The Building Code Compliance Office

1
The Building Code Compliance Office

• Lightweight Insulating
• Concrete
• Instructor
• Michael L. Goolsby, RRC

2
FBC definition

• Material produced with or without aggregate
  additions to portland cement, water and air to
  form a hardened material possessing insulating
  qualities, which, when oven dried shall have a
  unit weight no greater than 50 pcf (801 kg/m3).
  (1917.1)

3
Types of lightweight insulating concrete
mentioned in the FBC

• Aggregate Minimum compressive strength 125
  psi
• Cellular Minimum compressive strength 160
  psi
• Cellular/aggregate (Hybrid)
• Minimum compressive strength 200 psi (250
  psi for adhered membrane systems)

4
Cellular LWIC

• A foaming agent is added to the LWIC.
• The foam keeps the cement particles in suspension
  around the cells until the LWIC hardens into a
  honeycomb matrix.

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Advantages of LWIC

• Slope to drain
• Thermal value
• Thermal mass
• Keep weight off
• Surface irregularities
• Fire resistivity
• Nailable base
• Avoid tear off

6
What is the minimum thickness of LWIC that must
be poured?

• 1917.4.2 Minimum thickness of lightweight
  insulating concrete fill shall be 2 inches over
  the top plane of the substrate unless otherwise
  specified in the Product Control Approval. In
  all cases, lightweight insulating concrete shall
  be of sufficient thickness to receive the
  specific base ply fastener throughout the roof
  deck.

7
What is the R Value of LWIC

• FBC 13-404.2.AB.1 Data input per Appendix B.
• Shall obtain from 1997 ASHRAE Handbook of
  Fundamentals.
• R Values per ASHRAE for Cellular
• Density
• 60 pcf R 0.48
• 40 pcf R 0.71
• 20 pcf R 1.25
• When not available here
• Use manufacturers info based on lab or field
  testing. Four ASTM tests specified.
• EPS is used to enhance R value.

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EPS Board

• 1917.4.12 Insulation board with lightweight
  insulating concrete fill shall conform to Type I
  expanded polystyrene insulation as defined in
  ASTM C 578. 1.
• Check LWIC NOA for approved insulation.
• Insulation panels shall be provided with holes
  and/or slots for keying and/or slots for venting.
• Sometimes the holes do not extend through the
  board. In this case the board should not be used.

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What is holey board?

• EPS is required to have holes to allow for
  monolithic bonding of the slurry coat and top
  pour.
• Hence the name. Holey board is used as a brand
  name by at least one manufacturer.
• Size and density of the holes is established by
  the insulation manufacturer.
• 8-2 1/2 holes or 6-3 holes or 6- 2 7/8 holes
  for a 2 x4 EPS board.
• Minimum EPS density 1 pcf, 1 thick min., 2 x4
  min. dimensions. (Per NOA)

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EPS (Holey Board) stacked on the roof.
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EPS (Holey Board) stacked on the roof.
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How is EPS installed

• Thickness of EPS depends on R value required
  and slope required.
• EPS is placed in a 1/8 slurry coat of LWIC,
  while the material is still plastic.
• A minimum 2 topcoat of LWIC is then installed.
• Some manufacturers require that 24 hours elapse
  between placement of the EPS and installation of
  the top coat. Some allow both the same day.
• NOA typically requires the 24 hour delay for
  installations on structural steel.

13
Slurry coat being installed. EPS will be set in
the slurry coat.
14
EPS is being installed in the slurry coat.
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EPS (cont.)

• When installing EPS boards, dont drag the boards
  over the flutes, slurry coat will be displaced.
• EPS boards cannot be stacked, only one layer is
  acceptable.
• Solvent based adhesives may migrate through
  cracks in the LWIC and damage the EPS boards.

16
What is a floater?

• When an EPS board does not stay secured to the
  substrate, the board will sometimes rise to the
  surface of the top pour.

17
Fasteners that bottom out.

• Insufficient depth of top pour. (1917.4.2)
• The legs of the fastener hit the EPS board and
  the fastener bounces up.
• Resulting in a fastener that has no holding power.

18
Over what substrates may LWIC be poured?

• Structural steel (as thin as 26 gauge)
• (2222.4.3)
• Structural concrete also twin tees and pre-cast
  units
• Existing roof systems, i.e. gravel, smooth or
  granule surfaced BUR.

19
Moisture content of LWIC

• 267-350 lbs of water used to batch one cubic yard
  of 200-249 psi LWIC.
• How much is left after hydration?
• Can you tell if the deck is dry based on the
  color of the LWIC?
• What is the EMC? Moisture affects R value. Air
  has a k value of .17 /water k 4.
• What happens if rain occurs prior to installation
  of the roof cover on a deck without underside
  venting/with underside venting?
• Is there a way to remove excess water?

