Carbon Neutral?

[Greg Steckler]

I suspect the carbon sequestration? of a log home is better than a stick home. How about the energy used to create it? The overall impact of energy and CO2 release of the home over its life is better? Would someone like to tackle this and give us the reasons from a "green" standpoint of consumption why our suspicions may be right?

[Jim Morvay]

If it's a true handcrafted log home, theoretically all the work could be done by hand.

In reality, they are cut down with chain saws and probably de-limmed using the same. That would be followed by whatever heavy equipment is required to get them to where they will be needed. Then, most likely, chainsaws and electric grinders are used for all the necessary work, notching, scribing, etc. plus running portions of them through a saw mill to get flat surfaces when required. And then more heavy equipment to get them to the home site

Is the amount of energy used to create the required number of milled logs more or less than that required for the handcrafting process for the same home?

Again, theoretically, once the log home is built, whether milled or handcrafted, the only ongoing cost would be stain/sealant and caulking. Yes there is a cost to create those items, but over expected life would that cost be less than it takes to create brick or whatever kind of man made siding comes to mind?

My gut says logs will come out better than stick built, but there are so many variables. A simple example would be that more energy, chainsaws and grinders, goes into a full scribe log home than would be required for a full round chinked style. However, there is the cost of creating the chinking plus the energy required to drive a chinking gun that may or may not offset the energy required for a full scribe. And then one could argue that you only do the scribing once, but may have to chink more than once during the homes life.

And we could go on and on.

[Greg Steckler]

And we could go on and on. and we should...

The energy required to harvest logs whether for log homes or stick is the same per cubic foot of logs to the point where one log is turned into 2x4's and another is headed for the log home production yard, I would think. From there it is a different story. Obviously, more logs will be used in a log home (and therefore more carbon is sequestered?) but the stick frame energy path goes for insulation, OSB, nails, sheetrock, etc. Other than a few wood products like OSB, not much carbon is sequestered here....and I suspect more energy is used to get it habitable.

Then there is the life expectancy of both... As a group, which will last longer? And therefore need NOT be replaced?

So whose got the facts?

[Alberta Loggie]

I did a fairly comprehensive review of a "total energy audit" of a log home vs a stickbuilt on the forum here several years ago.

Greg is correct, up to the point that the timber has been harvested, the energy consumed is the same. However, there is a whole lot less processing/energy consumption required in preparing logs for assembly however than what is involved in creating dimensional lumber, plus its shipping to and from a mill. Then you've got the energy costs to mine, refine and produce all the other stuff that is involved in a stickbuilt house, from nails to gypsum board to vapour barrier, F-glass or foam insulation, etc.
The energy consumed there can be fairly large, given where iron is mined, its shipment in raw form, its smelting and manufacturing into metal products, the shipping and storage of the finished product before it ever gets to the house. Same thing for gypsumboard - mined, shipped, processed, manufactured, shipped again to retailer, then shipped again to you.

Almost all the energy used in those manufacturing/processing/shipping stages consume hydrocarbons and definately produce "unsequestered CO2"

Once the log house is up, the finishing energy consumption/CO2 production should be about the same, assuming you finish the log home with the same kinds of tubs, sinks, flooring, windows, lights, etc.

I think the big difference is the unsequestered CO2 produced by all of the extra manufacturing/processing that goes into the materials in a stickbuilt house.

[dr.]

The term "embodied energy" used to be used (not sure if it is still the correct buzzword) for the total energy incorporated into something. Less processed items like logs look good from that standpoint.
The biggest change we can make however is to reduce. No amount of feel good consumerism is going to have more effect than reducing consumption. I've built super insulated, state of the art homes that consume several times the amount of energy as compared to a simple small home. And there is less embodied energy in that small house of any type. Sorry, but if we continue to put lipstick on Miss Piggy, it won't change the fact that she's still a hog ;).

[Bob Warren]

Its not the processing that is the key, it is that wood is 48% carbon by weight. Take this example; I deliver a truck load of logs that weighs about 40,000 lbs. (That is about a 1000 sq. ft house.) Water will be 10-12% of that load so oven dry its around 35,000 lbs of wood. At 48% carbon you have more or less 17,000 lbs of carbon.

It all came out of the air during the last 100 years. So cut the trees and replant so that the new ones will also take a lot of CO2 out of the atmosphere. If you build the house properly with a good foundation and generous roof protection the building will last much longer than 100 years. Effectively you are removing from the loop and sequestering all that carbon.

The ration for carbon to CO2 is about 1 to 3.6, There is one ton of carbon in 3.6 tons of CO2. So that 17,000 lbs of carbon that is locked away in the walls of the house was just over 60,000 lbs of carbon dioxide.

Trees are the answer, cut them, use wisely and plant new ones.

[Greg Steckler]

So I saw on PBS last night another article in this vein...namely carbon footprints and carbon credits. Seems big polluters/green companies are buying and selling credits. I wonder is there a built in credit for a log home? If you build a log home could you sell the credit for that 60,000 lbs of CO2? You don't suppose we are on to something? :D:D:D

The Log Home as a bank account? It's full of carbon....is it full of money?

[Rick in WA]

Maybe I missed the point in the previous threads but what about "where" the log is harvested for each of the building types. Its not at all hard to imagine that a log home would have logs from BC sent to TN then back to OR for the finished product. Thats a lot of miles. I don't know if the same could be said of stick houses. They may even travel further. Don't even think of it in China since that is where much of the North American limber is going. Maybe it is too complex to accurately follow for many houses.

There is the flip side of that. Bob might get his logs locally then send them directly to the site. There may be much less carbon footprint for that then a stick frame built next door to the same project.

I do like the idea of the carbon bank rebate though. Selling your carbon accruals in the logs to the "big guys" is kind of like net metering with logs.

Rick