One question we often field is whether our passive house kit is the same as a prefab house. It’s not. It’s something much better, in our view, and here’s why:
Unlike a prefabricated house, which comes straight from the factory ready for final assembly on your property or site, our material kits provide quality materials installed in the correct steps and the option to be as involved as you like in the build. These are quite significant differences.
Our weathertight material kit can be shipped across North America, and can be assembled by any experienced carpenter. It’s down to you and the details of your project to decide on foundation and finishes.
We’ll state our bias upfront: we think that our passive house kits win hands down over prefab assemblies, particularly for our northern climate where weathertight wall assemblies matter a great deal.
Prefab Homes: The Cons
- Transport – large prefab walls require multiple large trucks, adding cost to the project’s bottom line.
- Site access – large trucks often have trouble accessing building sites, requiring additional vehicles and steps at increased cost.
- Build integrity – insulation in prefab walls demand just the right weather conditions during transport and assembly.
- Assembly & foundation issues – prefab buildings need cranes for assembly, which are costly. This cost is often driven up by site / foundation irregularities affecting installation.
- Hidden costs – fully prefabricated homes are marketed as being cheap and quick, but as the points above illustrate, at what additional cost?
- Air leakage – prefab systems come with just one chance to seal the building with exterior tape, compared to the stringent triple-protection of a passive house build (vapor barrier, air barrier, and water barrier).
- Mechanical penetrations – there are a number of items required to pass through walls, such as plumbing vent pipe, exterior light and outlet wiring, HRV supply and exhaust lines, heat pump lines, etc. Prefab walls containing insulation will compromise thermal break at all of these points, making the building envelope far inferior.
Passive House Kits: The Benefits
- Flexible, local – our kits allow you to be as involved as you like, as well as to involve local builders and tradespeople.
- Transport – we partner with national carriers and distributors, allowing us to minimize delivery and travel distances regardless of property location.
- Site access, build versatility – our weathertight material kit is provided unassembled, simplifying delivery options and providing flexibility for adapting to building site conditions.
- Sensible construction – insulation isn’t installed in the roof and walls until the building is proven to be weather-tight; an on-site build just makes more sense.
- Quality assurance – the integrity of installed materials is best accomplished when they are installed together. The vapor barrier goes first, followed by the air barrier, and then the water barrier. The only method of quality integration is with a site-built kit, not a pieced-together panelized home.
- Customizable – we offer the choice of structural wall assembly: standard wood frame or optional internal timber-frame core.
- Insulation – this is the main component designed to keep the building easy to heat and cool, and to remain problem-free. Any super-insulated building needs to have a vapor permeable system in place for the wall to maintain dryness. EkoBuilt wall insulation R75, roof insulation R120.
- Wind tight: an EkoBuilt PassiveHouse is guaranteed to be under 0.6ACH (air exchange per hour). Any modern building should be able to perform to this degree of air-tightness.
- Timing – pre-assembled kit elements achieve an accelerated build timeframe.
We think you’ll find that the quality and energy efficiency that can be achieved by building on-site far outweighs the apparent convenience of a fully pre-fabricated house. Contact us to find out more.
Pingback: ICF vs. the EkoBuilt passive house kit | EkoBuilt