External Envelopes Flashcards
What is a mortar formed from?
A mixture of cement, lime, sand and water
What sets out mortar classifications?
BS 998-2 Specification of mortar for masonry
What is the minimum heights and laps for a DPC?
150mm above ground level. Lapped by at least 100m adhesive sealed and continuous with DPM.
What are the primary functions of a DPC?
resist moisture penetration from below (rising damp)
Resist moisture penetration from above
Resist moisture penetration horizontally
What is the primary function of a DPM
Prevents moisture entering from floor below
What are some common DPC materials?
Historically:
- Lead
- Bitumen
- Slate
- Engineering bricks
Today:
- Low density polyethylene
- bitumen
- polypropylene
What is the spacing of movement joints in a brick wall?
Every 12 meters
What are the functional requirements of external walls?
Strength and stability
Weather resistance
Sound insulation
Thermal insulation
Fire resistance
Durability
Appearance
What types of non-load bearing external wall are you aware of?
Curtain walling
Rain screen cladding
What is curtain walling?
Curtain walling is non-load bearing cladding which separate the interior from the exterior of a building, typically formed of a lightweight aluminium frame with glazed in-fill panels.
What is rainscreen cladding?
A rainscreen is part of a double wall construction, It is comprised of an outer skin of panels and an airtight insulated backing wall separated by a ventilated cavity.
What is cladding?
Cladding is components that are attached to the primary structure of a building to form non-structural, external surfaces.
What is structural glazing?
A structural glass wall is a minimal and modern alternative to framed curtain walling, used to create a large or long elevation of glazing where the glass is the primary design feature. The result is a large glass elevation with no visible framing or fixings
What is the difference between rainscreen cladding and curtain walling?
Rainscreen cladding is part of a double wall construction, whereby there is an outer skin of panels fixed to a load bearing external wall with a ventilated cavity between the two.
Curtain walling, whilst also a form of non-load bearing cladding, typically forms and integral part of the external envelope with glazed glazed panels supported by lightweight frame.
What is the spacing for wall ties in a cavity wall?
The maximum horizontal spacing is 900mm, whilst the maximum vertical spacing is 450mm, sitting at least 50mm onto each wall leaf.
