Wall Shield Selection

My idea would be metal studs (z tracks) rock wool between studs and corrugated (galvanized?) roofing tin.
corrugated metal roofing behind wood stove - Google Search

For "maximum" as you say, metal stud all the walls and insulate. Will only take a small fire to heat the whole garage

 

Just to follow up, I finally got the IS installed in the shop. All who predicted the concrete walls would pull all the heat were correct, it takes two full loads a day to keep it above 50° with outside temps below freezing. Please keep in mind I am not experienced with all of these subjects, and therefore I’m pretty ignorant to how this all works.

I didn’t want either the expense nor the square footage lost by walls to insulate the concrete walls. I understand that ideal is studs and insulation, and I’m still considering that option for the whole shop. I also thought of doing that behind the stove, and just taping up reflected double sided bubble insulation on the walls to save money and space. Does anyone think that would work well enough to save some firewood, and the space required for a huge wall project?

Reflectix 48 in. x 100 ft. Double Reflective Insulation Roll-BP48100 - The Home Depot

 

I put 1/2" rmax on my basement walls.
Unbelievable the difference! Going from no insulation to r3.5?

 

Zero insulation now. Rmax is the foam board? Encouraging that it helped! Thanks!

 

I heat our 2,800 sq. ft. house with our non-cat wood stove that is located in our basement. The outside temps have been lows in the teens and highs in the 20s for two weeks now and the furnace has only kicked on a few times. The whole house is kept at 70 to 72*. I have been playing with getting the most heat from the stove transferred into the rest of the house for a couple years now.

Free corregated roof panel on some screws with 1-1/2" long 1/2" pvc pipe spacers mounted it to the contrete block wall without insulation. The wall behind the panel is cool. The panel stays cool pretty much because most of the energy is reflected. It would be nice if it was wider, but the rest of the wall isn't all that warm. This panel took care of the most of loss on the back wall.

The new reflector I made to sit on the door shelf of the stove have been a very effective part of the system. I noticed the floor near the stove being very hot and decided to reflect that wasted energy up into the floor joists above to recover the heat into my furnace ducts. I would think a flat reflector on the floor would keep that energy in play in your shop instead of toasting the concrete. A 24" by 24" flat reflective sheet on a small lightweight stand a few inches below the door window of your stove may assist. You wouldn't need the bends like mine beause you aren't wanting to reflect it up, just keeping it from the floor. Painting the floor white or silver may also help too, but would be hard to keep clean...

Good luck with your project and try some things. It doesn't have to be expensive to work well.

My experiences are here: Relflecting the heat back into the house

 

Thanks for the detailed post! Your results are quite encouraging. I’m afraid your block construction is better than my below grade solid concrete, but we will find out!

First I will get up a bigger heat shield behind the stove, the concrete gets into the 80s when the stove is running hard. I have a small sheet of aluminum, but headed out to grab a few 8ft sheets of roofing material in the next few days.

I measured the floor in the shop at 49°, and in front of the stove after running for 4hrs it’s 60°. It looks like I need a small shield or insulation of some sort. Thanks for the tip!

 

Spoiler alert... At -6 F this morning our funace has kicked on some overnight to keep the house up where the wife likes it (happy wife, happy life). I'm OK with that since I could NOT drag my lazy rump out of bed at 3:30 this morning to load the stove... I have the stove cranking now hoping to catch up.

Where I used the metal reflectors, I didn't use any insulation and it didn't seem to make much difference without it. I typically prefer air movement in a basement over insulation simply to ensure keeping the molds and mildews at bay. I did use the relfective bubble wrap insulation on the doors and some of the block that was away from the stove, mainly for it's reflective propeties. I wasn't worried about mold / mildew on the fiberglass doors. If they were wood I may not have used that. I will peel some of that off part of a door next summer to see if anything is showing up under it. I do worry about possible condensation under it although I tried to seal it well with metalized duct tape when installing it. The door surface is cool to the touch.

