I'd hate to guess how many homeowners, when planning a renovation, only ever consider the "lipstick and mascara" and never think about what's inside. When it comes to home construction, beauty really is only skin deep. What I care about most when it comes to an upgrade -- and what you should, too -- is the stuff you don't see.
Probably 90 per cent of people don't even think about what matters most. And trust me, it's not the cupboards, the paint or the flooring. I'm talking about the building envelope -- and that's what you need to think about first with any upgrade or renovation, because that's where you'll save the most money, make your home more energy-efficient, and prolong the life of your home.
What is the building envelope? It's the layer between "outside" and "inside" -- the layer that contains the insulation and vapour barrier, the house wrap, and the sheathing, the foundation walls, the windows and doors and the roof. It's what separates the living space from the outdoor environment, both above and below grade, as well as your unheated attic (which doesn't count as "living space," because it's meant to be an unconditioned zone).
The building envelope is what protects you and maintains your comfort in your home, by providing insulation and water control and preventing air leakage.
If your home's insulation is good, heat transfer is minimized. That means you don't lose heat you're paying for in the winter, or lose cooling in the summer.
Adding insulation will improve the efficiency of your home, because it provides resistance to heat flow (R-value). But, unless your building envelope is tight, the benefits insulation provides will disappear.
If your house "sucks" -- that means it has uncontrolled airflow or leakage -- then your envelope is poor. You'll probably have drafts, you're losing money on wasted heating and cooling, and it's likely your home is deteriorating without your being aware of it. The structure might be rotting from condensation caused by air leakage.
You need to seal all leaks and all penetrations in the building envelope to prevent air movement and possible moisture penetration. Moisture vapour can do as much or more widespread damage than water leakage over time.
An important element of the building envelope is the drainage plane, which is the way your home controls rainwater that might penetrate the external sheathing. Every type of cladding will allow some rain to get through -- it is inevitable. Rainwater can and will get through brick, stucco and siding somehow, someday. So, it's important to make sure the drainage plane -- the part of the envelope that's behind the exterior facade -- is effective in getting that water down and out so it can flow away from your home.
What used to be called "tar paper," or building paper, is a simple drainage plane. It's been replaced in the industry by newer more effective material such as house wrap and waterproof membranes. Ideally, you want to use a water- and vapour-resistant barrier, overlapped and sealed so any water can drain out of the wall cavity.
Think of a cooler, or a nice simple Styrofoam box, with a tight-fitting lid: if you fill that cooler with ice-cold beverages on a hot day, what happens? What happens is... nothing. The ice stays ice for a long time, the beverages stay cold, and the hot outside air stays outside the cooler for a long time. And, there's no condensation on the outside of the cooler. That tells you that there's minimal heat transfer and that the thermal break is good.
That's what you want your house's envelope to do: Just like a cooler, you want it to keep the air movement to an absolute minimum, and provide a thermal break to reduce the risk of condensation forming. A superior building envelope will reduce or eliminate air and vapour and water and moisture movement between inside and outside.
All types of insulation provide a thermal barrier; some provide a superior barrier I like to call a thermal break. Building code typically calls for a minimum of batt insulation, with vapour barrier, sealed to prevent air leaks. You may still have spots that have thermal bridging, where there is the possibility of cold meeting warm.
A superior envelope would have closed cell spray foam insulation in intimate contact enveloping or encasing the entire structure -- ceiling, walls, above and below grade -- just like a cooler.
When you are planning your renovations and upgrades, you've got to make sure the choices you make are the best ones. Remember these are choices you'll be living with a long time -- for the life of your house. It's not like a coat of paint or flooring choice you can change. So stop paying more attention to the facelifts for your home and start thinking about its bones and heart. A house's beauty really is on the inside.
Catch Mike on Handyman Superstar Challenge airing Thursdays at 8 p.m. ET/10 p.m. PT on HGTV. For more information visit www.hgtv.ca.
-- Canwest News Service
