Latest / Logosofia no Dia a Dia / Concrete Screws vs Plastic Anchors: Best for Renters
Transcript
- [Prompt] custom: We're in the middle of getting set up in our new rental apartment here in Jerusalem. The landlord gr | Hosts: corn, herman [Response] Corn: Daniel sent us this one — and honestly, it's the most Israeli-renter question imaginable. He's in a new rental in Jerusalem, got the landlord to agree to drilling because there's a one-year-old in the apartment and shelving units need to be anchored for safety. But here's the tension: he goes to the hardware store, they hand him plastic anchors, they feel flimsy, and he's wondering if there's a better way. He's got a mix of concrete and drywall, he's read about concrete screws, and he knows professional users don't recommend plastic anchors anymore. The real question is: what's the best anchoring solution that holds heavy loads securely but can be removed cleanly when the lease is up, so the deposit doesn't vanish into a wall full of patched holes? Herman: This is the question every Israeli renter eventually asks, usually while standing in the hardware store aisle holding a bag of those little ribbed plastic things and thinking, this cannot possibly hold a bookshelf full of children's books. And they're right to think that. The plastic anchor is the default not because it's the best option, but because it's the cheapest thing distributors can stock and every handyman has used them for forty years. Corn: The avocado of wall anchors. Ubiquitous, familiar, nobody questions it until they have to clean up the mess. Herman: So let's break down what's actually happening when you drill into that concrete wall and stick one of these things in. The standard plastic anchor — the kind you find in every Israeli hardware store, usually in a little plastic bag with no brand name — works by expansion. You drill a hole, you push the anchor in, and when you drive the screw into it, the plastic body expands outward against the walls of the hole. The holding power comes from friction between the expanded plastic and the rough interior surface of the concrete. Corn: That friction is enough? It feels like the whole thing is held in by good intentions. Herman: In good concrete, a properly installed plastic anchor can hold fifty to eighty kilograms per anchor in a straight pull-out test. That's not nothing. The problem isn't the static load. The problem is what engineers call cyclic loading. You put a storage shelf on the wall, you load it with books, you take books off, you put different books on, the shelf vibrates when someone walks by, the door slams, the toddler pulls on the shelf — and each of those cycles applies a tiny bit of movement to the anchor. Over months, the plastic can develop micro-cracks. The expansion force weakens. One day you notice the shelf is tilting forward by a few millimeters, and that's the anchor starting to fail. Corn: It's not that plastic anchors are useless. It's that they're fine right up until they're suddenly not, and the failure mode is gradual enough that you might not notice until the shelf is leaning at a concerning angle. Herman: And with a one-year-old in the apartment, concerning angles are not acceptable. The other failure pattern is installation error, which is incredibly common. If the hole is slightly too large — and with concrete, drill bits wander, especially if you're not using a hammer drill with a depth stop — the anchor doesn't expand enough to grip. If the hole is too small, you force the anchor in and it deforms before the screw even goes in. If you over-torque the screw, you strip the plastic threads inside the anchor. All of these are invisible from the outside. The shelf looks fine. Until it isn't. Corn: What's the alternative that professionals actually recommend? Daniel mentioned concrete screws. Herman: Concrete screws — the brand name everyone knows is Tapcon, but there are equivalents — work on a completely different principle. Instead of expanding a separate anchor body against the hole, the screw itself has hardened threads that cut into the concrete. You drill a pilot hole that's precisely matched to the screw diameter, and then you drive the screw directly into the concrete. The threads create a mechanical interlock with the concrete itself. There's no plastic body, no expansion sleeve. Just screw into concrete. Corn: That sounds almost... Herman: It is elegant. And the numbers back it up. A Tapcon-style concrete screw in four thousand PSI concrete — which is standard structural concrete — has a typical pull-out strength of a hundred fifty to two hundred kilograms per anchor. That's roughly two to three times what a plastic anchor can hold in the same hole. And here's the thing that matters for renters: when it's time to move out, you unscrew it. The screw comes out. What's left is a five to six millimeter hole. Compare that to a plastic anchor, where you have to pull the anchor body out — if you can — and you're left with an eight to twelve millimeter hole to patch. The concrete screw leaves a hole half the diameter. Corn: Stronger and easier