SARC 221 Building Materials and Construction Assignment One: Townhouse Model
Daniel Benton Shayna-Lucy Curle Tutor: Kate Walker
Roofing
Design Intent
Monopitch Affordable Spacious Luxurious Open Light
The initial aim of this design was to create a naturally-lit, central enclosed space. Through the design of this space the curved central staircase took its form and was designed to allow the light from this space to spill out into the bottom level. The aim was to create a light source for the whole building, and any large structural members would interfere with this light transmission. By designing the floors to clear span without any posts or columns to support them, we were able to create a light source with minimal framing. Specifically curved LVL beams are necessary to support flooring edges but the staircase itself is self-supporting.
22 Degree Roof Pitch
The roof is designed to shed water as efficiently as possible and to allow natural light to be gained from the north through clear polycarbonate sheeting over a centrally located clearstory.
The townhouse has been designed structurally so that the gravity loads are carried by the longitudinal exterior walls. This allows for large windows with no lintels to be accomodated on the front and back facades, which adheres to the design concept.
Roof Cladding The roof is clad with Coloursteel with a fire retardant, self-supporting underlay. Polycarbonate roofing over the lightwell is the most cost-effective and simplest option as it is a seamless component of the roof. It is easy to replace with tinted options if in-use lighting or heat gain is excessive. Glass skylight options could be designed into the roof if a more expensive option was desired. Light well cladding: http://www.alsynite.co.nz/polycarbonate-roofing/laserlite-2000.aspx Roof cladding: http://www.nzsteel.co.nz/products/colorsteelRoof underlay: http://www.pinkbatts.co.nz/assets/DataSheets/Flamestop-950-datasheet.pdf
Exterior House Cladding
Stairs
The cladding specified for the townhouse is Shadowclad. It is a lightweight, durable and sustainable plywood cladding. Shadowclad is suitable for use in all wind zones and is fixed over a 20mm cavity system with TyvekŽ Homewrap™ building wrap. http://www.pinkbatts.co.nz/assets/DataSheets/Tyvek-HomeWrap.pdf
Shadowclad can be painted any colour and has a life span of up to 50 years depending on coatings. If correctly detailed it can also serve as structural bracing. Cladding has been designed to specifications laid out in this document: http://www.chhwoodproducts.co.nz/userfiles/file/02620_CHH_ Shadowclad_Brochure_web.pdf
Precedent
One of the main design features of the townhouse is the staircase. Wrapped around the light-well, the staircase is the first thing seen when entering the house. The staircase divides spaces while allowing light to flow thorugh the interior of the house.
The stairs adhere to the specifications of Acceptable Solutions D1/AS1, specifically: section 1.4 deaing with height clearances section 4.3 dealing with Landings section 4.4.1 dealing with curved stairways with tapered treads.
Elevations
Walls All exterior walls were constructed with 90x35 studs @ 400mm spacings for timber efficiency. The 400mm spacings had the added benefit of allowing more layout options for the exteral cladding. The interior of the shared walls could be lined in GIB Fyreline速 16mm for a 30/30/30 fire rating. http://www.gib.co.nz/assets/Uploads/GBUW30aGBUW30b.pdf
Floors
Front Facade - West Facing - Street
Back Facade - East Facing - Backyard
The upper story floor is constructed with ply flooring. REDtongue ply has been used because the tongue & groove system it employs allows the flooring to be self-supporting, requiring less timber for the structure of the floor and reducing the chance of squeaking. This upper floor has carpet (not modelled) as floor covering to make the space acoustically comfortable.
North Elevation
South Elevation
http://www.chhwoodproducts.co.nz/ecoply-flooring/ The ground floor level is polished concrete wich is a cost effective, asthetically pleasing and durable surface. The concrete floor also assists in thermal regulation of the interior.
Group Photo