We recently ripped out our deck because it was rotted and laid a level of cinder blocks 10ft x 32in for a small patio, basically just a step for coming out the back door. I was just wondering if I could use mortar the better level at a slight angle and maybe cover with polyurethane.

  • The word sand should be and. Also, one more question. How long does it take for mortar to set? – Danella Feb 19 '18 at 14:04
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    You can use a mortar base but I would probably get a few bags of sackcrete and make a bed for your blocks, sackcrete will be stronger than mortar with the same thickness because of the rock it binds to the cement and sand, mortar only has sand not as strong. – Ed Beal Feb 19 '18 at 14:52
  • Do you have winter where your patio is? If so, you will need much more of a base, or it will not last (remain level) through a winter. – Ecnerwal Feb 19 '18 at 15:40

No. Mortar isn't designed to carry span loads, and your block patio will almost certainly sag and settle, meaning your mortar will disintegrate in short order. Proper concrete would even need to be poured at a thickness adequate to span gaps, say 3".

To my knowledge, polyurethane isn't an appropriate masonry sealer. There are other products for that purpose.

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