Help with blocking plate installation (eastern MA)

[lml999]

I have an Enviro 1200 installed in my living room fireplace. It was professionally installed about 8 years ago.

I would like to have a blocking plate fabricated and installed, along with some Roxul, to keep the heat from going up the chimney. I have called a couple of chimney sweeps in eastern Mass, asking if they would be interested in doing the work. So far I haven't gotten any bites.

I'd appreciate it if someone can recommend a service provider in the area (metrowest Boston) who could do this work. Alternately, if someone on the forum is interested in doing the work, with me assisting, I'd be very open...I'm handy and level-headed (mostly), but not comfortable with doing the work on my own.

Compensation -- cash, beer, an opportunity to split some stubborn pine?

Thoughts, comments much appreciated.

 

[Jags]

They are a pretty easy job. If you are even handy(ish) you can probably get the job done all by yourself.

https://www.hearth.com/talk/wiki/make-a-damper-sealing-block-off-plate/

Keep in mind that these things aren't replacement heart valves. They really don't have to be perfect to do their job.

 

[Enzo's Dad]

I hate working with sheet metal. I read alot of links here. Keys to doing it are taking your time, and a really good jig saw with a blade designed for cutting metal. Also cut a square opening for the flue, its easier to move around.
Oh yeah and some band aids...its easy to cut yourself.

 

[lml999]

They are a pretty easy job. If you are even handy(ish) you can probably get the job done all by yourself.

Thanks Jags, you're right. If I do a split plate, I won't have to move the stove. And if I can use the Poor Man's mounting method (threaded rods hung from above, I won't have to drill holes...

Many things on my Honey Do list...

Guess I'll get started on this one. Time to order some Roxul backing panels...

 

[Jags]

Easy peasy. As a side note: tapcon screws into the masonry might be just as easy as threaded rods. It doesn't take a bunch, just something to keep it in place.

 

[lml999]

I took a good look behind the stove. Probably should have done this before.

The chimney houses three flues -- one for the living room fireplace (wood stove liner), a basement fireplace, and the oil burner. The basement fireplace is not used and the flue is currently closed off at the top. The oil burner was replaced with a high efficiency gas condensing unit and we no longer use that flue either. it is also closed off.

So the liner goes into this large cavernous area, and the outer wall of this section is on the outside of the house. There's nothing between that cold area and my living room, except for the wood stove surround.

I've posted a couple of pictures of the stove with the surround and without it, along with a couple of views into the firebox

In the pictures you can see the black firebox bricks and behind that the outer wall of the chimney...(there is a gap between the two)

Looks like putting a two piece backup plate will be pretty straight forward. I'm going to order some Roxul backing plate and will probably also pick up some Roxul wool to stick up into the cavity.

One question -- the installation looks more complete with the surround on the stove, but if I'm keeping the heat in with the backing plate, does it make sense to keep the surround off. Others that have added backing plates have commented that their insert surrounds get pretty hot...and I'd rather get that heat into the room...

What else could I do to tidy up the installation? (Yes, I have some black stove paint!)

Comments appreciated!

 

[Jags]

Do you use a fan with the insert? If so, it is probably evacuating the trapped heat behind the surround but below the block off.

 

[Nick Mystic]

Is the black soot on the stone facing above the fireplace opening left over residue from when it was burned as an open fireplace? I'm assuming it is unless you ran your insert slammer style in the past. In any case, one thing you can do is clean that off the bricks. I had something similar when I switched out my insert for a freestanding stove. I can't recall the name of the product, but I got it at the stove shop and it was made to clean soot off bricks. It came in a spray bottle and worked like a charm. Cleaning that up and a fresh coat of flat black stove paint on the entire insert would go a long way to sprucing things up. If you leave off the surround you would probably want to paint the part of your flue pipe that can be seen above the insert.

 

[fossil]

Get a pair of safety cut-resistant gloves (~10 bucks) and don't use a saw of any kind to cut sheet metal...use sheet metal shears (~15 bucks). Both readily available at pretty much any hardware store. Use a fine flat file to clean up the cut edges before you start fiddling with the pieces. You'll be a more comfortable and happy camper, and you shouldn't need the band-aids. Rick

 

[lml999]

Do you use a fan with the insert? If so, it is probably evacuating the trapped heat behind the surround but below the block off.

Yep, we do run the fan part of the time. It helps to move the heat across the living room towards the 1/2 flight of stairs up to the bedrooms. I have a feeling that leaving the surround off will do more to move the heat into the room, though.

 

[Jags]

I have a feeling that leaving the surround off will do more to move the heat into the room, though.

You are probably correct on that.

