What’s the minimun thickness of a reinforced mud bed for floor tiles? I read in John Bridge’s book that it was 3/4″ but the average mud bed is more or less around 1 1/4. What’s the proportion of the mix?
Tom
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Minimum thickness is 3/4" for a floor. It won't have much strength below that. Strength can enhanced by using Ad-Mix (acrylic or latex), using a curing membrane below the slab, using 16 ga. 2x2 wire in the lower third of the mix, although I usually use 3.4 lb diamond lathe nailed to the floor. Damp curing also makes the slab stronger, although you sacrifice some workability.
Inch and 1/4 is fairly standard and is the industry standard for mud beds. Strength can also be increased by doing the above.
I buy Deck Mud at the Moscow DalTile or a masonry supplier in pre-packaged 94 lb (ugh) bags. Only use what I need, never waste over a bag, and always have some extra. Cost is about $4 a bag. Figure on about 10-12 sq feet per bag. Mix is 5-1, sharp sand to portland cement. For walls, add 1/2 part lime, although I buy pre-packaged "Wall Float". Mix very, very dry. Only wet enough to barely dampen the product so that it is no longer a dusty pile but clumps together, about 1.5 gals of liquid to each bag, slightly more for walls and curbs.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927
'Damp curing also makes the slab stronger, although you sacrifice some workability.' Do you mean covering with poly while curing? Why do you sacrifice workability? How long is the curing time? One day?
Thanks, Tom