Moisture Protection and Thermal Insulation Flashcards
Admixtures
mixtures added to conrete mix to make it water repellent
- materials such as salts of fatty acids, mineral oil, and powdered iron
- reduce strength of concrete, but make it less permeable to water
bituminous coatings
asphalt or coal-tar pitch materials applied to the exterior side of the foundation wall
-brished or sprayed on, not or cold
cementitous coatings
- portland cement mortar troweled on masonry or concrete foundation walls
- mostar coatings are used on rough surfaces to make them smooth
membrane
- built up layers of hot or cold applied asphalt felts or membranes of butyl, polyvinyl chloride, and other synthetic materials
- usually used for waterproofing walls subject to hydrostatic pressure
plastics
made of silicone and polyurethane coatings
-reserved for above grade damping
dampproofing
control of moister that is not under hydrostatic pressure
waterproofing
control of moisture under hydrostatic pressure
bentonite panels
flat packages of bentonite panels inside kraft paper packages
- placed under slabs and against walls
- after backfilling the clay expands in the presence of moisture to form a waterproof barrier
Longterm Thermal Resistance (LTTR)
thermal resistnace value of a closed cell foam insulation product measured after storage for five years under prescribed laboratory conditions
Loose fill
- Glass wool/ rock wool
- all loose fill require vapor barrier or vapor retarder
- Fill is blown onto attic floors and into wall cavities through holes drilled in siding
- Good for retrofit insulation in older building, may settle in walls
cellulose insulation
shredded wastepaper or wood fibers
- contains 75% recycled matrials
- combustible but chemicals are added to make it fire resistant
fiberglass loose fill
insulation is made by spinning molten glass into fibers
-contains 20-30% recycled materials
vermiculite
- hydrated laminar magnesium aluminum ironsilicate
- may contain asbestos
Batt or Blanket
- Glass wool/ rock wool
- Between framing members and held in place by friction or facing stapled to framing
Rigid Board
Polystyrene Foam Boards are applied over wall framing members either as sheathing on the exterior or as a layer beneath the interior finish material
High R value, can be used in contact with the earth, moderate cost
Foamed in place
Polyurethane
Foam is mixed from two components and sprayed or injected into place where it adheres
High R value, high cost, good for structures that are hard to conventionally insulate; conforms to shape of cavity; seals all cracks
reflective insulation
whan a radiant barrier is combined with a backinf of insulation
where should a radiant barrier be placed to block heat gain?
to block heat gain, a radiant barrier is placed on the outside of conventional thermal insulation, such as on top of attic insulation
-heat radiated from the hot roof deck is reflected back toward the roof, reducing the heat that would normally strike the top of the thermal inslation
refective surfaces have two properties that make them good for insulation
-reflectivity: measure of how much radiant heat heat is reflected by the material; measure between 0-1; material with a reflectivity of 0.8 means that 80% of the radiant energy striking the material is reflected
–emissivity: measure of how much energy is emitted; energy given off as a result of surface temperature
to be effective radiant barrier must have amonimum reflectivity of ___ and emissivity of ___
reflectivity - 0.9
emissivity - 0.1
insulated concrete form (ICF)
- interlocking foam insulation blocks or panels that serve as forms for pouring concrete walls
- ICF remain in place while concrete cures
- serves as backing for gypsum board
- foam used is usuallu expanded polystyrene (XEPS)
Approximate R values for SIPs range from
When describing size, estimating, and ordering materials, roofing area area is referred to in …
…squares. A square is equal to 100 square feet
Shingle Exposure
shingles are laid so that only a certain portion of each shingle is visible: this is caled exposure
- this dimension varies with the pitch of the roof
- 30 lbm asphalt felt is used as an underlayment
Slate tile
- made by splitting quarried slate into rectangular pieces from 6 in to 14 in wide and from 16 in to 24 in long
- about 1/4” thick
- laid over 30 lbm asphalt roofing felt
- very expensive but very durble and fire resitant ; can last over 100 years
clay tile
simalr to slate tile in roof buildup
-also expensive bu durable and fire resistant
concrete tile roofing
less expensive than clay tile
also very durable and fire resistant
metal roofing
- durable, attractive, can conform to a wide varaity of roof shapes
- high cost and difficult to installe properly due to a high coefficient of expansion
- joints must be design to account for expansion and contraction
- materials include copper, galvinazed iron, aluminum, and terneplatem stainless steel
- installed over asphalt roofing felt laid on top of wood or nailable concrete decking; exception to nuderlayment is for terne or tin roofs, which require a rosin-sized paper because asphalt can react with the tin
terneplate
steel sheet coated with lead and tin
minimum slope for metal roof
3:12
roof components
Horizontally applied board sidings are nailed so that the nails pass through the
sheathing and into the studs