Surfaces you don't want to heat, use reflective material.

Surfaces you want to absorb heat and warm the air around it, paint flat black (if that's ok)...

Good luck Rush although luck has little to do with it. A curious mind and the will to improve things are POWERFUL tools.

 

Below grade concrete foundation should have insulation panels on the outside of the wall (2" foam board?) at least in this part of the country they do...and if it does, then the concrete just needs to be heated up and kept warm...think of it like a heavy flywheel...takes a lot of "horsepower" to get it up to speed (warm) but then it will also take a long time to slow down (cool) once the engine (stove) is out of fuel.
Best plan is to run hard to get it warmed up, then you can just do 1 or 2 loads per day to maintain the warmth...but if the concrete is not insulated on the outside then this whole idea is kaput

 

Thanks for the info, it really helps to provide perspective. The moisture issue is another one I’ve been worrying about. Not having to insulate behind the heat shield is very nice, thanks for the tip.

brenndatomu I will only be insulating the concrete walls, which I’d forgotten is precast, not poured like I said before. I dug around, and it seems like there is only a moisture barrier outside the foundation, no insulation. I would be really happy if that was the case!

What do y’all think about a polyiso foam board taped into place on the walls?

 

I'm curious about this topic too... I have a daylight basement with 8" block walls with no insulation and have wondered how I could insulate them....

 

I'm a fan of exterior insulation when possible, but that is a lot of work in an existing structure. But if you get ambitious and go that route to get the block or concrete to act as a thermal mass, ensure there is good drainage between the insulation sheets and the ground. I've done a couple over the years and like putting gravel backfill in next to the insualation sheet and a landscaping cloth draped down the dirt side while backfilling to slow down the migration of the dirt into the stone. The freeze thaw cycle moves that dirt or clay into the stone pretty quickly. I'm not sure how much the landscape cloth helps but that's the way I was shown to do it. The reason I ended up having to do it that way was because in both cases the footer tile was clogged so the wall had to be dug up anyway.

 

I would love to insulate outside, and I will for sure if I ever have to excavate. A good bit of the precast is exposed, so I wouldn’t want to insulate outside there. The top half with siding is well insulated framing, and the roof is super well insulated. The precast concrete on the bottom half is mostly buried on the back of the building from this picture.

 

It looks like 2” polyisocyanurate foam board with foil facing is the best insulation for the space required. I’m gonna give it a shot, but still working out how to attach it to the concrete. Anybody have any ideas about quick, easy, inexpensive and easily removable attachment method for the foam board?

 

I'd glue it on with caulk...it will hold the panel on just fine, but I'd think it would peel off just fine if the time came...a lot easier than construction adhesive would.
You'll still have a concrete floor soaking up heat...but not as much as the walls.
Might want to put a ceiling fan or two up there to push the heat back off the ceiling too, since its a fairly tall space.

 

I was hoping someone would suggest that! It will make me feel better when I am installing it; I won’t feel like I am * rigging it as much!

For the floor, I am going to try a shield like MAF143 suggested first. I hope it helps. The concrete floor does warm, but not as much as I was fearing it might.

Thanks for the help!

 

I was just about to head to HD to buy the Rmax to put up, and I read that it is not recommended for below-grade applications. Anyone have an opinion on whether it would be an issue? I would just put up the extruded polystyrene but it is pink and I don't want a pink shop for obvious reasons.

 

Not sure why exactly...I know the foil faced JM polyiso board is OK with it. https://hw.menardc.com/main/items/media/MANVI001/Install_Instruct/JMAPFFSheathing.pdf

 

I think it has to do with whether both sides are foiled, or just one. I found the moisture rated double foiled panels at HD, which I preferred anyhow. I’m super jealous of your Menards! Great store/chain. Pictures later of the beginnings of the install.

 

Yes, since they came to our area I hardly set foot in bLowes or HD anymore...and Menards is planning another store even closer to us than the one we have now...I'm excited about that...but it could be a little dangerous too!