https://leakexpertslondon.co.uk/services/acoustic-leak-detection 2026-10-19 https://leakexpertslondon.co.uk/diagrams/acoustic-two-sensor-sound-path.svg Pipe with a sensor at each end of a run and a leak between them closer to the left sensor, with sound arriving at the left sensor first and the right sensor later. Two sensors either side of the leak: the sound reaches the nearer one first, and the gap in arrival times places the leak between them. https://leakexpertslondon.co.uk/services/non-invasive-leak-detection 2026-10-19 https://leakexpertslondon.co.uk/diagrams/non-invasive-leak-detection-step-ladder.svg Ladder of six steps from history and sight, through meter and pressure tests and surface methods, to a camera and last a larger opening, with disruption rising at each step. The six steps, taken in order from least to most disruptive; the larger opening comes last and only where the pipe must be reached. https://leakexpertslondon.co.uk/price/fixed-price-package 2026-10-19 https://leakexpertslondon.co.uk/diagrams/fixed-price-package.svg The scope of the detection package as two columns, what is included, one visit to one property with whichever methods the leak needs and a written report, and what is not, larger repairs, access and making good, followed by four situations where the package does not apply. The package covers locating a leak inside one property; situations outside it, such as a neighbour source or no leak, are charged at the hourly rates on the price pages. https://leakexpertslondon.co.uk/price/what-is-included 2026-10-19 https://leakexpertslondon.co.uk/diagrams/what-is-included.svg A line showing the survey scope on the left, finding where the water escapes and recording it with tests, marking and a written report, and separate jobs on the right, larger repairs, opening up and making good, with the lists of what the visit covers and what it does not. The survey ends at the finding; larger repairs, access and making good are separate jobs quoted from the report. https://leakexpertslondon.co.uk/leaks/bubbling-paint-on-a-wall 2026-10-19 https://leakexpertslondon.co.uk/diagrams/bubbling-paint-on-a-wall.svg Six small wall panels showing paint bubble patterns: a cluster of pin-head blisters, coin-sized soft bubbles, one or two large sagging bubbles, bubbles low near the skirting, bubbles under a window and bubbles in a straight line, each with the likely moisture route. The size, position and feel of the bubbles point to vapour, persistent damp, a liquid source, ground moisture, rain or a pipe run. A schematic, not to scale. https://leakexpertslondon.co.uk/leaks/dishwasher-leaking-from-the-bottom 2026-10-19 https://leakexpertslondon.co.uk/diagrams/dishwasher-leaking-from-the-bottom.svg A dishwasher cycle drawn as a bar from filling through washing and pumping out to idle, with the place the water shows and the likely source and whose job it is at each phase. Where in the cycle the puddle appears separates inlet pipework, the machine and drain pipework. A schematic, not to scale. https://leakexpertslondon.co.uk/leaks/flexible-tap-connector-leaking 2026-10-19 https://leakexpertslondon.co.uk/diagrams/flexible-tap-connector-leaking.svg Drawing of a braided flexible tap connector from the tap tail to the supply pipe, with the nut at the tap, the crimped collar at each end, the braid body and the nut at the supply pipe marked 1 to 4, and what dry paper shows for each. A flexible connector leaks at the tap nut, the supply nut, the crimped collar or the braid, and each leaves a different mark on dry paper. A schematic, not to scale. https://leakexpertslondon.co.uk/leaks/how-to-detect-a-water-leak-in-your-house 2026-10-19 https://leakexpertslondon.co.uk/diagrams/how-to-detect-a-water-leak-in-your-house.svg Cross-section of a house with the loft, a bathroom, the kitchen, the boiler and utility area, the floors and ceilings below wet rooms, and the outside, numbered 1 to 6 in the order a walk should take them. Walk the house with a torch, a dry tissue and a thermometer, starting where leaks are most likely. A schematic, not to scale. https://leakexpertslondon.co.uk/leaks/kitchen-floor-wet-near-the-sink 2026-10-19 https://leakexpertslondon.co.uk/diagrams/kitchen-floor-wet-near-the-sink.svg A blank log sheet for a wet kitchen floor with six check times over two days, a column for water used, and blank columns for whether the floor is wet and whether the wet edge has moved, with a short guide to reading it. The log sheet: dry the floor, mark the wet edge, then fill in the blank columns at each check. Water that returns with nothing in use is a pipe. https://leakexpertslondon.co.uk/leaks/leak-inside-a-wall-how-to-tell 2026-10-19 https://leakexpertslondon.co.uk/diagrams/leak-inside-a-wall-how-to-tell.svg The layers of a wall from the paint through the plaster and the brick or stud void to the edges at skirting and floor, with the sign a leak leaves in each layer and a pipe marked in the void. A leak shows through the wall outermost