applied to the laitance bearing concrete that finish material will not properly bond to the concrete due to laitance interference, since concrete requires a clean and sound substrate; the coating most likely will delaminate over time. If any finish flooring such a vinyl tile is to be applied, the flooring will again over time delaminate, since the adhesive is bonding to the laitance and not to the concrete. Therefore, various finish flooring specifications should include a paragraph in PART 3 - EXECUTION requiring the removal of any laitance. Wording in the Examination or Preparation Articles might be something like the following:
Examination: Verify that finishes of substrates comply with tolerances and other requirements specified in other Sections and that substrates are free of cracks, ridges, depressions, laitance,, and deleterious deposits that might interfere with floor covering adhesion.
Surface Preparation: Prepare concrete leaving sound surfaces free of laitance, glaze, efflorescence, curing compounds, form-release agents, deleterious films, and other contaminants incompatible with finish flooring system materials.
DELETERIOUS: There are many problems that can occur during an installation, application, and construction of various products. When something is harmful or its use causes trouble, often in a subtle or an unexpected way, it can be considered deleterious. One can better understand a term when considering synonyms and antonyms, some of which for deleterious are as follows: Synonyms - adverse, bad, damaging, dangerous, harmful, injurious, and noxious; and Antonyms - advantageous, beneficial, benign, favorable, innocent, inoffensive, and safe. The reference of deleterious in specifications is used as an adjective and should include a noun such as film, deposit, effect, result or like term. The word deleterious occurs in both of the aforementioned examples for laitance.
DUNNAGE: During construction it is always beneficial to have shop-fabricated and manufactured materials delivered to the site, stored, and handled unharmed and ready for incorporation into the project. The term dunnage is taking from the shipping industry where it means ‘pieces of wood, matting, or similar material used in stowing cargo in a ship’s hold’ with another definition being ‘loose packing material used to protect a ship’s cargo from damage during transport’. The Material Handling Industry of America (MHIA) defines dunnage as “materials or devices used in the securing and/or bracing of products during shipments”. During a quick internet investigation, I was unable to find a synonym or antonym for dunnage. The following MasterSpec example using the term dunnage in a specification most likely would be found in the Delivery, Storage, and Handling Article in PART 1 - GENERAL: Store materials to permit easy access for inspection and identification. Keep steel members off ground and spaced by using pallets, dunnage, or other supports and spacers. Protect steel members and packaged materials from corrosion and deterioration.
Next time: When editing, reading, or interpreting specifications, you should understand the meaning of these three less commonly used, construction related terms; cool terms I like to use.