Or how to build a better house in 2020.
Building a new house is an exciting experience for you and should make you happy. For the general builder it is a routine, these opposite attitudes will crash, especially when you try to implement new ideas or viewpoints.
However building your new home cannot be a passive undertaking.
You will have to make lots of decisions, if you are not willing to do that, get someone reliable onboard who will follow your vision. Otherwise the builder will make those decisions for you.
Relying on your builder will come at a cost.
To be more competitive, builders tend to keep heaps of necessary items out of their quotations or say there is not enough detail to provide a fixed price, this bad practice is used everywhere.
Think of all details in advance, get them quoted and written down in a detailed contract.
Don't try to rush this part of the process. The more time and effort you spent up front, planning, designing, and understanding, as well the specifics of the project, the better the whole construction process will unfold.
Try not to change or add anything during the building process.
Anything you add to the house after the contract is signed, the builder will painstakingly keep track of, and you will pay full price for it.
Site conditions / weather delays are not to create additional costs, get that signed in your contract.
Follow up on verbal discussions and instructions with written verification. Keep records and receipts, samples you approve, all model, type, and style numbers. Keep records of all correspondence. Photograph each part of the build.
Any occurring issues you can then prove and resolve.
As a contractor we have designed and build multiple houses, and we have experienced the luxury of living in a "passive" house.
Some of the tips below are going to save you money, others will cost you. But they will definitely give you a better, healthier and more comfortable home.
General
Building with an eye for detail & harmony, will bring your house to a higher level.
Your home and your comfort is essential for your health and well being.
Get an open and flexible floorpan, adaptable to changing lifestyles. and future demands.
Use Low formaldehyde emission materials.
To prevent air and moisture infiltration, houses need to be sealed properly. This means closing all joints, caulking, taping or using expandable foam.
Radon is a radioactive gas that gets into your house trough cracks and holes in walls and floors, it's the second leading cause of lung cancer. Use these simple protective measures:
Install a layer of clean gravel or aggregate beneath the slab or flooring system.
Lay polyethylene sheeting on top of the gravel layer.
Include a gas-tight venting pipe from the gravel level through the building to the roof.
Seal the foundation thoroughly.
Use concrete piles, recycled hardwood or concrete blocks for retaining walls.
Use hardwood timbers such as western red cedar or redwood for weatherboards and decking
All CCA treated timber. (CCA stands for: Copper, Chromium and Arsenic) are poisonous and leak into the soil.
Don't grow veggies near treated timber & don't use it as firewood.
Walls
People have an innate sense of mass, so don't build hollow walls.
Using ply barriers on inside and outside walls on both sides and insulating them, will give them mass, make them stronger and more durable. No more problems with hanging objects or punctured holes. Perfect for soundproofing.
If possible use durable thermally broken steel framing, It won't be compromised by rot, mould or termites and doesn't have nasty chemicals.
Use low maintenance high quality building materials.
Windows & doors
When using aluminium windows, only use the thermally broken ones, otherwise you will get a cold window frame inside full of condensation.
If possible use high quality Upvc windows or hardwood timber windows with the best rated glass you can afford.
Laminated wooden windows with double gaskets are almost 100% pure nature".
Good glass panes start from R=0.91.
Standard double glazing has a R value of only 0.388, Low E double glazing has a R value of 0.528.
Low E glass layers protect against ultraviolet light and fading.
The main advantages of triple glazed windows are: no cold radiation when sitting near them and the highest R ratings. They also provide the best noise insulation.
Install wider & higher inner doors, not only they look better but are also a necessity in case of an accident or illness.
Bigger windows provide more sunlight, but use outside blinds for safety and overheating in summer.
Use smaller windows on the South side.
Size and place windows for practical use.
Passive & low energy house
Build an airtight outer shell for increased energy efficiency.
Insulate all interior walls for sound.
Double insulate your exterior walls, not only it will keep your house warmer in winter but also will protect against summer heat.
The double outside layer prevents thermal bridges and acts like a winter coat.
Floors insulated keep your feet and thus your whole body warmer.
Aim for a R value between 4.5 and 8.5. Consider the standards as bare minimum.
Invest in a "passive" or high performance low-energy house, roughly that's a house build taking in regard it's materials, positioning, window sizes, high insulation, airtightness and solar panels. In return you will get an extremely comfortable, healthy home with a 90% reduction for heating and cooling.
Get an insulated garage door, and insulate the garage, it's the first barrier against heat and cold.
Even a "tropical" island like New Zealand needs proper insulation and double glazing. :))
Ventilation & Condensation
Breathing and transpiring produces about 1 to 2 L of water vapour per person a day.
A family produces together with cooking and showering up to 12 L per day. This moisture together with harmful substances can provoke allergies or respiratory diseases. So ventilation is a must, just as a vapour barrier on the inside of walls. One of the biggest mistakes is not installing airtight barriers on the inside of outer walls and using open flush boxes for electrical. As soon as moisture enters the wall the insulation starts to deteriorate and your house will loose it's insulating properties
Use a continuous central ventilation system with a low-noise emitting vent fan and an air cycler. It not only removes the daily toxic fumes and water vapour but also keeps your house warmer.
Start cooking with induction instead of gas. Gas cooking releases CO2, NO2 and water vapour from the gas.
A highly insulated house with proper Low-E glazing and ventilation will have no condensation whatsoever.
For these reasons house ventilation is mandatory in most European countries.
Use a ground based air intake, this will heat your fresh air in winter and cool it in summeRoof
Sheeted roofs provide an extra barrier, mass and strength for roof tiles.
Roof tiles made of concrete or clay, are less noisy and much cooler in summer. Have no condensation.
Real roof tiles have a long lifespan with no need for extensive maintenance or painting.
Only an insulated ceiling and an insulated roof combined will give you the best insulation results.
Use a large overhang or soffit to keep the high summer sun out, but let the low winter sun in. Aim for 70-100 cm
Heating & Cooling
Underfloor heating is one of the most comfortable heating systems, it's upto 40% more economical than traditional radiators.
Place 10cm of insulation on top of your concrete slab, cover it with heat reflecting foil, install underfloor heating pipes, and finish it off with a 8 cm topping screed.
Solar panels in combination with a large water cylinder are great for your underfloor heating.
For days without sun your water cylinder can be heated by a heat pump or electrical spiral.
When building an airtight house make sure your wood burner gets its combustion air trough an exterior vent.
If possible use geothermal energy.
The easiest way is to warm up your ventilated outside air trough an underground duct system.
Invest in Solar panels and PV panels. It's Free energy for 20 to 30 years and less polluting.
Use outside insulated blinds for safety and sun protection.
Try to move the water meter into the shade, warm water can get legionella contaminated.
Keep your water cylinder above 60 degrees C.
How much does it cost to build a smarter home
generally worldwide construction costs are 50% labour and 50% for the building materials.
Roughly starting at $2500 per m2, depending on building quality and demands.
Architectural build average at $4000 per m2.
Strict budgeting and smart shopping can bring this number significantly down.
If you have the time You can build, your own home using the Owner-Builder Exemption.
