Drilling into walls and cracking plasterboard, old lathandplaster or ceramic tile is one of the most frustrating mishaps for DIYers. Scroll Reddit DIY communities, and you’ll find hundreds of posts showing spiderweb cracks and crumbled wall sections caused by improper drill settings or wrong bits. This practical guide walks you through stepbystep drilling techniques, anchor selection, drill bit and clutch tips, limitations of wall detectors, dust control and hole repair solutions. We’ll start with old lathandplaster walls — the trickiest surface, where mistakes lead to expensive repairs.
Old Lath and Plaster Walls
Among overseas oldhouse DIY enthusiasts, lathandplaster walls remain a hotly debated topic. Some DIYers warn against drilling into old plaster at all due to high risks, while other experienced hobbyists successfully mount full bookshelves using proper techniques. Based on hundreds of community discussions, the consensus is clear: drilling is possible, but you must treat plaster as a thin, brittle shell — never drill it the same way you drill solid brick walls.
Most beginners do not understand the structural risks. Old plaster may look solid and thick, but it is applied over thin wooden laths, locking into gaps between the strips. Continuous vibration from hammer drilling breaks the bond between plaster and wooden laths. Even when only fine cracks appear while drilling, the plaster behind the surface may already be separated from the wood. Many users share followup disaster photos: the wall looks intact right after installation, yet within two weeks after hanging heavy items, whole sections of plaster peel away. Once this principle clicks, we can move on to proven, reliable methods validated by the DIY community.
FieldProven Methods
1. Apply cross masking tape over your marked spot. This is no placebo trick; it is a longused trick among oldhome DIYers. Masking tape holds the surface plaster together and prevents chipping around the hole. Mark your hole directly onto the tape instead of bare plaster. One golden rule from the forum: stay away from existing cracks. Keep at least a hand’s width between your drilling spot and old cracks, otherwise vibration will extend cracks toward your new hole.
2. Never use hammer mode, no exceptions. Many forum users ask whether hammer mode works on hard old plaster, and topvoted answers always say no. Use rotationonly mode at low speed and avoid heavy hand pressure. This is a hard habit to break. When drilling slows down, many people instinctively push harder. Compressive force crushes fragile plaster. Let the bit cut through the material naturally instead of forcing it through the wall.
3. Start with a small pilot hole and gradually widen it to your target size. Do not drill to the final diameter in one go. Begin with a thin bit and step up sizes. On feeling the bit suddenly drop through, you have pierced the plaster and entered the hollow cavity behind. Ease pressure immediately. Reddit users repeatedly warn: this sudden breakthrough can make the bit jerk forward and nick old wiring inside walls. Rubberinsulated wiring in old homes follows no modern routing standards, and even wall scanners cannot guarantee 100% accuracy.
4. Tap the wall to test the spot before drilling. Tap the surface; a dull hollow sound means plaster has detached from the laths. Many skip this test and drill into hollow plaster, resulting in crumbled plaster and anchors pulling straight out. A solid, heavy thud means the plaster still bonds securely to the wood laths. Dust also helps diagnose wall type: fine white powder followed by sudden hollow space indicates lathandplaster. Gritty grey sand dust means you have hit brick behind the plaster.
5. Fastener selection makes or breaks your project and is a top source of failures.
The forum constantly debates toggle bolts vs plastic hollowwall anchors. One group favors toggle bolts for lathandplaster walls for higher load capacity. The downside: they require larger holes, cause more wall damage should drilling go wrong, and the toggle falls inside the cavity after removal and cannot be reused. Others recommend small plastic hollow anchors for very light items. They require smaller holes with less surface damage, but their maximum load rating is low and they pull out easily under extra weight.
A critical community reminder: do not trust load ratings printed on product packaging. Those test values are measured on intact, solid plasterboard. On aged lathandplaster walls, real load capacity drops by half or more. Many DIYers hang items strictly following package ratings only to have fixtures fall off eventually.
· Light loads (artwork, small decor, <5kg): Toggle bolts (butterfly anchors), the forum’s top recommendation. Ordinary plastic expansion plugs perform poorly in plaster walls. Many users report plugs loosen within months because crumbly plaster cannot grip them. Toggle bolts spread weight across the rear side of the wall instead of relying only on the thin plaster layer.
· Very lightweight objects: Should you luckily hit a wooden lath behind the plaster, wood screws can work. Keep in mind hitting laths is hitormiss. You may drill three holes in a row and miss every stud. Never rely solely on wood screws for heavy loads.
· Heavy items (bookshelves, large mirrors): The only reliable method is locating wooden studs and screwing directly into them. Where your fixture cannot line up with studs, the highly recommended workaround from the community: mount a horizontal wood batten securely to studs first, then attach your fixture to this batten. Do not hang heavy items relying purely on plaster wall anchors.
Now that we have covered proper procedures, let’s review common mistakes that lead to permanent wall damage.
Common LathandPlaster Drilling Mistakes
· Overtightening screws. This is the #1 cause of failures. After installing the anchor, people keep turning the screw chasing “extra strength”. Tension pulls on brittle plaster and creates invisible radial cracks. Stop tightening the moment the bracket sits flush against the wall.
