Materials and Methods Quiz 4

Control Layers in a wall

Weather Barrier: for bulk water

Vapor Retarder: controls water vapor

Air Barrier: helps prevent infiltration

Weather Barrier

- Keeps out bulk water

- Protects structure

- Keeps insulation from getting wet

-helps reduce wind wash

Vapor Retarder

- Prevents warm, moist air from being able to condense within the wall cavity.

- Always on warm side of wall

-not perfect

-measured in permeance

Air Barrier

- Prevents drafts.

- Helps to slow vapor movement by reducing the stack effect.

can be the same as weather barrier or vapor retarder

insulation (such as foam board) can also be used as air barrier

The "perfect" wall

Structure inside, control layers in middle, cladding outside

Airsealing

- the process of making the building air tight.

-necessary to control heat and vapor flow

-can be same as weather barrier and vapor retarder

-insulation can also be air barrier (foam board)

Stack effect

movement of air within a building caused by the difference in temperature between indoor and outdoor air, creating a pressure imbalance.

Blower Door Test

Used to measure airtightness of buildings by blowing air into or out of a building and creating a difference in pressure.

Ventilation

intentional process of exchanging indoor air with fresh outdoor air

ERV

Energy Recovery Ventilator-transfers both heat and moisture between stale outgoing and fresh incoming air.

Ideal for humid or very dry climates

HRV

Heat Recovery Ventilator-Transfers heat between stale outgoing and fresh incoming air.

Ideal for cold climates

Permeance

measure of how easily water vapor can move through a material

Diffusion

Slow movement of water vapor through a material

Air Leakage

rapid movement of air through holes or gaps in a wall

Thermal Insulation

Material used to reduce heat transfer between inside and outside of a building, preventing excessive heat loss or gain

reduces energy required for comfort

R-value

-measure of resistance to heat flow

-higher value means better insulating properties

-depends on material type, density, and thickness

R-value units

-measured in F/Btu/hr (sf)

change in degrees Fahrenheit

per british thermal unit

per hour

for one square foot of material

U-value

-measures rate of heat flow

-lower value means better insulation

-typically used for assemblies (such as wall assembly or window)

-Inverse of R value: U=1/R

IR Camera

visualizes surface temperatures of materials. Can be helpful to show where heat is escaping or entering a building

Fiberglass

Approximate R-Value: 3.5

Mineral Wool

Approximate R-Value: 4

Cellulose

Approximate R-Value: 3.8

Expanded Polystyrene (EPS)

Approximate R-Value: 4

Extruded Polystyrene (XPS)

Approximate R-Value: 5

Polyisocyanurate

Approximate R-Value: 6

Polyurethane spray foam

Approximate R-Value: 7

Aerogel

Approximate R-Value: 10.3

Vacuum Insulated Panels

Approximate R-Value: 29

Additive method of assembly R-value calculation

Calculate R-values of thickness of each material in the assembly then add them up

Crown Glass

An old form of window glass formed by blowing and whirling a hollow sphere of glass into a flat, circular disk

Cylinder Glass

glass sheet produced by blowing a large, elongated glass cylinder, cutting off its ends, slitting it lengthwise, and opening it into a flat rectangle

Float Glass

molten glass is poured onto a bath of molten tin, creating a continuous, flat ribbon of glass

Reflective coatings

Thin films of metal or metal oxide that are applied to standard glass.

Wet Glazing

Applying silicone sealant to create watertight and airtight bond between glass and frame

Dry Glazing

Rubber or vinyl gasket compressed between glass and frame

Extruded metal

Long pieces with section profiles designed to receive glazing units

Mullion

Vertical bar dividing window or door into sections

Thermal Break

break the path of heat flow through extruded metal that receives glazing

Curtainwall

Lightweight, self supporting cladding systems hung from the structure

Stick system

A metal curtain wall system that is largely assembled in place

Unit System

utilizes prefabricated, framed curtain wall panels

Unit and mullion systems

mullions are put in place first, then premade panels are lowered into place behind them

Panel System

A curtain wall system consisting of premade units

column cover and spandrel system

panels placed between columns then cap is put over columns.

Storefront vs curtain wall

storefront allows drainage out of mullion and is supported by building structure.

curtain walls are sealed to keep water out of mullions and are self supporting.

Pressure equalized rainscreen

Cladding system that uses gap behind cladding to balance air pressure on both sides of the cladding. This keeps water from being driven into the wall cavity

Pressure equalization chamber

reduces water and air infiltration by creating a sealed cavity. used in rainscreens and curtainwalls

Rainscreen cladding

a wall assembly that protects a building from moisture by creating a ventilated air cavity between the outer cladding and the weather-resistant barrier. Cladding is used as rain barrier, while the cavity allows any infiltrating liquid water or vapor to escape

point supported glass system

holes are drilled into glass and are used to anchor the glass to mounts

precast veneer

concrete panels with stone or brick pattern

safing

high-density mineral wool material used as insulation because of its non-combustible qualities

sealant and backer rod

backer rod: placed in crevice that has too much volume to use sealant efficiently

siding panels

large, sheet-like materials used as a protective and decorative covering for a building's exterior walls, shielding it from weather and enhancing its appearance

Wall shingles

overlapping pieces of material, typically wood, but also stone, asphalt, or slate, that are used to cover the exterior walls of a building for protection and decoration

lap siding

horizontal siding style made of long, flat boards that overlap each other, creating a layered and visually appealing exterior.

fiber cement

composite building material made from cement, sand, water, and cellulose fibers, used primarily for exterior siding and cladding.

engineered wood siding

a durable composite material made from wood fibers, resins, and other binders, designed to look like natural wood while offering enhanced resistance to warping, rotting, and pests