to remove. Why isn't this the default? Herman: One, you need a proper masonry bit that's exactly the right diameter, and you need to drill the hole to the right depth. If the hole is too shallow, the screw bottoms out before the threads fully engage. If it's too deep, you've weakened the concrete around the screw. Two, if you over-torque a concrete screw, you strip the threads in the concrete itself — and then you have a stripped hole that won't hold anything, and you can't just pull out a plastic anchor and start over. You have to drill a new hole. So the installation requires more precision. But with a depth stop on your drill bit and a decent hammer drill, it's not difficult. It's just less forgiving of sloppy technique. Corn: Which brings us to the tool question. Daniel's drilling into concrete — probably the boilerplate concrete that's standard in Israeli apartment buildings. Can you even do this without a hammer drill? Herman: This is one of those misconceptions that needs to die. You can drill into concrete with a standard drill and a masonry bit, but only for shallow holes in relatively soft concrete. The moment you hit aggregate — those little stones embedded in the concrete — a standard drill just spins on the surface. A hammer drill adds a percussive action that chips the concrete as the bit rotates. For anything deeper than about two centimeters, or for any concrete that's been curing for more than a few years and has reached full hardness, you need a hammer drill. The good news is that decent hammer drills are not expensive anymore, and many hardware stores in Israel rent them by the day. Corn: There's the dust problem. Concrete drilling produces this fine silica dust that gets everywhere and is apparently not great to breathe. Herman: Yeah, silica dust is a real respiratory hazard. But there's a practical solution here that also helps with landlord relations. Some hammer drills — I'm thinking of the Bosch GBH 2-28 F, which is a popular model — have a vacuum attachment that captures something like ninety percent of the dust at the source. You're drilling, and the dust is going straight into a little canister instead of coating every surface in the room. When the landlord does an inspection and sees clean walls with small, neatly patched holes instead of a dust-coated disaster zone, that's the difference between getting your deposit back and having an argument. Corn: We've got plastic anchors, which are cheap and easy but leave big holes and can fail over time. We've got concrete screws, which are stronger and leave smaller holes but require precision. Daniel also mentioned reading about other options — chemical anchors, expanding metal anchors. What are those, and do they make sense for a renter? Herman: Chemical anchors are in a different league entirely. This is what you use when you're anchoring structural steel to concrete — like securing a building's frame to its foundation. The system is a two-part epoxy in a cartridge. You drill a hole, clean it thoroughly — and cleaning is critical, you have to get all the dust out or the epoxy won't bond — then you inject the epoxy and insert a threaded rod. The epoxy cures and bonds chemically to the concrete. Pull-out strength can exceed five hundred kilograms per anchor. These are the anchors that hold up highway signs and bridge railings. Corn: Massively overkill for a bookshelf, but also — what happens when you try to remove one? Herman: You don't. Removal is destructive. You cut the threaded rod flush with the wall using an angle grinder or a hacksaw, then you patch over the embedded rod. It's permanent. The rod stays in the wall forever. For a renter, this only makes sense if the landlord explicitly approves a permanent fixture — and even then, you're leaving metal embedded in the wall that the next tenant or the landlord has to deal with. I would not recommend chemical anchors for any rental situation unless it's something like mounting a heavy air conditioning unit where there's genuinely no alternative. Corn: The expanding metal anchors? Herman: These are things like sleeve anchors and wedge anchors. A metal sleeve expands against the concrete as you tighten a nut on the threaded stud. They're very strong — typically somewhere between concrete screws and chemical anchors in holding power. But the removal problem is similar. When you try to take them out, the expanded metal sleeve stays embedded in the concrete. You can sometimes hammer it deeper into the hole and patch over it, but you're still leaving metal in the wall. And if the anchor is near the surface, you might end up with a rust spot bleeding through your patch a year later. Corn: For a renter, the sweet spot really is the concrete screw. Strong enough for shelving, fully removable, smallest hole to patch. Herman: For concrete walls, absolutely. But Daniel mentioned he also has drywall in the apartment — and this is where the whole conversation changes. Drywall is a completely different material. It's gypsum plaster sandwiched between paper. It has essentially no structural strength in tension. A plastic anchor in