Most TV mounting problems trace back to the same small set of mistakes. Wrong fixings, no pipe and cable scan, mounting too high, skipping the level check. These are the errors we are called in to fix most often across London and the South East — and they are all completely avoidable.
Mistake 1 — Using the wrong fixings for the wall type
The single most common failure. Standard plastic wall plugs are designed for solid brick or concrete. Pushed into plasterboard, they have almost no pull-out resistance — they can fail under the weight of a large TV, particularly with a full-motion bracket that creates leverage on the fixings when extended.
The fix: Identify your wall type before buying fixings. Plasterboard on timber stud — use 75mm screws into the stud. Plasterboard on a cavity (no stud) — use Grip-It anchors or toggle bolts rated for your TV weight. Solid brick or concrete — use Rawlbolt anchors or heavy-duty nylon plugs with an SDS drill. Our UK wall types guide covers every construction type.
Mistake 2 — Skipping the pipe and cable scan
Drilling blind into a wall is one of the highest-risk things you can do in a DIY installation. Electrical cables and water pipes run through walls in positions that are not always predictable — particularly in older UK properties where cable routes do not follow modern building conventions.
The fix: A combined pipe and cable detector costs £20–40 from any DIY store. Sweep it slowly across the drill zone in both horizontal and vertical passes before marking any holes. Mark any detected pipes or cables with tape. On every job we do, this scan is the first thing performed after the wall position is agreed.
Mistake 3 — Mounting the TV too high
A visually obvious mistake — and one of the most common complaints we hear about DIY installations. The instinct to mount the TV high comes from comparing it to a cinema screen or a pub screen, neither of which represents a seated home viewing position.
A TV mounted with the centre at 140–150cm (common when guessing) requires constant upward neck tilt. Over a two-hour film, this causes genuine discomfort and is a frequent reason behind the remount requests we receive.
The fix: Mount the centre of the screen at 100–110cm from the floor — roughly your seated eye level. Sit on the sofa before drilling. Have someone hold the TV (or use a cardboard template) at the proposed height and check your sightline while seated. See our TV mounting height guide for exact measurements by TV size.
Mistake 4 — Fixing into plaster rather than the substrate
Plaster has very low tensile strength. Fixings that terminate in the plaster layer — rather than passing through it and anchoring in the brick, block, or timber behind — look fine initially but are under constant load. In dot-and-dab constructions (plasterboard bonded to a brick wall with adhesive dabs), this is particularly common: the fixing appears secure in the plasterboard but the gap between board and brick means it has no real backing.
The fix: For dot-and-dab walls, use fixings long enough (50–70mm) to bridge the adhesive gap and anchor in the brick or block behind. For lath and plaster (Victorian properties), use long timber screws into the structural laths. If you are unsure of your wall construction, professional installation is the safer option.
Mistake 5 — Not checking level before and after tightening
A bracket that is not level leaves the TV permanently off-kilter. Worse, most people only notice after the TV is hung — at which point correcting it means removing the TV, removing the bracket, filling holes, and redrilling.
The fix: Use a spirit level across the top edge of the bracket plate before marking the fixing holes. Check again after the bracket is hand-tight but before fully tightening the screws — the bracket can shift slightly as fixings seat themselves. Check one final time after hanging the TV. Most brackets have a ±3–5 degree levelling bolt that allows fine adjustment without remounting.
Mistake 6 — Using a bracket with an inadequate load rating
Very low-cost brackets from online marketplaces sometimes carry load ratings that are stated rather than independently tested. A 55-inch TV weighs 18–25kg. The bracket load rating should exceed the TV weight by at least 50% — so a minimum 35–40kg rating for a 25kg TV. Full-motion brackets in particular create moment loads on the fixings when extended that multiply the effective load.
The fix: Use brackets from established manufacturers — Vogels, Sanus, Invision, AVF — with published load ratings on the packaging or product page. These cost £25–80 for most domestic applications and are worth every penny compared to the alternative.
Mistake 7 — Loose VESA bolts on the TV
The connection between the TV and the bracket plate uses four bolts threaded into the VESA mounting holes on the back of the TV. Undertightened VESA bolts allow the TV to shift, wobble, and in a worst case work off the bracket over time — particularly with bass-heavy sound systems that create low-frequency vibration.
The fix: Tighten the VESA bolts firmly with the correct driver. Use M4, M6, or M8 bolts of the exact length specified — too long and they can damage internal components, too short and they have insufficient thread engagement. After 30 days of use, check the bolts again: vibration during this settling period is the most common cause of loosening.
Mistake 8 — Ignoring cable management until after installation
Leaving cables dangling from a wall-mounted TV eliminates most of the visual benefit of mounting in the first place. Planning cable routing after the TV is already on the wall is far harder than planning it before drilling.
The fix: Before drilling, decide how cables will be managed: surface trunking (cable cover clipped to the wall), in-wall routing (cables dropped through the wall cavity to a socket below), or a media shelf positioned directly below the bracket. Mark the socket and cable exit positions before the first hole is drilled. See our cable hiding guide for all options.
When to bring in a professional
If you have already made one of these mistakes — wrong fixings, bracket pulling from the wall, TV visibly off-level — the right move is to get it assessed and remounted correctly rather than attempting a patch. Our TV installation repair service covers remounts, unsafe bracket removal, and hole filling across London and the South East.
Get a free estimate from Mount TV → We cover London and the South East, 7 days a week. See our current pricing.