Perilite concrete not setting up--normal?

[DrakeRemoray]

Re: Perilite concrete not setting up--normal?

I agree with the coments from Elizabeth and Neil. I am concerned about the insulating properties of the layer you have created. If I were you I would either scrape it off and start again, or spring for some insulating board. This is an area that is pretty much impossible to correct after construction, so better to err on the side of caution...

Drake

[drogers]

Re: Perilite concrete not setting up--normal?

Whether you used concrete or cement, the same amount of solids exist within the mix as long as the ratio is the same, and the same amount of perlite exists.

[fxpose]

Re: Perilite concrete not setting up--normal?

Whether you used concrete or cement, the same amount of solids exist within the mix as long as the ratio is the same, and the same amount of perlite exists.

Although the ratio of perlite used is the same, 5 parts perlite / 1 part concrete contain large amounts of solids/aggregates which can negatively affect insulating properties compared to 5 perlite / 1 portland cement.

[Derkp]

Re: Perilite concrete not setting up--normal?

In regards to the 5/1 perlite cement, when mixed should it be the same consistency as if I was pouring a sidewalk or patio?

[Tscarborough]

Re: Perilite concrete not setting up--normal?

More like cottage cheese.

[Derkp]

Re: Perilite concrete not setting up--normal?

What is the consistency of the fireclay/sand mixture under the firebrick floor?
Ratio of sand to fireclay?

[Tscarborough]

Re: Perilite concrete not setting up--normal?

It is just a leveling bed, so I used regular mortar between peanut butter and heavy pancake batter.

[Derkp]

Re: Perilite concrete not setting up--normal?

My back wall 1st & second arches, oven arches all rest on the edge of my firebrick floor.

Do you mortar the joint between the floor and first course or let it float on the floor?

[Derkp]

Re: Perilite concrete not setting up--normal?

No fireclay in the leveling bed, correct? Just mortar.

[Tscarborough]

Re: Perilite concrete not setting up--normal?

Yes, there is no direct flame to the setting bed and even if it cracks it won't matter. I mortared, some float it.

[dmun]

Re: Perilite concrete not setting up--normal?

when mixed should it be the same consistency as if I was pouring a sidewalk or patio?

It's nothing like regular concrete, it won't flow, it won't float a smooth surface, and it takes days and days for it to get anything like hard. It never gets much more rigid than cork. You mostly want just enough water so there's not any sitting at the bottom of the mixing tub. The vermiculite/perlite absorbs a LOT of water. Everyone who works with it remarks how weird it is.

[dmun]

Re: Perilite concrete not setting up--normal?

What is the consistency of the fireclay/sand mixture under the firebrick floor?
Ratio of sand to fireclay?

You can do it one of two ways. The ratio is 50/50 for both. You can mix up the leveling mixture with water to the consistency of quickset, and put it on with a notched trowel, like you were laying floor tile. The notches let you push some bricks lower for floor leveling. Alternately, you can put the mixture down dry, arrange your floor bricks the way you want them, then wet the floor to solidify the leveling mixture. Both ways work fine.

There's no real need to mortar down your floor bricks. It makes it difficult if one is damaged and needs replacement.

[Tscarborough]

Re: Perilite concrete not setting up--normal?

The need and the reason is to get a perfectly level floor. I also do not recommend doing the dry set then wet method, if you are going to use a hydrated cementious mortar, vigorous mixing is required, not optional.

[BarryKeith]

Re: Perilite concrete not setting up--normal?

Well thank you all for your advise, I am going the safe route and tearing out the old and relaying a new vermiculite to "cement" mixture. Question so I don't have to tear out another one, do I just add 5 parts vermiculite to 1 part cement? Do I add anything else?

Also with the homemade mortar is it 1 part fire clay to 3 parts sand to 1 part lime to 1 part portland cement? It is portland cement and not a mortar mix?.?

I feel dumb asking, but not as dumb as I felt ripping out the old.

[egalecki]

Re: Perilite concrete not setting up--normal?

The homebrew recipe is in the plans online- I can't remember it offhand. And yes, it's portland cement, not a mortar mix.

I'm sorry you had to take it out, but it's best to be right from the ground up, much easier to fix it now than be sorry later....