# Poor Man's Block off plate - II



## EJL923 (Oct 8, 2011)

This is an extension of another thread, but i wanted to show how you can make a simple block off plate which is quick, effective, and doesn't require drilling into masonry.  Its not the prettiest, but it is out of the way anyway and will last.  Ive been burning two seasons with the block off plate the installers put in.  I finally went in myself and found how ineffective it really was, so after i did this im looking forward to an improvement in heat retention.

I should add how it is done.  Stuff with Roxul above the damper plate.  Cut a 1/8 thick piece of steel and drill a hole for a long threaded rod.  Two separate pieces of sheet metal, cut to the size of the damper area and made to fit around the liner.  Slide the steel into place, and tighten the sheet metal up to the damper with wing nuts.  Probably about a 30-45 minute job.


----------



## begreen (Oct 8, 2011)

Nice job and good pictures. I changed the title to include block off plate so that folks will find it in the future. Thanks for posting!


----------



## cowtown (Oct 8, 2011)

EJL923 said:
			
		

> This is an extension of another thread, but i wanted to show how you can make a simple block off plate which is quick, effective, and doesn't require drilling into masonry.  Its not the prettiest, but it is out of the way anyway and will last.  Ive been burning two seasons with the block off plate the installers put in.  I finally went in myself and found how ineffective it really was, so after i did this im looking forward to an improvement in heat retention.
> 
> I should add how it is done.  Stuff with Roxul above the damper plate.  Cut a 1/8 thick piece of steel and drill a hole for a long threaded rod.  Two separate pieces of sheet metal, cut to the size of the damper area and made to fit around the liner.  Slide the steel into place, and tighten the sheet metal up to the damper with wing nuts.  Probably about a 30-45 minute job.



I started the initial "Poor Man's Block off Plate" - nice job, question where did you get the metal for this project?  Can you give me details on the metal components as I would like to get some myself.


----------



## Danno77 (Oct 8, 2011)

Sheet metal should be available at any hardware store. ANY gauge of steel should work as it's not anything structural, just needed to keep the Roxul covered and in place.

The little metal strips need to be heavy enough to hold the weight of everything, if your sheet metal is heavy enough to cut them out of that stock, then great, but you can buy 1"+ wide strips of steel at the hardware store, too, then cut it to the appropriate lengths.


----------



## mhrischuk (Oct 8, 2011)

Very smart. I may do the same.


----------



## cowtown (Oct 8, 2011)

Danno77 said:
			
		

> Sheet metal should be available at any hardware store. ANY gauge of steel should work as it's not anything structural, just needed to keep the Roxul covered and in place.
> 
> The little metal strips need to be heavy enough to hold the weight of everything, if your sheet metal is heavy enough to cut them out of that stock, then great, but you can buy 1"+ wide strips of steel at the hardware store, too, then cut it to the appropriate lengths.



Might be a dumb question, but could some sheet metal "off gas" as the temp increases; hence, the sheet metal needs to be made of specific metal (e.g. aluminum or something like that ?)


----------



## Danno77 (Oct 8, 2011)

cowtown said:
			
		

> Danno77 said:
> 
> 
> 
> ...


Straight steel. Not any of the galvanized stuff for sure.


----------



## cowtown (Oct 8, 2011)

Danno77 said:
			
		

> cowtown said:
> 
> 
> 
> ...



I am not playing dumb here, but if I were to go to the harward store and ask for "Straight Steel" they know what I would be talking about?


----------



## Danno77 (Oct 8, 2011)

cowtown said:
			
		

> I am not playing dumb here, but if I were to go to the harward store and ask for "Straight Steel" they know what I would be talking about?


No, just say "steel"...I said straight to make sure it's understood that it doesn't need to be stainless, not galvanized, not expanded, nothing. Just some plain old sheet steel.


----------



## begreen (Oct 8, 2011)

It most likely will be galvanized. That is ok for a block off plate. It doesn't get that hot.


