Foam for Fence Posts

Discussion in 'Workshop and Home Improvement' started by 45Kevin, Aug 9, 2018 at 4:39 PM.

  1. 45Kevin

    45Kevin

    Messages:
    2,320
    Likes Received:
    800
    Joined:
    May 10, 2005
    Location:
    Calgary, Alberta
    My neighbour used this product instead of concrete to set his fence posts several years ago. The 25' long, 6' high fence is still straight and solid.

    So I thought I'd try it on a couple of posts that needed replacing in my yard.

    The package advertises that one pack can do two 4x4 posts.

    In theory.

    I mixed the two parts together for the suggested 20 seconds and the bag got hot and swelled up so when I opened the corner it streamed out like a shook up beer. All over the ground and trees and plants. I managed to get enough in post hole only.

    I got a second package for the remaining post and it worked out great. I didn't mix it as long and as soon as the pack started getting warm I cut the corner and poured it in to the hole. It was too much and I had to trim the mushroom off so to speak.

    Seems like a good substitute to concrete. Same or less price. Lots less work. Sets in a 1/2 hour.

    Your posts have to be set exactly as you want them because there is literally only a few seconds before the foam starts to set and adjusting the post becomes impossible without ruining the foam.


    20180808_182451.jpg

    20180807_201806.jpg

    20180808_183049_001.jpg

    20180808_192127.jpg
     
    Njck22 and 76FJ40 like this.
  2. PAToyota

    PAToyota Keystone Cruisers SILVER Star

    Messages:
    1,500
    Likes Received:
    416
    Joined:
    Oct 4, 2009
    Location:
    South Central Pennsylvania
    I've seen some demonstrations of foam being used to stabilize soil or fill in sinkholes. Unlike concrete, it doesn't add to the weight (potentially causing more settlement) and can be easily dug through in the future.
     
  3. 45Kevin

    45Kevin

    Messages:
    2,320
    Likes Received:
    800
    Joined:
    May 10, 2005
    Location:
    Calgary, Alberta
    This product specifically mentioned that it should not be used in that manner.
     
  4. PAToyota

    PAToyota Keystone Cruisers SILVER Star

    Messages:
    1,500
    Likes Received:
    416
    Joined:
    Oct 4, 2009
    Location:
    South Central Pennsylvania
    I was just commenting that foam products are replacing similar cementitious products.
     
  5. LS1FJ40

    LS1FJ40 GOLD Star SILVER Star

    Messages:
    9,078
    Likes Received:
    15,000
    Joined:
    Aug 9, 2005
    Location:
    Cedar Rapids, IA
    I sell fencing for a living (one of the things in addition to windows, roofs, decks, siding, etc). We tried this stuff for a customer with the agreement that if it doesn’t hold up we will replace it.

    It performed exactly as I expected foam to perform. Poorly. A year later we pulled it out and did it the “right” way.

    The only saving grace was that it made it super easy to tear out.

    Our method:
    Drill down 48” (frost line is 42” here)
    3” of river rock
    Set post
    100lbs of fast set Quikrete
     
  6. PAToyota

    PAToyota Keystone Cruisers SILVER Star

    Messages:
    1,500
    Likes Received:
    416
    Joined:
    Oct 4, 2009
    Location:
    South Central Pennsylvania
    So, what failed? One potential issue I'd see would be UV resistance - many of the foams aren't. I also see in Kevin's photo a crack around the top of the post in the foam that would let water down in - which could deteriorate both the post and the foam. I could see it possibly loosening up over time with that.
     
  7. LS1FJ40

    LS1FJ40 GOLD Star SILVER Star

    Messages:
    9,078
    Likes Received:
    15,000
    Joined:
    Aug 9, 2005
    Location:
    Cedar Rapids, IA
    The holes “wallowed” out. So the fence got “loose”. You could move the fence an inch in any direction.
     
  8. 4x4veteran

    4x4veteran

    Messages:
    307
    Likes Received:
    1,308
    Joined:
    Nov 6, 2013
    I have rail road ties for gate posts at the entrance of my driveway.

    I dug down two and a half feet and set them in cement that I mixed.

    They had set for over 25 years straight and solid until some butt wipe hit one breaking the tie at the base causing it to lean.

    The part of the post in the ground was still straight and solid.

    After some digging it took a couple of yanks with a cable hooked to the Toy to get it out.

    I guess if it had been foam instead of crete the whole post would have fallen over and I could have reused it.

    I put in a new post and mixed up some Portland to hold it.

    As for the f*** that hit the post didn't have the balls to stick around I can only hope it did some serious damage to his vehicle.
     
  9. 45Kevin

    45Kevin

    Messages:
    2,320
    Likes Received:
    800
    Joined:
    May 10, 2005
    Location:
    Calgary, Alberta
    I looked at that and considered cutting the "mushroom" down further until I got to a spot where the foam was tight against the post. I don't expect that to be a problem though I will be watching it.

    That's funny because my neighbours fence is holding out well after about 5 years.
    When you say wallowed out, do you mean the foam started breaking down, or the dirt around the foam started getting loose?
     
  10. LS1FJ40

    LS1FJ40 GOLD Star SILVER Star

    Messages:
    9,078
    Likes Received:
    15,000
    Joined:
    Aug 9, 2005
    Location:
    Cedar Rapids, IA
    The area between the post and foam. The post rocked back and forth and compressed the foam. Maybe it was too windy in that area? I know we didn’t have any issues with the concrete in the same application.
     
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.