Topping Slab for Mat Foundation
Topping Slab for Mat Foundation
(OP)
Hi All,
I'm designing a mat foundation with a 5" topping slab. The topping slab is added so the architect can depress the finish elevation for walk-off mats and restroom tiles, and also coloring the topping slab w/o coloring the entire mat.
My question is: Should the topping slab be poured directly on the mat foundation, or should there be a slip plane between the two, so the topping slab can shrink as it cures.
If the topping slab is poured directly on the mat, should I provide more contraction joints than the typical 15ft spacing I use for slab-on-grade?
Thanks in advance,
SMWA
I'm designing a mat foundation with a 5" topping slab. The topping slab is added so the architect can depress the finish elevation for walk-off mats and restroom tiles, and also coloring the topping slab w/o coloring the entire mat.
My question is: Should the topping slab be poured directly on the mat foundation, or should there be a slip plane between the two, so the topping slab can shrink as it cures.
If the topping slab is poured directly on the mat, should I provide more contraction joints than the typical 15ft spacing I use for slab-on-grade?
Thanks in advance,
SMWA





RE: Topping Slab for Mat Foundation
RE: Topping Slab for Mat Foundation
SMWA
RE: Topping Slab for Mat Foundation
I'm not knowledgeable about vapor transmission, but would consult with someone who is before you sandwich the mat between two impervious surfaces.
RE: Topping Slab for Mat Foundation
Sorry, I meant 10 mil vapor barrier.
I guess the vapor barrier under the mat slab is unnecessary if there is a vapor barrier between the topping slab & the mat. Would there be any reason to have a vapor barrier under the mat?
Thanks,
SMWA
RE: Topping Slab for Mat Foundation
RE: Topping Slab for Mat Foundation