----------



## JeffT (Oct 8, 2011)

My existing damper opening was 6'' so i saved my damper plate and did basically the same thing.Had to notch my damper frame for the flex(6 1/2'' for a 6'' i.d.) then cut a 6 1/2'' hole in my original damper plate.worked like a champ.I would like to post pics but there is a five hundred pound stove in the way.


----------



## cowtown (Oct 8, 2011)

BeGreen said:
			
		

> It most likely will be galvanized. That is ok for a block off plate. It doesn't get that hot.



Okay - thanks for the help, really appreciate it.


----------



## cowtown (Oct 8, 2011)

JeffT said:
			
		

> My existing damper opening was 6'' so i saved my damper plate and did basically the same thing.Had to notch my damper frame for the flex(6 1/2'' for a 6'' i.d.) then cut a 6 1/2'' hole in my original damper plate.worked like a champ.I would like to post pics but there is a five hundred pound stove in the way.



I thought about doing this as well - my issues is that I am the store do the install, so they don't want to fuss with doing this, nor a block off plate.  So the solution is to simply put up some roxul.  My plan is then to have some steel cut into bars and simply place these bars in a North/south fashion to hold up the insulation.


----------



## Danno77 (Oct 8, 2011)

BeGreen said:
			
		

> It most likely will be galvanized. That is ok for a block off plate. It doesn't get that hot.


At what temp does the zinc outgas and how hot will it get? I have a big sheet of galvanized I could use, but I figured that at 700 degrees on the stovetop and having my block off plate just a hair over a foot over the stove would heat it up enough that I should be worried... Actually, my black pipe transfers to the class A just after where I would use the block plate, so the plate would likely be in contact with the black pipe.


----------



## JeffT (Oct 8, 2011)

Danno77 said:
			
		

> BeGreen said:
> 
> 
> 
> ...


You would have to get your stove hotter than 700* at that part of the flue to off gas,and if it did it would only be maybe 1/2'' around the block off.


----------



## EJL923 (Oct 9, 2011)

The sheet metal used was galvanized.  I used the piece that my installers used, and it has shown no signs of overheating after two years of burning.  Galvanized should be good up to 400-500Â°, and that area should not get that hot.  You could use unfinished, it just might get some surface rust overtime.  Another thing that is hard to see, but my installers left about a 1.5" wide strip on the sheet metal to be bent down and secured around the liner with a large band clamp, not too tight.  From my engineering background, i usually wouldn't want to secure disimilar metals, but again, after two seasons it has shown no issues.

Home depot, lowes, any hardware store should have all of these materials, very common.


----------



## fire_man (Oct 9, 2011)

EJL923: Great ideas.

Another maybe dumb question, what is the purpose of the Roxul? If the block of plate prevents warm air from rising into the clay liner, what does the Roxul do? If the liner were not insulated, it might act as a liner islulator, but only as far up as you can stuff the Roxul.
How far did you stuff the Roxul?


----------



## EJL923 (Oct 9, 2011)

The roxul creates an air seal, as it is stuffed real tight and stops heat from leaving your house.  Without it, you will have to seal other ways to stop the air flow. This would negate the point of the poor mans block off, and would require more precise cuts and silicone to seal the edges, and another way to seal around the liner.


----------



## fire_man (Oct 9, 2011)

Makes sense, thanks.


----------



## stejus (Oct 9, 2011)

EJL923 - This looks great and far better than just stuffing insulation up there like my current situation.  One question, can this be done with the stove in place?  I had some reach issues with stuffing insulation up there so I'm trying to figure a way to do it like yours, without pulling the stove out.


----------



## rakuz66 (Oct 9, 2011)

Is that spray foam insulation?


----------



## begreen (Oct 9, 2011)

Packed Roxul.


----------



## EJL923 (Oct 9, 2011)

I did mine with the stove in place. Without pics I have no idea whether or not you can. It was tight, but I managed.


