Rocko's Build Log

[Gulf]

Rocko,

I'm not trying to gang up on you. I'm just curious about having to replace the septic tank in order to get the oven approved?

[Rocko Bonaparte]

Rocko,

I'm not trying to gang up on you. I'm just curious about having to replace the septic tank in order to get the oven approved?

The property did not have an existing septic tank plan on file, so for all they knew, I was trying to pave over my drainage field and shove fence posts into the tank. We anecdotally knew where the plan was, and it might have been possible to get a variance if we could have gotten the existing one surveyed. However, that tank was from 1971, had tree roots in it, and was a miracle it even worked at all. We had earmarked some money when we bought this property to replace it. We were not really bothered by it, although I probably should have been in retrospect. It took six months to go through the motions to get this all approved, and all they ever actually cared about was the septic plan. I had hired a septic planner that had previously worked in the county permit office to take care of business there. He was able to answer questions about the rest of my plan so I didn't commit any fouls with my concrete pad, fence, or outdoor kitchen.

Heck, my sink for the outdoor kitchen is going to dump out into the yard, and the county specifically saw that and were, "Meh."

We had the notion to get a permit because this house is on the corner with a highway, if you haven't figured it out. The neighbors on my side of the street have been totally fine with everything, but somebody could have called a foul on us. Besides that, the inspectors do just drive around and catch stuff, and this work would have been very visible over a long time. So we covered our butts. My issues have been with the people in the subdivision across the highway, behind a stone wall, possibly in a section that is actually gated off.

If I had known this in advance, I would have put off my sabbatical while I got that permit churned on, lined up my concrete guys, and gotten all my stuff under control so I could have just banged it out during the day. I had two months of paid vacation. I can't say I wasted it because I sure needed that time off haha.

[Gulf]

Dadgum,............................. I'm glad I live out in the sticks!.

[Rocko Bonaparte]

Last night I was thinking of trying to nail down the front entrance but I ran out of time. Hurricane Harvey is coming in and I got the call for doing some shelter stuff. It's going to be raining tonight through the whole weekend anyways.

My front door frame has some peculiar mount points for bolting it in. Given the weight of the door, I am trying to use these. Unfortunately, the top two would go right at the side of the bricks if I were laying them conventionally. So for that section, I am turning the bricks 90 degrees. I hope it works out.

I have an 8" stainless steel flue to mount on top of this. The plate itself is about a foot wide. Should I be looking into laying up a course of bricks or two or can I basically pop that in on top?

[Rocko Bonaparte]

Does anybody have any good tricks to wrap a dome in perlcrete? It's a tough shape to get started and perlcrete doesn't entirely want to stay put.

[david s]

I've mixed and placed tons of this stuff and that's a lot as it's so light. The trick is getting the mix nice and workable. I've found that a 50/50 mix of perlite and vermiculite works better than either of them alone. Also getting the correct amount of water in the mix is important. Usually for every 10 parts of perlite you'll need 3 parts of water, but this varies depending on the grade of material used, so just add the water until it just starts to pool in the bottom of your barrow. Too much water washes the cement off the grains of perlite/vermiculite. I use 10 parts perlite/vermiculite to 1 part cement which is pretty lean, but more cement reduces the mixes insulating capacity. For every litre of cement added I also add a handful of powdered clay which helps improve workability a lot. Skip the mixer as the stuff sticks to the blades and mixer sides too much, as well as the problem of abrading the grains of perlite or vermiculite if mixed too long. Mixed gently in a barrow is far better. Mix dry ingredients well before adding water. Lumps formed during mixing can be flattened out with the back of your mixing spade. Start at the base of the dome, Placing the stuff by hand (wear rubber gloves) press and hold, going all the way around and leave a ledge at the top to take the next layer. As this first layer is standing vertically, it is the hardest to do. You can do this about 6" high and leave it overnight to harden so you'll have a more solid base to work over the next day. It also gives you some experience in mixing and placing the stuff so you'll be more confident the second time. The hardened mix can be easily carved away if needed. After placement you can get a remarkably even and accurate hemisphere by tapping the stuff with the flat of your trowel and eyeballing the profile, although some folk have made elaborate templates for getting a perfect form, something I've not tried as it seems like a lot of work.
Hope this helps.

[Rocko Bonaparte]

That's a lot of practical knowledge. I think I can get some vermiculite but I think I'd have way to much extra if I went 50/50; it might be more like 75/25 or 60/40. I do have some clay left, and I also have most of a bag of HeatStop cement left. So I should be able to put something together based on that.

I used the mixer for my oven floor and got better results than when I used a wheelbarrow on my first oven years ago. Well, my first batch of that was horrible because I had undermixed and gotten a puddle with some loose perlite on it. I figured out afterwards to get the water and cement mixed first and then try to do the perlite. The mixer was doing a surprisingly good job of keeping loose particles in check and was very consistent once I figured out those intricacies. The wheelbarrow attempt was definitely over mixed and very compact. The mixer yielded something more like what I see in other people's pictures.

