Development of house

Reusing materials
I have decided to take sections of the old house's exterior cladding and place it on the new structure. Wood is considered a sustainable building material because it is derived from a renewable source and has low embodied energy. This reflects the minimal non-renewable energy used in the production of timber and its application in construction. It also has sound thermal properties, meaning that timber structures rely less on carbon-emitting heating and cooling appliances than buildings constructed of other materials.

Double Glazing Windows

http://www.energywise.govt.nz/your-home/insulation/window-insulation/double-glazing

Double glazing provides much better window insulation than single glazing. There are a few different features to look for that effect the performance. Double glazing is a way of creating an insulating layer between two panes of glass. This insulating layer can be normal air or special heavy gasses. Double glazing lets in as much sunlight as single-glazed windows, but holds in the heat much better. Double glazing is standard in most new houses, but it's also worth thinking about adding double glazing any time that you are renovating an existing home. If you need to prioritise, install double glazing to the main heated areas of the house and where there are large windows.

Good double-glazed windows:
- Can halve the heat loss through the window.

- Significantly improve thermal comfort of your home.

- Reduce external noise.

- Reduce condensation build up in cold weather.

Solar Panels
http://www.energywise.govt.nz/your-home/generating-your-own-energy/pv

New Zealand's sunshine can be harnessed to generate clean electricity for homes and businesses, but it can be expensive.

How PV works:
PV cells convert sunlight into electricity by an energy conversion process. In most PV cells, photons (light energy) hit the cells, exciting electrons in the atoms of a semi-conducting material. Silicon is the most commonly used semi-conductor. The energised electrons result in the generation of an electrical voltage. In other words, electrons flow, producing direct current (DC) electricity. PV cells are usually fairly small, with lots joined together to form a PV panel. These panels are then grouped together into PV arrays.

Where PV is used:
PV panels and arrays are used in both stand-alone power systems and grid-connected generation systems, as well as in other small applications, like weather stations, some road signs and parking meters.

Key components of PV systems:
- PV panels, cables, and mounting or fixing hardware.

- An inverter and controller. 

- Batteries, back-up generators, and other components in off-grid situations.

- Special electricity meters, in the case of grid-connected systems.

- Capacity rating of PV panels.

PV panels work well in both rural and urban conditions. The best places to use PV is in places that get a lot of sunshine each year and where the sky is generally clear rather than cloudy. PV works best in north-facing places with year-round sun. Panels are usually installed on roofs but can also be placed on facades, conservatory roofs, sun shades, garages or specially-built stands on the ground.

Make sure your site:
- Faces north (south-facing panels are for the northern hemisphere)

- Is free from shade and exposed to good sun all year

- Has enough space - a typical 1kW unit needs an area of around eight square metres.

Thermal mass

http://www.ccanz.org.nz/page/Thermal-Mass.aspx

All building materials require a certain amount of heat energy to warm up. In this respect, all building materials have a ‘thermal mass’. Materials like concrete masonry and brick, however, require much more heat to warm up than materials like timber or plastic. They therefore store greater amounts of energy which makes them more effective for heating and cooling a house.

The term ‘thermal mass’ is used to describe materials that have a significant capacity to store heat. Typically, these building materials are also ‘heavy’. Houses that contain high thermal mass are often referred to as being of ‘heavyweight’ construction, in contrast to houses of ‘lightweight’ construction, such as ones built with steel-framed or timber-framed walls. A house incorporating appropriate levels of thermal mass should be more comfortable in all seasons and less expensive to keep warm in winter as long as it is insulated well.

The most common high thermal mass material used in house construction is concrete (commonly in floor slabs and masonry walls). Concrete is readily available and can be used for the structure of the house as well as providing thermal mass. Other forms of thermal mass used in house construction are rammed earth, natural stone and brick. Concrete is often used as an example of a high thermal mass material, though these other forms of thermal mass can provide similar comfort and energy efficiency benefits.

High thermal mass materials such as concrete have not been very widely used for house wall construction in the past and as a result you may be concerned about factors such as earthquake resistance. Concrete, like all other materials used for house construction, must meet all the durability and structural safety requirements of the Building Code. You can therefore be assured that houses built from high thermal mass materials such as concrete are at least as safe and durable as timber-framed houses. High thermal mass materials are also fire resistant and reduce airborne noise transmission.

Roof Drainage

http://www.ashireporter.org/HomeInspection/Articles/Flat-Roof-Drainage/2554

Roofs should not be dead flat. They should slope to the perimeter or interior drainage. Any roof that still has water on it 48 hours after a rain is defined as a ponding roof. If there has been no rain for a considerable amount of time, there may be no water, but you may be able to determine that there has been ponding. Circles that are particularly dirty on the roof, or show algae or vegetation growth, are indications that water ponds on the roof.

Drainage from flat roofs can include:

- Gutters and downspouts

- Internal drains

- Scuppers

Gutters and Downspouts

Gutters and downspouts carry water from the roof away from the building, protecting the cladding system and the foundation. Gutters are also called troughs or eavestroughs. Downspouts are also called rain water leaders, leaders or conductor pipes. These are handled exactly the same way for flat roofs as they are for sloped roofs. Gutters and downspouts can be made with several materials, the most common of which are aluminum, galvanized steel, vinyl and copper.

Internal Drains

Internal drains are typically connected to pipes that go down through the house and discharge into a storm sewer. These are often laid into a roof similar to how a stack vent flashing is installed, except that the flange is at the top, and the sleeve extends down below the membrane inside the roof drain in the building. The roof membrane is laid up to the edge of the drain opening. The drain, which includes a 3-inch flange around the top, is set into the membrane and then stripped in.

Scuppers

Scuppers are simply openings through parapet walls or perimeter curbs that allow water to drain into a downspout running down the exterior of the building. Scuppers are essentially a continuation of the roof membrane. The scupper itself is usually surrounded with a metal box that acts as a flashing and allows water to run through the wall. Good roofing practice includes having primary scuppers at the elevation of the roofing membrane, and secondary scuppers about 2 inches above the low point, to act as emergency drains in case the primary scuppers are obstructed.

In my design, I have decided to add a slight tilt in the roof so that all rainwater can easily move into the guttering system and through the downspouts.