Chimney cap with wire screen?

[Tron]

I guess we'll really need to get a chimney cap with a screen. Those Eastern Bluebirds used to only come in through the chimney during the spring, but now we've already had the 2nd in the fall.
A 3/4" screen would probably keep them out but wouldn't get clogged with creosote, right?
The current cap is a Duravent cap, very likely this one although our invoice doesn't specify, which one exactly:

 

[begreen]

The Duravent cap screen is fairly fine meshed. You might want to change it to a coarser stainless screen that will still do a good job of keeping the birds out. Maybe 3/4" mesh?

 

[Tron]

That's what I'm thinking, yes. I haven't been able to reliably find out what this Duravent's cap screen mesh size is. Some say 1/2", some say 3/4". And their web contact form is broken...

Next problem would be to get someone to install it. The chimney cap is a good 8' above where it transitions the roof, so one would probably need to take down the top section to change the cap.

 

[begreen]

Ours was 1/2", but the wire diameter shrinks the mesh openings to a bit less than 1/2".

 

[Tron]

Ours was 1/2", but the wire diameter shrinks the mesh openings to a bit less than 1/2".

any issues with creosote clogging on that?

 

[begreen]

any issues with creosote clogging on that?

Only when I had an unexpected damp run of fuel.

 

[Tron]

Thanks!
My fuel is so bone-dry, that's rather an academical worry.

 

[DuaeGuttae]

@Tron, I heartily support screened caps in Eastern Bluebird country. I don't know why they are so attracted to chimneys, but they certainly are. I'm very glad for our screen. I'm afraid I don't know what size it is, but I've seen bluebirds make a determined attack on it, and it hasn't ever clogged with creosote on our Blaze King. We've only owned the stove for two winters, though. When we did our last chimney cleaning, I scraped more creosote out from behind the wall shields and above the tubes using a brush than I got soot out of the very long chimney. We burn low most of the time because of our well-insulated house.

 

[Tron]

@DuaeGuttae thank you very much for the insight. Could you perhaps find out which chimney cap you have?
And I absolutely agree with you, it's only the Eastern Bluebirds that find their way into our stove, no other species.
No idea what drives them to do that...

 

[Burnin Since 1991]

I had the same problem with sparrows years ago. I just went to the hardware store and bought hardware cloth. It comes in different sizes, but you cut it to size and wrap around the cap. I took the top cover off of mine. It was removable and wrapped it and it was fine. Cost less than $5 for the hardware cloth. Some hardware stores will cut you what you want and charge you a small charge for it.

I use the same hardware cloth to keep the rabbits out of my garden.

 

[DuaeGuttae]

@DuaeGuttae thank you very much for the insight. Could you perhaps find out which chimney cap you have?
And I absolutely agree with you, it's only the Eastern Bluebirds that find their way into our stove, no other species.
No idea what drives them to do that...

Off the top of my head, I think it's Excel brand rain cap with a "standard" screen added to it. I believe that means 3/4" mesh. It's not a spark arrestor but a wildlife shield. I did have a specific conversation with the installer about it, but that was two and a half years ago now. I'm afraid I'm not on the computer where the house build files are located right now, and I'm not sure if that detail is even included in the paperwork. I can try to get to it later if you'd like me to investigate more.

@Burnin Since 1991 , I had thought about just suggesting adding a hardware cloth wrap to the cap. What I wasn't sure about was how secure it would be added to a cap after the fact if one cleans it from below with a rotary cleaner. How do you clean your pipe and cap, Burnin Since 1991?

@Tron, do you use a Sooteater? I seem to recall that, but I'm not sure.

 

[Highbeam]

any issues with creosote clogging on that?

My original duravent cap at the house came with the optional screen. It was 1/2" like BG posted. Totally plugged up easily with brown, dry, flakey "creosote" when it was above my very low emissions and high flue temp hearthstone heritage noncat. More than once per year and the fuel and operation were always by the book. Clean flue actually cleaner than the BK. It was just that silly filter on the cap.

Screens are an awful idea for a working stove but during the offseason it would be easy to pop one in for bird control and remove once you start burning. Some people throw a 5 gallon bucket over the cap during the off season.

Our duravent caps were literally sold with or without the optional screen. I ordered the one without the screen for the shop stove.

 

[Tron]

Screens are an awful idea for a working stove but during the offseason it would be easy to pop one in for bird control and remove once you start burning.

A great idea in principle, the thing is that my cap sits about 8' above the roof, so I'd have to climb onto the roof, remove the top section of chimney to get to the cap. Nope, not doing that twice a year. So I'm looking for a permanent solution.

I agree that 1/2" mesh is too fine and therefore prone to clogging, whereas 1" is probably not enough to keep the birds out. So 3/4" seems to be the golden middle.

 

[Tron]

do you use a Sooteater?

I do. And yes, that means the screen needs to be fixed to the cap it survives that.
I have the strings of the sooteater about 3-4" longer than the flue's diameter, so once I reach the top it should be able to clean the screen as well.

