My turn for Stucco questions.

[asudavew]

I have a mortar dome over my brick and insulation.
It is about 2 inches thick.

1. Do I need to take the 3 layer stucco approach, or would just a finish layer be ok?

2. Also, do I have to paint it to be waterproof or is the finished layer of stucco waterproof?

3. Do I have to add anything specific (I'm going to add color) to the final layer to make it waterproof.

Thanks!!

Dave

[SpringJim]

I'll take a stab at this....let's see what others think...

1) A single layer of stucco finish over the dome is all you need!

2) A cement/sand stucco mixture should shed water (unless it cracks) but....
Some form of treatment may be advisable ( I recently sealed some old terracotta steps with some kind of silicone sealer, went on a lot like water).

KISS

By the way, I had some perlcrete left over from my hearth insulation layer and it worked well filling holes in my hearth stand. I called it perlite stucco....it has set up very firmly!

[Ken524]

James, If you happen to be monitoring this thread:

I'm about to ask the same stucco questions as Dave.

I think it would be useful to have an official "Stucco How-To" thread stickied near the top of the "Design Styles, Chimneys and Finish" or "Building and Construction" forum (or some other appropriate forum).

The thread could include a consensus on how to do a stucco finish on a dome and also stucco on concrete block and Hardibacker.

Maybe we could have a discussion thread first, reach a consensus then let James or someone rewrite it and post it as a sticky.

What do you guys think??

[RTflorida]

Agreed

There should be a sticky on this topic. I'd be curious to know (from an exerienced pro) the differences in the various products. We all have heard of the 2 (some folks even do 3) step process. What about the single step products that are out there. Lowes & HD sell several variations of "stucco" here in FL; to the average WFO builder this could be a bit confusing - which one do I use? Is any one product or process that much better than the others??? Seems to me, the single coat stucco may simply be a rebagged Type N or S mortar....I don't know. Anyone have any practical knowledge of the products??? I'm pretty confident in my knowledge of the processes - I have seen many stucco jobs being done and the techniques used....it is the products that I would like some clarity on.

RT

[Jed]

And now that I have installed my version of stucco, and it didn't work out quite right, are there any fixes? ie: the spider web cracking shown in the attached picture... Will a 'fog coat' fill in these cracks and seal up the exterior? Or are these marks of character to take to the grave?

I can advise on one way that doesn't work so great!

JED

PS: this is a two coat installation. Perlcrete, then stucco, I was trying for a 5/8 inch thick layer scratch coat, then the top coat 3/8 inch with color... (and cracks). The cracks were developing as the stucco dried, within the first couple of hours of placing the stucco. Maybe I used an inappropriate 'stucco' mix? Probably... and my plan is to let all the concrete and stucco cure through the summer and then coat the whole bit with a concrete sealer to help shed water.

[david s]

I've been experimenting with adding fibre (polypropolene) to my stucco mix to minimize cracking and maximise strength. Also the cement manufacturers recommend that each subsequent layer of render should be weaker ie less cement. Also lime is more elastic than portland cement. I think that any waterproof coating should be left until the oven is really dry (say 10 cooking firings) because you want to get rid of all the moisture first and a waterproof coating on the outside may have the effect of locking moisture in.

[SpringJim]

A sticky or primer is a good idea?

What are the issues?

1) Stucco mix options
2) Number of layers to apply
3) Reinforcement options
4) How long to wait before applying
5) Application methodology
6) Preventing cracking
7) Various finishing techniques and designs
8) Curing
8) Painting or sealing options

what else??

...by the way, I added a little extra portland to my 12:1 perlite mix and that perlite stucco set up pretty hard.

[Frances]

What the bloody stuff is called in various different parts of the world! (pardon my French)

Btw Jed... if you can find a way of keeping the water out... I think it looks really cool with those cracks! Instant antique oven.

[asudavew]

Well I gave it a go.

I decided to go with one layer.

Home Depot had Finishing Stucco in 80lb bags, which had directions on the back.

The directions sad to add an acrylic...something or other (I can't remember the name.) to aid in waterproofing. It's a liquid and I found a 1 gallon bottle. I added 2 quarts to the bag of stucco, per the directions. I also added 5 oz. of "Buff" coloring.

I feel like George right now. Buff is supposed to be a light copper color.
But I think I added toooooooooooooooo much!!!

I'll have to call it my pumpkin oven.

Here ya go!

[rlf5]

Wow you didn't waste any time! Good job!

Originally Posted by asudavew

Well I gave it a go.

I decided to go with one layer.

Home Depot had Finishing Stucco in 80lb bags, which had directions on the back.

The directions sad to add an acrylic...something or other (I can't remember the name.) to aid in waterproofing. It's a liquid and I found a 1 gallon bottle. I added 2 quarts to the bag of stucco, per the directions. I also added 5 oz. of "Buff" coloring.

I feel like George right now. Buff is supposed to be a light copper color.
But I think I added toooooooooooooooo much!!!

I'll have to call it my pumpkin oven.

Here ya go!