Working on wood furnace install

I got my mechanical permit last week to install my wood stove last week (some things you can hide, but adding a chimney on the roof I figured could be pretty easily detected, especially with the software many places use to determine if there are any changes to a property). So, I have started the install and it is going pretty well. I had to make a few changes from what I thought and would have preferred, but overall its not too bad. I wanted to use one side of the closet, but I forgot to account for the 8-10″ of overhang of the floor joists on the basement wall, so when all the clearances would have been taken into account it actually would have been a couple feet into the closet. So, I put the stove on the other side to use the other corner of the closet.

The chimney installation itself has been fairly easy, if you are the DIY type and take on home projects you can feel pretty secure you can do it. If you’ve never done anything construction/remodel/repair related though it probably isn’t recommended to start. One of the harder things to figure out was how to mount the support in the floor I joists; I ended up using a hand saw to notch out a 2×6 so that it was flush with both the OSB and the bottom LVL portion of the I joist. At this point I’m just waiting for a few days of clear weather forecast so I can cut the hole in the roof to put the flashing in. The next 3 days are supposed to be sunny and clear, so this may be my opportunity. It for sure would be normally, but there was somebody who just moved here who asked my pastor for help, so I’ll be helping them move in the middle of the afternoon today so that will cut in on my project time.

While I anticipate the chimney being done with little additional work, the ducting for the wood furnace has been pretty hard. First off, there is very little information that can help the lay man in determining how to size the duct work. I finally found Loren Cook tools¬†which had some helpful tools and a few semi-tutorials that can help you determine some sizing. It probably isn’t helpful to MOST people, but if you have an engineering mindset it can be quite helpful. Its meant more for industrial scale, so some of the charts don’t go down so far as to help on a homeowner level (for instance, the velocity correction doesn’t go down as far as I wanted to go for noise purposes, so when I was correcting for equivalent length it ends up being a pretty conservative number.

Another obstacle in the duct work to the normal homeowner is the selection of fittings at the local hardware store. Home depot was about useless, they didn’t have any large fittings so you can only make branch ducts, no main ducts. Menards was decent, they at least had the basics, but the round duct work can be a huge limiting factor with what you can do. By far the best would be rectangular and putting on the take-offs manually. But, that looked like a huge pain, so I just made do. I don’t know how well it will work though until I fire up everything. For instance, the RIGHT way would be for me to run 10″ for the main duct, then have a takeoff for one room, then reduce size down. Unfortunately, there are no low profile takeoffs for 10″ duct and there isn’t enough room to do a 10″ T down do 6″ and hook it up to the duct, so I had to reduce the 10″ to 6″, and then T it to one vent and then continue 6″ to the down stream rooms. What does this mean? Well, it means I have 500CFM going through that 6″ T, it appears the linear velocity will be 2500 fpm (almost 30 mph!) and that means it will probably be loud. I may re-do this later, but I at least wanted to get it started now. Unfortunately the only way I see to do it right is to do the rectangular duct. And with lack of fittings and fabrication tools even that will be pretty difficult. For the majority of people I am thinking hiring an HVAC guy to install the duct is probably the right answer. Cost? Well I will have $300-500 into the ducting and rectangular was more expensive than round. So my guess is the HVAC guy will run you $1000-1500.

Speaking of costs, if you are interested in the chimney costs it is taking me 7 sections of chimney to get above the roof line which was around $400. All the misc other pieces (cieling support, attic insulation shield, chimney to stove pipe adapter, flashing, rain cap) are probably another $300, so parts are maybe $700. Time I’ll have probably 10 hours into when all is said and done in the planning, cutting, assembling, etc. I am not sure yet if that 10 hours will include the concealing that’ll need to happen in the closet. For that to look good and be done right will probably take a decent amount of time on its own even though it is a small area. A hack job could probably be done in a couple hours, but to make it look more professional will probably be more like 5-10 hours on its own. I imagine that to entail taking the drywall off the inside of the closet so I can fit boards between studs to securely fasten the wall.

I think this coming week I’ll be able to get the inspector to come out and be to the point of doing the first firings. I may leave the concealing to be a winter project, after this I need to work on rabbit cages, start moving firewood to the house, and then maybe work a bit more on next year’s firewood (cutting, bucking, and stacking, but not splitting until I get a splitter). Plus I would love to fit in a bit of fishing and hunting before its too terribly cold and while the salmon are in the rivers!

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