Basement expansion joint repair

Due to washout my basement has settled a lot and the original expansion joint is allowing many bugs in. I need to know the best way to repair this. I have caulking for multiple repairs on cement, but I don't know if I have to dig all the original fiber expansion joint out before applying anything for replacement filler. It goes quite deep so if I do have to remove all of it I will need to use a form of backer for the repair compound.
If there is a better item to use for this than what I have I will of course purchase that, but I wanted to check on what I do have.
I know it is a poor job on the "Great stuff" fix for airleaks behind my trim going on. It is a temporary fix. This repair is along the exterior wall and I have a window about 1 1/2" about this. I am aware the carpet is destroyed, I'm only fixing one thing at a time.
q basement expansion joint repair, basement ideas, home improvement, home maintenance repairs
q basement expansion joint repair, basement ideas, home improvement, home maintenance repairs
q basement expansion joint repair, basement ideas, home improvement, home maintenance repairs
  2 answers
  • Looks to me like you need a professional to come in and do the work, probable going to be expensive, but there is a reason that you have that big crack. I'm no expert but I have seen enough problems with stuff like that, I really think you would be safer to call in and expert.
    • See 1 previous
    • Tim's Man Blog Tim's Man Blog on Apr 09, 2015
      @Rockbiter If all you need it to last is a year....get some backer-rod that fits in the gap. (after removing old crap first of course) Then just use regular silicone. It will remain somewhat flexible, and do what you want it to do.....which is keep bugs out. Depending on how fast the house is sinking, silicone could last a few years.
  • Moxie Moxie on Apr 09, 2015
    It sounds like you are aware there is a serious settlement problem and for now you just want to keep the bugs out. As you can see the slab is poured up to the foundation wall and separated by the expansion joint. I too would cut out the top 1/2" or so of old expansion joint material. it should be installed originally the full thickness of the slab. Then I would put a very small amount of diatomaceous earth (get it at amazon cheap) to kill any critters without harming yourselves or animals (food grade) but keep in in the deep crack so it doesn't mess with adhesion of the calk. Then I would insert a backer rod foam (get twice the size of your space so if 1/2" wide then get an 1" to compress it into the space - get from a concrete supply lace or maybe big box stores but they may be limited on sizes offered) then I would seal it with BASF Sonolastic NP1 (used to be Sonneborne who got bought out by BASF). Bead it into the joint so that it bumps up a bit and let it cure before you replace flooring over it. The application should touch both edges (foundation wall and slab) so it seals. It can expand like up to 50% or more (it actually stretches but whatever). I would also note you may be able to request a "quote" from a professional and get some input in the process of what for sure is going on. You indicated a wash out not sure what the extent is. Just be sure your humble abode is stable at the foundations so it doesn't suddenly crumble around your head. The slab is designed to move separately from your foundation and could fail without serious effect to the building foundation but would effect any load bearing sitting on top of it, if applicable. I hope this helps and good luck!
    • See 2 previous
    • Rockbiter Rockbiter on Apr 19, 2015
      @Moxie I probably will buy the one you recommend since I will probably need more than one tube of what I have. If I have to go to the store I might as well get the better one. Still knowing which is better for other areas is very helpful though so thank you. As always thanks for the detail in your response, it covers all bases of what if's my mind has before having any sort of confidence in being able to do the task I am wanting to do. Have to at least know what I am doing before doing the damage. If all goes well and doesn't end up destroyed with my magic hands I will post a pic of it.