a canopy is a collector volume. that is all. period. full stop. one does not void a warranty of a shape, for a shape being a shape. then, any blower blows air out the exit. or, the blower pulls air (if it's an inline blower). you can put the air exit where you want. if you buy an entire kit with the blower motor inside the canopy as part of the product kit, the question gets more complex but not by much. If you buy the kit, you will have spent a lot of extra money. This is counter intuitive. Here is a situation where the blower costs less if you buy it as a blower alone, and the canopy costs less if you fold some metal and call it good, or buy (as spare parts) a ready made shape but not the entire product. Hope this answers "I am curious if anyone has modified one of Viking's canopy hoods to vent straight out the back?" I'm not going to go check out a specific model in order to describe how i would shape the corners of the turns. (It's idle thinking).

You can cut a piece of plywood (like 3/4" thick) and mount it on the wall to span the studs, then use that to mount the hood to. It will cause the hood to stick out that much further from the wall, so that might mess with your clearances. About mounting to the lath, depends on what you have. Now it your lath is like what we had upstairs, darn stuff was 3/4" by about 4" wide, with groves milled in to hold the plaster - and firmly attached with larger nails - even with a big pry bar that stuff held firm - and hard - wore out blades trying to cut through it. You could mount just about anything to that. Most of the house had the standard 1/4" thick by 1" wide lath strips - the kind you can break across your leg with minimal effort. Held on by 1" wire nails - very easy to pop off the walls. (they make wonderful fire starter- but mine are also 75+ years old). I saw lots of evidences where previous owners had mounting things to the walls. Sometimes the screw hole would be about 1/8" from the edge and the lath was split, sometimes they used a bit too much force and stripped out the threads that formed in the lath. From what I saw, I'd have no confidence using the lath for support other than to hang small pictures. if you go that route, you need to put in toggle bolts, not screw it to the lath. It could cause flex in the wall, and over time the plaster may crack. If you plan on tiling your backsplash, any flexing will could also pop off the tiles. For me, I'd be cussing, but I'd be finding a way into the wall (either front or back side, which ever is easier. Though with plaster that is a total pain, sheet rock is easy. Otherwise I'd be paranoid the fan it going to end up through my cooktop. We never mounted a fan to the wall, but we did have an OTR range that mounted to the wall and the upper cabinet. BTW - a good way to put in supports is to make a box out of 2x4's and then insert the box in between the studs, and attache the "sides" to the studs. No toe nailing needed, so you won't split the ends of the 2x4's. We had a lot of places we had to frame up using that method as we didn't want to open the wall up any farther than needed (just center line of the studs.

I like your MW placement and can see why you would want to do this - but remember the MW also vents steam back into the kitchen and it rises as well. Peke - I had to laugh when I read your response. So true(see below about my old MW) My Broan also vents directly outside, so no bends. I know my old MW over range was really grungy when we got rid of it. I also would check your local codes - you may be required to use tempered glass above a range for heat. i know some codes require tempered glass for backsplash behind a cooktop but I do not know about above a hood. What is your CFM for your hood? I would like to see the other half of the kitchen. We went with one glass cab (coincidentally right where our old range and MW was before the reno - but now it is just cabinets. One other thought - with your big square tiles and the same style for your glass - how about considering a glass without the trim - I think a plain or lightly seeded glass would add character without it looking matchy matchy. This is coming from someone who still dresses like a garanimal (and I predate the era) Looking good and can't wait to hear what you decide. Bottom line: If it meets code and you like it - go for it

Oh no, no OTR microwave! Unless your kitchen is too small for a separate spot for it, OTR microwaves are very impractical. The venting is poor, they are set up too high, and their use interferes with anyone using the range. Regarding the 8 foot ceilings, you have 96". The vent hood height from the top of the cooktop to the bottom of the hood is specified in the installation instructions from the manufacturer. Let's say that it's 30". So adding the 30" space to the 36" counter top height, you have 66". If the hood is 18" that comes to 84" and you then have 12" left between the top of the hood and the ceiling. That's not enough for a storage cabinet but definitely enough for some sort of decorative top treatment. If the manufacturer specifies more or less than 30" then your space above the hood will increase or decrease. But you need to plan for that as you select your vent hood.