Download - External Walls and Roof
-
8/2/2019 External Walls and Roof
1/101
Unit 4
SUPERSTRUCTURE DESIGN
external walls and roof
Mohamed Mohsin - Bahrain
-
8/2/2019 External Walls and Roof
2/101
Strength and stability
External walls fall into two main groups:-
1. structural
make a positive contribution in a structural
integrity of a building,
act in two ways:
load bearing (resist compression)
and/or stabilising. (resist horizontal or oblique forces)
2. non-structural. carry only their own weight
resist horizontal loads( wind loading ).
-
8/2/2019 External Walls and Roof
3/101
Wall properties
1. Weather protection
2. Thermal insulation
3. Durability4. Fire resistance
5. Noise resistance
6. Buildability
-
8/2/2019 External Walls and Roof
4/101
Weather protection
The main function of an external wall,
modifier of the external environment.
Walls must be able to exclude:
rain, wind, snow, frost and sometimes heat and glarefrom the sun.
need to allow naturally ventilated and naturallight to enter the building.
-
8/2/2019 External Walls and Roof
5/101
Thermal insulation
the pressure for better thermal insulationhas mainly been the result of increasedenergy costs.
-
8/2/2019 External Walls and Roof
6/101
Durability
To be durable the external walls of a building must beable to:
withstand the effects of the weather,
withstand physical damage to which they will be
subjected during their life,( e.g. damage fromhumans, vehicles, etc.)
walls will need to be maintained continuously
repainting, cleaning rainwater gutters.
etc
-
8/2/2019 External Walls and Roof
7/101
Fire
The internal walls required to
inhibit the spread of flames, smoke and gases from room to room.
External walls need to
inhibit the spread of flames, smoke and gases from room to room.
contain the fire within the building
All walls fulfill their structural function during a fire until all occupantshave had sufficient time to escape.
Wall materials are normally measured in terms of combustibility andsurface spread (Classes 0, 1, 2, 3 and 4).
-
8/2/2019 External Walls and Roof
8/101
Noise
provide acoustic insulation between the internal and external environment(stated in Hz).
two ways of propagating noise is: through the air (airborne) or by impact (structure borne).
Airborne sound is normally reduced by using materials that are heavy, Impact noise is dealt with using discontinuity. Providing discontinuity by jointing which a weak point in insulating against
airborne sound.
Thermal insulation normally is achieved by the use of lightweight foamed
materials, which are useful for insulating against impact noise butinadequate for airborne noise.
Normally openings, such as windows and doors, are the weakest part of thewall as far as noise.
-
8/2/2019 External Walls and Roof
9/101
Buildability
Using simpler construction methodswithout effecting the quality of the finishedproduct.
Buildability to be considered by:
architects
structural engineers
services engineers
-
8/2/2019 External Walls and Roof
10/101
Types of external walls
Masonry walls
Timber framed buildings
Lightweight profiled and flat sheetcladding
-
8/2/2019 External Walls and Roof
11/101
Masonry walls
constructed of bricks or blocks.
Bricks:
standard size of is 215 x 102.5 x 65mm.
classified by the material they are made from: Clay bricks
Calcium silicate bricks (sand lime)
Concrete bricks
Blocks: made of three main types of materials :-
clay, (hollow blocks)
pre-cast concrete (dense or heavyweight, lightweight)
aerated concrete.
-
8/2/2019 External Walls and Roof
12/101
Bricks
-
8/2/2019 External Walls and Roof
13/101
Blocks
-
8/2/2019 External Walls and Roof
14/101
The construction of masonry walls
Basically there are three main types ofconstruction used for masonry walls.
1. Solid wall
2. Clad walls
3. Cavity walls
4. Layered walls (cavity filled)
-
8/2/2019 External Walls and Roof
15/101
Solid walls
These walls are normally associated withinternal use.
