Do-it-yourselfers can expect to use about a bag and a half to two bags of quick setting concrete per hole. This assumes that the fence holes are three feet deep and dug as follows:
The perfect posthole
The Fence-All standard calls for the concrete in post holes to stop three to six inches below ground level Sunlight damages concrete, and this damage is most pronounced immediately after the concrete is poured. Heat and radiation from the sun cause a premature evaporation of the moisture in the mix that weakens the binding agents in the cement.
Covering the concrete with a shallow layer of soil gives it a chance to bind properly while it cures.
Is it bad for the posts?
No. All wood products are susceptible to rot and wear. If the fence is outside–as it usually is–every exposed facet will do battle with the elements on a daily basis. The thin layer of soil above the concrete, in our long experience, doesn’t cause any addition problems in this regard.
If you have more questions about cement or other subjects we’re happy to answer them. Call 613-736-1122 or hit the chat button on the right during business hours.