By utilizing a ribbed packet type of Tyvek, impregnated with silica sand in the ribs, and with the ability to support the weight of the roofing material per square, you would be creating an air-gap between the concrete and the roofing materials substrates, capable of not only breathing, but with the ability to actually absorb the moisture. Each day as the roof heats up under the sun, the heat transferred thru the roofing ...more »
GAF Roofing Systems Call for Innovation
Innovative Solutions for Ensuring Energy Efficient and Durable Low-Slope Roofing Systems Employing Concrete Decks
The National Roofing Contractors Association (NRCA) 2014-2015 Market Survey indicates that concrete decks represent about 14 percent of the new and retrofit low-slope construction market. The DOE Market Calculator1 lists the 2030 envelope-generated heating and cooling loads in commercial building roofs as 545 TBtu. Assuming that 14 percent of the roofing is installed over concrete decks and if problems exist with 50 percent of these roofs, 38 TBtu of energy savings could be achieved through this proposed innovation by eliminating the energy penalties associated with high material moisture contents.
In recent years, the roofing industry has become increasingly aware of the problems caused by moisture in concrete roof decks that migrates into the roofing system. When a concrete deck is poured, some of the mix water is used up in chemical reactions as the concrete cures, and some evaporates; but the rate of evaporation is slow, so large quantities of water remain stored within the structure of the concrete for extended periods of time. Moisture retention is exacerbated by construction methods where the concrete is poured over a non-venting form. While the concrete itself is generally not damaged by this moisture, the moisture typically migrates into the roofing system where it is absorbed by materials that are more sensitive to moisture.
While the primary function of a roofing system is to prevent water from passing into the building below, water or water vapor that collects within the roofing system can also be detrimental, both to the roofing system’s immediate performance and its long-term durability. Aside from leakage to the interior, moisture in roofing systems can have numerous negative consequences, including reduced thermal resistance of insulation and loss of strength of the insulation, cover board, adhesive, or fasteners. These effects could leave the roofing system vulnerable to uplift damage from wind, crushing from foot traffic or hail, deterioration of the structural deck, dimensional changes in the substrate (which can in turn damage the roof membrane), blistering or weakening of the roof membrane itself, and mold growth.
The challenge is to develop new materials or installation methods that can be employed with a concrete deck so that the likelihood of having moisture related problems is significantly reduced. Innovative ideas on the design of a roof assembly, the deck, or the materials are welcomed. Examples of innovative materials include but are not limited to: permeable decks, labor saving removable deck forms, vapor retarders and/or adhesives that work in moist conditions, moisture tolerant insulation materials, and methods or materials that accelerate the rate of moisture removal from the concrete decks, etc.
The solution should comply with the following design criteria:
- Ultimately result in a concrete deck that is a suitable substrate for the 15 to 20 year anticipated service life of the installed roofing system;
- Includes both new and retrofit construction;
- Minimum U-Value (inverse of R-Value) to the commercial requirements of IECC 2015 ranging from 0.050 to 0.029 hrft2°F/Btu (R20 to R35) for Climate Zones 1-8, respectively;
- Materials and/or methods should reduce the likelihood of improper installation and thermal bridging impact;
- Cost effective materials and designs meeting a simple payback calculation of under 10 years; and
- Materials should be non-toxic and eco-friendly.
This JUMP Call for Innovation requires only a written submission. If you are concerned about protecting the potential of your IP, Select the “On” option under “Only Allow Moderators and Admins to see my idea” on the “Submit Your Idea “page. This will not permit the JUMP community to comment, discuss, or vote on your idea.
Cash award of $10,000 will be sponsored by GAF for the top selected technology submission. The idea submitter will also be invited to discuss future collaboration with GAF and ORNL technical experts.
Depending on the needs identified ORNL may provide in-kind technical support of up to $20,000 to enable ORNL staff to provide prototype development, testing, 3rd party validation, or other defined support.
Additionally, Successful JUMP participants looking for funding and incubation support may be invited to participate in the Clean Tech Open Accelerator Program based on technical and market merit.
Idea Submission Deadline
Idea Submission Period Ends: Sunday August 27th, 2017 at 11:59 PM EST
Create Air Flow above slab form and below concrete roof deck by first adding a layer of 1/4" cement board on top of the slab form. The ribs of the slab form are then used as mini ducts to allow air to flow up the 1/4" roof slope between the cement board and the slab form. The sun warms the air and/or inside rising air from heating provides the uphill air flow force. The pour stop for the concrete roof deck is installed ...more »
The best way to resolve the moisture problem is to first install a perforated rigid insulation applied with strips of adhesive, then proceed to install pressure release in floating style and encapsulate with an additional layer of 1" insulation applied with the same stripping method. This will allow all moisture to travel to the vapor vents, then you can apply almost any roofing system on top of the rigid venting system ...more »
An engineered one-way vent that is cut into the roof with a fitting that allow for multiple-hoses to attach to the one-way vent and running through a large dehumidifier to dehumidify the roof thus evaporating the moisture from the concrete deck. It would be able to be done within hours depending on the saturation percentage.
Creating negative pressure (suction) immediately above the concrete is a direct and effective means of accelerating evaporation of moisture within the concrete. Imagine creating access holes spaced in strategic places around a roof deck - through the roof assembly - and inserting vacuum hoses. But what if those vacuum connections were powered by wind, rather than electrical connections? This is the same basic idea as ...more »