layer first: paint, plaster, sound, then the edges. A schematic, not to scale. https://leakexpertslondon.co.uk/leaks/signs-of-a-hidden-water-leak 2026-10-19 https://leakexpertslondon.co.uk/diagrams/signs-of-a-hidden-water-leak.svg A ranked list of twelve signs of a hidden water leak in rows that fade from dark to light, from the sound of water with everything off at the top to a higher water bill at the bottom, grouped as act on these, middle of the table, and leads not evidence. A sign is reliable when it is hard to explain without a leak: the first five change while nobody is using water. The fade is the ranking, not a measurement. https://leakexpertslondon.co.uk/leaks/water-leak-but-cant-find-it 2026-10-19 https://leakexpertslondon.co.uk/diagrams/water-leak-but-cant-find-it.svg The five steps of a self-check for a hidden leak, quiet house, stop tap, zones, dry paper and the log, above a printable observation log with seven things to note and a blank column to fill in. Five safe checks, then a written record: the log is the most useful thing to hand a surveyor. https://leakexpertslondon.co.uk/methods/how-do-plumbers-find-a-leak 2026-10-19 https://leakexpertslondon.co.uk/diagrams/how-plumbers-find-a-leak-decision-chart.svg Flow chart starting from whether the water meter turns with everything off, with a supply-side path through circuit tests, sound and gas and a camera, and a second path for waste, seals, heating and weather ending at moisture mapping. Each test result chooses the next move: a moving meter leads down the supply path, a still meter leads to waste, heating and weather. https://leakexpertslondon.co.uk/methods/how-pressure-testing-finds-a-leak 2026-10-19 https://leakexpertslondon.co.uk/diagrams/how-pressure-testing-finds-a-leak.svg Four pressure gauge dials showing the outcomes of a test, a needle that holds, a needle that falls steadily, a needle that falls then steadies, and a section that cannot be isolated, with what each does and does not let you say. The test says that a leak exists in the closed section, not where. A schematic, not a measurement. https://leakexpertslondon.co.uk/methods/how-thermal-imaging-finds-a-leak 2026-10-19 https://leakexpertslondon.co.uk/diagrams/how-thermal-imaging-finds-a-leak.svg Five small thermal-style panels in blue to red colours, a cool patch on a ceiling, a cool strip low on a wall, a warm stripe across a floor, a cool edge round a shower tray and an even image with no pattern, each with what a leak could explain and what else could. A thermal imager does not see water: it shows surface temperature, and each pattern has a leak explanation and an innocent one. Colours here are schematic. https://leakexpertslondon.co.uk/methods/how-tracer-gas-finds-a-leak 2026-10-19 https://leakexpertslondon.co.uk/diagrams/how-tracer-gas-finds-a-leak.svg The four steps of a tracer gas test, isolate, empty and fill, sample and compare and mark, above a bar chart on a log scale of the approximate wait for gas to reach the surface through dry sand, wet sand, wet soil, wet clay, asphalt and concrete. Gas goes into an isolated, emptied run and a detector follows it up. Wait times are approximate figures for gas to travel; bars are on a log scale. https://leakexpertslondon.co.uk/methods/non-invasive-leak-detection-methods 2026-10-19 https://leakexpertslondon.co.uk/diagrams/non-invasive-leak-detection-methods.svg A grid of seven situations against five methods, pressure testing, acoustic listening, tracer gas, thermal imaging and moisture meters, shaded where a method fits, weakened or masked, or does not apply, such as acoustic being masked in a noisy building and weakened under thick screed. Each method senses a different physical thing, suits different materials and stops working in its own conditions: red marks where a method is weak, weakened or masked. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16 2026-10-19 https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/tarnished-copper-supply-pipe-behind-toilet-pan-connector.webp Copper supply pipe with an elbow and black patches, running beside a white toilet pan and a grey waste connector The corroded 15 mm cold supply behind the pan connector, hidden from view by the access board. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/bath-side-panel-removed-showing-floor-void-beside-toilet.webp Bathroom with the bath side panel removed to show a dark floor void beside the toilet, with an orange glove on the lid The bath panel open to the void, the access that made the pipe reachable. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/pressure-gauge-held-in-orange-glove-in-tiled-bathroom.webp Pressure gauge with bar, kPa and psi scales held in an orange glove against a tiled bathroom wall The pressure gauge used during the visit. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/stained-bath-panel-joint-beside-toilet-before-opening.webp White bath with a brown stain running down the join between two side panels, beside a toilet and a green mat The bath side panel before it was opened: staining at the join between the two panels, beside the toilet. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/peeling-paint-and-dark-staining-at-skirting-beside-bathroom.webp Painted wall with bubbled, peeling paint and dark brown patches above a skirting board and a tiled floor Paint lifting and dark staining where the wall meets the skirting on the floor next to the wet area. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/mould-and-damp-staining-on-cupboard-wall-above-wood-floor.webp Cupboard wall with dark patches and a tide mark above the skirting, and darkened boards on the wood floor below Damp staining on the cupboard wall and darkened boards on the floor below it. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/raised-floorboards-with-staining-in-gap-at-hallway-edge.webp Gap at the edge of a wood floor where raised boards show yellow-brown staining on their exposed edges Raised boards with staining on their exposed edges at the edge of the floor. https://leakexpertslondon.co.uk/jobs/2026-08-corroded-pipe-behind-toilet-warped-floor-n16/cut-out-copper-elbow-with-green-corrosion-crust.webp Short cut-out piece of copper pipe with an elbow, held in a palm, with green and cream crust around the bend The section of copper pipe cut out during the repair, with green and cream crust around the elbow. https://leakexpertslondon.co.uk/jobs/2026-09-bath-waste-pipework-leak-into-flat-below-sw11 2026-10-19 https://leakexpertslondon.co.uk/jobs/2026-09-bath-waste-pipework-leak-into-flat-below-sw11/hoses-on-dirty-tiled-floor-beside-kitchen-dishwasher-cabinet.webp Ribbed grey hose and a smooth grey hose lying across a dirty tiled floor beside a white kitchen cabinet and dishwasher The floor beside the dishwasher, where the hoses were checked. The dishwasher was cleared as the source. https://leakexpertslondon.co.uk/jobs/2026-09-bath-waste-pipework-leak-into-flat-below-sw11/water-stain-and-peeling-paint-on-wall-ceiling-edge-in-flat-below.webp Pale water stain and a flaking paint patch on a blue-grey wall just below a white ceiling edge, with a recessed light below Staining and flaking paint photographed during the job. It shows that water had reached a wall, not where it came from. https://leakexpertslondon.co.uk/jobs/2026-09-bath-waste-pipework-leak-into-flat-below-sw11/underside-of-bath-with-timber-batten-and-stained-floor-void.webp Underside of a white bath above a bare floor void, with a timber batten at the left and a stained board below it The void under the bath once the plastic cover was off. The report records a significant amount of water under that cover. https://leakexpertslondon.co.uk/jobs/2026-09-bath-waste-pipework-leak-into-flat-below-sw11/white-bath-trap-and-grey-waste-above-wet-plastic-tray-under-bath.webp White bath trap and grey waste outlet hanging above a plastic tray with a wet film on it, with a metal clamp at the right The trap and waste outlet under the bath, with a wet film on the tray below, where the probable source was. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4 2026-10-19 https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/rotted-timber-and-black-mould-beneath-shower-tray-edge.webp Blackened rotted timber and mould under the edge of a shower tray, with rust staining on the metal frame above it Rot and mould under the tray edge, the evidence that water had been getting past the enclosure for some time. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/dropped-shower-tray-edge-above-open-gap-with-dark-timber-and-cobwebs.webp Curved shower tray edge sitting above an open gap, with dark rotted timber blocks and cobwebs visible beneath it The dropped tray edge, with the gap beneath it and the timber below. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/brown-water-stain-across-ceiling-corner-above-grey-vertical-blind.webp Brown water staining spreading across a ceiling corner and down a wall above a grey vertical blind The stain in the room below, beside the window, where the water arrived. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/peeling-plaster-and-stain-on-reveal-above-vertical-blind.webp Peeling, stained plaster on the reveal above a grey vertical blind, with a clear tide line where the damp stops Peeling plaster and a tide line on the wall above the blind in the flat below, a close view of the damage described in the record. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/ceiling-edge-tide-marks-and-dark-spots-above-window-blind.webp Ceiling and wall junction above a window blind with brown tide marks and a line of dark spots along the edge Tide marks at the ceiling edge and dark spots along the junction, above the window where water was arriving. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/void-beside-raised-shower-tray-edge-with-dark-timber-and-rusty-nail.webp Dark rotted timber in the gap beside the raised edge of a shower tray, with a rusty nail above the floor tiles The void beside the tray edge, with dark timber and a rusty nail: the same rot, seen from another side. