THE ConDeck CHRONICLE

A Publication of the ConDeck Corporation

ConDeck  is  a  New  Mexico owned Corporation Specializing in the sale and installation of Insulating Concrete Roof Decks, Perlite Products, Tectum Products and Elastizell Products.

 

ENVIRONMENTAL STEWARDSHIP  MADE  EASY!

 

During the course of our busy schedules, some people in the construction industry tend to forget who is paying all the bills of the industry.  IT'S THE BUILDING OWNER!!  The Owner deserves the best product for their money and a design solution that will not cost a fortune in maintenance or component replacements for the life of the building.  Fugitive products, ones that must be replaced during maintenance or reroofing operations, have become a thing of the past.  Owners are demanding design solutions that insure longevity and low life cycle costs.

 

Besides giving the Owner future headaches, the use of fugitive products increases the load on our landfills. Overloading our landfill with millions of board feet of polyisocyanurate roofing insulation during a reroofing operation is a very poor environmental practice.  Polyisocyanurate insulation stays whole and does not biodegrade.  When future anthropologists excavate our landfills, they will find millions upon millions of board feet of polyisocyanurate insulation.  Guess who pays over   and   over   again   for   all   of   that    insulation . . . THE BUILDING OWNER.

 

One way to prevent a building Owner from being tyrannized by future maintenance costs is to use Lightweight Concrete Roof Deck Insulation.  By using Insulating Concrete, the Owner is assured a life-of-the-building roof insulation system. Lightweight concrete insulation systems can be reroofed time and time again.

 

BUILD FLAT AND SAVE!

 

Many Architects and Design Professionals are beginning to see the benefits of building flat.  Many of the benefits are actually bestowed upon the Architect as direct savings in Construction Document production time and Construction Administration time, resulting in higher project profit.

 

By designing the structure flat there is no more time wasted figuring block coursings. Structural Shop Drawings are much easier to check, HVAC ductwork is much easier to route through a constant height interstitial space and equipment curbs become off-the-shelf items with shorter lead-times.

 

Design time and efforts can be allocated to parts of the building that the Owner will occupy and enjoy.  Why waste expensive production time in areas of the building not seen or used by the Owner?

 

Besides being very cost effective for the Architect, building flat is also a boon to the Contractor.  Construction times are greatly reduced with a less complicated design.  Interior studs and gypsum board materials can be ordered in precut lengths reducing waste; and ceiling, ductwork and plumbing hanger lengths can be standardized.  There would be no more major sequencing efforts for structural steel delivery and the list goes on and on . . .

 

By using Lightweight Concrete Roof Deck Insulation crickets and slope-to-drain can be provided at a very low price.

 

CONTRACTOR'S OPTION

 

One way to add Insulating Concrete to your roof insulation specification section  is as a Contractor's Option.  If you want to try Insulating Concrete Insulation, but do not want to commit to only one type of system, add the following to Part 2 of Roof Insulation Specification Section 07220:

 

"Contractor's Option: Contractor may use Lightweight  Concrete Roof Deck Insulation in lieu of the type specified and indicated.  Install insulation system in accordance with Perlite Institute Catalog 31-95."

 

This way, the onus will be on the General Contractor to evaluate whether the system is viable and cost effective.  If used, the Owner and our environment will benefit greatly.

 

POLYISO BOARD IS NOT EARTH FRIENDLY!

 

Expanded Polystyrene (EPS) Board is the major insulating component of lightweight concrete roof insulation systems.  From an environmental standpoint EPS Board is much more benign.  Polyisocyanurate Insulation Board has some characteristics that make it an environmental catastrophe.

 

Ø                   The Polyisocyanurate manufacturers are still dealing with the use of "greenhouse gas" blowing agents (Freon).  In 2003, these blowing agents will be banned completely.  Look for major price increases and quality problems.

 

Ø                   Polyiso Board is subject to "Thermal Drift."  This means that as the product ages its R-value decreases.  What was originally specified and sold as R=7 per inch degrades to an average value of R=5.6 in just a few months.  This means that most new buildings with 4 inches of polyiso board realistically have an R=22 roof assembly instead of the intended R=30 system.  The building Owner continues to pay the added utility charges for the missing R=8 throughout the life of the building.  The R-Value of EPS board, on the other hand, does not drift so designed R-Values are actually realized by the Owner.

 

Polyisocyanurate Board is also subject to many other functional problems such as:

 

Ø                   Defacer Delamination: Due to poor manufacturing quality control, leads to potential roof blow-off problems.

 

Ø                   Cupping or Bowing: Results from the insulation getting wet.  This can contribute to roof blow-off and to premature roof failure.

 

Ø                   Shrinkage and Dimensional Instability:  Most manufacturers are now recommending that two layers of insulation board be installed with joints staggered.  This is to compensate for shrinkage and dimensional instability.  Installing two layers is labor intensive and will increase installed prices.  Dimensional instability also contributes to premature roof failure.

 

Ø                   Crushing and powdering:  Polyisocyanurate has a very low compressive strength.  23 psi does not readily support maintenance equipment and personnel over a long period.  Over time, trafficked areas powder and crush which reduces effective R-Value and contributes to both premature membrane failure and roof blow-off.  Insulating concrete systems provide a minimum compressive strength of 125 psi and are a very stable roof substrate.

 

ANATOMY LESSON

 

Insulating Concrete Roof Deck Insulation is comprised of perlite or cellular concrete and expanded polystyrene board insulation.  Perlite concrete consists of a ratio by volume of 1 part portland cement to 6 parts perlite.  The compressive strength is 125 psi.

 

The system is installed as follows:  A 1/4 inch slurry coat of insulating concrete is installed over the metal or structural concrete roof deck.  Stair-stepped EPS board is walked-in to the slurry coat.  EPS boards measure 2 feet by 8 feet and the thickness is determined by the required R-Value and by the slope required.  EPS boards are solid blocks of EPS with no horizontal joints.  A two inch thick layer of insulating concrete is installed over the EPS board and finished to a smooth roofing substrate.  Slope-to-drain is accurate and custom, accommodating field variations gracefully.  Total system weight for R=30 over B deck is 7.58 pounds/sq. ft. and 4.8 pounds/sq. ft. over structural concrete!  The only variable in the weight is the addition of EPS board.