----------



## tickbitty (Oct 9, 2011)

Hmmm... makes me wonder if it could be held up with magnets, that's how I did my mantel shield.  A metal sculptor gave me a thick blanket of kaowool, but I haven't put it up there yet, and I'm certain it would be a bad idea in my particular situation to have it in there without a plate of some sort.  (I have an insert, but no surround panel, so I feel like it would be dropping junk on my stove as well as blowing out...)  We will see.


----------



## DanCorcoran (Oct 9, 2011)

tickbitty said:
			
		

> Hmmm... makes me wonder if it could be held up with magnets,



Not sure, but I think heat causes a loss of magnetism.  Someone on this site will know for sure....


----------



## Danno77 (Oct 9, 2011)

DanCorcoran said:
			
		

> tickbitty said:
> 
> 
> 
> ...


It does, but not at these low temps. Many a flu thermometer is held on with magnets. I overfired once and my magnet gave out a little and never recovered. It kinda slid down the pipe. Now it sits on the stovetop. Still sticks, just not like it did.


----------



## mhrischuk (Oct 10, 2011)

magnets and heat don't mix


----------



## begreen (Oct 10, 2011)

My understanding is that magnets don't lose their magnetism until north of ~900F. If your lintel is hotter than this, call 911!


----------



## NCredneck (Oct 13, 2011)

If you have an existing damper assembly and have to cut or notch some of it out for the liner, can't the remaining damper be used as a block off plate? I was originally going to construct one but I got to thinking the damper could be used for the same thing. I guess the biggest issue would be how hard it is to get the roxul up there but figuring that out might be easier than constructing and mounting a plate.


----------



## rakuz66 (Oct 13, 2011)

I get so many conflicting reports on these block off plates.  Not trying to create drama, just some things people have told me.  
1.  Don't use insulation in the chase if you have a blower, it will only blow the nasty stuff into ur house.
2.  Not necessary if you have an insert with surround panels and a positive connection( full ss liner)
3.  Could create a fire hazard.
4.  Won't give you back as much as it takes to install.
5.  You want warm air in the chimney to help decrease creosote build up.
6.  Just for free standing stoves.
7.  No need if you have an interior chimney.
8.  If ur draft is working fine, don't mess with anything.  
9.  Block off SS liner at top of flue with insulation and your fine.


----------



## begreen (Oct 13, 2011)

It is confusing, especially when confounded by conjecture. Welcome to the internet.


----------



## EJL923 (Oct 13, 2011)

One thing is for sure, you want to block air flow around the exterior of the liner.  Some people do it at the top, some at the bottom, some both.  I have been going back and forth about sealing the top.  My installers originally siliconed the top plate to the top of the clay tile, like a lot of people do.  I read through my Jotul manual, and they say specifically not to seal the top.  Even though the flue will be be warmer when sealed from the top, i tend to agree with the manual and the issue is safety.  What if something were to happen to the liner, and gases were allowed to escape?  They would have nowhere to go.  I am guessing that is the reason for this.  My top cap has since slightly seperated from the top clay, but still has flanges to keep it water proof.  I am hesitant to seal this back up, which is why i made the poor mans block off.

I went back to edit this post, when i realized they were talking about amount a prefab fireplace.  I did end up sealing at the top, no problems.


----------



## mhrischuk (Oct 13, 2011)

10. Keeping the heat in the room/house with insulation and a blockoff plate keeps insulation from getting into the room and keeps heat from leaving the room through convection into the chimney space. Heat rises, cold air falls. Convection occurs. The masonry in your chimney will absorb the heat and won't give it back. By not allowing convection to occur, more heat is available for your room/house.

I read this in a rocket science book.


----------



## NCredneck (Oct 13, 2011)

Is there a problem with using the existing damper as a block off plate, providing you can get the insulation above situated well enough to stop air flow?


----------



## DanCorcoran (Oct 13, 2011)

"I read this in a rocket science book. "

Kudos!  I'll be using this myself, but just want to give credit here.


----------



## EJL923 (Oct 13, 2011)

no problem using the damper as a block off plate, but it is much easier to cut sheet metal than the extra thick damper in the existing fireplace.