• Allows for installation over insulating sheathing materials without requiring a nail
based sheathing
• In the US, boards are nailed tightly over the wall sheathing and housewrap
• In Europe, siding is nailed to vertical wood spacers (1x3’s) that are aligned over
the studs…called a rainscreen and creates a pressure equalization chamber
behind the siding that acts to prevent water penetration in a wind drive rain
preformed roof panels
- shaped mpieces of metal or assemblies of metal with insulation between that are self supporting an apn intermediate supports
- roof panels span purlins, and wall panels span horizontal girts
- corrugated or fluted sheets
- made from aluminum, galvanized steel, and porcelain enamel steel
- most economical when used on large, flat, unbroken expanses of walls and roofs
Membrane roofing
- includes materials applied in thin sheets to nearly flat roofs
- includes liquid applied products that can b applied to any roof slope
built up bituminous roofing
- consists of several overlapping layers of bituminous saturated roofing felts cemented together with roofing cement
- bituminous material can be either asphalt or coal pitch tar
built up roof can be installed over nailable and non-nailable decks
for nailable deck: a base sheet of unsaturated felt is nailed tot he deckand covered with a coating of roofing cement
on non-nailable decks: base sheet is omitted and a base coat is applied
- three, four, or five layers of sturated roofing felts are then laid on top of each other, each layer bedded in roofing cement so that felt does not touch felt
- a final coating of bituninous coating is placeed over enire roof and covered with gravel
- gravel protects the roof grom sunlight and other effects of weathering
inverted membrane roof
- built up roof is placed on the structural decking and rigid, closed cell insulation is placed over the roof rather than under it
- insulation is held down with gravel ballast
- purpose of this type of construction is to protefct the membrane from the normal deleterious effects of expansion and contraction, drying ultraviolet rays, and foot traffic than can cause leaks
cricket
saddl shaped projection on a sloping roof used to divert water around an ostacle
scuppers
- also called overflor drains
- built through parapet, positioned with their low edge slightly above the top of the roof to provide a second means of drainage should the primary drains become clogged
single ply roofing
-a single membrane layer of various types of materials
Thermoset Plastics vs thermoplastics
thermoset plastics: permanently harden when they are subjected to heat and then cured; they permanently lose their shapeif heated again; EPDM, CSPE
thermoplastics:can be repeatedly softened with heat and then harden again when cooled; PCV, TPO
EPDM
ethylene propylene diene monemer
- only available in black
- must be sealed with adhesive or pressure sensitive tape
CSPE
chlorosulfonated polyethylene
- also known as Hypalon
- available in black and white
PVC
polyvinyl chloride
- relatively inexpensive
- seams are heat welded
- available in white
TPO
thermoplastic polyolefin
which can be recycled and reused for roofing: thermoplastics or thermoset plastics
thermoplastics only
Liquid applied roofing
- includes butyl, neoprene, hypalon
- also used for below grade waterproofing on foundation walls, tanks, and pools
- well suited for complex roofs such as thin-shell conrete domes
roof expansion joints
- required in buildings to allow for roof movement caused by temperature changes in materials and differential movement between builing section
- located evey 100 ft in long buildings
- located at the junciotns of T, L, and U shaped buildings
sealants are classfied as…
low: used in joints with +-5% movement
intermediate: +- 12.5% movement
high: +- 25% movement
- type used depends on expceted joint movement
- width and depth of a selant are critical; width is determenined by expected joint movement; depth is equal to width of joint
- example for joints 1/2 in to 1 in thick, the depth should be 1/2 in
- for wider joints, the selant depth shouldn’t be greater than one half the width
exterior insulation and finish system (EIFS)
caldding assembly consisting of a wet applied cementitious finish over a rigid insulatoin board that is attached to building sheathing
3 classifications of EIFS:
polymer based (class PB): use expanded polystyrene insulation with the base coat applied direectly to the insulation w/ embedded fiberglass mesh
polymer modified (class PM): used extruded polystyrene that is mechanically fastened to the building sheathing and strcuture along w/ reinforcing mesh
mineral based (class MB): uses portalnd cement stucco in traditional manner
waterstop
a preformed piece of material used to seal construction joints
A building with a basement is being design in a wet climate. Which of the following water control materials/method would an architect recommend?
cementitiou coatings
geotextiles
french drains
sloping soils away from the building
geotextiles
french drains
sloping soils away from the building
cementitious coatings are only used for dampproofing
geotextiles
Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextile fabrics come in three basic forms: woven (looks like mail bag sacking), needle punched (looks like felt), or heat bonded (looks like ironed felt).
