Do I absolutely need a block off plate?

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bigdaddybry

Member
Jul 3, 2008
40
N. Prov. RI
I mentioned it to my installer when he was here inspecting the chimney, he basically said "we don't do that" "you don't need that". I even showed him the ICEMAN thread with the pictures. He took a quick look and said, nope, not necessary if everything is properly sealed at the top of the chimney.
 
Your call. Do you want some of the heat output of your stove warming up the chimney and outdoors? Or in the house?
 
[quote author="Glowball Worming Bust" date="1217369439]warm air holds more humidity than warm air[/quote]

must be the heat
 
Get some ice GWB, you're talking to yourself again.
 
I don`t have one on our exterior chimney,only at the top. and we still get cooked out of the room, often have to open a window.but then we really don`t get much freezing weather or snow around here.
 
at least ask him to stuff the bottom with kaowool that would stop most of it just not give you the fire safety the plate would......a plate just about eliminates the chance of a fire inside your headers and keeps the heat in.....you can do it your self its very easier..if you are short on time measure and have sheet metal place make it.. stick it up there screw it in and caulk...np all done then tell installer to continue with his part
 
"He said he won't install it"
UM, who is hiring & paying who here? I suggest the paying customer should get what he wants.
That guy would be off my property real quick with a boot print on his arse, telling me, the paying customer what he is going to do and tell me he will not do something I am willing to pay him to do.
Not a smart business man. Anyone knows the extras are time & material basis & the meat & potatoes of any business.
 
bigdaddybry said:
He took a quick look and said, nope, not necessary if everything is properly sealed at the top of the chimney.

Thats is 100% correct by the code.
 
im with HOG on this one , you may not "need" it now, but there are several reasons stated above as to why you will later wish you had done it. get it done , if the guy you have lined up now isnt willing to do it (which is so stupid of him to say so it boggles the mind), im sure someone else would be.
 
bigdaddy, I was assuming that this was an exterior stack due to the insulation, but to be sure I have it correct, is this an exterior or interior chimney?
 
They shouldn't have a problem. But perhaps they are just trying to stay competitive. I would ask them to give you a quote for the additional price of installing this option.
 
They don't want to do it because it takes time. They would probably go from two installs a day (one morning and one afternoon) to one a day if they were to install block off plates. That would be a big dent in their paychecks. Code doesn't require one but that doesn't matter to me. When mine was installed I didn't have one put in. My installer gave me the same line, don't need it, code doesn't require it, without it it lets some heat up the chimney to increase draft and reduce creosote, blah blah. That's when I found this site and started reading and reading and reading. I was new and didn't know better. Long story short, I have a block off plate that I did myself and the difference was amazing. Without it it would heat the room with the insert and that was about it. With it it heats the entire main level (approx 1100 sq ft.) of my ranch house. You'll be unsatisfied with the insert if you don't have one installed. Your choice though.
 
you might be able to do an easy block off plate like I did. My damper was large enough for the liner to pass through. It took it out cut a whole in it the size of my liner and put it back in. Then I ran the liner down through the chimney with the damper closed, sealed the damper shut, and sealed around the liner damper connection. There was no sheet metal work at all other than cutting a whole in the damper.

As for the need for it. I've never used my insert without one, but I am going to insulate the block off area this year. I noticed where enough heat it going up the chimney that the snow melts off the roof around the chimney.

That said, I kinda think the installer is right, even if a bit lazy. If you seal the chimney at the top then there will no air flow in the chimney with the except of possible up and down drafts. The air near the liner will climb and the air near the chimney wall will fall. The insulating properties of sheet metal are practtically nothing. So if you stop the convective flow either at the top or the bottom you accomplished the same thing, even though installing it at the bottom would help more. However, I strongly feel that insualtion is needed to prevent heat from going up the chimney. I'll test my theory this year when I insulate mine.

If it were me, I'd go with the blockoff plate and insulation. Ask me again this January and I'll tell you for sure how important this stuff is.

Just remember, there is a big uninsulated whole in your roof right where the majority of heat in the house is concentrated. This would be like opening a winow and setting a space heater in it.

Stoves are more efficent than inserts because they have 6 sides exposed to the room. Inserts only have one side exposed to the room. They produce the same heat, just with an insert it goes up the chimney.
 
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