I ve been containing either stormwater, industrial spills or gasoline, for 18 years.

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1 Michel Gravel Employed by the roofing division of Tremco Canada, since 1995 Previously sold and installed concrete liners to the chemical and paper industries. I also worked as a technical trainer and underground tank tester in the petroleum industry

2 I ve been containing either stormwater, industrial spills or gasoline, for 18 years.

3 Waterproofing and the Inverted Roof Prepared by Michel Gravel for: October

4 Before we begin

5 No auditing of actual energy performance versus predicted No auditing of performance over time No life cycle analysis required

6 What is an inverted roof?

7 Ballast Filter Fabric Membrane Extruded Polystyrene Insulation

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9 Why do inverted roofs drive us crazy?

10 Location of interior leak

11 as long as we use The inverted roof waterproofing need not be the principles black sheep in its design

12 Waterproofing vs roofing Definitions taken from the manual of the Anything in (brackets) is my 2 cents worth

13 A conventional low-slope roof assembly:

14 Four ply Built-up up Roofing

15 Two ply Modified Bitumen

16 Single ply Membranes

17 For the purposes of this presentation, these assemblies will be collectively referred to as ROOFS!

18 An inverted roof assembly:

19 Inverted roofs are commonly designed by using roofing membranes to accomplish what is a WATERPROOFING function!

20 The designer should have a waterproofing mindset when it comes to creating an inverted roof assembly!

21 He should design his membrane to be a WATERPROOFING SYSTEM

22 Waterproofing and roofing overlap where does one start and the other end? There is plenty of grey area between the two

23 For example: When does a body of water stop being a bay

24 and when does it becomes a gulf? I will explain the nuances between the two: Roofing vs waterproofing

25 Waterproofing systems, a definition : Waterproofing is defined as the treatment of a surface or structure to prevent the passage of water under hydrostatic pressure. Water exerts a pressure of 62 pounds of force per foot of depth. Thus, water Iying against a barrier exerts a steadily increasing pressure as the depth increases. Waterproofing is used to protect tunnels, floors and walls below grade from ground water. It is used to protect spaces beneath roofs and plaza decks.

26 Waterproofing systems design considerations: The waterproofing system must perform for the life of the building. Unlike a roof, a waterproofing membrane must perform completely trouble and maintenance free. (It is therefore imperative that a waterproofing system be designed with sustainability in mind.) The waterproofing system must perform in a constantiy wet environment as it is usually in continuous contact with water, or is retaining water. A roof is only exposed to water during and shortiy after a rainfall. (Roofs are designed to shed water, not contain it.) The waterproofing barrier must resist construction abuse as other construction trades work from the waterproofed surface. Although this is a problem for roofs as well, it is more critical for waterproofing because the membrane is not readily accessible for repair.

27 The waterproofing system must be able to accommodate some movement in the substrate to which it is attached. Horizontal plaza decks experience thermal movement and load deflection. These characteristics make it necessary for the waterproofing material to be able to bridge small cracks and expand and contract at least a small amount without rupture. (A good way to achieve this is to combine liquid membranes with one or more reinforcements.)

28 This said Waterproofing systems are placed into more forgiving environments than roofs. Materials can thus be used for waterproofing that would not perform if used for roofing. (A waterproofing system may not be durable enough to be used as a roof.) Following are some conditions favourable to (properly designed) waterproofing systems:

29 Waterproofing systems are subjected to limited thermal stress as they are in proximity to relatively constant interior temperatures. Roof membranes are generally installed over insulated decks, and their temperatures fluctuate with daiiy and seasonal temperature changes. (Roofs are also subject to thermal shock.)

30 Waterproofing systems are not usually exposed to the deteriorating effects of ultraviolet radiation, unlike roofs.

31 Waterproofing systems have the advantage of being adhered directly to structural substrates, therefore, water penetrating them cannot move laterally. Thus, leaks tend to show up very close to the point of penetration. (This implies that waterproofing membranes should not be loose-laid.)

32 (One installed) waterproofing membranes are protected from physical abuse. People cannot walk on or otherwise easily damage the waterproofing membrane, as they can a roofing membrane. (The external fire rating of a waterproofing system is provided by other elements of the inverted roof system)

33 Design recommendations (MINE) for inverted roof system membranes: An inverted roof should be designed as a waterproofing system, that is able to resist hydrostatic pressure. (Avoid assemblies that do not warrant against standing water) Use a combination of elastomeric liquid membranes combined with plies of inorganic reinforcement, all the while avoiding exposed felt-laps or joints. Elastomeric liquid membranes, used with an inorganic reinforcement, will conform correctly to the substrate, bridge gaps and ensure a monolithic barrier. UV resistance is redundant.

34 Design recommendations (MINE) for inverted roof system membranes (con t): Full adhesion of the waterproofing system to the substrate is critical. Loose-laid systems are a NO-NO. As stated by the NRCA, a waterproofing system should be designed for the LIFE OF THE BUILDING. Although a waterproofing membrane does not need the same kind of durability we see on exposed, traffic bearing roof membranes, it must be designed to last. It is not a consumable component of the building. Its probably wise to flood-test the waterproofing system, after the other trades are gone, and before the rest of the inverted roof system is installed.

35 I ve bought into this, and consequently, my inverted roof membranes are significantly different from my conventional roof membranes.

36 This is a waterproofing system used in an inverted roof

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40 Its not the best system to resist Hydrostatic pressure. Example of a roof used as a waterproofing system Remember, we are designing This system to last as long as the building This is a roof system with the UV protection removed. It has no liquid element

41 Case study: Two buildings with concrete decks and inverted roofs. A health facility- Ottawa built 1980 A Condominium Montreal, built 1985

42 Case study: I was asked to inspect the healthcare facility in 2005 because it was NOT leaking! I was asked to inspect the condo in 1999 because it was leaking

43 Case study: Both buildings have an inverted roof system composed of a modified (probably SBS) asphalt liquid membrane, extruded polystyrene insulation and stone ballast.

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45 Case study: The inspection revealed that the roof membrane was composed of an elastomeric asphalt liquid membrane, WITH NO REINFORCEMENT and was only 1/16 th of an inch thick!

46 Case study:

47 Case study: The inspection revealed that the roof membrane was composed of thick elastomeric asphalt liquid membrane, reinforced with two plies of polyester felts, sealed with a monolithic finish.

48 Case study: Although both roofs were composed of a hot applied elastomeric asphalt of good quality, the design of the condo roof did not meet all the requirements for a good waterproofing system. The result was the requirement for an early replacement of the condo roof. The other roof was of a sustainable design, and should last for years to come.

49 The White BUR Prepared by Michel Gravel for: October

50 The emissivity of a material is the relative power of its surface to emit heat by radiation. The reflectivity is the radiation reflected by a surface

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54 Evaluating the Energy Performance of Ballasted Roof Systems Andre Desjarlais, Thomas Petrie, Jerald Atchley; Building Envelope Program, Oak Ridge National Laboratory; Richard Gillenwater, Carlisle SynTec Inc.; David Roodvoets, SPRI Inc.

55 Evaluating the Energy Performance of Ballasted Roof Systems Andre Desjarlais, Thomas Petrie, Jerald Atchley; Building Envelope Program, Oak Ridge National Laboratory; Richard Gillenwater, Carlisle SynTec Inc.; David Roodvoets, SPRI Inc.

56 Innovation is the mother of necessity Thorstein Vebien

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63 And now the movie!