Expanding foam is a lightweight, waterproof choice to concrete for homeowners wanting to put fence posts. The foam may be used in cold or hot weather and doesn’t require mixing with water or some other fluid. Most expanding foam made for postholes intended for home usage is sold in a self-contained bundle, with each bundle intended for one posthole. The foam is combined in the bag, so there’s little cleanup.
Dig a hole with a spade or shovel into the thickness you wish the set the post and about twice the diameter of the post.
Place the post in the center of the hole. Ensure it’s upright, and brace the post into place using one or two small pieces of wood. Nail the brace in place, but just drive the nail in sufficient to hold the brace so that you may remove it afterwards. You may need somebody that will help you hold the post steady as you add the braces.
Lay out your leaf bag and exhale and wear a pair of vinyl gloves so that you do not receive any wax in your skin. The gloves could be included with the foam wax kit.
Follow the manufacturer’s directions for mixing the leaf. To create the expanding foam, each bag includes two resins. One resin is loose from the outer bag, while the other is contained in a smaller pouch within the outer tote. When you’re prepared to use the foam, then lay the bag flat on the ground, then roll or step on the outer bag to break the inner pouch, permitting the resins to blend. When the inner wax breaks, squeeze each of the resin out of the inner bag.
Squeeze or knead the bag until the resins are thoroughly mixed and the contents of the bag turn a light yellowish-tan color.
Cut off one corner of the bag with scissors. Do this immediately after mixing; do not allow the combined foam to set from the bag.
Squeeze the foam out the corner of the bag and into the posthole. Apply an even amount of foam mix all of the way round the post. The foam will only fill a small segment of the hole, but it is going to extend up to 15 times its original volume.
Wait for the foam to expand and heal prior to touching the post. This may take from three minutes to one hour, based on the brand of foam that you use. The foam will even set narrower in cooler temperatures. Refer to the directions that came with your foam to get the wait period before you’re able to remove the braces and attach the fencing into the post.