Resilient design features for new home construction

Future-proofing homes:

Our society has a collective trust in its commercial building industry为了给我们提供我们认为符合现实弹性标准的房子。在一定程度上确实如此，但只是很小的程度。假设气候相对正常，你的家会让你感到温暖、干燥，有热腾腾的晚餐、温暖的淋浴和无尽的娱乐。

When some sort of adversity does arrive, like an abnormally challenging weather event or power outage, there can be a general feeling that it is just par for the course and there was little a home builder could have done to protect your home. That is not often the case - and it really is becoming important to prepare for things to get worse as Climate Change accelerates. If in any doubt, discoverwhy we need Future-Proof Resilient homes building for a changing Climate here.

即使不增加建造成本，一所房子也可以建造得更耐用，更能抵御频率和强度不断增加的极端天气事件。目前房屋建造的弹性水平最多是轻质的，并且是基于已不复存在的气候条件;这是你的基本家居设计被创造出来的时候。

Note:the main image above is of Ecohome's Kenogami House, which was called 'The Most Resilient Home in North America'by Alex Wilson, founder of the Resilient Design Institute.

Resilient home design basics:

The basic definition or premise of resiliency is to be prepared或者从逆境中恢复过来的能力。如果天气预报说有70%的可能下雨，有韧性的人可能会带上雨衣或雨伞。当将这一理念应用于房屋建设时，弹性的概念意味着预期你的家在未来将面临更大的挑战，并建造来承受它。

When you set out to build a new home, resiliency starts withcareful building lot selectionto avoid obvious problems, then determining if that location would make your home particularly susceptible to any or several of the following - wildfires, high winds, heavy rains, heavy snow loads, flooding, extreme humidity, heat or drought, tornadoes, hurricanes and storm surges.

Avoid the most troublesome areas if possible, then if you can, build to withstand the future climate predictions of that region. Here are three basic guidelines that are worth keeping in mind:

Simple is better than complicated.

被动比主动好。

Moving parts fail.

We attribute these three conclusions to Rob Dumont, one of the designers of theSaskatchewan Conservation Housebuilt in the 1970s that inspired the original GermanPassivhaus / Passive Housetrend. Those were his words when asked to reflect on the home design he was part of that started a global movement towards extremely high-performing homes.

你的家越简单、越“被动”，它就越有可能继续工作。Solar panels, heat pumps and other high-efficiency mechanical equipment are truly excellent features to have in a home, but from a resiliency point of view,passive heating, passive cooling, and natural lighting design are even better because design features like that won’t break down and don’t require power.

Building to survive climate change:

The primary concern for people in most of Canada and other cold climates is the ability to stay warm in the event of a power outage, and there are numerous ways to achieve this. That would most sensibly begin with increased levels of insulation, an airtight building envelope and, if possible, incorporating a passive heating strategy and thermal mass inside the building enclosure. Collectively, those measures will help retain heat much longer than conventionally built homes and, hopefully, long enough until the power returns.

Keeping a house warm during power outages:

Beyond basic passive solar heat collection, the following is a list of supplementary heat sources that can operate in the event of grid failure.

• Wood stoves:This is thesimplest heat source to have in the absence of power. Assuming you are in a region that allows them (they are banned in some urban cores), firewood is fairly easy to come by, along with manufactured pressed-wood logs that can be found at most hardware stores.
• Manually-operated pellet stoves:Most pellet stoves require power to feed the hopper. You could rig up a small PV solar panel to run it; optionally,there are a couple of models of pellet stove that don't use electricthat are manually operated.
• Gas fireplaces:All gas fireplaces can be operated without power. The options are either have a CPI (continuous pilot ignition) where a pilot light is always burning, or an IPI (intermittent pilot ignition) that does not have a constantly lit pilot light and instead uses power, but it would have the ability to be lit using a store-bought battery.
• Masonry heaters:large stonemasonry heatersare very expensive, but they are a very efficient way to heat with wood. While a wood stove provides heat primarily when burning, a fire in a masonry heater warms the mass of stone, which then releases heat over many hours or even days. Due to its thermal mass and greater extraction of heat from its exhaust, a masonry stove can reduce wood consumption by as much as 2/3rds compared to a conventional wood stove.
• Solar thermal panels powered by photovoltaics:pumps and fans forhydronic solar panels(liquid) orair solar thermal panelsor evenair solar heated floor slabscan be powered by a smallphotovoltaic panel. Heated concrete floors are a great way to store and distribute heat over extended periods of time making the most ofthermal mass acting like a heat battery.
• Heat pumps powered by photovoltaics:Aheat pumpis about 2/3rds more efficient than other sources of electric resistance heat such as boilers, baseboard radiators or forced-air electric furnaces. This would then reduce the number of solar panels required to heat your home with electricity by about, you guessed it, 2/3rds.
• Home battery systems will be required for some of these options,read here about the newest technologiesin home power storage