----------



## rakuz66 (Oct 13, 2011)

mhrischuk said:
			
		

> 10. Keeping the heat in the room/house with insulation and a blockoff plate keeps insulation from getting into the room and keeps heat from leaving the room through convection into the chimney space. Heat rises, cold air falls. Convection occurs. The masonry in your chimney will absorb the heat and won't give it back. By not allowing convection to occur, more heat is available for your room/house.
> 
> I read this in a rocket science book.



I'm not trying to be a smart a**, just trying to figure out what might work best in my situation.


----------



## mhrischuk (Oct 13, 2011)

Then make 10. the only answer. You don't have to do it at all. As we all have read on here many installers just put in a bare flex and go home. I hate it when the word "professional" or "professionally installed" is used as it often means the cheapest way at the highest price and they pocket the difference. Professional crooks.

Disclaimer.... not all dealers and installers are like that so it's important to become educated before talking to them. You can pick out the good ones that way.

Insulating the liner takes care of the cold air in the chimney issue. That's the whole point of insulating the liner. Now why would you want to use your stove heat to heat the chimney masonry if you already have the liner insulated?


----------



## rakuz66 (Oct 13, 2011)

So, #10 would be????


----------



## mhrischuk (Oct 13, 2011)

rakuz66 said:
			
		

> So, #10 would be????



https://www.hearth.com/econtent/index.php/forums/viewthread/80548/P22/#967702


----------



## rakuz66 (Oct 13, 2011)

Yeah, probably right, it's just gonna be a beeeach to make one in my chase.


----------



## mhrischuk (Oct 13, 2011)

It's an option, not a necessity.


----------



## rakuz66 (Oct 13, 2011)

I f you don't mind me asking, whereabouts in SE Pa, do you live? because I live in SE Pa as well.


----------



## mhrischuk (Oct 13, 2011)

I'm in Delaware county in Bethel Twp. I'm just on the PA-DE border not far from where I-95 goes into Delaware.


----------



## rakuz66 (Oct 13, 2011)

Cool, you can buy me discounted wine.


----------



## mhrischuk (Oct 13, 2011)

Total Wine is right down the road.


----------



## stejus (Oct 13, 2011)

EJL923 said:
			
		

> I did mine with the stove in place. Without pics I have no idea whether or not you can. It was tight, but I managed.



Here's a view of what I am against.  I can reach up there and stuff Ruxul in there like you did.  My bigger challenge is putting in the plate.  I don't have much room to measure for the right cut.  Can I support the Roxul with stips of metal just layed in there like your support strips?  I'd love to get the plate in, but Im not sure I can get up there.   Any tips?


----------



## begreen (Oct 13, 2011)

The best job with the least hassle will be to disconnect the stove and slide it forward to give yourself working space. You can put some blocks or planks down on the hearth extender, then use a plate of metal to slide the stove on to make it easier.


----------



## atcomo (Oct 14, 2011)

Read this thread and today I installed the poor man's block off plate.   What a horrible ...disgusting...job
The Roxul (like fiberglass insulation) is horrible to handle.  Anyway its done.
Only question I have.....it only took about 3/4 of batt....should I have stuffed more into the smoke chamber?
I only laid a single batt above the damper plate.
Have not finished with sheet metal yet.  Still trying to decide if I should add more Roxul.  What are your thoughts?


----------



## mhrischuk (Oct 14, 2011)

I got about 3 batts up there. I had full access though as the stove wasn't in place yet. The more the merrier.


----------



## stejus (Oct 15, 2011)

Went and picked up some Roxul Safe n Sound this morning.  I couldn't figure out how there were 12 3x15.5x47"inch peices of insulation in this bag.   I open it and it expanded about twice the size!  This stuff was so much easier to work with than fiberglass insulation.  

I did this with the stove in place and it was not that bad.  I cut sections into 4" strips.  Just started stuffing them into the open damper area.  I was able to get a 2 full bats of insulation up in the smoke shelf area.  Then I cut a section to fit into place on each side of the liner.  I then supported this with insulation hangers.  These are made of steel so I didn't see any problems with this approach.