Usually brick thick (102.5mm),
-
8/2/2019 External Walls and Roof
16/101
Clad walls
Solid walls with external porous nature will permit water to migrate from the outside to the
inside.
the application of a cladding material on theoutside face can overcome this weakness(rendering or harling)
way of cladding render tiles,
shiplap boarding /Timber Shingles waterproof coating systems
-
8/2/2019 External Walls and Roof
17/101
Cavity walls
Today almost all externalmasonry walls are built usingcavity construction
basically constructed of two brick thick skins separated by a50mm wide void or cavity.
-
8/2/2019 External Walls and Roof
18/101
Layered walls (cavity filled)
used to
prevent the transmission of moisture throughwalls
install thermal insulation
-
8/2/2019 External Walls and Roof
19/101
DPC in brick walls
Traditional door opening
Scottish door opening
From a thermal insulation pointof view, what is the major defectin figures?
-
8/2/2019 External Walls and Roof
20/101
Modern Door opening
Modern construction overcomes this by closing the cavity withthermally insulated proprietary cavity closers.
The use of plastic extrusions has a double benefit :-
acting as a DPC being strong enough to fix a window of door to the extrusion.
-
8/2/2019 External Walls and Roof
21/101
window opening
the horizontal DPC positioned under the window sill
To provide complete waterproofing the horizontal DPC
and the vertical DPC must overlap.
-
8/2/2019 External Walls and Roof
22/101
Windows opening
-
8/2/2019 External Walls and Roof
23/101
-
8/2/2019 External Walls and Roof
24/101
Opening Lintel
lintel Install to support brickwork above the opening
Lintel type
concrete lintels
Pressed steel
-
8/2/2019 External Walls and Roof
25/101
-
8/2/2019 External Walls and Roof
26/101
Steel Lintel
-
8/2/2019 External Walls and Roof
27/101
-
8/2/2019 External Walls and Roof
28/101
-
8/2/2019 External Walls and Roof
29/101
Steel Lintel
-
8/2/2019 External Walls and Roof
30/101
-
8/2/2019 External Walls and Roof
31/101
-
8/2/2019 External Walls and Roof
32/101
Timber framed buildings
the external walls of the building areconstructed of timber framing
normally rests on a concrete raft foundationand supports timber roof trusses.
The space between the vertical timbermembers (studs) is filled with insulation. The inner face of the studs has sheeting
applied, normally plasterboard. The external face can also be covered in
sheeting, such as ship lap boarding,
A brick skin is normally used, due to the dampnature of the climate. Note the use of a vapour barrier on the inner
side of the wall and a breather membrane onthe outer side.
-
8/2/2019 External Walls and Roof
33/101
-
8/2/2019 External Walls and Roof
34/101
Timber Frame
What are theroles of theVapour barrier
and Breathermembrane?
-
8/2/2019 External Walls and Roof
35/101
The role of the Vapour barrier
Vapour barrier
This sheet is imperviousto water in both liquid andvapour state.
Impermeable membranethat block air to inter
Placed in the inner side
Preventing the passageof the water vapour that iscontained in air
Function of Vapour Barrier
Protect envelop structure
Prevent air leakage
Maintaining interiorhumidification
-
8/2/2019 External Walls and Roof
36/101
Vapour barrier
-
8/2/2019 External Walls and Roof
37/101
-
8/2/2019 External Walls and Roof
38/101
The role of the Breather Membrane
Breather Membrane
Water Resistance material
Used outside under theexterior finish material
Shed moisture and restrict rain Allow water vapour to pass
Act as wind barrier
Allowing moisture with cavityto escape out side
Breather Membrane must have:
Water resistance
Water Vapour permeability
Air Barrier properties
-
8/2/2019 External Walls and Roof
39/101
Lightweight profiled and flat sheet cladding
Used in frame structural to formthe outer walls and often the roofas well.
used for low cost, low qualitybuildings
single sheet cladding had:
no insulation,
limited life expectancy
little visual attraction
Todays sheets are made in awide range of materials, colours,finishes, size and profile
-
8/2/2019 External Walls and Roof
40/101
Typicalsteelprofiles
-
8/2/2019 External Walls and Roof
41/101
Component Elements of sheet Cladding
External Cladding:
Normally steel or aluminum
Breather membrane
Spacer:
Spacer bar to Protectthermal insulation
Vapour Barrier
Impervious to water bothliquid and vapour
Acoustic absorption
Internal lining
-
8/2/2019 External Walls and Roof
42/101
typical detail in a vertical wall.