I originally planned to start on this over the weekend, but I got tugged into helping at the hurricane shelter some more, and then I got sick. Hopefully that'll all stop soon and I can put the finishing touches on it.

There's another problem. This door I had ordered has a frame that is already showing a little rust. I was thinking of getting grill paint, taping off around it, and giving it a zap. Sound about right?

[Rocko Bonaparte]

It looks like my ratio will end up actually being about 50/50 after I recalculated and looked at what I actually had.

For the base, I actually suspended some of the lath as a kind of form I could dump the mix into. Now that I can starting to slant it up the dome, I can start to dump it free-form. The only issue is the front, which has to be flat and plush. I figured out I had some scrap plywood I could cut in the shape of the facade that should do the deed.

I did screw up the mix originally by using even less cement than a 1:8 mixture. I suspect I was anywhere from 1:12 to 1:16. It says something about adding a little clay and mixing perlite with vermiculite that it was hard for me to tell. It was only after I went through a bag of each that I realized I think I only used half the cement I should have used. This was just for one layer at the bottom so I am kind of hoping that it'll be fine with the rest of the wet mix seeping in on top of it and the final stucco coat.

I have a new problem to deal with. The door I got is just ever-so-crooked. It looks like in retrospect that the frame is mounted well, but the door itself mounts just a tad crooked on its hinges. It didn't bother me but my wife made a beeline to it. I can't readily remount the frame just a little bit rotated since I drilled into the bricks to make it work in the first place. I don't think the HeatStop has enough strength to hold up this door over the long term so I want to anchor it. I was thinking I could try to do the rotation with the existing holes, shove some HeatStop in the holes, and have that firm up around the bolts. I'm too afraid to try it though.

I asked my wife what finish to aim for in the short term and she's fine with just acrylic stucco. We have to pick a color.

Am I okay in thinking that the oven is generally going to be ready-to-use 2 weeks after the base stucco coat? I'm aiming for about a half inch of stucco on the lath. I understand the base is still slightly permeable and I would have to recalculate if the oven got absolutely drenched, but I'm assuming I can start to consider myself in the 2-week cure window when I have put that on. I know after the acrylic is on that I'm definitely there.

[Rocko Bonaparte]

This thing is eating up insulation. I calculated I needed something like 27-31 cubic feet. With that, I got up almost to the top of the brickwork of the dome and a bit of the front. It's more than half-way done, but not too much.

I am also paranoid that the place I got vermiculite from was messing with me. I understand this stuff settles, but it was more than halfway down the bag. The bags are sturdier than the perlite sacks, but are sown together with string on top. I know another place that sells this exact brand so I will see what their bags are like. I also wound up running out of vermiculate before my perlite. I had equal bags when I began.

[Amusinglisa]

Rocko - we are in similar places n our builds, so I am posting here to keep an eye on your progress. I found your thread when I was looking up the whole perlcrete concept == I was pretty sure there would be somewhere someone was laughing at the concept of someone trying to make it work, but the details from david s (thanks, david) are a huge help.
HOpe your oven goes well in the finish!

[Rocko Bonaparte]

Perlcrete seems to be the in-vogue thing in Austin for insulating. 100% perlite perlcrete worked fine on the floor with inexperienced mixing because I was just plopping it out in a form, but the vermiculite does appear to help hold it up. I did however make one or two wet mixes after dark and they were horrible. It just wanted to run down everything. My old saving grace was that I have built up the oven enough that I can start to cup the wet stuff if I have enough regular mix to make a little bit of a wall on the outside.

I got more materials last night, but did not get home until 11PM so I couldn't play with it. I hope to take care of the last hard parts tonight and even potentially finish the insulation. I am putting the insulation up to an inch from the front, but not plush, so I have to cut something like a form to make the front insulation plumb. I'm recessing because I need that room to stucco and tile to make it plush.

[Rocko Bonaparte]

"Yaaaay! I have the base stucco on and now I just have to put the finish on. It should only take a few hours this week. In two weeks I can use the oven!"

RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN RAIN

[Martin Mikush]

I did the perlcrete base layer overnight.

The outer frame looks crooked and it is in the front, but the inner frame supports everything correctly.

I went for a 1:8 perlcrete mix augmented with some stucco reinforcing fibers and a quick spurt of dish soap. The dish soap thing was based on a tangent from: http://www.perlite.com/concretemixdesigns.PDF

They recommended an air entraining agent, but I was using type I cement rather than IA so I tried to look up what to do. Apparently the poor man's solution is to use a teaspoon of dish soap. I guess the normal reason to use an air entraining agent is to survive freeze-thaw cycles in Yankeeland. That's not really my problem, but the goal in this case is to maintain some porosity and keep the insulative value high.

T

here is the link to the document above :
http://perlite.com/public_html/broch...ix-designs.pdf

[Rocko Bonaparte]

If I finished the brickwork around a month ago, the perlcrete insulation about two weeks ago, and the stucco a week ago, do I have another week to wait on curing? I recall the rule of thumb of two weeks, but my finish was so spread out that I'm wondering if it's pretty much just there already.

[Gulf]

Rocko,

Do, you have blanket between the brick and the perlcrete?