20
Venting of LWIC

• 1917.4.1 Lightweight insulating concrete fill
  shall be poured over bottom slotted galvanized
  (G-90) steel decking as follows cellular, 0.5
  percent open hybrid, 0.75 percent open,
  aggregate 1.5 percent open. No lightweight
  insulating concrete shall be poured over a
  painted or non-galvanized steel deck.
• 1. Lightweight insulating concrete fill over
  structural concrete slabs, twin tees, precast
  units or other non venting substrates shall be
  vented, to allow the escape of excess moisture

21
Roof system venting

• 1519.5.3 Lightweight insulating concrete. All
  lightweight insulated concrete shall be vented
  per roofing system manufacturer recommendations.
• It seems a conflict exists between 1519.5.3 and
  1917.4.1.
• The more restrictive applies per 101.4.1.
• How can venting be accomplished?

22
Must the LWIC have an NOA?

• 1917.2.1 Product Control Approval shall be
  required for all lightweight insulating concrete
  fill systems.

23
Must LWIC installation comply with wind load
requirements?

• Yes. Maximum design pressures are listed in the
  NOA for various substrates.
• These pressures must meet or exceed the design
  pressures of the building for all pressure zones.
• What is the effective area for LWIC?
• Effective area for a mechanically fastened roof
  system is the area attributed to one fastener.

24
LWIC strength, bar joist spacing and maximum
design pressures

• Spacing has a direct impact on the uplift
  resistance developed between the steel deck and
  the LWIC.
• Deflection of the steel deck causes the LWIC to
  fail in tension.
• Typically the closer the bar joists the higher
  the maximum design pressure of the LWIC.
• Are compressive strength, bar joist spacing and
  maximum design pressures being cross referenced
  against the LWIC NOA and roof system NOA at the
  processing stage?
• Section 104.2.1.1 drawings and specifications.

25
Maximum Design Pressures
26
Polyester fibers improve tensile and shear
performance.
27
Is testing of new LWIC required?

• 1917.3 Testing. The building official may require
  tests of the lightweight insulating concrete fill
  to confirm the
• fastener withdrawal resistance
• compressive strength
• drainage ability.

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How can the physical properties of LWIC be
determined and quality control be maintained?

• By establishing
• Wet density (cast density)
• Fastener pull out resistance
• Compressive strength
• Dry density
• Walkability

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Wet density (cast density)

• Determined during installation.
• Is an indication of correct batch mix.
• NOA gives an acceptable range in pcf.
• To establish, fill a container of a known volume
  and weigh.
• Foam densities for cellular LWIC can also be
  established.
• Which weighs more, 1 ft.3 of water or 1 ft.3 of
  LWIC?

30
NRDCA procedures for establishing cast densities.

• Weigh an empty cast density container of known
  volume. Knowing volume is critical.
• Container must not distort when filled, or
  volume of container will be altered. Galvanized
  container is recommended.
• Fill the container directly from the hose.
• Scrape the top with a straight edge.
• Wipe outside of container clean.
• Weigh the full container and subtract the empty
  weight of the container.

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NOA requirements.

• Cast density container must a minimum of 5
  quarts. (NRDCA 10 quart)
• To weigh use a calibrated scale accurate from
  1-50 lbs.
• Scale must display in ¼ lb. increments.
• Scale must be accurately calibrated to 1/16 lb.
• Cast densities must be taken hourly and entered
  in the job log. (NRDCA 30 min.)
• NOA shows required cast densities in PCF.

32
Cast density measurement about to taken. A 5
quart plastic container is to be used.
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Calibrating cast density container.

• Using a 10 Qt. galvanized container.
• Empty weight 2.00 pounds
• Weight filled w/water 23.50 pounds
• Net weight of water 21.50 pounds (23.5
  2)
• Calibration factor 2.9 pails per ft.3
  (62.4/21.5)
• By volume 21.5/62.4 0.34 ft.3

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Cast density example. Using info from previous
slide.

• 14.6 2(empty weight) 12.6 lbs
• 12.6 x 2.9 (calibration factor) 36.54
• Cast Density 36.54 PCF.
• Compare this figure to the cast density range
  shown in the NOA. NOA must be in the job log.
• If the measurement falls within the range then
  cast density is acceptable.

35
Table is found in the LWIC Notice of Acceptance
36.54 pcf From Previous Slide
36
Further cast density information per NRDCA.

• Container calibration should be checked monthly.
  Volume could be changed by dents in container or
  accumulation of dried LWIC in the container.
• If calibration factor changes by more than 3,
  replace the container.

37
Fastener withdrawal resistance

• 1917.4.10 requires that new pours achieve a
  fastener pull of 40 lbf at the time of roofing or
  60 lbf after 28 days.
• Pull out values are assumed to increase over
  time.
• Fastener pullout test is required for existing
  LWIC decks.
• Test per TAS 105. TAS 105-8.3 The number of test
  samples required shall be increased by an
  additional 25 for LWIC decks.

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Compressive strength requirements

• Minimum after 28 days for cellular is 160 psi for
  nailed system and 250 psi for adhered systems.
  (1917.4.3)
• 300 psi LWIC is typically required for fully
  adhered roof systems per NOA.
• How is enhancing the strength of LWIC
  accomplished?
• Is this requirement identified at the plans
  processing stage?

