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I'm pulling a bunch of insulation from my basement to get ready to finish it, and have found it's bolted to the concrete walls. I've been able to google my way to identifying the bolts as Hilti X-SW 30 fasteners (https://www.hilti.com/direct-fastening/insulation-fastenings/r66753).

I managed to pry one out with a claw hammer, but naturally this damaged the surrounding concrete. I tried a second one and it managed to support all 200lbs of my bodyweight without budging.

So, I suppose I'm really asking two questions; How do I remove these things with minimal damage? And assuming some damage is unavoidable, what's the right way to plug the resulting holes and fix the damage?

If it's relevant, my plan after this is two coats of waterproofing paint, followed by XPS rigid foam insulation.

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  • If there aren't too many, simply bending them side to side a few times should shear them off. Patch right over the stubs if you think it's necessary, but your waterproofer should do the job on its own.
    – isherwood
    Sep 7 '17 at 17:00
  • Since you're going to add foam on top, If it's okay with you to leave the bases of the fasteners in there, you could also cut them off with an angle grinder fitted with an abrasive cutting disc.
    – Fizz
    Sep 8 '17 at 0:31
  • In most cases I would just pry back and forth to snap the fastner, don't try to pull it you will do more damage to the wall than is necessary. In some cases I will use an angle grinder with a very thin metal cutting blade cutting 1/4 to 1/2 way through then they break off with 1 o2 2 wobbles and not much force with no broken wall to worry about.
    – Ed Beal
    Sep 8 '17 at 1:57
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I would suggest a crowbar for removing them. The overall length of the crowbar body will determine the amount of force it's capable of producing. Obviously the fulcrum will be at the end against the wall where the head turns towards the fastener.

With a relatively long crowbar, your leverage will multiply significantly and they will come out much easier.

Basically - go to any home goods store and see how long of a crowbar you feel you could live with having around - the longer the better.

As for the damage to the cement - I'm stealing a page out of another website because it's well written:

Patching such holes is a necessary part of keeping your concrete foundation wall in good repair. If your aim is to make the wall look better, a smooth surface is also easier to paint. An ideal patch to use for both purposes is hydraulic cement, which expands to fill cracks and holes as it dries.

1 Remove loose material from the hole in the wall by probing it with the tip of a screwdriver or blade of a putty knife. Clean the hole and surrounding area with a wire brush. Vacuum any remaining dust or debris out of the hole.

2 Dampen the hole and surrounding area with water using a spray bottle.

3 Mix a small portion of hydraulic cement in a clean container according to package directions. Stir the cement with a putty knife until it has the consistency of thick peanut butter. Make only as much cement as you can use in three minutes or less.

4 Pack hydraulic cement firmly into the hole with a putty knife or trowel. Smooth the surface of the patch as quickly as possible before the cement sets.

5 Spray the patch lightgly with water several times over the next 24 hours. Allow the patch to cure for 48 hours before painting, or for as long as recommended by the manufacturer. Things You Will Need

Screwdriver
Putty knife
WIre brush
Wet/dry vacuum
Spray bottle filled with water
Hydraulic cement
Clean mixing container
Trowel (optional)

Tip

Unless the wall is well shaded, it's best to apply hydraulic cement early in the morning when the wall surface is cooler so the cement won't dry too quickly.

Warning

Wear rubber or latex gloves when working with hydraulic cement.

Those notes apply to an interior or exterior cement surface. With a proper putty knife technique you will have a very smooth surface ideal for painting.

Happy fixing!

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  • 1
    Taking text directly from another website is not a good idea, especially without attribution.
    – bib
    Sep 7 '17 at 12:03
  • @Sovtek How big a crowbar are we talking here? I just tried an 18" one with a sledge and nothing happened other than my seeing a crowbar flex for the first time in my life... Sep 7 '17 at 15:33
  • "Just a heads-up that I'm plagiarizing here."
    – isherwood
    Sep 7 '17 at 16:55
  • 1
    @XeroxDucati Use a rigid crowbar (not a flatbar) and a heavy hammer. Strike the crowbar partway up the long lever arm with the hammer while applying tension at the end of the crowbar. The resulting force will be many times what you can do with muscle.
    – isherwood
    Sep 7 '17 at 17:07

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