Concrete fasteners - problem

Mark Harvey

I am attachinh a metal threshold to a concrete foundation of a 50 year old building. I've drilled the holes (3/16) into the concrete but the the 1/4" x 2" concrete screws are not grabbing the insides of the hole. I think the cement is just too weak and is flaking as I try to screw. I could use anchors but that would mean undoing a lot of work to remove the threshold, the underlying wood, then drilling the concrete. Any suggestions? Is there something that I could fill the holes with that would cure and then allow me to screw into? Or any other ideas would be appreciated.
Thanks.

joecaption

What kind of screws are you trying to use?

Mark Harvey

I don't have the brand name in front of me but they are blue and meant for concrete. Phillips head.

Beepster

Check out Ramset. I will never use the blue concrete screws ever again.

B

Sadde10

I have had great difficulty getting Tapcons to grab in a concrete floor. Went Ramset this last time for my treated 2X's and was impressed. 3" Ramset anchors and a #4(yellow) shot. Did Ramset for all of my furring strips as well, bees knees!

carpdad

Try using 5/16 screws. If Tapcons don't come in that size, you can use stainless wood screws. Steel screws will rust. Although this is wood trick, rubbing the screw in bar soap helped me once. If you can, should remove the threshold and vacuum out the hole. Hand screw only.

You could try this. Protect the threshold hole with tape. Squeeze in epoxy, one that looks like 2 part syringe, coat the tapcon with same epoxy, set into the hole and weigh the screw down. Masonary epoxy may be more logical choice, but applicators wouldn't fit into the holes.

stubborn1

Since it's only a threshold and not something that is going to take a load, try putting a toothpick or two in the hole and then reinstall the screw. I'd try that first before I drill a larger hole and try the next size up screw.

__________________
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kwikfishron

A Ramset is a great tool but I defiantly wouldn't use it for a threshold.

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mae-ling

Piece of wire in the hole hen the screw.