Bond vs. waterproof additive in mortar: which is actually better for retaining walls?

I built a retaining wall about 3 years ago using just standard type S mortar and it's already cracking. A buddy of mine used a polymer bond additive on a similar wall 5 years ago and his looks perfect still. But another old timer told me those additives just make the mix weaker over time and you should focus on drainage instead. So which is it, does the additive actually help or is it just a bandaid for bad prep? Anyone here done a side by side test on their own jobs?

3 comments

3 Comments

margaret30420d agoMost Upvoted

The real test is freeze-thaw cycles, not just strength. Additives can trap moisture inside the block and cause spalling long before the mortar itself fails.

casey1620d ago

Did you catch that study out of Maine a few years back? They tested like 50 different block mixes over 3 winters. Stuff with calcium chloride additives was crumbling after just 2 freeze-thaw cycles. Regular plain concrete blocks held up fine for years. Kinda scary what some cheap shortcut can do to a whole wall.

tyler619d ago

@casey16 saw that same study. Pretty wild how fast some of those mixes failed.