Floodproofing

Louisiana got besieged by a 500-year flood a couple weeks ago. I received a firsthand account from my cousin, who lives in Baton Rouge. He was one of the lucky ones – flood waters didn’t reach his house – and he has spent days helping neighbors clean out.

An unnamed, weeklong storm dropped more than 20 inches of rainwater over a third of the state. Rivers reached record flood stage, mixing with mud and sewage as the water submerged low-lying land. Outsiders tend to assume all of Louisiana is low-lying, but many affected houses are not officially in a floodway and many residents do not have flood insurance. Even for those who do, the federal provisions are messy and limited to $100,000 of personal property. In homes where the water has receded, the stench is almost unbearable. Cleanup involves removing personal items from the house, then gutting and replacing everything below the high-water line… and often, because of wicking moisture, well above that line too.

How can you design or retrofit a house to minimize the damage a flood would cause? LSU College of Agriculture developed this proposal, which divides walls horizontally in two. A chair rail hides a gap in the drywall and a partition between lower and upper insulation. Thus, any flood water that infiltrates the house can’t damage anything above the chair rail. The concept is to eliminate “water bridging”, much like a Passive House avoids thermal bridging to keep heat in.

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LSU proposal for floodproofing. For more information, click the first link in the paragraph above.

To further protect the lower half of the house, LSU recommends water-resistant flooring and wall panels, along with insulation that doesn’t absorb water, such as rigid foam. Electrical wiring is as high as possible. None of the details seem overly expensive to install, other than requiring a like-minded contractor to do the work correctly. I’d recommend all homeowners in a floodway, and even outside of it (500-year floods do happen), to consider protecting their property with details like these.

Of course, you could also literally elevate your house, or surround your property with a cofferdam, or (if your house is on wheels) drive it to higher ground when heavy rain threatens. But most folks who take action at all will probably go for the LSU ideas.

To help rebuild the affected communities, you can send funds to the Baton Rouge Area Foundation or the Louisiana Red Cross.

The Rail World

David hired me to repair a stair rail that had pulled out of the wall during a furniture move. His tenant had patched two of the holes where the brackets attached to the drywall, and it fell to me to finish the job.

Stair rails take a lot of abuse. People lean on them, knock into them, and pull and push as if they could carry the weight of the world. They can’t. Like everything else in the house, a stair rail is only as strong as what it’s attached to. For the best chance of withstanding abuse, the rail has to be anchored in the structural wall behind it.

So I was relieved when I cut out the remaining two rectangles of drywall and found solid wood behind both of them. (Normally I could use a jab saw to cut out drywall, but in this case the wood prevented me from jabbing through, so I made several passes with a utility knife pushing hard.) I measured my openings, cut new drywall slightly too big, sanded the new pieces down until they just fit, and secured them to the studs with drywall screws. Then I applied spackle, waited a day, sanded, and repeated the process.

When the wall was smooth, it was time to reinstall the rail. (I didn’t paint because David plans to repaint the entire wall sometime soon.) The top end of the rail returns into the wall, and that connection dictated its height. David helped me hold the rail up so I could mark the bracket locations; it took a couple tries to get it right. Then I drilled holes for the toggle bolts we’d use to distribute load where the bracket didn’t quite line up with the stud. Finally, I changed my drill bit to Phillips head, and with David holding the rail steady again I buried the screws.

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David reattaches a stair rail bracket to the wall.

Sounds Like a Good Idea

Jas hired me for an interesting soundproofing project in his Mad River Valley cabin. Noise travels easily through the kitchen ceiling (which is also the second floor) and disturbs renters in the bedrooms upstairs. That is the problem we’re trying to fix.

Jas doesn’t want to hide his gorgeous exposed timber joists, so our acoustic solution consists of two extra layers of ceiling within each bay. The first layer, Advantech, ties adjacent floorboards together and stiffens the floor. The second layer, drywall, serves as a smooth paintable finish surface while providing additional thickness. Between the layers we sandwiched a healthy squeeze of acoustical glue for extra dampening.

Beautiful, rustic ceiling bays... one with a freshly-installed piece of Advantech.
Beautiful, rustic ceiling bays… one with a freshly-installed piece of Advantech.

First we measured and cut Advantech. In ideal circumstances, this task would be as simple as measuring the width and length of each bay… but built houses never present ideal circumstances. Our timber joists were slightly crooked, making each bay vary in width. Worse, there was a joint above the kitchen island where two joists butted end-to-end, and the two joists didn’t line up at all.

In many cases we settled for cutting the Advantech pieces narrower than the bays so they’d fit easily between the unruly timber joists. We did the same with the drywall later, varying the seam locations. The downside of this approach was leaving unsightly gaps alongside the timer joists, which we’ll have to hide later. “A little bit of spackle and paint/Make a carpenter what he ain’t.”

Jas screws drywall to the Advantech, with a T-stick supporting its weight.
Jas screws drywall to the Advantech, with a T-stick supporting its weight.

We had to balance each piece in place over our heads while one person drilled in the first few screws to hold it permanently. That was a challenge, especially for the densely-packed Advantech… we took to drilling pilot holes so the wood would accept screws more easily. Jas dreamed up a T-stick to prop up each piece from the floor, giving us a crucial extra hand on the largest pieces.

With only about one bay complete, we can’t yet gauge how effectively the system absorbs noise. Stay tuned to hear the final report.

One bay (almost) complete.
One bay (almost) complete.