07 Jan 2010, Posted by Shawn in Live Work, Sustainability, 6 Comments, Short-URL:http://portlandbuilt.com/j34kn

Live/Work Update: Roof, Electrical, Plumbing, House Wrap

It’s been a busy month at the Live/Work project. After the guys at Bronze finished framing, we started in on roofing, plumbing, electrical, and the exterior house wrap. Let me just say that the addition of the roof (thanks T-Mix!) was a huge blessing, especially with the recent spat of bad weather.

The Electrician Arrives

I’ve made the decision to tackle the rough-electrical myself. The project budget dictated some cuts, and doing the wiring made the most sense. It’s not for the faint of heart – up and down ladders, drilling holes, pulling wire…it makes for a long day. There’s a good reason electricians get paid well – they generally earn it! That said, I’m happy with the decision. It’s enabled me to make small changes to the lighting, plug placement, and switches. All of this would have been difficult (or expensive) if someone else were wiring the project.

Wrapping it Up

Another big change you can see in the photo above is that we’ve started to wrap the house. We went round and round over our final wall details, and finally settled on a system that’s affordable, energy efficient, and weather resistant. Here’s a simple graphic showing how the exterior wall works:

The idea here is to accomplish several things. The Tyvek (house wrap) prevents water from reaching the plywood. This is a fairly typical use of the product – you’ll see it used over and over in new developments because it’s cheap, goes up quickly, and keeps the water out (mostly). What’s different about this configuration is 1) the use of plywood instead of OSB and 2) pink foam board (R5) on the exterior.

Thermal Bridging

The purpose of the pink board is to prevent thermal bridging. Thermal bridging occurs when you have a material with poor insulation characteristics that touches both a warm and cool surface. In home construction, the primary source for thermal bridging are the 2×6’s used in the stud walls. Because studs touch the exterior envelope AND the interior drywall, they act ass conduits for heat loss. The pink board creates an insulated envelope that reduces the heat loss, while also reducing air infiltration and providing a second layer of water protection.

Flir, a company that makes thermal imaging cameras, has some great shots of this in action on their website. Here’s just one example showing the “cold” 2×4’s in the wall:

My contractor, Rory Read, has also spearheaded several advanced framing techniques to better insulate the home. Thes have included things like 24″ spacing on studs, hangers for door and window headers, and hollow-corners when possible. I’ve really come to appreciate the level of detail he put into making sure the house was an energy efficient as possible…without breaking the bank.

Related Posts

1. Live/Work Video Update: Siding!
2. Live/Work Update: Slab Insulation
3. Live/Work Update: Framing!