drywall is relying on friction against a material that crumbles under pressure. The failure pattern isn't gradual cracking like in concrete — it's sudden. The anchor pulls out, and you're left with a hole the size of a fist. Corn: Which is the nightmare scenario for the deposit. Herman: For drywall, the physics of anchoring has to work differently. You can't rely on friction against the hole walls because the hole walls are made of compressed powder. What you need is something that distributes the load across the back surface of the drywall panel. That's what a toggle bolt does. You drill a hole, you push the toggle through — it's a spring-loaded wing mechanism — and when it opens up behind the drywall, it spreads the load across a much larger area. A good toggle bolt in half-inch drywall can hold up to fifty kilograms. Corn: Fifty kilograms from something that fits through a hole the size of my finger. That's impressive. Herman: It's a clever bit of engineering. The wing mechanism is basically creating a clamp — the drywall is sandwiched between the toggle wings on the back and the bolt head on the front. The load is in compression across the drywall panel, not in tension trying to pull something out of a hole. And when you want to remove it, you unscrew the bolt, the toggle wings fall off inside the wall cavity, and you're left with a clean hole to patch. The toggle stays in the wall, but it's just sitting loose in the cavity — it won't cause any problems. Corn: What about those molly bolts? I've seen those in hardware stores — they look like a metal sleeve with teeth. Herman: Molly bolts are the middle ground for drywall. You drill a hole, insert the molly bolt, and as you tighten the screw, the metal sleeve collapses and expands behind the drywall, creating a clamping effect. They're easier to install than toggle bolts because you don't have to hold the toggle wings while tightening, but they don't spread the load quite as widely. I'd use them for medium loads — picture frames, small shelves, things in the ten to twenty kilogram range. For anything heavier, toggle bolts are the safer choice. Corn: We've got a clear hierarchy now. For concrete: concrete screws for heavy loads, plastic anchors for light loads if you really want to save money. For drywall: toggle bolts for heavy loads, molly bolts for medium loads, and honestly, avoid plastic anchors in drywall entirely. Herman: That's the short version. And I want to emphasize the "avoid plastic anchors in drywall entirely" point. They're sold for drywall, they say "for drywall" on the package, but the failure pattern is catastrophic and sudden. I've seen it happen. The anchor pulls out, the screw comes with it, and now you have a hole that's too large to patch with spackle alone — you need to do a proper drywall repair with mesh tape and joint compound. It's a half-hour job instead of a two-minute job, all because you saved three shekels on an anchor. Corn: Let's talk about the removal and patching side, because that's where the deposit lives or dies. Daniel mentioned seeing rentals where walls were covered in removed anchors — presumably the scars of previous tenants who didn't patch properly. Herman: The patching problem is where most renters fail, and it's usually because they use the wrong material. In Israel, the standard spackle — shpakhtel, as it's called — is often a heavy, cement-based filler that's designed for initial filling of large holes in concrete. It shrinks as it dries, it's hard to sand, and if you use it for the final surface coat, you end up with a visible patch that's slightly recessed and has a different texture than the surrounding wall. Corn: It's the right material for the wrong step in the process. Herman: The right approach is a two-step process. For concrete walls, you first fill the hole with a cement-based patching compound — this gives you structural fill that bonds to the concrete and won't crack. Let it dry completely. Then you apply a thin finish coat of a lightweight joint compound — the kind used for drywall finishing — which is much easier to sand smooth and can be feathered out to blend with the surrounding wall. Sand it with fine-grit paper, a hundred twenty grit or higher. If the wall has a textured finish — and a lot of Israeli apartments have that slightly stippled texture — you can match it by dabbing the wet compound with a sponge or a stippling brush before it dries. Herman: For drywall, skip the cement-based filler entirely. Use lightweight spackle or joint compound for the whole job. The hole from a toggle bolt or molly bolt is usually clean and round — fill it, let it dry, apply a second coat because the first one will shrink slightly, sand it smooth, and paint. If the hole is larger than about a centimeter, you might need to use a small patch of mesh tape to prevent cracking, but for anchor holes, that's rarely necessary. Corn: The difference between a five-millimeter hole from a concrete screw and a ten-millimeter hole from a plastic anchor doesn't sound like much on paper, but when you're trying to make a patch invisible, that extra