1 thermal and moisture protection. 2 major topics moisture control waterproofing membrane clay ...

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Thermal and Moisture Protection

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Major Topics

Moisture Control Waterproofing

Membrane Clay Cementitious

Dampproofing Hot-applied Cold-applied

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Major Topics con’t

Building Insulation Rigid Mineral Fiber Loose-fill Foamed-in-place

Roofing Low vs. steep slope Types of roofing materials

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Major Topics con’t

Flashing Siding Sealants

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Moisture Control

Moisture is NOT damaging to construction in its vapor form…the problems arise as it Condenses (liquefies) Freezes (solidifies)

These may cause organic materials to decay, metals to corrode, paint coatings to blister, and in the case of freezing, may cause concrete and masonry to crack.

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Key Moisture Absorption Considerations

Dimensional instability – the changes in moisture can cause a change in material dimensions (ex: wood drying)

Deterioration – causes physical, chemical, and biological breakdown of materials (ex: steel rusting)

Condensation tolerance – varies for each material

Effect on heat flow – if material contains moisture it can increase the conductivity

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Permeability

Permeance – measure of water vapor’s flow through a material of specific thickness or an assembly of several materials

Metals & glass – very low permeability Materials with a permeance of 0-1 are

considered vapor retarders See Figure 7.1-7 on page 431 for examples

of various materials and their permeance

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Moisture Condensation

Moisture condensation in walls, floors, and roof and ceiling assemblies can be controlled by: Providing a vapor retarder on the interior side

of the assembly which limits vapor entering the structure

Provide adequate ventilation for the structure in spaces such as attic areas and crawl spaces

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Waterproofing

As defined in ASTM D1079: “the treatment of a surface or a structure to prevent the passage of water under hydrostatic pressure.”

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Membrane

Fluid-applied membranes are usually: Polyurethane Hot Rubberized Asphalt – not as

elastic as polyurethane and requires a thicker coat

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Sheet Membranes

Butyl synthetic rubber sheet [60 mils thick]

Ethylene propylene diene monomers (EPDM) [min. 1/16” thick]

Pre-molded bituminous [7 ply] Rubberized asphalt [56 mils] Self-adhesive butyl [60 mils-

requires adhesive primer]

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Bituminous

Usually applied on vertical below-grade surfaces

Hot coal-tar pitch or hot asphalt The number of plies, overall

thickness, and content vary according to the depth of the hydrostatic head (in ft. – all increase as the depth increases)

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Clay waterproofing

Bentonite clay – when wet, it expands to between 10 to 15 times its dry volume.

It is typically mixed with water & sprayed in place (also available in dry sheets between cardboard)

Placed below grade to exterior surfaces

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Cementitious Waterproofing

Composed of portland cement, aggregate, and an acrylic or plastic admix.

It may also contain iron fillers (then known as iron oxide waterproofing)

Hydraulic cement – another form of cementitious waterproofing used to seal holes, cracks and open joints (often in free-flowing water)

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Dampproofing

May be hot- or cold- applied Hot consists of an asphalt primer

or a coal-tar-based primer Used on the exterior of buildings-

not interior because of lingering odor and the problems associated with using “hot” products indoors.

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Building Insulation

Usually added to the roof, walls, and floors of a structure

4 basic classifications are: Rigid board Mineral fiber Loose fill Foamed-in-place

Listed according to their R-Values

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Rigid Insulation Usable in all parts of a building –usually in a board form Most are [Resistance/inch]:

Polystyrene – sensitive to daylight, give off carbon monoxide while burning

Polyurethane [6.25] – may expand after exposure to moisture Polyisocyanurate [7.2] Perlite [2.78] – will not burn, tends to absorb water Phenolic [8.3] –breaks easily, corrodes metal Cellular glass block- [2.5] – breaks easily, deteriorates if exposed

to freezing & thawing Organic fiber – roofing systems primary use, wood fibers and

water resistant binders Glass fiber Composites – take advantage of high R-values of some materials

in combination with the stability of others

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Mineral Fiber Insulation

Products made from fibers from rock, slag, or glass

Naturally resistant to fire, moisture, and vermin

May be semi-rigid boards, batts, or blankets (longer than batts and sold in large rolls). Intended to fit between studs (16” or 24” o.c.)

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Loose-fill Insulation

Comprised of fibers, granules, or chips

May be poured or “blown” into attics or wall cavities

Common additives may include: adhesives, and chemical treatments to resist fire and vermin

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Foamed-in-place Insulation

Created by a chemical reaction that expands a mixture of components as much as 30 times

Curing typically takes from 24-72 hours, at which time the mixture solidifies into a cellular plastic

Care must be taken not to “overfill” a cavity

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Roofing

Low slope – in general, these are roofs which slope less than 41/2”/ft.

