Guides
The building science, in plain words
25 guides to how a high-performance envelope actually works. The science is general engineering; wherever a Guardian figure appears it is cited to the document it came from.
The building envelope
Thermal bridging in walls, and how to stop it
A thermal bridge is a conductive path that bypasses the insulation. In a framed wall the studs and plates are the bridge, and they can cost a wall a third of its rated R-value.
Read →Continuous insulation: what it means and what it fixes
Continuous insulation is insulation uninterrupted by framing across the whole envelope. Codes increasingly require it because cavity insulation alone cannot deliver the performance the model assumed.
Read →R-value and U-factor: which number to use
R-value measures resistance to heat flow and is reported for materials and assemblies. U-factor measures the rate of heat flow and is what codes use for windows and whole assemblies. They are reciprocals, and mixing them up is a common specification error.
Read →Air tightness: the cheapest energy measure there is
Up to 40 percent of a home's heat loss is air leakage, not conduction. Sealing the envelope usually costs less than adding insulation and saves more.
Read →Moisture, mould and why the wall assembly decides
Mould needs moisture, a food source and time. Remove any one and it cannot grow. A wall that stays dry and offers nothing to eat is the durable answer.
Read →Durability: what actually makes a building last
Buildings rarely fail because a material was weak. They fail because water got somewhere it could not dry, or because thermal and moisture cycling worked a joint loose over decades.
Read →Materials
Cold-formed steel framing, and why it behaves differently
Cold-formed steel is shaped from sheet at room temperature. It is light, dimensionally stable, non-combustible, recyclable and highly conductive, which is the property that shapes how it must be detailed.
Read →EPS insulation: what it is and how it behaves
Expanded polystyrene is a rigid closed-cell foam that is about 98 percent air. It has no blowing agent to lose, no food value for mould, and enough compressive strength to act as a structural web.
Read →Structure and loads
Designing an envelope for high wind
Wind design is about pressure on surfaces and the continuity of the load path from the cladding all the way to the foundation. The strictest US category is the high-velocity hurricane zone.
Read →Basement and below-grade walls
Guardian lists basements among the applications for the system, alongside walls and roofs, as part of the total exterior envelope.
Read →Building by climate
Building in a cold climate
In a heating-dominated climate the envelope is almost the whole story. Insulation, air tightness and the avoidance of cold spots decide both the bills and whether the building stays dry.
Read →Building in hot, humid and island climates
In a cooling climate the envelope has to keep heat and humidity out rather than in, and on an island it also has to survive the wind and the logistics of getting materials there.
Read →How buildings get built
Panelization: what moves to the factory and what it buys
Panelization moves the wall and roof from the site to a factory. The gains are less waste, better tolerances, a shorter cycle and less exposure to weather and labour supply.
Read →The framing labour shortage and what it changes
Skilled framers are scarce and getting scarcer. Prefabrication does not remove labour; it moves it somewhere it can be trained, supervised and retained, and it lowers the skill needed on site.
Read →Sustainability
Embodied carbon and the honest comparison
Embodied carbon is the emissions locked into making, moving and installing a building's materials, before it is ever occupied. As buildings get more efficient to run, it becomes the larger share.
Read →Net zero: what the envelope has to do first
Net zero means producing as much energy over a year as you use. The cheapest route is to shrink the demand first, because every unit of load you remove is a unit of generation you never have to buy.
Read →Cost and value
What drives the cost of a panel building
Comparing a panel price against a lumber package answers the wrong question. The comparison that matters is the delivered envelope: material, labour, insulation, schedule and the equipment the envelope lets you shrink.
Read →Working out what an efficient envelope saves
The saving comes from three places: less conduction, less air leakage and smaller equipment running closer to its sweet spot. Only the first is visible in an R-value.
Read →The E3 mortgage savings programme
Energy-efficient mortgage programmes recognise that a house costing less to run leaves more income available to service a loan. Guardian publishes an E3 Quotient document on the subject.
Read →Certifications and incentives worth pursuing
PHIUS, LEED, ENERGY STAR and the National Green Building Standard all reward the same envelope work. Which to pursue depends on the building type and who is paying.
Read →Total cost of ownership over a building's life
Capital cost is one year. Operating cost, maintenance and replacement run for fifty. An owner who keeps the building should compare all four.
Read →Talk to us about your project
Tell us what you are building. We design and produce the envelope to your exact drawings, residential or commercial.