39
Compressive strength

• Methods for determining strength
• ASTM C 495 Standard test method for compressive
  strength of LWIC. (1917)
• ASTM C 796 (1917)
• ASTM C 513 Obtaining and testing specimens of
  hardened LWIC for compressive strength may be
  used for existing LWIC installations.

40
Table is found in the LWIC Notice of Acceptance
41
Container for collecting compressive strength
cylinders.
42
Dry density

• Dry density ranges are found in the NOA.
• Samples of new pour are allowed to cure 28 days.
• Samples are oven dried.
• Divide volume by weight to establish dry density

43
Table is found in the LWIC Notice of Acceptance
44
Walkability test

• 1917.1.4 Walkability. A term defining the ability
  of lightweight insulating fill to withstand
  anticipated construction traffic during the roof
  membrane application without significant
  indentations in the lightweight insulating
  concrete fill surface.
• 1917.2.4 Building Official is to have clear
  access and path to perform this test 24 hours
  after the pour.

45
What happens if a test fails?

• If walkability fails NOA- Ask for additional
  testing to establish fastener spacing.
• NOA- If fasteners fail to hold 40 lbf after
  curing 5 days, such areas of the deck shall be
  removed and recast.
• Wet and dry density and compressive strength must
  meet NOA and code requirements.

46
Is a permit required for the installation of LWIC?

• Section 104.1.1 requires a permit.
• Permits are being required by various
  municipalities.
• Licensure requirements.
• 1917.2.1 Application of all lightweight
  insulating concrete fill roof decks shall be by
  applicators approved by the lightweight
  insulating concrete deck manufacturer.
• Who is the permit holder?

47
Is an inspection of the LWIC installation
required?

• Permit Holder must notify the Building Official
  48 hours before pouring.
• Permit Holder must make available the job log.
• Inspection criteria is given in 1917.2.2, (3) and
  (4).

48
Job log

• 1917.2.3 The permit holder shall make available
  to the Building Official a job log with the
  following minimum items.
• 1. Cast density recordings/hour
• 2. Product evaluation for application
• 3. Date and job locations identified
• 4. Results of any field test conducted.

49
When LWIC is poured over an existing roof
assembly.

• 1519.5.3.1 Lightweight concrete shall not be
  applied over an existing roof deck unless the
  supporting structure has been approved as
  adequate to sustain the added weight.
  Calculations verifying the adequacy of the
  existing structure to sustain the added weight
  shall be prepared, signed, sealed and dated by a
  Florida-registered architect or engineer,which
  architect or engineer is proficient in structural
  design, and submitted with the Uniform Roofing
  Permit Application.

50
When LWIC is poured over an existing roof
assembly. (Cont.)

• 1917.3.1 Existing roof assemblies to receive
  lightweight insulating concrete fill other than
  galvanized G-90 steel deck or structural concrete
  deck shall be tested for uplift for adhesion to
  the substrate to confirm compliance with design
  pressure.
• Testing per TAS 124 to meet design pressures and
  TAS 126 for moisture in the existing roof system.
  (1521.10 and 12)

51
When LWIC is poured over an existing roof
assembly. (Cont.)

• Preparation steps, per NRDCA.
• Remove dirt, algae, loose gravel, and any other
  loose material.
• Repair blisters.
• Remove any large deposits of oil, grease, acid or
  other contaminants.

52
Reroofing LWIC deck. Fasteners remain and are
flattened
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Can roof systems be adhered directly to LWIC?

• In some cases. Check the roof system NOA,
  however
• 117-6.2 Rigid roof insulation panels shall not be
  applied directly over lightweight concrete decks.
• 109-15.4 Spray applied polyurethane foam shall
  not be applied to lightweight insulating
  concrete.

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Expansion Joints

• 1917.4.11 Lightweight insulating concrete fill
  system expansion joint shall be provided at the
  following locations
• 1. Where expansion or contraction joints are
  provided in the structural assembly
• 2. Where steel framing, structural steel, or
  decking change direction
• 3. Where separate wings of "L", "U", "T" or
  similar configurations exist
• 4. Where the type of decking changes (for
  example, where a precast concrete deck and a
  steel deck abut)
• 5. Whenever additions are connected to existing
  buildings
• 6. At junctions where interior heating conditions
  change
• 7. Wherever differential movement between
  vertical walls and the roof deck may occur.

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Woodblocking Attachment

• 2330.1.3 Wood blocking attachment for lightweight
  insulating concrete, gypsum concrete,
  cementitious wood fiber and cellular concrete
  decks shall be designed by a Registered Architect
  or Professional Engineer. The deck itself shall
  not be used as a wood blocking attachment
  substrate.

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Woodblocking (Cont.)

• 111-3.8.2 Lightweight decks should not be used as
  a woodblocking attachment substrate unless
• The selected woodblocking anchor is fastened to
  the underside of the deck or attached directly to
  a structural member.
• The selected woodblocking anchor can achieve an
  average withdrawal resistance of not less than
  450 lbf tested in compliance with TAS 105.