 

[Burnin Since 1991]

I don't have a good picture of my cap and it's raining now. It looks similar to the first picture. The second picture. shows what it looks like after it is wrapped. Basically I cut the hardware cloth the width between the top and bottom parts of the cap. I used an angle grinder and it took less than 2 minutes to cut it out to what I needed. Then I unscrewed the top cap. Wrapped the hardware cloth around the cap supports and then bent the ends into the under wrapped hardware cloth and secured them. Then I just slipped it over the supports and screwed the cap back on. Once I'm full into burning season, I take the hardware cloth off. I have bluebirds and all sorts of birds all winter long and none of them ever came near the chimney pipe in burning season.

I clean my chimney top down as my woodstove has a secondary burn chamber that prevents access from inside the stove. After I sweep the chimney I remove my stove pipe and clean out the secondary burn chamber since I can't access it from inside the stove. I will probably clean bottom up at some point when climbing a ladder no longer appeals to me. If your access to your cap isn't too crazy, you could wait to just before you're going to start your burning season. Remove the hardware cloth, sweep, clean etc and burn away. If anyone has every had problems with birds trying to build nests in a working chimney, let me know, because I've never experienced that. Also, no spark arrestor requirements here.

 

[Burnin Since 1991]

I agree that 1/2" mesh is too fine and therefore prone to clogging, whereas 1" is probably not enough to keep the birds out. So 3/4" seems to be the golden middle.

agreed

 

[Tron]

If your access to your cap isn't too crazy

It kind of is. Code requires the top of the chimney to be above the roof line, and since the chimney doesn't exit there, it extends about 8' above the 45-degree roof. So kind of difficult to get to the cap.

 

[Highbeam]

It kind of is. Code requires the top of the chimney to be above the roof line, and since the chimney doesn't exit there, it extends about 8' above the 45-degree roof. So kind of difficult to get to the cap.

Which is exactly why you don't want a filter on your cap. You'll be cleaning that in the middle of winter. Sooteater might not be able to clear the funk that forms up there, it could be much different than the dry stuff in your actual insulated flue.

I wonder if there's not something you can lower over the cap from a ladder or the roof without having to actually disassmble your chimney for access. Like a wire trash basket with a hook on top that you can set with a long stick.

Also, I wonder if burning a little fire now might stink up the chimney enough to prevent birds from trying.

 

[Tron]

Hmm, I see your point.
I mean, I totally don't need a screen except for those birds.
But no, getting up there all the time to put something over the chimney and remove it again is not going to work. Here's a picture...
The chimney is pretty much straight up, and AFAIK it's 21-22' or so...

 

[Tron]

Also, I wonder if burning a little fire now might stink up the chimney enough to prevent birds from trying.

True, that might work now, but not over the Summer.

 

[Burnin Since 1991]

True, that might work now, but not over the Summer.

Now that is a roof. Mine is on the roof of a one story family room addition. I wouldn't burn with the wire on the chimney cap. It will definitely clog.

Maybe we're looking at this wrong. I put back the recliner for a moment and pondered. Maybe the solution is to buy or build some nesting boxes as far away from the house as possible?

Blue Bird Nesting Boxes

 

[Highbeam]

True, that might work now, but not over the Summer.

Nice place Tron! We could never have that much chimney sticking up without roof braces here.

Did you start having these bird issues recently just in the fall? Is it like a mating season thing? Burn something stinky every so often in the fall might help.

I don't know but the location of that stack makes maintenance difficult. Whether that maintenance is cleaning the plugged filter or putting up and taking down an off season bird blocker.

The good news is that it's pretty easy to install and remove a filter into your cap so you can always try it. The larger mesh size can only help extend the cleaning interval. You might be surprised how little of a hole they need to worm their little bodies through. The birdhouse making community suggests a hole size of 1.5" for that eastern bluebird. That's already much bigger than the width of the gap between the bars in your screenless cap.

It's not like the roof will be snow covered much. The interwebs say your annual average is 0.6 inches. So walking up there to deal with this isn't as bad.

Have you tried to find 3/4" mesh SS hardware cloth? Maybe expanded metal like what you see in fireplaces with the 3/4" diamonds would work.

 

[Tron]

Nice place Tron! We could never have that much chimney sticking up without roof braces here.

Thanks!
If you look closely, I actually had the roofers (roof was installed this spring because the old shingle one was done after 20 years, but don't ask about the cost...) install a brace near the foot of the chimney. The previous boot was a lot higher than the new one, that's why.

But no, snow is not really an issue, but I still don't want to climb (or have someone climb) up there in the dead of winter to clean the screen.
As you can see, one would need to stand on the roof and take that top section down to access the cap.

We've had the occasional bluebird in the stove ever since we built the chimney in 2020, but usually only a few in the spring. This year they started doing that in the fall, too.

 

[Dieselhead]

Those little guys just love to get themselves into trouble!

 

[Dieselhead]