It really goes without saying but I will say it anyway – the better insulated your home is, the more comfort any of the above-mentioned heating methods will deliver. You are better to invest in a greater amount of insulation than investing in additional solar panels, more bags of pellets or more cords of firewood. Even if you have a forested property and feel you have ‘free heat’, it still needs to be cut, split, stacked and transported.

Burning biomass in stovesprovides a single point source of heat, so they are ideally placed in a centralized location, and an open concept design will also mean less temperature variations throughout the home.

将热质量融入建筑围护结构将有助于通过吸收和释放热量来调节室内温度。

In winter,thermal mass will absorb heat as it is being generated(whether that is passive heating or mechanically generated) and help keep a home at a more constant temperature, along with acting to store heat during power outages.
In summer, thermal mass will also help regulate temperatures as it will absorb unwanted heat during peak sun hours, which can later be released by natural ventilation as the outside air cools. This can take the edge off a heat wave and at least reduce if not eliminated the need for additional cooling. The minor downside is that after an extended heat wave it will take a bit longer to cool your home to pre-heat wave temperatures, but the overall result in terms of comfort and efficiency is usually a positive one.

Significant thermal mass can also serve as athermal batteryand help make solar thermal heat collection more comfortable and a better investment.

Reduce dependency on automated systems:

Moving parts fail, it’s a fact of life. And the more complicated systems a house has, the more there is to go wrong. Systems like automated skylights, window shutters, garage doors andclimate control systemscan lead to convenience and home efficiency, but resiliency would mean working to ensure those systems continue to operate in the absence of power. Be sure they can all be operated manually or by stored battery power during a power outage, and consideravoiding installing air conditioning in homes with a vapor barrier.

Future-proofing Resilient Homes:

It simply cannot be stressed enough that we just don’t know what is coming down the pipe in terms of climate. We regularly see extreme weather predictions coming true, and if there is any consistency it seems to be that the long-term projections are often upgraded in severity from what we may have been told only a few years earlier.

It is not hard to find examples in Canada and the rest of the world that show there is an increase in the frequency and severity of storms. One recent example to note is Ellicott City, Maryland, U.S., which in May 2018 had its second extreme weather event within 2 years which climate scientists had previously called a‘once in a thousand-year storm’, making city planners wonder whether the historic city should even be rebuilt.

As the climate warms, it brings many increased dangers. In terms of flood risk from rainfall, the effects can be devastating for two particular reasons - warmer air holds more moisture, which regularly causes levels of rainfall far beyond the designed capacity of infrastructure. Also,hurricanes are now being found to be 20 to 30% slower after making landfall导致大量的水被倾倒在内陆社区。

Home flood protection:

Basement flooding is one of the more common catastrophes a homeowner can face, even though they could have been easily avoided in most cases. First thing to note - if you dig a hole, the universe will want to fill it in. Call it karma, Murphy’s law or erosion, but it will happen. Perhaps not in the first year, decade, or even century, but nature will fill it in sometime in the future.

To start a home below grade in the wet ground invites problems. For logistical reasons they are somewhat unavoidable in many situations, like downtown urban cores where space is at a premium, but basements are best avoided if at all possible.

Homes seated on a slab-on-grade (orfrost-protected shallow foundation) will not flood unless you build them in a low point that can entirely fill with water. That would be foolish beyond measure, and you would probably have a hard time even getting a permit to do so in this day and age. Beyond that, a slab-on-grade is a first huge leap towards home resiliency and durability.

If your home were built on a slab, you could paddle away from your front door in a canoe during a catastrophic neighbourhood flooding event with no interior damage whatsoever, while surrounding homes with basements may incur losses in the tens of thousands to make repairs and replace personal items.

Slab-on-grade constructionis more affordable, healthier and more durable than basement construction as you have no porous concrete walls to absorb moisture and no rising water-table issues to contend with.

Durable basement construction:

Water tables can rise from normal spring melting, extreme rain events, or a lack ofproper rainwater management from roof runoff. A durable basement is one designed to divert any bulk water away from the foundation and to handle the higher humidity levels caused by building below grade.