-
8/2/2019 External Walls and Roof
43/101
Typical of the construction from thebottom of a foundation
-
8/2/2019 External Walls and Roof
44/101
Detail at a gutter (eaves)
The main component elements
Portal frame
Cladding railsFixed at 90 to the portal frame.
Cladding
Gutter lapped by the roof cladding and the
flashing. noted the continuity of the insulation
under the gutter.
-
8/2/2019 External Walls and Roof
45/101
Gutter
http://www.ambiancerestorations.com/images/Install_Gutters.jpg -
8/2/2019 External Walls and Roof
46/101
Gutter
-
8/2/2019 External Walls and Roof
47/101
Question
What type of problems do youthink the owner of a building
would have, to maintain a hiddengutter?
Would this problem be removedby the use of half-round gutters?
Bit h d f
-
8/2/2019 External Walls and Roof
48/101
Bitched roofRidge detail.
-
8/2/2019 External Walls and Roof
49/101
Detail of Corner of a building.
-
8/2/2019 External Walls and Roof
50/101
Ventilation duct penetrates the cladding.
-
8/2/2019 External Walls and Roof
51/101
Why is the cladding profile different fromthat shown in the previous cladding details?
-
8/2/2019 External Walls and Roof
52/101
Composite Panels
-
8/2/2019 External Walls and Roof
53/101
Question
Sketch the symbols for the followingmaterials:
brickwork concrete
DPC & DPM soil insulation blockwork
-
8/2/2019 External Walls and Roof
54/101
Symbols ofmaterials
-
8/2/2019 External Walls and Roof
55/101
W ll i l ti
-
8/2/2019 External Walls and Roof
56/101
Wall insulation
-
8/2/2019 External Walls and Roof
57/101
Ground supported concrete slab withinsulation located below the screed
Ground supported concrete slab withinsulation located below the slab
-
8/2/2019 External Walls and Roof
58/101
-
8/2/2019 External Walls and Roof
59/101
-
8/2/2019 External Walls and Roof
60/101
Type of Cladding
Profile metal sheet
Flat metal sheet
Rainscreen
Curtain Walling
R i l ddi
-
8/2/2019 External Walls and Roof
61/101
Rainscreen cladding
The rainscreen, as its name
suggests, is designed to deflectrainwater from the buildingsfacade.
A Rainscreen system allows theflow of air into the system
ventilating the cavity. This allowsany water which penetrates thepanel joints to flow down the backof the panels and out at the base
Rainscreen consists of an outerpanel, a cavity and an inner leaf.
Normally, the internal leaf of thebuilding is constructed inreinforced concrete or concreteblock
-
8/2/2019 External Walls and Roof
62/101
Rainscreen Cassette Panels
-
8/2/2019 External Walls and Roof
63/101
-
8/2/2019 External Walls and Roof
64/101
Terracotta RainScreen Cladding
From ItalyTerra: mean earthCotta: mean cooked/baked
use of terracotta tiles, usedas a rainscreen.
In this method of claddingthe metal panels, arereplaced with terracottatiles.
water which penetratesbetween the terracotta tilebeing drained away by thewaterproof membranebehind the tiles.
-
8/2/2019 External Walls and Roof
65/101
Curtain Walling system
-
8/2/2019 External Walls and Roof
66/101
Curtain Walling
The traditional curtain wall isa frame of aluminum withmullions and transoms quitesimilar to large framedglazing except that the wallsform an independentenvelope around the mainstructure and are generallynot resting on the concretestructure but only connectedto it.
