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Concrete and Foam Roof Decks for Greenroofs
We are highly recommending Quadlock's foam forms assembly for not only your building's walls but also for their roof decking. These forms can significantly reduce installation costs and increase the thermal performance of your entire building envelope. I would highly recommend that if you are interested in learning more about their systems that you sign up for one of their technical webinars or download some of their installation and design manuals. For more information on these systems please feel free to contact Steven Carroll at Innovative Building Solutions.
Speed of Installation
- Lightweight forms; average 1 sqft/minute install time (2-person experienced crew)
- Less than half the weight of other hollow core precast floor systems
- Uses about 40% less concrete than flat suspended slabs
- Delivered to site ready to install (pre-cut and labeled at the factory)
- No forms to be stripped
- Less shoring than traditional wood joist systems
- R-Values from R-16 to R-34 [h*ft²*°F/BTU]
- U-Values from 0.35 to 0.17 [W/(m²*K]
- Smaller HVAC requirements
- Thermal Mass properties - more consistent indoor temperatures
Edited Thu, Jan 29, 2009 6:20 PM
Replies to this Topic
One thing not mentioned here Greg, is that a "one-way" reinforcement scheme in a suspended concrete slab is much more efficient that the traditional "two-way" slab structure. Because the main reinforcement only runs in on direction, and is supported on two ends versus 4, the consumption steel falls by about 50%, along with the commensurate amount of installation labor. This is a major cost saver and very much fits with sustainable building standards by simply eliminating the need for additional materials.
Thanks Douglas....does Quadlock have any research on how the QuadDeck composite concrete and foam form could reduce the chance for toxic mold and mildew to build up on the underside of the roof deck/substrate. I know that this product is popular in northern climates where a higher R-value and extra thermal resistance is desired but in the mid atlantic region I am finding that condensation build up on the underside of concrete slabs is an issue. Especially, if there is poor air circulation or in areas like mechanical penthouses where there is equipment that might increase the humidity.
As required by ICC and other code agencies around the world, we manufacture to very specific standards, which are verified regularly by independent inspection. One of the standards that we have to comply to is ASTM C1338 "Standard Method for Determining Fungi Resistance of Insulation Materials and Facings". This test method sets up ideal growth conditions (il.e.: temperature and humidity) for mold and subjects samples to all known mold types. Our tests indicate "no growth" of mold detected on our samples.
What this says is that there is a critical factor missing for mold to even begin to grow, which is an organic food source. While technically EPS is an organic compound (made from the residue of dead dinosaurs), it does not have sufficient "organic" qualities to serve as a nutrient source for mold.
While this speaks well for the EPS product alone, it would not prevent mold from finding nourishment in accumulated dirt, dust, pollen, and etc. that may conceivably contaminate the underside of the roof deck/insulation assembly. My suggestion is that all three environmental factors that influence mold growth (i.e.: humidity, temperature, and organic food source) be controlled with adequate ventilation.
Factoid: Almost no mold species can survive below RH levels of 50%. Therefore, the higher your RH goes above 50%, the better the environment for mold growth. This is why Granny's house has mold in it: She keeps ALL doors and windows closed, the heat cranked up, and the tea kettle boiling.
Hi, Greg, et. Al.
A great article on mold that just hit the street is from Joe Lstiburek at Building Science Corp. Joe is not only a brilliant building enclosure scientist, but a very entertaining writer, as you will see in the "BSI-027 Material View of Mold" file that I just posted.
Thanks for that article from Joe Lstiburek I hadn't seen that one yet. Steve Carroll with Innovative Building Solutions had forwarded to me two other articles that was published by the BSI which are interesting reads and helps break down the physics behind therodynamics and vapor intrusion. It is amazing how he breaks down a complicated topic into something that is easy to wrap your mind around. I just posted those two articles as well which other members might find helpful.
What I don't understand is why we continue to build using sub par low performance building materials that are often more expensive....when there are plenty of better products like Quad lock on the market? Is it because those materials are more readily available at our building supply stores like Home Depot? To your knowledge does any major chain like Lowes or Home Depot even carry insulated concrete forms? What is it going to take to realize the benefits of having an "air tight" highly insulated home? Or do people just prefer to live in toxic temporary trailers like the ones in Louisana erected by FEMA.
The short answer to your question is (as you might expect)......"cheap".
I have been been building with and designing ICFs since 1989, and have heard the same "Cheap-Is-Good" argument daily for that entire 20 yr. period. While the price differential in energy efficient buildings has been proven over and over to be very small, and the payback immediate, people can't seem to accept the long term value proposition, either in cash savings to themselves or benefit to the environment.
Builders are the worst culprits, for the most part. If any aspect of the project costs 5 cents more, then it is automatically disqualified.
ICFs, like green roofs, are an emerging technology that in most cases adds a small to moderate price premium over the whole project. Those of you who are new to this business, know this: If the decision to include either of these great systems is left to a player who does not have a compelling interest in paying that premium in order to get the benefits available, then they will always take the first opportunity to eliminate it. Consequently, it is critical that the entire project development and execution chain be well known to any of us who hope to have our ICF, green roof, or other product retained in the design of the building. Any potential point where the technology can be "value engineered" out of the project must be identified and monitored closely, from beginning to end. Even when technical issues are thrown up in the air as a "barrier", the truth usually comes to light that cost was the real issue. I have witnessed this 500 times if I have seen it once.
Until we are somehow able to break through that old "cheap-is-good" thinking, the green road is, unfortunately, going to be a rather steep up-hill climb.