Wasted $150 on those pre-mixed concrete bags for posts

I tried using the quick-set concrete bags from Lowe's for six fence posts last month in Springfield. Turned out they don't cure right in wet soil and three of my posts shifted after two weeks. Had to dig them out and redo everything with actual gravel mix and postcrete. Anyone else had bad luck with those bags or was it just me?

2 comments

2 Comments

michaelw2610d ago

Man, that sucks big time. I think a lot of people get burned by those premix bags because the instructions make it look too easy but they don't warn you about drainage. I switched to something similar, mixing my own Portland cement with gravel and sand from a local yard, and it set up way stronger even in our clay soil here. Did you have to rent a jackhammer to get the old posts out or just dig around them?

angela_kelly10d ago

Actually, Portland cement is just one part of that mix. Portland cement is the powder that hardens when wet, but you need coarse aggregate like gravel to give it body and sand to fill the gaps. If you're just using Portland cement with sand and calling it concrete, it'll be weak and prone to cracking. Technically what you described is a mortar mix, not a concrete mix for fence posts. You really need the gravel in there to handle the ground movement and weight. I learned that the hard way when my first batch of DIY posts crumbled after one winter.