-
8/2/2019 External Walls and Roof
67/101
-
8/2/2019 External Walls and Roof
68/101
Curtain Walling
-
8/2/2019 External Walls and Roof
69/101
-
8/2/2019 External Walls and Roof
70/101
-
8/2/2019 External Walls and Roof
71/101
Curtain walling systems
Curtain walling systems are:1- Framework (Stick )2- Unitised frame
They are presented to site in three basic ways.:
Framework (stick ): of site-assembled componentswhich is used to support pre-assembled infill panels.
sections of prefabricated wall which are transported to
site as unitised frames, often preglazed.
prefabricated unitised frames, often pre-glazed, whichare hung on a site-assembled carrier framework.
-
8/2/2019 External Walls and Roof
72/101
Stick curtain walling systems Stick systems are installed on site, component by component
They get their name from the fact that the vertical structural mullions(sticks)
normally using a pressure plate and face cap.
That a building has to be unoccupied during refurbishment.
Stick systems allow on site adjustment, but the performance of thesystems is dependent upon the quality of the installation in what areoften uncontrolled conditions.
In conclusion, stick systems are economical and, if correctlydesigned, detailed and installed, extremely reliable. They are,however, slow to assemble, which may not suit certain fast trackprojects.
-
8/2/2019 External Walls and Roof
73/101
-
8/2/2019 External Walls and Roof
74/101
Unitised curtain walling systems
installed as a series of factory-assembled frames, usually withinterlocking mullions and transoms.
The glazing panels and spandrels are usually factory-glazed andseals are also applied or prepared in the factory
Advantages fabrication in controlled environment, very rapid assembly on site (speed of installation,) minimal on site labour, lower installation costs.
Disadvantages
expensive storage and shipping costs, the need for very careful site handling, require longer lead limes. expensive lifting equipment on site.
-
8/2/2019 External Walls and Roof
75/101
Curtain wallCladding with
Aluminium and glass
-
8/2/2019 External Walls and Roof
76/101
Bridge
Spandrel glass as viewed
-
8/2/2019 External Walls and Roof
77/101
Spandrel glass as viewedfrom the inside
Steel structureWithout glazing
vision glass as viewedfrom the inside
-
8/2/2019 External Walls and Roof
78/101
Spandrel glass as viewed
from the outside
vision glass as viewedfrom the outside
Anchoring
-
8/2/2019 External Walls and Roof
79/101
Anchoring
-
8/2/2019 External Walls and Roof
80/101
Curtain wall anchoring
Anchor clips- typical stick applications
-
8/2/2019 External Walls and Roof
81/101
Spandrel Glass
-
8/2/2019 External Walls and Roof
82/101
Opaque glass used for covering the bands of wallaround the edges of floors
Spandrel Glass
4 3 2 1 (Glass surface order)
-
8/2/2019 External Walls and Roof
83/101
Cladding System
-
8/2/2019 External Walls and Roof
84/101
Cladding System
Stick System
1-Anchors 2-Mullion 3-Horizontal rail( gutter section at window head)
4-Spandrel panel (may be installed from inside building) 5-Horizontal rail (window sillsection) 6-Vision glass (installed from inside building) 7-Interior mullion trim
Other variations: Mullion and rail sections may be longer or shorter than shown
Vision glass may be set directly in recesses in framing members, may be set withapplied stops, may be set in sub-frame, or may include operable sash.
-
8/2/2019 External Walls and Roof
85/101
Unit System and Unit-and-Mullion System
(A) Unit SystemSchematic of typical version 1-Anchor 2-Pre assembledframed unit. Other variations: Mullion sections may be interlocking spilt type ormay be channel shapes with applied inside and outside joint covers. Units may beunglazed or may be Pre-plazed .Spandrel panel may be either at top or bottom ofunit.
(B) Unit-and-Mullion SystemSchematic of typical version1-Anchors 2-Mullion(either one-or two-story lengths) 3-Pre assembled unit-
lowered into place behind mullion from floor above 4-Interior mullion trim. Othervariations :Framed units may be full-story height (as shown)either unglazed orpre-glazed, or may be separate spandrel cover units and vision glass units.Horizontal rail sections are sometimes used between units.
