Roofing Science Flashcards
How many degrees above dewpoint temperature should the ambient temperature be for SPF
5 degrees
Roofing should not be installed below how many degrees?
40 degrees
Roofing should not be installed above how many degrees?
85 degrees
Can asphalt roofing be installed directly on gypsum sheathing?
No. Typically ashpalt roofing is installed over a base sheet if installed over a nailable surface like plywood, gypsum, or light-weight concrete.
A light-weight pre-manufactured concrete panel that is attached to the structural steel beams and joists via clip attachment. They consist of a thin cross section and are considered non-nailable.
Channel slabs
What does EVT stand for in relation to asphalt
Equiviscous temperature
The precise location where fluid roofing material is being applied.
point of application
What is the correct temperature at the point of application for asphalt roofing?
EVT +- 25 degrees
What is the maximum kettle temperature specified by ASTM D312 for asphalt.
550 degrees
How many degrees below the flash point should the kettle remain at all times?
25 degrees below the flash point
Flash point
the minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with the air near the surface of the liquid.
What type of asphalt should be used for “dead level” roofing applications
Type I - This type is rarely used and is considered the lowest asphalt grade. Softening point is 68 degrees. used in slag and gravel surfaced roofs on inclines up to 1/4”/ft
What type of asphalt should be used for “flat” (low slope) roofing applications
Type II - moderately susceptible to flow. used on built up roofs with slopes from 1/4”/ft up to 1/2”/ft. This type is most commonly used.
What type of asphalt should be used for “ steep” BUR roofing applications
Type III - relatively non-susceptible to flow. It is used on built up roofs with slopes above 1/2”/ft to 3”/ft. Can be used on vertical curbs and flashings
What type of asphalt should be used for “special steep” roof applications
Type IV - relatively non-susceptible to flow. It is used on built up roofs with slopes above 3”/ft to 6”/ft It is useful in areas where relatively high year-round temperatures are experienced.
In built up and Mod Bit systems, voids in the inter ply moppings due to inconsistent installation or insufficient fluid volume is the primary cause of what deficiency?
blistering.
What is the minimum depth the nails should penetrate through the plywood when the sheathing is at least 3/4”?
3/4”
If the roof deck is less than 3/4” what is the minimum through penetration of the nails at the back side of the sheathing?
1/8”
What is the maximum recommended roof slope for coal tar pitch?
1/4”/foot max
What is the physical property of coal tar vs asphalt that has the greatest impact on how it performs and ages.
coal tar has permanent fluidity and low softening point which means it is perpetually susceptible to flow. Asphalt hardens over time.
What two board sizes are polyisocyanurate provided in?
4x4 and 4x8
What is the maximum recommended size for polyisocyanurate in adhered applications?
4x4. 4x8 can be used in loose laid and mechanically attached.
What are the standard minimum head laps for slate tile roofing?
4” for 4:12 to 8:12
3” for 8:12 to 20:12
2” for greater than 20:12
What ASTM document describes the four different types of asphalt and what conditions they should be used?
ASTM D312
All asphalts meeting the ASTM D312 should have what characteristics.
Homogeneous and free from water
What ASTM standard describes specifications and requirements for asphalt shingles?
ASTM D3462
What slope is standing seam appropriate for metal roof and what slope is flat seam (welded)?
Standing seam 3:12 or greater
Flat seam 3:12 or less
How wide are roofing felts in BUR.
3 feet
Vapor drive is in what direction
Hot to cold
What insulation is the only one recommended for wet conditions?
EPS
Extruded poly styrene
Insulation fasteners should be a minimum of how many inches from the edge of the board?
6”
Temperature at which the viscosity of bitumen is optimum for application
Equi viscus temperature
What is the difference in asphalt felts between residential shingles and built up roofing
Built up roofing felts are perforated so the asphalt can bleed through.
Between APP and SBS which is mopped and which is torched down?
APP torched
SBS mopped
Which single-ply membrane resists chemicals and animal fats?
PVC
XPS
Expanded polystyrene (styrofoam), closed cell
Which rigid insulation has the highest published r-value?
Polyisocyanurate
Long name for EPDM
Ethylene propylene diene monomer
What material breaks down PVC?
Asphalt which accelerates plasticizer migration which can cause it to become brittle. Plasticizer gives membrane its flexibility.
What is used to separate PVC from asphalt based waterproofing tie in?
Aluminum tape.
Two single-ply roofing types that are sensitive to chemicals and grease.
TPO and EPDM
Two single-ply roofing types resistant to chemicals and grease.
PVC and KEE
What is KEE?
Ketone Ethylene Ester
Bitumen based SAF often used for flashing transitions will not permanently stick to which single ply roofing?
TPO
Coal tar is described by what standard?
ASTM D450
What attachment method does NRCA not recommend for rigid board insulation for steel roof decks?
low rise foam adhesive
When installed in a single layer, rigid insulation should be
Mechanically attached and not allowed to overhang the rib openings
What is the NRCA recommended spacing between penetrations, parapets and curbs on the roof?
12” minimum clearance between elements and 2’ between curb and parapet.
Does NRCA recommend sealant at the bottom exterior vertical face of a coping cap or metal edge flashing and building exterior?
No. As it does not add to the waterproofing integrity and may hinder the ability of the wall construction to dissipate moisture.
What is the minimum NRCA-recommended overlap between coping vertical leg and exterior finish.
1”
What is the correct sizing for a drain sump?
24” plus the drain bowl diameter.
Members and registrants of IIBEC should hold what things paramount?
The safety, health, and welfare of the public.
Some building codes require the use of water and ice-dam protection membranes in areas where the mean January temperature is:
25 degrees Ferenheit or less.
When ice-dam protection is specified what is the minimum width?
Generally 24” measured from the inside face of the exterior wall toward the interior.
What is the mixing ratio between Part A and B components of Sprayed Polyurethane Foam (SPF)
1:1
Tack-free time
A curing phase of SPF that lasts until the material is no longer sticky.
What are the principal contributing factors to variations in the surface texture of SPF.
- Equipment Adjustment
- Environmental Effects/conditions
- Applicator technique
What SPF surface textures are considered acceptable for receiving elastomeric surfacing?
Orange peel, coarse orange peel, and verge of popcorn.
(popcorn and treebark are not acceptable)
What is the typical minimum base flashing height for horizontal to vertical transitions?
8” above the deck.
What are the minimum SPF lift thickness and final thickness?
Minimum 1/2” per lift. Minimum 1” total thickness.