· Drilling into hollow plaster then filling the hole with repair compound and reusing it. Many DIYers try this shortcut. Filler will not bond permanently to already loose plaster and will fail under load. Should tapping reveal a hollow spot, abandon this hole and shift a few centimeters sideways to pick a new spot.
· Continuing to drill with dull bits. 70% of chipped wall holes come from worn drill bits. Blunt bits crush and grind plaster instead of cutting it. Replace bits promptly once edges round over; do not skimp on consumables.
For anyone who feels nervous drilling old walls, just like many r/DIYUK beginners, practice on hidden spots behind cabinets first. Get familiar with how this wall feels before drilling visible surfaces. Leave mounted fixtures unloaded for 24 hours, check for new cracks, then add weight. Fine cracks fully covered by the bracket are acceptable. Where cracks spread outward, the wall structure is compromised.
After drilling techniques and anchor choices, there is an oftenoverlooked safety hazard. Many people treat wall scanners as infallible, yet hidden utilities in old homes carry far greater risks than most realize.
Limitations of Wall Scanners & Hidden Utility Hazards in Old Homes
This is one of the most complainedabout topics on oldhouse forums: wall scanners are not magic devices. False positives and missed targets are common on older buildings.
Metal mesh embedded in old plaster, old nails, and leftover metal fasteners on laths will trigger alerts and mislead the scanner into flagging them as electrical wires. Many users waste time reselecting drill points due to false alarms. Rubberinsulated vintage wiring lacks modern shielding and often runs diagonally, not just vertically above or below outlets. The rule “do not drill directly above/below outlets” is only basic guidance and is not fully reliable for old homes. One DIYer shared his experience: he hit diagonal old wiring 30 cm horizontally away from an outlet.
Water pipes also present hidden dangers. Cast iron pipes and early thin plastic pipes in old buildings are often buried directly inside plaster rather than inside wall cavities, making them hard for scanners to detect. Use these backup safety rules:
1. Turn off the corresponding circuit breaker before drilling as your baseline safety measure.
2. Drill a small pilot hole slowly, stop every few millimeters and feel for resistance. Bring work to an immediate halt on contact with plastic or metal.
3. Never fully depend on electronic scanners. Tapping the wall and sensing resistance serves as your second line of defense.
We have finished covering lathandplaster walls. Next up is plasterboard (drywall), the wall type most underestimated by beginners and easy to mess up.
Plasterboard (Drywall)
Plasterboard is soft with a paper facing and hollow behind. Many beginners underestimate its fragility. Countless online failure cases show rushed drilling tearing the front paper layer and creating large holes, leaving no way for anchors to grip the plaster core. Hammer mode must stay off for plasterboard drilling; use rotationonly mode.
The drilling process is straightforward: mark your spot and apply masking tape to guard against paper tearing. Use medium speed and light hand pressure. Release pressure immediately once the bit breaks through the board. Wrapping tape around your drill bit creates a handy depth stop to avoid drilling too deep and cutting pipes or wiring on the other side of the partition.
Plasterboard Anchor Selection
· Lightweight wall art: Selfdrilling plasterboard anchors
· Medium loads (towel racks, narrow floating shelves): Spring toggle bolts
· Heavy items: You must locate wall studs; there are no shortcuts. Plasterboard itself carries almost no weight.
Common Plasterboard Mistakes
Applying heavy hand pressure while drilling, oversize pilot holes, or mismatched anchor and hole sizes. Oversized holes make anchors spin freely inside the cavity, and fixtures will fall off over time. Always scan for utilities before drilling. In cases where your plaster partition borders a bathroom or kitchen, pipes and wires are very likely hidden in the cavity.
Once you master plasterboard drilling, we move to tile walls, another surface prone to cracking — many people accidentally shatter whole tiles while drilling.
Tile Walls
Using hammer mode will almost certainly crack tiles; this point is nearly undisputed.
Match your drill bit type to tile material: Use carbidetipped tile bits for regular ceramic tiles. For dense porcelain tiles, diamondtipped drill bits are mandatory. Carbide bits only slide and overheat on hard porcelain.
Follow this stepbystep method refined from countless DIY tests:
1. Stick cross masking tape on your marked spot. Tape prevents bit slippage on the glossy glaze and reduces chipping at the hole edge. Mark directly on the tape. Avoid tile corners; stress concentration there raises cracking risk. Where practical, drill in grout lines — this is easier, but grout cannot support heavy loads.
2. Start at low speed. Tilt the bit to roughly 45° and grind a small stable indent into the glaze. Once the indent forms, slowly straighten the bit to drill vertically. Pressing straight down from the start lets the bit skid and scratch the tile glaze.
3. Continuous water cooling is essential. Dry drilling builds up heat inside porcelain and creates invisible microcracks. The tile may look intact right after drilling but can fully crack later from vibration or minor knocks. Drip water onto the drilling spot with a sponge, or make a small dam with putty to hold water over the hole.