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/shower-waste-cover-lifted-beside-tray-with-gap-to-floor-tiles.webp Shower waste cover lifted off its outlet on a floor strip beside a curved tray, with a gap and tile joint beside it The waste cover lifted off beside the tray, with the floor tiles and the gap along the tray side in view. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/open-dirty-floor-tile-joint-beside-curved-shower-tray.webp Open, stained joint between grey floor tiles running up to the curved side of a shower tray A stained, open tile joint running up to the tray, where floor and tray meet. https://leakexpertslondon.co.uk/jobs/2026-09-cracked-shower-tray-tw4/hairline-crack-through-wall-tiles-beside-shower-enclosure.webp Hairline crack running down through white wall tiles and a grout line beside a glass shower enclosure frame A hairline crack through the wall tiles beside the enclosure frame, another sign of movement or damage in the shower area. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8 2026-10-19 https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/worn-black-sealing-ring-and-green-ring-on-blue-paper-towel.webp A worn black rubber sealing ring and a green ring lying on a blue paper towel, with a bathroom wall behind A degraded black sealing ring from the waste joint, photographed beside a green ring on a paper towel. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/shower-waste-pipe-end-tilted-out-of-trap-nut-in-joist-void.webp White plastic waste pipe end tilted out of its nut in a joist void, with a black and an orange sealing ring on it The shower waste pipe separated from its trap, seen in the void between the joists. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/shower-waste-trap-and-union-nuts-in-joist-void-with-insulation.webp Plastic shower waste trap with two white union nuts in a joist void, loose insulation and a copper pipe beside it The waste trap and its union nuts in the void. The record notes the nuts had loosened and the washers had degraded. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/ceiling-opening-showing-laths-with-brown-water-stain-beside-it.webp Rectangular opening cut in a ceiling showing dark timber laths, with brown water staining on the paint beside it The small ceiling opening in the flat below, the only access needed for the endoscope. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/endoscope-monitor-resting-on-blue-case-beside-bath.webp Handheld endoscope monitor held beside a bath with a glass screen, resting on a blue plastic case The endoscope monitor in use beside the bath while the camera was passed through the opening. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/brown-stained-ceiling-corner-with-pull-cord-switch.webp Brown stained patches on a white ceiling beside a pull-cord switch fixed in the corner of the room Brown staining on a ceiling next to a pull-cord switch. The stain shows where water had reached, not where it started. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/bathroom-ceiling-small-drill-holes-and-stain-near-light-fitting.webp Bathroom ceiling with three small holes and a faint stain, a light fitting and a shower arm visible Small holes in the ceiling by the light fitting, with a brown tide mark curving along the ceiling edge. https://leakexpertslondon.co.uk/jobs/2026-09-shower-waste-separated-endoscope-cr8/bathroom-ceiling-tide-mark-curving-past-open-light-fitting.webp Bathroom ceiling with a brown tide mark curving past an open light fitting, with a shower head and window below A brown tide mark curving across a bathroom ceiling past an open light fitting, with the shower head and window below. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak 2026-10-19 https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/hydrogen-probe-and-detector-beside-underfloor-heating-manifold-cupboard.webp Hand holding a long gas probe towards a heating manifold cupboard, with a yellow hydrogen detector on the tiled floor The probe held at the manifold cupboard, with the hydrogen detector on its sampling tube on the tiled floor. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/hydrogen-detector-reading-378-ppm-high-at-heating-manifold.webp Hydrogen detector showing 378 ppm and a HIGH marker, held in front of a heating manifold with the probe at a fitting The detector reads 378 ppm and flags HIGH with the probe tip at the fittings on the right of the manifold. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/hydrogen-detector-reading-34-ppm-norm-probe-at-manifold-fitting.webp Hydrogen detector showing 34 ppm and a NORM marker, with the probe tip resting at a fitting beside a heating manifold A lower reading, 34 ppm marked NORM, with the probe at a fitting on the right of the manifold. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/hydrogen-detector-display-37-ppm-norm-on-tiled-floor.webp Close view of a hydrogen detector screen headed H2 and reading 37 ppm, marked NORM, in a yellow and black case The detector screen on the floor reading 37 ppm, marked NORM. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/heating-manifold-flow-meters-orange-staining-and-water-droplets.webp Underfloor heating manifold flow meters with orange rust staining running down the body and water droplets on the metal The leaking flow meters: orange staining and water at the connections where the readings pointed. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/heating-pipework-in-dusty-void-beneath-floor.webp Copper pipe and a clipped plastic pipe in a dusty void beneath a floor, under a rough cracked surface Pipework in a void beneath the floor, photographed during the same visit. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/boiler-display-showing-pressure-of-0-9-bar.webp Boiler display with a blue backlight showing 0.9 bar, with a printed working range of 0.5 to 3.0 beneath the figure The boiler display showing 0.9 bar, with the 0.5 to 3.0 range printed under the reading. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/hydrogen-detector-350-ppm-high-with-probe-at-manifold-pipework.webp Hand holding a hydrogen detector reading 350 ppm and HIGH, with the sampling tube running to pipework in a manifold cupboard A second HIGH reading, 350 ppm, with the sampling tube tip at the pipework to the right of the manifold. https://leakexpertslondon.co.uk/jobs/2026-10-hydrogen-tracer-gas-heating-manifold-leak/underfloor-heating-manifold-both-flow-meters-stained-orange.webp Two flow meter tubes on an underfloor heating manifold with orange staining on the fittings, manifold body and pipes below A wider view of the manifold: orange staining at both flow meter fittings and running down to the pipes below. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18 2026-10-19 https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/grey-soil-pipe-in-duct-beside-blue-toilet-frame-with-timber-supports.webp Grey soil pipe running through a duct beside a blue toilet frame, resting on timber, with dark mould on the wall behind The soil pipe in the duct, with timber supports below it. The record describes the pipe as bowing and out of alignment. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/gas-cylinder-with-two-gauge-regulator-in-front-of-open-kitchen-sink-cupboard.webp Gas cylinder with a two-gauge regulator and hoses on a wood-effect floor in front of an open kitchen sink cupboard The gas rig set up in the kitchen, with the sink waste visible in the cupboard behind. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/sink-dye-test-orange-powder-poured-into-running-tap-water.webp Hand pouring orange powder into a running tap over a white sink, with a yellow dye trail curling round the plughole The dye test at the kitchen sink: dye added to running water to see where it goes. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/pressure-gauge-on-manifold-beside-red-handwritten-tag.webp Round pressure gauge with a 0 to 100 dial, mounted above a red tag carrying handwritten labels A pressure gauge on a manifold, from the hot and cold pressure tests. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/inert-gas-regulator-with-two-gauges-and-braided-hose-on-wood-floor.webp Inert gas regulator with two pressure gauges and a braided hose, resting on a wood-effect floor beside coiled cable The regulator on the inert gas cylinder, with its two gauges and the hose that carries gas to the pipework under test. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/black-mould-and-brown-tide-marks-on-wall-beside-sliding-door-track-with-probe-on-floor.webp Wall corner beside a sliding door track with black mould and brown tide marks above the skirting, a metal probe on the floor Staining and mould at the foot of a wall beside a sliding door track. A long metal probe rests on the floor. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/cut-out-in-stained-plasterboard-wall-below-sliding-door-track-with-black-mould.webp Cut-out in a stained plasterboard wall beside a sliding door track, with black mould spots and brown tide marks around it A section of plasterboard cut out at the foot of the stained wall, with mould spotting the surface around it. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/cut-opening-in-plasterboard-showing-yellow-insulation-behind-mould-spotted-wall.webp Close view of a square opening cut in mould-spotted plasterboard, with yellow insulation visible inside the wall Close view of the opening: yellow insulation sits behind the plasterboard, which is spotted with mould. https://leakexpertslondon.co.uk/jobs/2026-10-toilet-leaks-on-flush-soil-pipe-sw18/yellow-insulation-in-wall-cavity-beside-metal-stud-and-dusty-base-plate.webp Yellow insulation inside a wall cavity beside a metal stud, with plaster dust and debris on the base plate below Inside the cavity: insulation beside a metal stud, with plaster dust and debris on the base plate below it.