canic ceilings and other "old" building materials

[unknownjulie]

I did search the forum, but didnt find info about this. I was wondering if anyone had personal experience with canic ceilings installed over wood slat ceilings (I know they contain arsenic)? My new house has this. Also, just wondering, but I am amazed that there isnt more termite damage. It is made out of almost 100 yr old redwood. Was the wood by any chance, back then treated with something to retard insects? (probably something illegal now!)

[Seeb]

The canic board has got so much arsenic in it that it's hazardous waste, you can't take it to the dump

[Carey]

Some wood (inc. the wood in the Palace) spent time in slat water in transit to the island... have heard folk knowledge from neighbors that this has kept the termites at bay....

Have no idea how true, but salt is not a friend to most soft body insects...so maybe a salt water immersion might be a reason for your lack of termites.... also redwood does have oils that have some termite resistance...

[unknownjulie]

That is an excellent explanation Carey! My newer redwood house that I rent has lots of termites in it. Possibly the older redwood had a "more salty" trip over the ocean to get here. Anyhow, I imagine there is also lead paint and that is why the exterior is mostly protected also. I'll be careful working on it, but I am leaving almost everything and just trying to minimally restore it. I like the old materials because they are outlawed now, and they last forever. Definately not going to the landfill!

[kalakoa]

I've heard that waiwi can be made "useful" by soaking it in seawater.

I believe that the "boric acid" treatment is also a salt.

[rainyjim]

Molly and I, were instructed by a local lauhala weaver that to facilitate proper care for our lauhala mats you can submerse them in seawater, this helps repel bugs, mold, and mildew. I can't imagine why the same wouldn't go for other organic materials like redwood or waiwi, however that canic stuff sounds scary and you'll probably give yourself nightmares about your ceilings gobbling you up as you slumber - better replace that stuff eh?

[unknownjulie]

Oh no. I like the ceilings. They are staying. No worries about moldy drywall. I think you'd have to eat it, to be affected by the arsenic. They appear fairly solid. I'll paint of course.

[Bullwinkle]

Redwood is toxic to bugs (the oils and sap) - or at least resistant - that is why it was almost cut to extinction in the 1800's


you dont want a splinter from red wood either - will fester and burnSome non-arsenic substitutes for CCA-treated wood include:

Alkaline Copper Quaternary (ACQ). This treated wood has been used successfully for more than 10 years and has the same green look as CCA treated wood, but does not contain arsenic or chromium. It has been found to have performance characteristics similar to wood treated with CCA. Preserve®, Preserve Plus®, NatureWood® are brand names for ACQ pressure-treated wood.

Copper Boron Azole (CBA). CBA is a copper-based preservative with an organic fungicide. The treated wood is a dark honey brown color and turns a silver-gray after it weathers. Wood products treated with Copper Azole have been used successfully since 1992. Wolmanized Natural Select™ is a brand name for CBA-treated wood.

How long will treated wood last? It depends on the use and location. For best results, it is important to use a treatment level appropriate to the end use. Retention is the amount of wood preservative placed in the wood. When selecting treated wood, refer to the following chart.

Minimum recommended retention for various applications:

Application Retention (lbs/cu. ft.) Uses
Above ground decking 0.15 + water repellent Decking, hand rails, spindles, trellises, gazebos, fence boards
Above ground - general use 0.25 Framing lumber, trim and fascia, flooring, sill plates
Ground contact 0.40 Deck support posts, fence posts, landscaping
Critical structural members 0.60 Permanent wood foundations, building poles

Naturally Resistant Woods. Naturally resistant woods include redwood, cypress and cedar, but these woods are not long-lasting as treated lumber. For maximum termite and rot resistance, it is important to use the heartwood where resistant compounds are concentrated. Construction common grade wood contains sapwood and will only last a few years with ground contact."

http://lancaster.unl.edu/pest/resources/...ices.shtml

"

[Carey]

The big problem with the ACQ & CBA wood here is that it is very hard to find here...just the borate/boric acid (highly water permeable) is readily available...have even heard of people shipping a container of the copper treated wood here so they can build with it... It is not something you can just run into the hardware store (or big box) & purchase copper treated dimensional lumber...

[unknownjulie]

I bought some copper stuff at ACE that I was going to paint my Ohia's with to preserve them, but i was thinking of using this as a "primer" under my paint on my new house. Is this the copper stuff you speak of? and can I use this as a primer under regular exterior housepaint? thanks. I'm also going to just paint this alone on the beams up in the attic etc.