Construction Detailing Flashcards
1
Q
Board feet
A
Piece of lumber 1 inch thick by 12 inches wide by 12 inches long or 144 inches^3.
A 2x6 that is 12 inches long
A 2x4 that is 18 inches long
Ex. how many board feet is a 1x10, 8’ long?
(1x10x8) / 12 = 6.67 board feet
Ex. 2x6x12’
(2x6x12) / 12 = 12 board feet
2
Q
EPDM vs PVC single ply fully adhered roof membrane
A
EPDM weathers well and handles temperature fluctuations. Good for flat roofs with pavers in temperate climate.
3
Q
Refrigerants that are banned in the US
A
Halon and chlorofluorocarbons (CFC)
4
Q
Type of construction to use for 4 story hotel with exposed structure, high fire resistance and fast construction
A
One way solid slab concrete frame
5
Q
Low slope roof vs steep roof
A
2:12 and lower (1/4” per foot min)
6
Q
Pitch pan
A
Sheet metal open box that is filled with sealant called pitch. More likely to leak than cone-shaped boot because relying on chemical, not mechanical solution.
7
Q
Cone-shaped boot
A
Mechanically diverted and also seal
8
Q
Cricket
A
Mini pitched element to mechanically divert water around something (like a chimney)
9
Q
Topside roof vent
A
Vents vapor in space between roof membrane and insulation (mushroom shape)
10
Q
Options for roof insulation location
A
- Below structure (2 types: ventilated cavity OR closed cell spray foam where it acts as air/vapor barrier)
- Above deck (vapor barrier, rigid insulation, membrane)
- Above deck, insulation over membrane
11
Q
Ice damming
A
A home’s escaping heat warms the roof sheathing and melts the underside of the snow layer on the roof. Insulating and ventilating the roof will prevent this.
12
Q
Hardwood v softwood
A
Hardwood comes from deciduous trees, which grow slower and tend to be denser. Higher modulus of elasticity, More resistant to wear, more expensive. Also more prone to splitting from hammering a nail (use screw or bolt).
Softwood comes from evergreen trees. More common in structural lumber.
13
Q
Plainsawn vs quartersawn
A
Plainsawn cheaper and less durable. All cut in parallel direction across log.
Quartersawn is cut in quarters and then diagonally parallel across log. More dimensionally stable so will be more durable. More visually consistent and finer grain.
14
Q
Moisture content of wood
A
MC15 = 15% moisture when delivered to site
Low number is good because it is stronger
S-DRY is shorthand for MC-19
Wood shrinks mostly tangentially and cracks (called checks)
15
Q
Wood warping
A
Warps more when cut parallel to grain
Shrinks evenly when cut perpendicular to grain
16
Q
Glulam
A
Laminating small pieces together. Length is only limited by transportation to jobsite.
17
Q
Cross-laminated timber
A
Alternating strips of timber in perpendicular directions. Can make really strong, large panel and large openings can be cut because it has 2-way support.
18
Q
Laminated strand lumber (LSL) and oriented strand lumber (OSL)
A
Shredded wood strands glued and pressed
Least strong and least expensive options
Used as rim boards or short span headers
LSL has longer strands
19
Q
Parallel strand lumber (PSL)
A
Shredded wood strands glued and pressed in parallel direction. Stronger than LSL or OSL.
20
Q
Wood I-Joist
A
Dimension wood flanges and OSB flange create longer spans
21
Q
Laminated veneer lumber (LVL)
A
Layers of veneer laminated together
Used for headers, beams, rim boards
22
Q
Wood plastic composite
A
PLastic, wood and chemicals are injection formed. Used otudoors because less likely to shrink, warp and decay.
More flexible than wood so needs more support.
23
Q
Oriented strand board (OSB)
A
Strands of wood pressed and glued together. Layers alternate directions of strands. Odd # of layers so exterior faces have same dimensional stability. Used for exterior sheathing.
24
Q
Particle board
A
Smaller fibers, used with veneer/laminate on top. Not very strong or moisture resistant.
25
Fiberboard
Smaller fibers than particleboard so more stiff and able to handle fasteners better. aka Masonite
Low and high density fiber board can be used for sheathing (non-structural)
26
32/16 rating on plywood means...
Rated for roof construction with supports at 32" O.C. and rated for floor construction with supports at 16" O.C.