在设计基本结构时，一定要防止水进入，然后在设计内部时，假设它无论如何都会被洪水淹没。Some basic points:

• Install drains around the exterior base of footings.
• Install a capillary break between the footing and foundation wall. Concrete is porous and will continue to absorb moisture and deposit it into your wall assembly for as long as the building stands. One of the cheapest (and most often overlooked) basement durability measures is the installation of a membrane between footings and foundation walls to cut off the supply of moisture. You can buy a membrane specific for this purpose, or you can even use a standard 6 mil polyethylene membrane.
• Don’t rely just on damp proofing spray; install a waterproof exterior foundation membrane. The bituminous spray coating does not fill all the cracks and holes and will let some moisture pass through, and it is susceptible to damage when backfilling.
• Backfill foundations with sand or stone to facilitate better drainage.
• 将地面与地基墙倾斜至少5度，以防止雨水渗入。
• Surface drains and swales can further prevent the water table near foundations from rising.
• Exterior insulation will better protect against foundation cracking and interior moisture damage by eliminating the freeze/thaw cycle that a foundation wall insulated from the inside will experience. Discoverhow to insulate and build better basements here.
• 安装水泵;包括一个电池备份是一个很好的保护措施，因为停电通常发生在暴雨期间，这也是你可能需要你的水池泵的时候。
• Prevent Mold by finishing basement walls correctly
• Raise wood-framed basement walls以及任何木结构的地板结构通过放置在泡沫块上脱离地面。
• Even though it still happens in almost every tract home basement, do not install interiorvapour barriers on basement walls; this will trap moisture and cause rot and mold in basements.

Resilient wall construction:

各种形式的水分是建筑物倒塌的主要原因;风吹雨，积水，屋顶漏水，室内相对湿度高，潮湿的空气泄漏，霜冻，积雪对墙壁和室内凝结由于热桥。

A durable wall is energy-efficient and airtight, with anairspace between wall structures and exterior cladding to allow walls to dryand allow us toInstall windows and doors correctly. The reason we make that connection between durability and efficiency is that energy loss often brings with it moisture damage in the following ways:

• Humid air leaking from a poorly-sealed air barrier will mean greater heat loss; it can also leave condensation in wall assemblies that will lead to rot and mould.
• Insufficientinsulationandthermal bridgingthrough wall assemblies will cause heat loss and can also cause interior condensation and moisture damage.
• A low-quality windowwill lose heat quicker than ahigher quality triple-paned window; they will also collect more condensation that can damage sills, drywall and structural materials.

A resilient wall is one that is well-suited to the challenges posed by its particular climate and microclimate. The solution is to build a wall that protects against wetting (both from the inside and out) but always assume it will still get wet and allow for it to dry.

Roof design - simple is better than complicated:

Aesthetics are important for quality of life and value, but you should always design primarily for function. Your roof is there to protect your home, so don’t let style take precedence over durability.

• Skylightsare very popular for the natural light they provide, they are in no way a resilient design feature. They increase operational costs by causing considerable heat loss in winter and heat gain in summer. There are alsosignificant durability concerns with skylightsin terms of condensation and water damage to roof and walls.
• Roof valleyswill often be necessary with certain designs, but they add complication and cost, so just keep that in mind.
• Ensure sufficientairflow through attics to avoid any buildup of moisture.
• A roof overhangof 2, 3 or even 4 feet will reduce the frequency of wall-wetting from wind driven rain and make your walls last longer.
• Green roofsandmetal roofswill last longer than asphalt shingles, and they will better withstand extreme weather events – (high winds, heavy precipitation, hail etc.). Asphalt shingles are only cheaper the first time you put them on. By the second install in as little as 15 years later, the cost will catch up to what you would have paid for metal roofing. Over the lifespan of a well-built home, asphalt shingles will need to be replaced so many times that in reality they are the more expensive, least durable and most environmentally damaging roofing material option.
• Metal fascia and soffitwill reduce long-term maintenance costs and prevent invasion by rodents and insects.
• Storm water runofffrom roofs should be moved far from the home. Further resilience is realized if that water is collected and put to good use for irrigation or other greywater uses.

None of this should make one feel unprepared if you can’t scratch everything off your list when building. It is intended to offer sensible suggestions so that you are as prepared as possible for any adverse conditions you may experience in the future.

Resilience and future-proofing in homes is about taking steps to ensure that basic human needs are provided for in adverse conditions (food, water, heat, shelter) and continues on to various levels of home protection and maintaining quality of life.

Be inspired, took a look atPassive House Design here in the EcoHome Guides