Started the Process - A couple of Questions

[George T]

Thanks for all the help.....regarding the hearth. I am assuming you pour the concrete first and then the insulating slab. Is it hard to get the vermiculite portland mixture smooth enough for the fire brick to sit on?

If you order the FB board how long does it take to get?

Also I have a tile saw with a 7.5 inch blade. Will that cut the firebrick? Or do you need a 10"?

Tomorrow we build the stand.

[RTflorida]

George, I did not find the vermiculete difficult to work with...even hardened the heavy grained, high clumps were easy to scrape away. I confess to using a wetter slurry coat of heatstop mortar to smooth it out a bit further, don't know if it help much...all in all my hearth bricks came out pretty flat; I think my biggest problem was the size/shape variance of my firebrick (wire cut) - no two bricks were the exact same size.

As for the saw, go for the 10", it will cut through firebrick in one pass; with the 7.5" you will have to flip your bricks over to finish your cuts. The 10" saw from Harbor Freight is a verry reasonably priced workhorse for this task. I got mine just over a year ago on sale for $199 plus $29 for the blade...it works like a champ. Not sure of today's price - may be $229-$249 if not on sale.

RT

[PizzaJNKY]

George, the insulating slab goes on top of the structural slab. I made my insulating slab with portland cement and perlite instead of vermiculite, but my guess is they are very similar to work with. I wouldn't worry too much about getting it smooth, I think level is more important. As for the FB boards, mine were delivered within two days of ordering them.

For the tile saw, I concur with RT Florida. The 10" Harbor Freight saw is hard to beat. I bought mine two months ago for $199.

[DrakeRemoray]

I used a 7" saw it can be done...If I had to do it again I would get the 10"...makes life much easier.

[Frances]

I actually got quite attached to my 7" angle grinder during the build... made it all a bit more of callenge

[dmun]

With the seven inch saw it's either cut-and-break, or flip and cut twice. A 10 inch saw makes life easier, no doubt, especially when it gets to any fancy fitting. I have both, (and a 4.5" cheap angle grinder) and I never touch the 7" saw anymore.

Again - the table saw like model throws stuff up in your face. Most disagreeable.

The roughness of the vermiculite layer was the original reason for a slurry (now used as a dry powder layer) of fireclay and sand under the floor: You can get the floor bricks to lay flat.

[George T]

You guys are amazing. Thanks for the insights. If I use the board I dont use the vermiculite/portland mix right?

PS. do you guys ever sleep?

[RTflorida]

Never!!!!!!!!

[asudavew]

Originally Posted by DrakeRemoray

I used a 7" saw it can be done...If I had to do it again I would get the 10"...makes life much easier.

I agree with Drake. I used a small saw too.



The mixture wasn't bad to work with at all.

But I topped mine with about a 1/2 inch of high heat mortar.

Here's a picture. You can see the layer on top.

[George T]

Got the stand finished. And a start on the fireplace structure.....all for today. This afternoon and tomorrow hope to pour the hearth. If I am going to use the FB board, no vermiculite.....correct?

Pictures.
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