 

[lml999]

Is the black soot on the stone facing above the fireplace opening left over residue from when it was burned as an open fireplace? I'm assuming it is unless you ran your insert slammer style in the past. In any case, one thing you can do is clean that off the bricks. I had something similar when I switched out my insert for a freestanding stove. I can't recall the name of the product, but I got it at the stove shop and it was made to clean soot off bricks. It came in a spray bottle and worked like a charm. Cleaning that up and a fresh coat of flat black stove paint on the entire insert would go a long way to sprucing things up. If you leave off the surround you would probably want to paint the part of your flue pipe that can be seen above the insert.

Yes, the black soot is left over from open fireplace use. Can't imagine how an insert would create that soot!

I will clean that off before I paint the stove (and flue pipe). Thanks!

 

[Nick Mystic]

You wouldn't be able to get soot like that with an insert installed with a liner unless the liner detached or got a hole in it, etc. My insert had been installed slammer style by the original owner some 20 years ago when it was common to install inserts that way. You basically had the insert dumping smoke into the fireplace opening before the draft drew it up the chimney. The metal surround fastened to the front of the fireplace and made a reasonably tight seal, but I guess some smoke must have leaked causing some staining after 20 years.

 

[brenndatomu]

I'm gonna spread around a great idea that I seen here somewhere. Use a stove pipe trim ring to cover the hole in the block off plate (around the pipe) if it doesn't turn out "pretty" enough for ya

 

[lml999]

I've got everything I need for the blocking plate installation. May end up with some excess Roxul, if anybody is interested (metrowest Boston).

Looking for ideas on how to finish the installation -- I'm going to leave the original surround off, and want to cover the opening with something that lets air through. The big box stores have sheet aluminum with patterns cut, but I'm not sure how I'd finish that (edging).

Thoughts appreciated!

 

[lml999]

Looking for ideas on how to finish the installation -- I'm going to leave the original surround off, and want to cover the opening with something that lets air through. The big box stores have sheet aluminum with patterns cut, but I'm not sure how I'd finish that (edging).

Okay, I think I know what I'm going to do...

I'm going to cut a hole in the original surround and install a metal grate or two in it. (see examples here). I think this will be the easiest, most finished, and least expensive way of providing for more airflow. A minor issue is that the stove is not centered in the fireplace (don't know why), about 3" off center.

 

[weatherguy]

You can make the block off plate out of cardboard (in 2 pieces) then scribe it onto the sheet metal.

 

[lml999]

Well, I made good progress today.

I stuffed Roxul in the chimney cavity and above the stove. I made a template and cut two pieces of sheet metal for a blockoff plate. Sprayed the plate and touched up the stove top.

Tomorrow I will install the plate and fire it up.

Next weekend I'll modify the surround, cutting a hole in the top part and installing a vent grille so it looks finished and passes the hot air from above the stove.

A bit tedious but pretty straightforward. No band aids needed, yet.

Still have some spare Roxul.

 

[lml999]

Just installed the blocking plate. Haven't had an opportunity to fire up the stove yet, but I'm optimistic that I'll get more heat. With just the Roxul and no blocking plate I could tell a difference. Below are a couple of pictures of the plate installed.

Over the weekend I'll modify the cosmetic surround. I'm cutting holes in it above the stove and installing 2 grates for airflow. Pictures to follow.

Then I'll get back to annoying the pine rounds that refuse to split. They're just like my kids...no matter what I say or do, they just sit there.

 

[lml999]

Finished up the installation yesterday. Cut two holes in the cosmetic surround, sanded and refinished it, then installed two grates for air flow. Looks pretty good. Great heat transfer! I'm really pleased with how it came out!

 

[Nick Mystic]

Looks like you're ready for some serious heating! Let us know if you feel much heat finding its way out your new vents.

 

[Hogwildz]

Looks good. Nice job.
If you want an even tighter fit, fill the gaps between the elbow & block off plate with stove door rope gasket material.

 

[jrems]

I used some thick rope gasket around the pipe on my block off plate and it does the trick.

 

[mstoelton]

looks good! Nice Job.

 

[lml999]

Thanks for the comments.

Both my wife and I are pleased with the results.

I haven't bothered to fill the gap between the blockoff plate and the elbow as I have a good amount of Roxul stuffed up above the plate.

I am getting more usable heat from the stove. It's installed at one end of our living room, and at the other end, 6 steps lead to our bedrooms (multilevel style house). We're getting plenty of heat upstairs.

I still have to fabricate a narrow heat shield for the bottom of the mantle. With more heat coming from the stove, I'm concerned that the mantle will get too hot...

I'm also considering insulating the brick fireplace walls. I have some board Roxul to use...but i think I'd want to sandwich it between the brick and some lightweight sheetmetal. The sheetmetal would help reflect the heat forward into the room.