Still to warm to test so I'll have to wait until next week when temps fall into the 50's.


----------



## atcomo (Oct 15, 2011)

stejus....any chance of some pictures


----------



## stejus (Oct 15, 2011)

atcomo said:
			
		

> stejus....any chance of some pictures



If you look back a few posts you will see what I was up against beause the stove is in place.  I got this idea from another post (see link) who shared his install of the softplate.  Mine looks identical to this other than the wire. In place of the wire, I used insulation hangers to hold the final peices in place. 

http://www.getdieselpower.com/misc/Sharon/Wood-Stove1/Clydesdale/install2/album/


----------



## DanCorcoran (Oct 16, 2011)

Whoa, in those photos (not yours, the ones you linked to) it looks like his flexible liner is just pulled down over the stove outlet, without any screws to hold it on.  Yours appears to be screwed in place (the right answer).


----------



## Mr A (Feb 8, 2012)

Does anyone know if it would be a good idea to  pour some of that chimney insulation mix down from the top?  The Rockford Chimney Supply website suggests using a chimney balloon to seal off the bottom of the flue. The mix cures into a lightweight, semi hard mass that supports a liner in the chimney and forms a thermal barrier that keeps the flue gases warm. Looks like it costs the same to fill the whole chimney up, as it does for same length of insulation blanket. Also looks it would reduce the PITA factor considerably.  I think some of the other sheet metal lids around the liner, then pour this stuff for a good seal would be better, it might be difficult to get a balloon to seal around the liner.
http://www.chimneylinerinc.com/insulation_kits.php


----------



## Excavator (Feb 8, 2012)

I did something like that last year only I used a fire proof board sold at Ace Hardware. I cut it in 2 halves and shaped it to fit against damper frame. I used fire proof insulation to seal it tight. 
i used large toggle bolts and made 10 inch brackets that bolts go through and grab top of damper frame to tighten up against.
In first pic, you can see how I enlarged damper frame for 8 inch double liner and chipped out some fire brick as needed.


----------



## EJL923 (Feb 8, 2012)

Insulation mix would work, but again, this thread is the POOR mans block off.  I would have needed 3 bags @ $75/bag according to the site.


----------



## stejus (Feb 8, 2012)

Mr A said:
			
		

> Does anyone know if it would be a good idea to  pour some of that chimney insulation mix down from the top?  The Rockford Chimney Supply website suggests using a chimney balloon to seal off the bottom of the flue. The mix cures into a lightweight, semi hard mass that supports a liner in the chimney and forms a thermal barrier that keeps the flue gases warm. Looks like it costs the same to fill the whole chimney up, as it does for same length of insulation blanket. Also looks it would reduce the PITA factor considerably.  I think some of the other sheet metal lids around the liner, then pour this stuff for a good seal would be better, it might be difficult to get a balloon to seal around the liner.
> http://www.chimneylinerinc.com/insulation_kits.php



My installer used the Everguard that you mention.   The way he did it involved removing a few bricks on the outside of the chimney where he could get at the bottom of the last tile.  Once he removed the two bricks, he stuffed in Roxul in the last tile around the liner to form the barrior to hold the Everguard mix.   

He took a large tarp and spread it out.  Poured some mix and water together to make the mix.  It looks like wet cat litter when mixed properly.  He had another guy on the roof with a bucket.  The guy on the ground fills the bucket, the guy on the roof pulls the bucket up with a rope.    The first pour is the most important.  You need to have the guy on the ground hold the Roxul in place while the guy on the top pours it in.  Jiggle/tap the liner to get the mix to drop through the gaps.  Let this set for about 1/2 hour and now you can start pouring in more.  Again, be sure to tap the liner to vibrate the liner to move the mix down.

Once he was done, they buttoned up the brick work and you would never know.  I'm not a mason so I would not feel comfortable cutting into the chimney.  If you are not comfortable, maybe you can find a mason to open it up, leave, and come back when you are done.  The rest is simple work.


----------