a deep excavation for a high rise building in an urban area would require
tieback
a deep excavation would require the use of verical soldier beams supporting timber brease boards or cribbing. The vertical soldier beams must be anchored into the adjacent earth with grouted tieback rods. Even steel sheeting would require tieback for support
polyisocyanurate
type of roof insulation
which of the folliwng is the best sealant to use between exterior, precast concrete wall panels
polyurethan
Either one part or two part provides excellent resistance to weather and is capable of 25% to 50% movement
- can span wide joints typical of precast concrete
- available in colors
- can be painted
Acrylics are unsuitable sealants for wide joints because…
…of its limited potential for joint movement and their inability to fill the large width joints that are typical of precast conrete
disadvantage os butyl selants
limited joint movement and because they are only available in darker colors
-generally used for areas underwater
disadvantages of latex sealants…
-limited joint movement
typucally used for joints with no expected movements, suc as those around door and window frames
the minimum suggested pitch for a normal slope asphalt composition shingle roof is
4:12
in order for a asphlat or composition shingle roof to have a 2:12 slope, what must me built into the roofing
a double layer of roofing felt is required
-most manufactureres don’t recommend this slope
Whic of the following materials provides the highest insulation value (R value)?
a. expanded perlite
b. expanded polystyrene
c. fiberglass
d. polyisocyanurate
d. polyisocyanurate
asphalt imregnated building paper is ued under siding primarily to
- increase water resistance of the wall
- also serves to prevent air infilitration
Which of the following would be LEAST apporpriate for insulating a steel stud wall
a. polystyrene boards
b. rock wool
c. fiberglass batts
d. perlite boards
b rockwool
rock wool is a loose insulation poured or blown into cavities
-usually not used in commercial constuction
Which of the following would be most apporpriate for dampproofing an above grade concrete wall with a moderately rough surface
a. cementitious coating
d. bituminous coating
c. synthetic rubber
d. silicone coating
d. silicone coating
it acan be sprayed , painted, or rolled on
if the wall was below grade, a cementitious or bituminous coating would be apporpriate
What is used to keep water from penetrating an expansion joint at the intersection of a roof and wall?
counterflashing
perm rating
is the measurements of how much moisture passes through a certain material in a given amount of time
vapor retarder are selected based on …
their perm ratings
the best vapor retarders have the lowest perm ratings
rate the foloowing materials by their perm ratings (lowest to highest)
10 mil polyetheline
gypsum wall board
1 mil aluminium foi
exterior oil paint
1 mil aluminum foil - 0
polyethelene - 0.03
exterior oil paint (3 coats) - 1.6 - 3.0
gypsum wall baord - 50
aminimum diameter for a weep hole in a masonry wall is
1/4 in
normal slope asphalt or fiberglass shingles are to be isntalled on roofs with a mininmum pitch of
4:12
the average R-value per in of fiberglass unsulation is ….
3.3
aluminium wondow are specified for installation in a masonry wall. which material is the least desirable choice for flashing at the head of the window?
a aluminum
b. copper
c. stainless steel
d. lead
c. stainless steel
because of the metals listed, it is furthest from aluminum on the galvanic action table, even further than copper
which of the following strategies will NOT prevent ice dams?
a. provide ridge and soffit vents
b. place batt insul between the roof rafter
c. seal and insulate decutwork in the attic space
d. caulk all penetrations from below, esuch as electrical conduit or vent stacks
b. place batt insul between the roof rafters
- the warmth of attic spaces heats up the roof and causes the snow that has accumulated on the roof to melt.
- the eaves are not as warm as the rest of the roof so as melted snow runs down the roof, it refreezes as it reaches the colder eaves
- the best strategy is to keep the attic as cold as possible
- ridge and soffit vents allow cold air to flow through attic
- insulation between rafter will make ice daming worse, instead insul should be placed on the floor of attic
PM
polymer modified
mineral based system that has high impact resistance and provide good insulation
-consist of a base and finish coat of synthetic stucco applied over XPS (extruded polystyrene)
PB
polymer based
- systems made up of a very thin base coat of portland cement and polymer over fiberglass mesh with a thin finish coat of polymer based synthetic stucco over EPS (expanded polystyrene), insulation board
- do not resist impact well because their coats are so thin
- lighter system than PM
MB
-advantages of unventilated roofing
- simplicity of detailing, low roof profile , no risk of wind blown water into the roof assembly
most architectural coatings are composed for four basic types of ingredients
-solvents, vehicles, pigments, additives
-advantages of latex paint
-good when used for exterior; breathable, preventing moisture from becoming trapped behind the painted siding; flexible coating, able to stretch as painted material expands and contracts with temperature changes
-enamels
- glossy surface paints; high proportion of vehicle
-sealer
-unpigmented liquid that can be thought of as a primer for a clear coating; it seals that pores in the substrate so that the clear coating will not be absorbed
-why are clear coatings not recommended for exterior surfaces
-they are particularly susceptible to UV damage, lasting no more than a year before peeling occurs
-most damage caused to paint is a result of what?
- caused by water getting behind the paint film and lifting it off the painted surface; good construction practices and proper design of air barriers can eliminate damage to paint
sodium bentonite
a naturally occuring highly expansive clay
-used for bentonite waterproofing
blind side waterproofing
used where there is no working space between a sheeted excavation and the outside of the foundation wall
