Moisture in Lightweight Structural Concrete Roof Decks

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Moisture in Lightweight Structural Concrete Roof Decks

lightweight structural concrete roof decks and encourages you to notify NRCA’s Technical Services Section about moisture-related problems regarding lightweight

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Moisture in concrete roof decks Professional Roofing ...

Sep 01, 2017  The issue of moisture in concrete roof decks is not new. Since 2009, NRCA has received numerous reports of moisture-related problems with roof systems installed on

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Moisture in Concrete Roof Decks

Moisture in Concrete Roof Decks March 12, 2021 AIA Baton Rouge 11 Trial ASTM F2170 tests Existing lightweight structural concrete roof decks Roof 1

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Moisture in new concrete roof decks - Construction

Oct 06, 2017  However, challenges related to moisture still persist. When a normal-weight structural concrete roof deck is poured (i.e. cast) in place, it contains a high

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Moisture in Concrete Roof Decks

Moisture in Concrete Roof Decks March 12, 2021 AIA Baton Rouge 11 Trial ASTM F2170 tests Existing lightweight structural concrete roof decks Roof 1 Roof 2 Roof 3 Roof age (yrs) 477 Area (ft2) 13,200 23,840 14,760 Thickness (in.) 6.5 7.5 7.3 No.

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Better Understand Why the Combination of Moisture and ...

Jul 27, 2016  It is NRCA’s opinion that the risks of moisture-related problems associated with lightweight structural concrete roof decks outweigh the benefits. Should lightweight structural concrete be used, NRCA recommends designers clearly state the concrete’s drying parameters and ASTM F2170 should be used for this purpose.

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Moisture Issues in Concrete Roof Decks - Cotney Attorneys ...

The National Roofing Contractors Association (NRCA) has stated that they have received, and continue to do so, a significant number of reports regarding problems created by moisture in concrete roof decks. Both normal-weight structural concrete and lightweight structural concrete contain additional water that is added to ensure the concrete ...

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MRCA Bulletin: Moisture in New Concrete Roof Decks ...

Background: Latent moisture in new concrete roof decks has been an issue in the roofing industry for some time. Initially the issue was thought only to be with light weight structural concrete [see MRCA Technical Bulletin 2011-1 STRUCTURAL LIGHTWEIGHT CONCRETE ROOF DECKS]. However, recent research within the roofing industry raises concerns on ...

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STRUCTURE magazine Is Lightweight Concrete All Wet?

For the purposes of this article, we are considering only structural lightweight concrete: a mixture of portland cement, water, fine (sand) aggregates, and expanded clay, shale, or slate coarse aggregates. While normal-weight concrete mixes typically weigh 145 to 155 pcf, lightweight concrete typically weighs 110 to 115 pcf.

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Wet Concrete can Ruin a Good Design: Insights to Cement ...

"Moisture in concrete is only an issue with lightweight structural concrete." As the industry began to pay attention to increased reports of moisture related issues with roofs installed over new concrete roof decks in the 2000's, it was noted that many of these roof failures were primarily over lightweight structural concrete roof decks.

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Structural Lightweight Concrete Roof Decks - Luna and ...

Apr 01, 2015  With standard structural concrete the aggregate used is sand and stone. With structural lightweight concrete a mix of shale, slate, slag and clay are used and, with this mix, the aggregate is fully saturated prior to mixing. The end result of the structural lightweight mix is a deck that can be 20-25% lighter than standard structural concrete.

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Concrete Moisture and Roofing - Concrete Moisture Test Spec

Moisture levels in any concrete slab are affected by a number of conditions and therefore a final drying time cannot be predicted with any certainty outside of accurate moisture testing. Most concrete roof decks make use of lightweight concrete mixes; a big benefit to the load weight of the structure, but a drawback in terms of accurately ...

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Moisture in new concrete roof decks - Page 4 of 4 ...

Oct 06, 2017  However, litigation initiated by property owners over roof system failures caused by concrete deck-sourced moisture can no longer be ignored. By 2011, several research papers had been introduced at the International Roofing Symposium concerning roofing over new concrete decks. “Currently, we have a pile of legal cases in our files.

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Reroofing Over a Wet Concrete Substrate

Since the roof deck on the 1970 building is structural concrete, the severe leaks manifested themselves at . openings in the concrete, mainly at roof drains. However, eflorescence and build-up of salt crystals deposits, ranging from 1 to 12 inches in length, had developed on the underside of the concrete deck, indicating that the concrete deck ...

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Roofing Systems WBDG - Whole Building Design Guide

May 10, 2016  Refer to the NRCA's Industry Issue Update, "Moisture in Lightweight Structural Concrete Roof Decks." Also, the NRCA recommends steel roof deck installations conform to the requirements described in the Steel Deck Institute's (SDI's) Manual of Construction with Steel Deck and Composite Steel Deck Handbook. Review attachment with structural ...

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VENTING OF COMPOSITE STEEL FLOOR DECK

are more affected by moisture levels in the concrete than previously available adhesives. Steel form deck products have traditionally been made available with venting to allow for excess mix water to drain from the cementious slurry component of lightweight insulating concrete systems (LWIC) in roof

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Re-Roofing

1. Inability of the structural support system to bear the added weight of a re-cover system. 2. Deficiencies of the structural support system attributable to movement or deterioration. 3. The presence of moisture in the existing roof or deck system. 4. Any condition that would prohibit adequate attachment of the re-cover system. 5.

