DIY Crown

[Smoked]

If someone wanted to do a DIY chimney crown, what is the right cement mix?

 

[weatherguy]

Mines portland

 

[bholler]

2 sand 2 stone 1 portland with acrylic modifier and fiber reinforcement.

 

[Easy Livin’ 3000]

2 sand 2 stone 1 portland with acrylic modifier and fiber reinforcement.

Is that sold pre-mixed?

 

[bholler]

Is that sold pre-mixed?

I have no idea what is in the premixed stuff which is why i wont use it

 

[Smoked]

I have no idea what is in the premixed stuff which is why i wont use it

What is on mine currently and deteriorating badly just looks like play sand and cement. Don't know the right term but what size stone? Thanks for the reply too!

 

[bholler]

What is on mine currently and deteriorating badly just looks like play sand and cement. Don't know the right term but what size stone? Thanks for the reply too!

Well what type of crown will you be doing?

 

[Smoked]

Well what type of crown will you be doing?

It is a brick chimney with 2 terracotta/w/stainless liners. The clay liners probably only extend about 3 inches above the top brick layer. Most of that is currently covered by the crumpling existing crown.

 

[bholler]

It is a brick chimney with 2 terracotta/w/stainless liners. The clay liners probably only extend about 3 inches above the top brick layer. Most of that is currently covered by the crumpling existing crown.

Yes but are you going to do it right and build a form and pour an over hanging slab of just another wash crown?

 

[Smoked]

Yes but are you going to do it right and build a form and pour an over hanging slab of just another wash crown?

Awe snap, I knew I was over my head. You guys have taught me to do stuff right, of course I want to do it right. But now I have to understand this overhanging thing Splain please

 

[bholler]

It is best to build a form so your crown will over hang the chimney by about 1.5" or so. You also want a bond break between the top of the chimney and the crown as well as around the clay liners. We usually make them about 4" thick but they can be a little thinner.

 

[Smoked]

I think I can do this! Summer project on the list Thanks sir!

 

[weatherguy]

Look it up on you tube, I came across one the other night when I was looking for something else.

 

[bholler]

Look it up on you tube, I came across one the other night when I was looking for something else.

Yeah someone posted a good youtube vid of pouring a crown a while ago. Just be careful there is some really bad info there too.

 

[webby3650]

I did mine a few years back. It's a lot of work!

 

[bholler]

I did one this mourning and one yesterday. With this weather we got an early start on masonry repairs this year

 

[Smoked]

Thanks guys! I looked at some videos. Not real fond of being on the roof but at least my chimney is right at the peak and only about 3 feet above it. It does seem like a lot of work but I think it is something I will try! I need to get up there and make some measurements. What I have up there is thin do demo should be easy. The terracotta does not stick up very far so getting something thick enough and still having a decent slope might be tuff. The tape will tell though.

 

[bholler]

Thanks guys! I looked at some videos. Not real fond of being on the roof but at least my chimney is right at the peak and only about 3 feet above it. It does seem like a lot of work but I think it is something I will try! I need to get up there and make some measurements. What I have up there is thin do demo should be easy. The terracotta does not stick up very far so getting something thick enough and still having a decent slope might be tuff. The tape will tell though.

you can always just add a piece of terracotta

 

[Smoked]

I took this photo in mid Jan but it is relevant here because it shows the step-out and then step-in on the upper layers of brick...that until this evening had not even figured into the equation. So on chimneys like this, do you attempt to make the crown broad enough to cast a shadow on the widest part or do you just go the 1.5 inches on top and take what you can get? Well photo won't post and I shrunk it to less than 1 MB. Anyway, you may get the idea?

 

[begreen]

Well photo won't post and I shrunk it to less than 1 MB. Anyway, you may get the idea?

shrink the picture to less than 1200 pixels in the maximum dimension, 72dpi.

 

[Smoked]

Ok there is a baby version!!

 

[begreen]

Great, that works. Looks like there is a lot of white space on the right and bottom that is increasing the size.

 

[Smoked]

Great, that works. Looks like there is a lot of white space on the right and bottom that is increasing the size.

Day job...computers, hate them

 

[begreen]

OK, I fixed it for you.

 

[bholler]

For chimneys like that i typically take off the top 2 courses that corbel back in and pour the crown on top of that other wise it looks silly. If the customer does not want that I will do a wash crown. I will not pour an over hanging slab on a corbeled chimney like yours as is though.