five millimeters is the difference between a dot of filler and a repair that needs multiple coats and texturing. Herman: And this is why the concrete screw is the superior choice for renters even beyond the holding strength. The smaller hole is easier to make disappear. A five-millimeter hole, properly filled and sanded, is essentially invisible once painted. A ten-millimeter hole requires real skill to hide, especially on a textured wall. Corn: There's a strategic dimension to this that goes beyond the hardware. Daniel mentioned that Israeli landlords seem to be getting more accepting of drilling, but that acceptance probably depends on how the walls look when you leave. Herman: This is where the social engineering comes in. I've talked to enough landlords and tenants over the years to know that the deposit deduction for wall damage is rarely about the fact that holes exist — it's about the quality of the repair. A landlord walks into an empty apartment and sees a bunch of lumpy, discolored patches on the walls, and they immediately think, I'm going to have to repaint this entire room. That's when the deposit gets docked. But if the patches are invisible, or at least professionally done, the landlord doesn't even notice them, and the deposit conversation never happens. Corn: Daniel's in a particularly strong position here because he got written permission to drill. He explained the child safety issue, the landlord agreed. That's the ideal scenario. But even without that, I think a lot of tenants underestimate how far a simple conversation goes. "I need to anchor shelving for safety reasons, I'll use concrete screws and patch everything professionally before I leave" — that's a reasonable position that most landlords will accept. Herman: Having it in writing is key, though. Even if it's just a WhatsApp message. Israeli rental law can be fuzzy on what constitutes normal wear and tear versus damage, and a written agreement that drilling is permitted with the understanding that holes will be professionally patched eliminates a lot of potential disputes. Corn: Let's put together the practical shopping list. Daniel's got concrete walls and drywall, he needs to anchor storage shelving — probably something like an IKEA Kallax unit, which when loaded with books and toys can easily weigh thirty or forty kilograms — plus lighter things like picture frames and maybe some hooks. Herman: For the heavy shelving on concrete walls: concrete screws. Tapcon is the brand name, but any equivalent concrete screw will work. You want a diameter of about six millimeters — that's the sweet spot for shelving brackets. Buy a masonry drill bit that's exactly matched to the screw size — the packaging will tell you which bit diameter. Get a depth stop for the drill bit so you don't drill too deep. And you need a hammer drill. If you don't own one, rent one for the day. It's worth it. Corn: For the drywall sections? Herman: Toggle bolts for anything over fifteen kilograms. Molly bolts for the medium stuff. And for really light things — small picture frames, decorative items — you can actually use adhesive hooks if the weight is under a couple of kilos, but don't trust them for anything you'd be sad to see fall off the wall. Corn: What about the patching supplies? Daniel's going to need to undo all of this eventually. Herman: For concrete: a small tub of cement-based patching compound, a small tub of lightweight joint compound, fine-grit sandpaper — a hundred twenty grit or higher — and if the walls are textured, a stippling brush or a sponge. For drywall: just the lightweight joint compound and sandpaper. And a small putty knife, maybe two inches wide, for applying the filler cleanly. Corn: The total cost for all of this — anchors, drill bits, patching supplies — is probably what, a couple hundred shekels? Herman: Maybe a hundred fifty to two hundred shekels, not counting the hammer drill if you need to rent one. Compare that to losing a deposit of several thousand shekels because the walls look like they were used for target practice. The math is not complicated. Corn: There's a safety dimension here that's worth naming explicitly. The reason Daniel's doing this is because he has a one-year-old. An unanchored shelving unit is a tipping hazard. A toddler pulls on it, or climbs on it — and toddlers climb on everything — and the whole thing comes down. The plastic anchor that felt fine for six months suddenly isn't fine anymore. The concrete screw, properly installed, doesn't have that failure pattern. Herman: This is the point where my pediatrician background kicks in. I've seen what furniture tip-overs do to small children. It's not theoretical. A forty-kilogram shelf falling on a one-year-old is a life-threatening event. The anchoring isn't about protecting the deposit — it's about protecting the child. The deposit is secondary. But the beautiful thing about concrete screws is that you don't have to choose between safety and getting your money back. You get both. Corn: What should Daniel actually do next time he's at the hardware store? Give me the short version. Herman: Skip the plastic anchors entirely. Grab a box of concrete screws in the six-millimeter size, the matching masonry bit, and a depth stop. For the drywall, get toggle bolts for the heavy stuff and molly bolts for the medium stuff. Buy the patching supplies now — the cement filler and the joint compound — so you have them when you need them, not in a panic the day before the move-out inspection. And if you don't own a hammer drill, rent one. That's the list. Everything else is technique, and technique you can learn from a five-minute video. Corn: The one thing I'd add is to test on an inconspicuous spot first. Drill a hole in the back of a closet or somewhere the landlord will never look, install a concrete screw, remove it, patch it, and see how the whole process feels. Better to make mistakes somewhere invisible than right next to the light switch in the living room. Herman: That's good advice. And it connects to something I've been thinking about — the broader trend here. Israeli landlords are coming around to the idea that drilling is inevitable. The old model of "no drilling ever, use adhesive hooks for everything" is dying out, partly because adhesive hooks fail and cause their own damage when they rip paint off the wall, and partly because tenants are pushing back with reasonable arguments about safety and functionality. The question is whether the hardware stores will catch up. Corn: Right — will they start stocking concrete screws and toggle bolts as prominently as they stock those bags of plastic anchors? Herman: That's the open question. Right now, if you walk into a typical Israeli hardware store, the plastic anchors are right there at the counter, in bulk, cheap as chips. The concrete screws are usually in a different aisle, in smaller quantities, more expensive per unit. The toggle bolts might not even be in stock — you might have to go to a specialty store or order online. The supply chain is optimized for the old way of doing things. Until that changes, renters who want the better solution have to know what they're looking for and be willing to hunt for it. Corn: There's also a class of solutions that might make this whole conversation obsolete eventually — the rental-friendly mounting systems that are designed to minimize wall penetration from the start. French cleats, for example, where you mount a single horizontal rail into the studs or concrete and then hang everything off that rail. You're drilling fewer holes, and the holes you do drill are in a straight line that's easier to patch. Herman: In concrete, you're still drilling holes. The French cleat reduces the number of holes but doesn't eliminate them. The real game-changer would be some kind of adhesive technology that actually works on textured concrete walls and can hold fifty kilograms without failing — but we're not there yet. For now, the concrete screw is the best tool we have for the job. Corn: The thesis holds: the best anchor isn't the strongest one — it's the one that balances holding power with clean removability. In concrete, that's the concrete screw. In drywall, it's the toggle bolt. The plastic anchor is the default because it's cheap and familiar, not because it's good. And when you're protecting both a child and a deposit, "cheap and familiar" isn't the standard you want. Herman: The final piece is just doing the patching properly. Two coats, the right materials, sand it smooth, match the texture. It's not complicated, but it requires patience. Most bad patch jobs are just rushed patch jobs. Take your time, let each coat dry fully, and the result will be invisible. Corn: One last thought on where this is all heading. As more renters figure this out and start demanding better anchors, the hardware stores will eventually respond. The plastic anchor won't disappear — it's too cheap and too entrenched — but I think we'll see concrete screws and toggle bolts become more visible, more available, maybe even recommended by the people behind the counter. The knowledge is spreading. Daniel asking this question is part of that spread. Herman: Next time you're at the hardware store, skip the plastic anchors and grab a box of Tapcons. Your walls will be stronger, your child will be safer, and your deposit will still be there when you move out. Corn: Now: Hilbert's daily fun fact. Hilbert: In the nineteen forties, the British Royal Navy maintained a single telegraph station in Berbera, British Somaliland, where a tradition persisted of hoisting a black pennant whenever a ship's cat was transferred between vessels — a practice that survived nowhere else in the fleet and was recorded only in the station's handwritten logbooks, now held at the National Maritime Museum. Corn:...a black pennant for a cat transfer. Herman: I have so many questions, and I know none of them have answers. Corn: This has been My Weird Prompts. Our producer is Hilbert Flumingtop. If you've got a question like Daniel's — something practical, something weird, something you've been staring at in the hardware store aisle — email the show at show at my weird prompts dot com. We'll dig into it.