27
Bond classifications for plywood
90% of plywood is Exposure 1 which can be exposed to water but not for long periods of time. Exterior rating is best.
28
Forest Stewardship Council (FSC)
Certifies wood products. Binders with formaldahyde offgas in OSB and MDF. Can be spec'd with low finish
29
Treated wood - when is it required and what types can be used where?
Required when wood joists are less than 18" above grade, wood beams/girders are less than 12" above grade, plates,sills or sleepers are in direct contact with masonry or concrete which is touching earth, OR wood framing or sheathing is less than 8" from soil.
ACQ and CPA have copper in them and can't be used with steel or aluminum fasteners. Stainless steel, copper alloy or zinc galvanized. Hot dipped galvanized can be used above ground.
Micronized Copper and PTI is paintable, can contact ground, is non-corrosive and nontoxic
DOT and SBX are nontoxic and can contact ground. Can be used where termites are a problem.
Phased out for toxicity: Creosote, CCA
30
Naturally decay resistant wood species
Black locust, red mulberry, osage orange, pacific yew
Slightly less resistant:
Cypress, catalpa, cedar, chestnut, white oak, redwood, black walnut
31
Naturally termite resistant wood species
Easter red cedar and redwood but only heartwood
32
Nails
Expensive until recently that's why complex joinery was used.
Flat heads:
Common nail, sinker nail, box nail, roofing nail
Tiny heads:
Finish nails, casing nails, brads
Deformed shank nail has teeth, used for sheathing, subflooring
Sized in units called pennys (d)
Large = 60d
Small = 2d
33
Nail coating
Bright nails have no coating
Hot dipped galvanized have highest level of weather resistance
Hot galvanized not as weather resistant
34
Three types of panelization
Framed panels (arrives with sheathing on one side)
Stressed-skin panels (sheathing on both sides, very strong)
SIP/Structural Insulated Panels (Insulation in between sheathing so no thermal bridging)
35
Balloon framing
2 story tall studs
| Requires fire stopping because the continuous stud cavity is a path for fire
36
Platform framing
1 story tall studs with platform in between
Allows for tilt up construction
Doesn't require long lumber (tall trees)
Doesn't require fire stopping at floors
37
Wood framing terminology
```
Sole plate
King stud
Jack stud
Header
Cripple studs
Rough sill for rough opening
Double top plate
Rafter ties
Ridge
Hip
Collar tie
Rim board/band joist
```
38
Vent or insulate a crawlspace?
Ventilate crawlspace and insulate under the floor
OR
Insulate walls and not floors and don't ventilate crawlspace.
39
Required amount of ventilation for an attic
1/150th of attic footprint
>50% of vents must be located high or 3' above the joists
You can reduce to 1/100th of attic footprint if you have a vapor barrier on warm side
40
What types of mortar offers higher strength and lower permeability? Mortars with masonry cement or portland cement?
Portland cement
41
Highest strength mortar type to lowest strength
M - use below grade or with high loads or in a climate with severe frost (not easily workable). Compressive strength = 2500 psi
S - use with reinforced masonry, load-bearing masonry, or veneers subject to seismic or high wind loads Compressive strength = 1800 psi
N - general purpose, good balance of strength and workability. use with non-load bearing veneers, chimneys, interior load-bearing walls.Compressive strength = 750 psi
O - low strength, use in interior and non-load bearing uses like fireplace. Compressive strength = 350 psi
K - lowest strength, not used anymore
Remember: MaSoNwOrK
42
How long after mortar is mixed does it need to be discarded?
2.5 hours unless you use an admixture
43
Water struck vs stiff mud brick
Water struck brick uses soft muds pressed into mold by hand (labor-intensive). Stiff mud process is least expensive, most common method. Sent through a vacuum to reduce air, and extruded through a rectangle.
44
2 types of brick kilns
Periodic kiln takes 2 weeks, is emptied and refilled.
| Tunnel kiln has a continuous train of bricks moving through it
45
What types of mortar joints are acceptable to be used outdoors where it rains and freezes?
Concave and Vee
46
Most common appearance grade for brick?
FBS is most common
FBA - more variation in size and more chippage
FBS - some variation in size and chippage
FBX - more dimensionally uniform and less chippage
Remember:
S - standard
X - exact
A - anomaly
47
Which type of brick is most appropriate below grade?