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how to fix structural problems in a house

Itâ s just a good idea to take a look up there. How to fix this: If you’re quite handy, you can replace your own flashing. I recently purchased a house off the back of the sellers house survey report showing only minimal maintanence advice around a flat roof repair and guttering You may be starting to see horizontal or vertical cracks in walls throughout your home and on the outside ...

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Moisture Issues in Concrete Roof Decks - Cotney Attorneys ...

The National Roofing Contractors Association (NRCA) has stated that they have received, and continue to do so, a significant number of reports regarding problems created by moisture in concrete roof decks. Both normal-weight structural concrete and lightweight structural concrete contain additional water that is added to ensure the concrete ...

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Moisture in Concrete Decks - Western States Roofing ...

Increased use of lightweight structural concrete, with its pre-wetted aggregates, contributes additional moisture to concrete that further extends a concrete deck's drying period. In addition, roof deck design has changed. Cast-in-place concrete roof deck design may now include composite construction with the steel forms (metal deck) left in place.

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Wet Concrete Roof Decks Spawn a Rise in Litigation in 2017 ...

May 21, 2017  Given the severity of moisture damage to roofs and the recent warnings against roofing over concrete decks, one way to avoid it is to stop using lightweight structural concrete altogether. Opting instead for normal weight concrete means using

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Concrete Roof Deck Issues - Sika USA

Jul 23, 2019  Lightweight concrete (LWC) and lightweight insulating concrete (LWIC) will allow for the excess water to move through the pour much quicker than structural concrete. The slide with the graph from SGH shows the LWC losing most of the water in two weeks or less. It is typical to adhere a roof cover to LWC within 10 to 14 days after pouring.

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Tech Today Professional Roofing magazine

Feb 01, 2010  Lately, NRCA has experienced an increase in reports of moisture-related problems with low-slope membrane roof systems applied to newly poured, normal-weight or lightweight structural concrete roof decks. In the reported instances, significant amounts of water have been found within roof systems within several months to up to three years after construction.

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Normal vs. Lightweight Concrete Roof Deck Construction ...

May 27, 2014  Cement deck roof systems installed over structural lightweight concrete in the tight time-driven sequence of construction will likely incur a very heavy upward water vapor drive. Heavy moisture vapor accumulating within concrete roof decks lead to problems, which could include: loss of insulating value, face degradation, physical damage to the ...

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ChannelDry Roof Assembly for Lightweight Structural ...

Roof Deck Criteria and Preparation . a. Roofing Assembly described herein intended for use on newly poured structural concrete decks (normal and lightweight) once they have reached their designed structural strength. b. Surface imperfections, fins or cracks, must be documented and reportedto the specifier, general contractor and

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Reroofing Over a Wet Concrete Substrate

Since the roof deck on the 1970 building is structural concrete, the severe leaks manifested themselves at . openings in the concrete, mainly at roof drains. However, eflorescence and build-up of salt crystals deposits, ranging from 1 to 12 inches in length, had developed on the underside of the concrete deck, indicating that the concrete deck ...

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Roofing Systems WBDG - Whole Building Design Guide

May 10, 2016  Refer to the NRCA's Industry Issue Update, "Moisture in Lightweight Structural Concrete Roof Decks." Also, the NRCA recommends steel roof deck installations conform to the requirements described in the Steel Deck Institute's (SDI's) Manual of Construction with Steel Deck and Composite Steel Deck Handbook. Review attachment with structural ...

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Introducing Duro-Guard™ EPS Fan Fold CONCRETE ROOF

Lightweight Structural Concrete (LWSC) (85-110 lb/ft3) – Cast or poured in place over a metal deck that is not removed. Metal decks should be vented in order to facilitate faster drying of the concrete deck.

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VENTING OF COMPOSITE STEEL FLOOR DECK

are more affected by moisture levels in the concrete than previously available adhesives. Steel form deck products have traditionally been made available with venting to allow for excess mix water to drain from the cementious slurry component of lightweight insulating concrete systems (LWIC) in roof

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Re-Roofing

1. Inability of the structural support system to bear the added weight of a re-cover system. 2. Deficiencies of the structural support system attributable to movement or deterioration. 3. The presence of moisture in the existing roof or deck system. 4. Any condition that would prohibit adequate attachment of the re-cover system. 5.

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Installation Guideline Tips For Modified Roofing Part I ...

* Lightweight structural concrete is a high moisture content deck that should not be confused with structural concrete or lightweight insulating concrete. Lightweight structural concrete, with its high moisture content and prolonged drying times, makes it very difficult to determine when a roof can be installed appropriately over these decks.

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US Solutions USG STRUCTURAL PANEL CONCRETE ROOF

USG Structural Panel Concrete Roof Decks can carry a total load, live and dead, of 150 psf (7.2 kPa) on cold-formed steel framing is spaced 48 in. (1220mm) o.c. USG Structural Panel Concrete Roof Decks have a linear variation with change in moisture content

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