-
8/2/2019 External Walls and Roof
86/101
Panel System and Column Cover and SpandrelSystem(A) Panel SystemSchematic of typical version 1-Anchor 2-Panel Other variations:Panels may be formed sheet or castings, may be full story height (as shown) orsmaller units, and may be either pre-glazed or glazed after installation.
(B) Column Cover and Spandrel SystemSchematic of typical version
1-Column cover section 2-Spandrel panel 3-Glazing infill. Other variations:
Column covers may be one piece or an assembly, may be of any cross-sectionalprofile, and either one or two stories in height. Spandrel panel may be plain,textured or patterned. Glazing infill may be a pre-assembly, either glazed orunglazed, or be assembled in place.
Unitized: finished glazed panels shipped to
-
8/2/2019 External Walls and Roof
87/101
Unitized: finished glazed panels shipped to
jobsite ready for installation
F t f h i th t
-
8/2/2019 External Walls and Roof
88/101
Factor of choosing the system
The choice between stick and unitisedsystems is dependent on a number offactors:
1. The cost,2. site access
3. construction timetabling,
4. the overall design and structural requirements.
-
8/2/2019 External Walls and Roof
89/101
The methods ofStructurally Bonded of Curtain Walling
Structural Glazing
-
8/2/2019 External Walls and Roof
90/101
Structural Glazing
It is a system of bonding glassto an aluminium window frameutilizing a high-strength, highperformance silicone sealant.
No mechanical retention such
as beads, clips or bolt fixings
It is a uniform large glazedsurfaces, not interrupted bytraditional frames or any othersupporting or fitting system
projecting out of the frame.
the glass is fixed to a support,which in turn is attached to astructural element of thebuilding,
Bolted Glazing
-
8/2/2019 External Walls and Roof
91/101
Bolted Glazing
holds the glass bymeans of visible metalparts and covers asmall part of the glasssurface.
For small or mediumglazing not exceeding7m in height and 50m in
length, rigid boltedsystem can be used.
-
8/2/2019 External Walls and Roof
92/101
Fin Supported Glazing
-
8/2/2019 External Walls and Roof
93/101
Fin Supported Glazing
Glass fins are used toachieve the all glass clarityrequired by designers whilemeeting the structuralrequirements of the glazing
system
A glass fin replaces a frameor mullion and must be
assessed as to size andthickness and securely fixedor supported at the headand sill.
Cable Supported Glazing
-
8/2/2019 External Walls and Roof
94/101
Cable Supported Glazing
In these systems stainlesssteel or carbon fibre highstrength cables are usedto transfer loads to the
main structure.
Cables systems creategreater levels of openness,
visibility & natural light andenhance the dramaticappearance of thebuilding.
Suspended Glazing
-
8/2/2019 External Walls and Roof
95/101
Suspended Glazing
This method of providing aframeless glazing facade is to fixtogether a matrix of toughenedglass lites, hung from the buildingstructure
allow designers to glaze large
openings in buildings, withoutusing metal frames or mullions, tocreate light and space withminimum visual barriers.
The glass faade is hung from thebuilding structure like a curtain.The top tier panels are connected
to the structure by adjustablehanger brackets and lower panelsare connected by special fittings attheir corners.
Traditional Glazing
-
8/2/2019 External Walls and Roof
96/101
Traditional Glazing
The traditional framed glazing using wood
Roof GlazingP t t Gl i S t
-
8/2/2019 External Walls and Roof
97/101
Patent Glazing Systems
Patent Glazing isthe most widelyused product inoverhead glazing
It consistsessentially of aseries oflongitudinalsupportingmembers (glazing
bars), and aninfilling of glass orother suitablematerials.
-
8/2/2019 External Walls and Roof
98/101
Patent Glazing
-
8/2/2019 External Walls and Roof
99/101
Patent Glazing
-
8/2/2019 External Walls and Roof
100/101
-
8/2/2019 External Walls and Roof
101/101