SW (Severe Weathering) is used most often below grade, is most resistant to weathering, and can be used in any climate
MW (Moderate Weathering) is weather resistant, only used on exterior in warm areas
NW (Negligible Weathering) is Not used outside
48
How far can a brick corbel?
Each brick can corbel 1/2 the height of the brick
49
Types of brick arches
```
Segmental
Jack
Tudor
Elliptical
Gothic
Roman
Parabolic
```
50
Name for formwork used to make brick arches
Centering
51
What are quoins for?
Cast stone or masonry protruding edge at corners or above doors. Used to prevent horse and buggies from chipping building. Now just used decoratively.
52
Most porous stone
Limestone/Marble
53
Which stone is okay to use below grade?
Granite - most impervious and strong
54
Types of stone that are sedimentary rock?
Limestone (including marble) and Quartz (includes sandstone, brownstone and bluestone) - comes from streams, shells - meaning it's porous and weak
55
TYpes of stone most easily carved and polished
Marble
56
Types of stone you can't use in areas with air pollution
Limestone and marble - very porous, can deteriorate in acid
57
Types of stone planes of cleavage
Slate - has orientation, metamorphic, comes from clay
58
Igneous rock?
Granite - comes from volcanoes
59
Modulus of rupture
The metric most important to determining the ability of a stone to accept metal anchors that hold them to buildings
60
Types of quarried stone
Field stone - from river beds
Rubble - irregular quarry stone with one exposed face
Dimension stone - quarry stone cut into rectangular shapes
Flag stone - used for floors or paving
61
Compressive strength of concrete
2000 psi - 20,000 psi
62
Concrete admixtures (11)
1. workability agents - easier to work and form
2. air-entraining - reduces freeze-thaw damage and increases workability because air pockets give freezing water a place to expand
3. water reducing - don't need as much water, so higher strength
4. superplasticizers - increase workability and flow so you can use less water and get more strength
5. accelerating - cure faster
6. retarding - slow it down so you have time to work it before it cures
7. shrinkage-reducing - reduce shrinkage and therefore cracking
8. corrosion inhibitors - reduces rusting of rebar (parking garage near ocean with salty water)
9. freeze protection - concrete can cure in temps as low as 20 degrees
10. extended set control - delays curing until activator is added
11. coloring agents
63
How can you make concrete more sustainable?
Fly ash can replace up to 1/2 of portland cement. It is a byproduct of coal production and can be reused so it doesn't become a pollutant. Reduces embodied energy of concrete by up to 1/3. Benefits: Denser, stronger, shrinks less, less permeable.
64
How is diameter of rebar measured?
Measured in 1/8's of an inch so #8 rebar = 8/8 or 1"
65
What are rebar grades?
Grade 60 means 60,000 psi tensile strength (60k psi)
| 60 is most common grade but you might use 75 in columns
66
How do you treat rebar in marine climates?
1. coat rebar with epoxy
2. galvanized rebar
3. stainless steel rebar
4. zinc coated rebar
5. polymer coated rebar
67
Welded wire reinforcing
2" min to 12" max spacing
| Resists tension forces in bottom of slabs
68
What are stirrups used for in concrete design?
U shaped bars. Resist diagonal forces at ends of beam near supports. Slabs don't require stirrups due to the width of the slab (minimized diagonal forces)
69
Types of reinforcing in concrete
Bottom bars resist tension at bottom between beams. Top bars resist compression near columns/beams.
Shrinkage temperature steel bars used in beams instead of stirrups near ends of beam.
70
What are "chairs" in concrete design?
Keep rebar at proper height
Row of them are called bolsters
Usually metal unless SOG which would rust. For SOG use plastic or concrete bricks to hold up rebar.
71
Types of reinforcing in concrete columns
Vertical bars pick up compression and tensile loads
Column ties prevent outward buckling
Can use rectilinear or column spirals (which perform better in seismic conditions)
72
Why do we use fiberous reinforcing in concrete?
1. Microfiber - smaller hairs which resist cracking
| 2. Macrofiber - larger hairs, may take the place of shrinkage temperature steel bars
73
Concrete creep
Over time concrete gets compresed downwards
| Need to allow for tolerance with brick ties, etc.
74
Pre-stressed, pre-tension and post-tension concrete
Pre-stressed (overall category): Cable run through concrete and stretched to add camber and therefore strength. Concrete is squeezed together as a result.
