I'm helping a friend install hurricane panels over the windows in their house. These panels are 5/8"-thick extruded clear(ish) plastic sheets, dimensionally similar to 5/8" plywood. These panels are removable, obviously not mounted and stored (usually in the garage) when not in a hurricane situation.

There are two typical anchor methods for these types of panels (or other similar panels):

  1. Permanently install threaded studs into the wall. These threaded studs are often (usually?) Tapcon SG into the wood or block substrate, with a 1/4"–20 machine thread sticking out, so that the panels can be attached with washered-wingnuts. When the panels aren't installed during a storm, the exposed machine threads are usually covered with a plastic or nylon cover.
  2. Permanently install female machine thread anchors, to receive "street bolts" or other large head 1/4"–20 machine screws to hold the panels onto the wall. When the panels aren't installed during a storm, short street bolts, or plastic bolt-shaped inserts, are placed into the threads to protect them from dirt and moisture.

My friend wants to use method 2 (permanent female threaded inserts) for aesthetic reasons. My friend's house is block construction, but in my experience hanging plywood over the windows in previous years, I don't believe the block voids surrounding the windows are filled with poured concrete. At least, I can't assume they are.

The anchors will be about 3 inches beyond the stucco corner. I believe that for the most part, I will be drilling to the block voids, not the web or the mortar between blocks. Given that, what is the best type of anchor to install?

From what I understand, ''single-expansion'' anchors only expand from the bottom, which provide no hold in block voids (because the expansion occurs beyond the thickness of the block, and also because the block will tend to spall when drilled into the void, reducing the effective thickness of the wall of the block). ''Double-expansion'' anchors, from what I've read, can be okay in the void of the block, but I wonder if they're good for non-permanently installed threads/screws?

Is an epoxy female thread anchor the best option? Again, only the female anchor will be permanently installed, threading in a bolt only when needed during storms. I've also seen lead+brass sleeves that expand during installation, leaving a reusable female thread.

  • The only epixy anchors I have found leave a stud protruding - but that may be market or shop driven. More imporatantly epoxy anchors work best in blind holes as the resin cannot run away.
    – Solar Mike
    Commented Aug 10, 2021 at 6:12
  • @SolarMike Yeah, I've never seen epoxy set for female thread inserts. I would imagine the insert would have to have a closed bottom, if it existed. It seems to me like such a thing would be very useful, but as you mention, if one drills through the hole into the void, it would be awful difficult to get an appropriate bond.
    – scottbb
    Commented Aug 10, 2021 at 18:26

1 Answer 1


I used the lead sleeve anchors that have 1/4-20 female threads. They are reusable and I've had them in for 30 years and have never had one pull out and i install my shutters every year... living in South Florida.

The anchors are about 3/4" in length and 9/16" in diameter. I have block construction with 1/4" stucco on my wall so I have 1-1/2" to work with. I drilled 1" deep holes so I still have 1/2" of block wall for support. The trick is not to use a hammer drill or you'll blow the back of the block off.

You need to start drilling holes and see what you've got. Those sleeve anchors worked great for me. If I had drilled through the block I would have used some lag shields and lag screws but I didn't need them. I have not tried any epoxy held anchors.

  • Do you use flat bolts or plastic inserts in the anchors during the "off season"? It sounds like the anchors are about 1/4" below the surface. Did you do anything to water proof the hole other than careful caulk & paint?
    – scottbb
    Commented Aug 10, 2021 at 15:53
  • @scottbb I used the flat stainless steel bolts I would normally use for the shutters. That way I didn't have to worry about loosing them. Didn't do anything to waterproof the hole except a bit of caulk and put some silicone grease on the screws.
    – JACK
    Commented Aug 10, 2021 at 16:29
  • @scottbb Yes, they are about 1/4" below the surface. I actually have some wood window sills/shelves I bolt into the same holes when the panels aren't in use...... I just need longer bolts.
    – JACK
    Commented Aug 10, 2021 at 16:35

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