On low slope roofs a system of compatible components is selected to work together to form a waterproof membrane

Common systems used are: built-up roof or single-ply

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Examples of Single-Ply Membranes

EPDM – [ethylene propylene diene monomer] factory cured elastomer, bonded to themselves using adhesives

CSPE (DuPont Hypalon) –synthetic rubber, may also be liquid

CPE – un-reinforced or polyester reinforced sheet material

PIB – formulated from isobutylene and other polymers, carbon black, and additional additives

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Example of Built-up Roof

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Steep Roofing

Slopes exceed 41/2”/ft. Many materials used in modern

roofing practices existed centuries ago (clay tiles, and stone)

Material used is based on: cost criteria, slope of roof, expected service life, wind resistance, fire resistance, and local climate.

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Roofing Material and Slope

Min. Slope

Type of roof

2 in 12 Asphalt shingles (warranty may require a steeper slope - 4 in 12)

3 in 12 Mineral fiber-cement shingles, wood shakes or shingles

4 in 12 Slate shingles, concrete tile (other than flat)

5 in 12 Flat clay tile, concrete tile

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Roofing Underlayment

Should be asphalt-saturated felt (usually a No. 15 or No. 30 used, may require more than 1 layer-depending on roofing material selected) –see pg 463, fig 7.6-6

Applied immediately after the roof sheathing is in place

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Underlayment Performs These Functions:

Protects sheathing from moisture absorption

Prevents the entrance of wind-driven rain onto sheathing

Prevents direct contact between asphalt shingles and resinous areas in wood sheathing (chemically incompatible-may damage shingles)

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Types of Roofing Materials

Asphalt shingles Slate Tile Mineral-Fiber-Cement shingles Wood shingles and shakes Metal

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Roofing Styles

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Examples

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Examples

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Examples of Roofing

http://www.tricityroofing.com/types.html

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Comparison of Types of Roofing

http://aihomeinspection.com/exterior.html

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Flashing

Should be installed at all intersections of other roofs, walls, and projections from roof.

Flashing should be made of corrosion resistant materials such as: Galvanized or stainless steel (min 26 gauge) Aluminum (0.019 inch min.) –avoid using next to

masonry Copper (16 oz.) –if not lead coated…may stain

surrounding materials Flexible sheet- made of PVC or modified polymers-

used in single-ply & some BUR [built up roof]

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Typical Locations for Flashing

Valleys –joint formed by 2 sloping roofs

Chimney Eaves – ice forming along the

eaves Drip edge All roof penetrations

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Siding

The type of wall siding selected depends on cost, expected life service, wind resistance, fire resistance, local climate, and maintenance.

Possible materials include: Mineral-Fiber-Cement shingles Wood shingles & shakes Aluminum and Vinyl siding Wood or Hardboard siding

Bevel, Tongue & Groove, Lap, Board and Batten (see pages 519-522 for examples of these)

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Sealants

Basic types of building sealants include: Elastomeric (rubber like) –polysulfides, silicone,

polyurethane [expansion joints] Solvent release curing [small-joints (3/16” or less] Latex emulsion [small interior joints, doors,windows] Tape [glazing, concealing lap joints] Acoustical [seal sound transmission, electrical

outlets] Preformed Foam Oil-based caulking compounds [doors, windows,

masonry subject to little or no movement]

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References

Construction Materials and Processes, 3rd Edition. Watson, Don A.. McGraw-Hill, 1986. Imprint 2000. ISBN: 0-07-068476-6

Construction Principles, Materials, and Methods, Seventh Edition. H. Leslie Simmons, John Wiley and Sons, Inc., 2001.

Olin’s Construction Principles, Materials, and Methods, Eighth Edition. H. Leslie Simmons, John Wiley and Sons, Inc., 2007

Architectural Materials for Construction, Rosen, Harold J. and Heineman, Tom. McGraw-Hill, 1996. ISBN: 0-07-053741-0

Basic Construction Materials, 6th Edition. Marotta, Theodore W. Prentice Hall, 2002. ISBN: 0-13-089625-X

Building Construction: Materials and Types of Construction, 6th Edition, Ellison, Donald C., Huntington, W.C., Mickadeit, Robert E.. John Wiley & Sons. ISBN: 0-13-090952-1.

Architectural Graphic Standards: Student Edition, Abridgment of 9th Edition. The American Institute of Architects. John Wiley & Sons. ISBN: 0-471-34817-1