Category Archives: general construction

Bracing for the cornice issue

Our house came with a beautiful cornice that was attached to and supported by the parapet behind it. It was constructed out of copper, but the bottom section had been painted, unfortunately.

It has terrified me for years. This was because upon closer inspection, the top of the cornice was in dire need of repair and we had water infiltration issues, which led the supporting parapet to crumble. And no matter who I asked, I never got a straight answer on how it actually was constructed, supported or attached to the building. It remained shrouded in mystery, leaving me to procrastinate.

With the looming solar array installation, there was no avoiding this any longer. I opened up the top copper sheet to get a visual on the inside and the attachment mechanism – or lack thereof. And the more I started digging the more terrifying it got.

The “support mechanism” was rotting pine boards, which were rotting either in the masonry or the opposite end. And the supporting masonry had deteriorated into loosely stacked bricks.

The crumbling masonry had to be removed and rebuilt. The bottom of the cornice was salvageable, but the top sheet had to be entirely replaced to prevent any further water infiltration into the masonry behind. Mind you, the job of the cornice is to shed water away from the building façade. Along with all this we needed a new support mechanism.

To save and reuse the bottom section of the cornice, I had to brace it before I could remove and repair any of the masonry or top copper sheet. The last thing I wanted was for it to fall off the building.

I managed to score a stack of reclaimed two by fours at The Rebuilding Exchange, which I used to rig up a solid bracing system.

Next step, taking down the crumbling parapet.

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Container framing

Now that I managed to get some daylight into the container, I thought of the best way to store equipment and materials. To maximize the space, I needed to hang things on the inside walls.

That was easier said than done, considering that the walls are steel. And I did not want to put screws or any other kind of fastener or any holes through that steel wall.

The idea that emerged was to frame the inside with a few two by four studs that would provide the support for hooks and other things I may want to attach to the walls. And it turns out that a two by four fits rather nicely into the ribbed indentions of the container walls.

To hold the stud in place, I screwed a small block at the bottom into the wood floor. I used another stud across the ceiling and attached it to the two by fours in the walls with an angle iron. This horizontal piece is basically a blocking at the top that secures the framing firmly into place. Certainly firmly enough to hold my ladders.

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Wall board wrap-up

In the last post I mentioned that we’ve kept fine-tuning along the way. We’ve also gotten savvier with some of the processes. One of those processes is making cut-outs for the electrical boxes that are lurking behind the drywall.

A couple of years ago I used what I called “the carbon paper trick”. It worked really well, but that required me to lift and place each drywall sheet a couple of times.

I don’t remember who it was, but someone encouraged me to use a rotozip instead. It is a tool similar to a router, but used to cut openings into drywall.

 

Before I placed the drywall, I measured and marked the center of each electrical box the sheet, which I then tagged to the wall with a few screws. The rotozip bit is tooled so that I can plunge it through the drywall at my center marks. I then started cutting to one side until I hit the mud-ring of the electrical box. At this point, I had to carefully lift the bit over the mud-ring and then use it as a cutting guide for the opening. And like with a regular router, the movement always has to be clockwise, otherwise what should be a snug opening around the electrical box would give way to elaborate artwork.

Hanging drywall is an art unto itself. And because I already finished the sound insulation at the ERV closet, I am now at a point where I can put the final patina on this art project.

My friend Leon likes when the camera follows me through the building, so I will play the drywall installation time lapse from the very beginning.

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ERV closet sound insulation

Going through our deep energy retrofit in phases has allowed us to fine tune along the way where needed.

One example is the ventilation closet, which on the 1st and 2nd floor borders along the bedroom. On the 1st floor the access doors to the ventilation closet are on the bedroom side. To better manage the little noise the ERV emits, we shifted the access doors for the 2nd floor ventilation closet to the living room side.

But the sound management doesn’t have to end here. We can further soundproof the wall between the ventilation closet and bedroom with the magic material I alluded to in my last post: rock wool.

I started the process before we installed the ceiling drywall by blocking the small attic space. That should prevent most of the ERV noise from travelling across the bedroom ceiling. The next step was to fill the wall framing cavities.

The beauty of rock wool is that it doesn’t only provide sound insulation, but also excellent fire protection and thermal insulation. We used rock wool for these latter two properties in the ceilings and all exterior walls. But for the wall between the bedroom and ventilation closet, we were mostly after its sound insulation properties.

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Drywall data dabbling

It is a good idea to get the difficult tasks out of the way first, and then move on to an easier job.

In this most recent case, the difficult task was the drywall installation in the staircase. And those who read that blog post may have noticed that I was lugging sheets around that weigh 86 pounds.

Why didn’t I use light weight drywall?

The primary reason is fire resistance.

The drywall we used was fire rated Type X 5/8 inch drywall. It has an advertised fire rating of 1 hour, compared to standard drywall, which has an advertised fire rating of 30 minutes. That said, a publication by the Association of the Wall and Ceiling Industry puts the failure time for regular 5/8 inch drywall at 10 to 15 minutes when exposed to 1850F, whereas a 5/8 inch Type X panel would fail after 45 minutes under the same conditions.

Type X drywall has a denser gypsum core and is reinforced with glass fibers, thus the heavy weight. When exposed to fire, the water bonded in the gypsum core is released in the form of steam, a process called calcination. This phase change absorbs the thermal energy from the fire and thus delays the thermal energy transmission from the flames beyond the drywall.

Source: Gypsum Association – Using Gypsum Board for Walls and Ceilings Section I

With the release of the water, the drywall begins to shrink and would start to crumble if it weren’t for the glass fiber reinforcement. The glass fibers buy some extra time before the panel will fail.

Building codes require the use of Type X drywalls for certain applications, but not others. But building codes are not a high bar. They just define the minimum standard a building must meet without being illegal or unsafe. Rather than saving a few bucks and handling lightweight drywall, we thought of Type X drywall throughout the building as cheap insurance.

That isn’t enough to convince you? Well, here is another reason: Because Type X drywall is denser than regular drywall, it has a higher mass which provides better sound absorption. In short, it has some cool features that I wanted to quietly mention.

Even though I was still lugging around 86 pound drywall sheets, the job got a lot easier once I moved from the staircase to the remaining rooms on the 2nd floor.

And this is a perfect point to stop the time lapse. Before I keep going with the drywall installation, we will pause for a minute to talk about another magic material that provides fire protection, sound proofing, and thermal insulation. Stay tuned.

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