1. Pre-tension: Precast concrete
2. Post-tension: Cast in place with tubes cast in it, pulling cables through tubes
75
Steps for creating concrete slab on grade pad
1. scrape topsoil off to find more stable fill or truck in more stable fill
2. Add min. 4" of 1-1/2" crushed stone for capillary break
3. Polyethylene moisture barrier
4. Formwork around perimeter
5. Welded wire reinforcing put in place on chairs or grid of rebar depending on design load
6. Pour slab
7. Screed slab/striking off with wood formwork for level surface
8. Float the slab
9. Trowl the surface
10. Cover to keep slab moist for at least a week
11. Add control joints at least 1/4 depth of slab (while curing when wet or afterwards with saw). Usually every 15'.
12. Isolation/construction joints fully separate different pours of concrete.
76
Methods to reduce shrinkage cracking in concrete slabs
```
Control joints: Thinner slabs require closer spacing than thicker slabs. 15' minimum spacing or more as desired. You can also do the following:
Use drier mixture
Use fly ash concrete
Use admixture for less shrinkage
Use post-tensioning
Use microfibers
```
77
When to use one-way vs. two-way concrete slab
One way: Rectangular bays
Two way: Squareish bays
<25' span, you can use a flat plate or flat slab system with minimal floor profile and minimal formwork
>30' span, use one-way joist system
Spans can increase with post-tensioning
When there's lateral loads like seismic, you can't use one way flat slab
78
Lift slab system
Pour all slabs at bottom and use hydraulic jack to lift them up and weld in place
79
Flying formwork and slip forming
Flying formwork is large, reusable sections of formwork for concrete floor slabs, lifted into place by crane
Slip forming is used for walls, moves up vertically..
80
8 types of concrete
I - Normal
IA - Normal, air-entrained to help with freeze-thaw and workabilty in exposed cold climate conditions
II - Moderate resistance to sulfates found in groundwater (below grade use)
IIA - Moderate sulfate resistance, air entrained
III - High early strength concrete (use with precast, concrete block, tilt up, slip forming, and cold weather)
IIIA - High early strength concrete, air-entrained
IV - Low heat of hydration for massive structures like dams.
V - High resistance to sulfate attack.
81
Termite deterrant design
Slope grade near foundation away from building to keep foundation dry (they like moisture)
Soil poison applied to footprint of building before construction begins
Wood members are above ground
Don't surround base of building with shrubs or plants
Pressure treated lumber doesn't make it resistant to insects
82
Masonry drips/drip edges
Extensions of thru-wall flashing that extend beyond primary plane of wall and force water to fall away from wall (and not re-enter via capillary action)
83
Masonry mortar joint types
Concave (Tooled)
Vee (Tooled)
Weathered (Troweled - best one for shedding water)
Struck (Troweled)
Flush (Troweled)
Raked (removes mortar, for interior use only)
84
Stacked bond brick reinforcing spacing
16" OC for stacked bond
85
Rebar chairs
Small wire supports that help to keep rebar spaced a specified distance from the outside of the concrete ad help ensure adequate concrete coverage. A bolster is a type of chair used in beams and broad slabs.
86
Plywood grades
Face ply/back ply designation + interior or exterior rating. CDX (X=exterior) is most common for roof sheathing.
N = natural finish, no defects
A = smooth and paintable (most expensive)
B = Solid surface veneer
C = Splits limited to 1/8"
D = Knots limited to 3" and splits limited
87
Moisture content in architectural woodwork
Should match the conditions of the location it is installed. Dry arid climate: less than 5%
88
Max aggregate size for concrete slabs
1/3 of slab thickness or 3/4 of minimum space between rebar, whichever is smaller.
6" slab with #4 rebar spaced 4" on center:
6/3 = 2"
#4 = 4/8" = 1/2" so 3-1/2" space between rebar
3/4 x 3-1/2" = 2.625"
Therefore aggregate must be 2" max (smaller of two)
89
Equivalent thickness of CMU
Used for calculating fire resistance. Equivalent thickness of a solid block with holes.
12" nominal block is 11-5/8" thick x percentage of solids = 8-3/4"
90
Radon acceptable levels and courses of action
EPA says that no action is requried if less than 4 pCi/L. If level is elevated (near 4), you should monitor with periodic testing. If above 4, steps should be taken to ventilate spaces in direct contact with the earth.
