Any problem using just sand to set floor

[mooch]

I am building a 42" pompeii. Using 2"fb board. I cant seem to get the fireclay/sand/water mixture right to trowel well. Using just masons sand seems to work well. Any reason not to do this?

[brickie in oz]

Re: Any problem using just sand to set floor

I cant see any problems in doing so.

[Faith In Virginia]

Re: Any problem using just sand to set floor

My thoughts on the subject, is the fireclay in the mixture acts as a binding and setting agent. So when you use your notched trowel to lay down your mixture of sand, fireclay, water when you set your floor block and level out the bricks there will be sections and areas that there will be a space between the trowel lines. The amount of squish to the lines is the adjustment factor to get your floor bricks even. So once you get the floor even the mixture dries out and becomes firm because of the fireclay.

I suppose you could just use sand but I think it would be more difficult to set. I imagine you would need to set it like cobble stone. That would require more thumping the top of the block to get it to level out. You will need just the right amount of sand under each brick. Then while your beating down and edge of one brick the other bricks also re settle because your on insulation board and every thing is feeling the vibration.

You can always give it a try and if it does not give you the results you want it would be easy enough to re-do.

Good luck let us know how it goes.

[mooch]

Re: Any problem using just sand to set floor

maybe I need to make my sand/fireclay mixture wetter and it would trowel better. I have done a lot of tiling and have no trouble with thinset but I am having trouble getting this to trowel on, it just slides off of the fb board.

[Gulf]

Re: Any problem using just sand to set floor

I believe that I have read a thread or two where just dry fireclay has been used sucessfully.

[azatty]

Re: Any problem using just sand to set floor

It doesn't have to stick per se. It's only a leveling compound, so it works wet or dry. Sometimes a wet mixture is the culprit--the top layer of board seems to peel off easily if the mortar is too wet.

[Mistertoy]

Re: Any problem using just sand to set floor

I had trouble using a wet mix as per plans as well because the insulating board "sucked" up the moisture so quickly.

I ended up using a dry mix of sand and fireclay instead. It seemed to work fine to level up the floor bricks. Even though I haven't finished the oven yet, I can't image any issue as it has to dry out anyway.

Brett

[dvm]

Re: Any problem using just sand to set floor

maybe I need to make my sand/fireclay mixture wetter and it would trowel better. I have done a lot of tiling and have no trouble with thinset but I am having trouble getting this to trowel on, it just slides off of the fb board.

I had the same problem (maybe my sand was too coarse?). I ended up drying the sand / brick trimming mixture out, "screeding it level, then placing the bricks and tapping them flat. It took several attempts and most of one day which was frustrating since I really wanted to be mixing mortar! Good luck and be patient.

dvm

[texman]

Re: Any problem using just sand to set floor

Mix the sand and fireclay dry and spread it on the FB board dry. Use a straight board as a screed and set two boards as guides to leave just enough sand/fireclay to fill the FB imperfections and have a level surface across. Make sure you completely cover the Fb board and have at least an1/8" of mix even in the highest spots on the FB board so you have some room to level the floor bricks with tapping. The bricks are not perfect. Slide the screed side to side and let the excess fall off and throw more in the voids as you screed until you like it. I wouldn't use water, just makes a mess. If you want it slightly sticky, use a hand spray bottle and mist water after it is level to hold it in place.
I used the FB board as well. It is good stuff, but can be tricky if it is warped and/or has variation in thickness as mine did. All you are trying to do is get the floor level. HTH
Texman

[spinal tap]

Re: Any problem using just sand to set floor

Besides cost, is there a downside to using the FB mortar (dry) as the leveling agent?

Nate