4. Stop drilling as soon as you hear a tone change once you break through the tile glaze. Where cement backing sits behind the tile, switch to a masonry bit. This is the only time hammer mode can be turned on. Do not waste expensive diamond bits grinding through cement mortar; they will wear out quickly.
5. Insert the expansion plug and tighten the screw gently. Stop once the bracket sits flush on tile. Excess clamping force can create tile cracks weeks after installation.
A key tip for porcelain tiles: patience matters most. Do not push hard on the drill. Let the bit grind slowly. Greater hand pressure brings higher cracking risk.
While forums debate drill bits and cordless drill performance, many users report that failed holes often stem from mismatched tool performance rather than poor technique.
Drill Bit Selection & Cordless Drill Clutch Considerations
Many drilling failures are not caused by bad technique, but wrong drill bits that damage walls and wear bits out quickly.
· Mistake #1: Using wood twist bits on old plaster. Wood bits have sharp but brittle cutting edges. They chip easily when hitting stones mixed inside plaster and get stuck in holes. Forcing the drill to keep spinning splits the plaster around the hole. Forum consensus: use multipurpose carbide bits for old plaster. Wood twist bits are not recommended. Even with hammer mode disabled, masonry bits crush fragile plaster by design.
· Mistake #2: Reusing tile bits to drill cement backing. Many people skip swapping bits. Diamond bits are designed for glaze grinding and wear rapidly on cement mortar, making them uneconomical for repeated use.
· Mistake #3: Ignoring bit length. Short bits only reach shallow plaster layers on old walls. Overlong bits wobble more, drift offcenter and widen holes. Pro tip: let the exposed length of your drill bit exceed your target hole depth by only 10 mm. Less overhang = less wobble.
One drill setting most beginners overlook is the clutch. People adjust speed but ignore clutch torque. A lower clutch setting triggers slip when the bit jams, preventing excessive force that crushes walls. Always use low torque for old plaster. Many users complain cheap 2speed drills lack adjustable clutch and have very low tolerance for mistakes on brittle old plaster.
Even with full mastery of these techniques, unexpected issues can pop up midjob. Below are troubleshooting solutions for common drilling failures shared by DIYers.
Troubleshooting: Common Drilling Failures Shared by Users
1. Fine cracks spreading from the hole: Full coverage of cracks by the fixture bracket means the hole can still be used. In cases where cracks extend past the bracket, abandon this hole and drill elsewhere. Many users ignore fine hairline cracks, which later spread across whole tiles or plaster.
2. Large chippedout cavity: Do not simply fill and reuse the hole. Surrounding substrate is already compromised. Choose a new drilling spot whenever possible. Should repair inplace prove unavoidable, fill fully with repair compound, wait for full cure, sand smooth and drill a smaller new hole.
3. Bit suddenly jams against hard material: Cut power immediately and do not force forward pressure. You have likely hit buried pipes or wiring. Multiple cautionary Reddit accounts describe piercing old cables from forced drilling.
Combine forum knowledge and our experience to build a prejob checklist to avoid most mistakes.
Universal PreDrilling Checklist for All Wall Types
1. Scan for electrical wires before drilling. Do not fully rely on wall scanners for old lathandplaster walls; old wiring runs unpredictably. Switch off the relevant circuit breaker near outlets and switches.
2. Always use sharp drill bits. Dull bits crush and tear brittle wall materials instead of cutting cleanly.
3. Start with small pilot holes and step up sizes. Holes can only get bigger; overdrilling cannot be reversed.
4. Proper fastener selection matters more than a perfectly neat hole. Even a clean hole fails if anchors are wrong, and fixtures fall.
5. Stop tightening once hardware sits flush. Overtightening creates hidden cracks in plaster and tile that show up later.
6. Wear proper safety gear: Safety goggles are mandatory. Flying hard plaster debris can injure eyes. A dust mask is also required, as old plaster dust contains paint and gypsum fibers. Do not wear thin gloves. Rotating drill bits can catch fabric and cause injury.
7. Simple dust control trick: Tape a folded paper bag below your drill spot, or use matching dust collection accessories to stop dust spreading all over your room. Fine plaster dust is hard to clean afterward.
8. Tiered repair guide: Tiny hairline cracks can stay hidden behind fixtures. Small surface chips can be filled with repair compound, sanded and painted once cured. Large hollow plaster delamination needs full removal of loose plaster, resecuring laths then replastering. Forum warning: severe widespread plaster failure is a structural repair best left to professionals; do not attempt complex DIY repairs.
Drilling success does not rely on raw power. The core principle is minimizing vibration, heat and sudden force. Old plaster hates vibration, plasterboard tears under tension, and tiles crack under heat and abrupt pressure.
Final Thoughts
Many hobbyists once believed an expensive cordless drill was all they needed for wall drilling. But countless community examples teach us: low speed, gentle pressure, proper anchors and patience beat raw power every time. Great tools are not built for brute force. They give casual DIYers controllable, gentle performance that minimizes wall damage.
Do not rush to drill all holes at once. Test a spot with uncertainty. Pick a new location when tapping reveals hollow wall sections. A few extra minutes of precheck can save hours of wall repair later.
