Service
Render Repair and Crack Remediation Across London & Kent
Hollow and cracked render cut back to sound material, rebuilt in matching coats and blended into the elevation, dealing with the cause of the crack, not just the line you can see.
18 years on rendered elevations · 10-year workmanship guarantee
- 18 years' experience
- £2m public liability insurance
- 10-year workmanship guarantee
- K Rend approved installer
- Listed on TrustATrader
What render repair involves
Render fails in two ways: it loses its bond with the wall, which you find by tapping and hearing a hollow note, and it cracks, which you can see. The repair is cutting the failed area back to sound, well-bonded material, preparing the exposed substrate, rebuilding in matching coats and finishing so the repair sits within the surrounding texture.
Crack remediation is the part people underestimate. A crack is information: its shape, position and behaviour tell you whether it is shrinkage in the render, thermal movement, a missing movement joint, a corroding lintel or structural settlement. Filling it without answering that question guarantees it comes back in the same place.
We repair sand and cement render, thin-coat silicone and K Rend systems, and pebbledash, matching the existing build-up where the rest of the wall is sound.
Who it is for and when
It is for owners of rendered properties where the elevation is broadly sound but has localised failure, a hollow patch, a crack over a window, a section that has blown at the base of a wall, or damage from a removed satellite dish, pipe or old flue.
Typical triggers: a hollow sound when you tap the wall, a crack that has widened over a couple of seasons, staining or damp inside behind the affected area, render lifting at the base of a wall, or a survey flagging cracking before a sale.
Where more than roughly a third of an elevation has failed, a full re-render usually gives a better and more economical result than progressive patching, and we will say so rather than sell repeat visits.
What happens if it is left
The cost of leaving it another winter
A crack in render is an open pipe into the wall. Water enters at the crack, spreads behind the render where it cannot evaporate, and debonds an area far larger than the visible damage. That is why a 200mm crack so often turns out to sit in the middle of a square metre of hollow render.
Freeze-thaw then converts debonded render into missing render. Sections fall, usually from the most exposed corner or the base of the wall, exposing bare masonry and leaving an elevation that now needs masonry repair as well as rendering.
Left long enough, the internal consequences arrive: damp patches, blown plaster, mould on the wall behind, and in the worst cases a corroding steel lintel that keeps expanding and re-cracking the render above the window until it is properly addressed.
Common mistakes we are called in to undo
- Filling a live crack with mastic or filler and painting over it, so it reopens in the same line within a year.
- Repairing only the visible crack without tap-testing the surrounding render for the hollow area around it.
- Patching with a stronger mix than the original render, which pulls at the edges of the repair and cracks around it.
- Rendering over a corroding lintel or a missing movement joint rather than dealing with the cause first.
Our process
How a render repair & crack remediation job runs from first call to guarantee
Step 1
Inspection
We tap-test the whole elevation to map the true extent of debonding, examine crack pattern, width and location, and look for the cause: movement, corrosion, water ingress or shrinkage.
Step 2
Diagnosis
We tell you whether it is a render fault or a structural symptom, and whether repair or full re-render gives better value. You get a written fixed price with the payment schedule spread across the project.
Step 3
Cutting out and preparation
Access is arranged by us. Failed render is cut back to sound, bonded material with a clean edge, the substrate is prepared, and any cause, corroded fixings, missing beads, a bridged detail, is dealt with.
Step 4
Rebuilding and blending
The area is rebuilt in matching coats, reinforced where needed, then the surface is worked to match the surrounding texture so the repair does not read as a patch from the street.
Step 5
Verification and guarantee
The repair is checked for flatness, texture match and hollow spots, protected while it cures, and walked with you before access comes down. Completed work carries our 10-year workmanship guarantee.
What you get
The results this work is actually bought for
The water route is closed
Cutting out and rebonding removes the void behind the render where water was collecting and spreading the failure.
Repairs you cannot pick out
Matching the build-up and working the texture back into the surrounding surface is the difference between a repair and an obvious patch.
The cause is dealt with
Corroding fixings, missing movement joints and bridged details are resolved, so the same crack does not reappear next year.
Far cheaper than a full re-render
Catching localised failure early keeps the job to a repair rather than a whole-elevation replacement.
Internal damp stops at the source
Closing the ingress point is what allows the wall behind to dry and internal redecoration to hold.
An honest call on repair versus replace
If patching will not give you a good result, we tell you and price the alternative rather than taking the easier job.
In detail
Render repair & crack remediation: materials, methods and where it applies
Reading cracks
Fine, random map cracking across a surface is usually shrinkage in the render, cosmetic, though it still lets water in and should be addressed. Straight vertical or diagonal cracks radiating from the corners of windows and doors are stress concentrations at openings. Horizontal cracking directly above an opening often indicates a corroding steel lintel expanding as it rusts. Stepped cracking following the joints behind the render points to movement in the masonry itself.
Width and behaviour matter as much as pattern: a crack that has clearly widened over a season is live and needs its cause resolved before any repair. That is a diagnosis made at the wall, not from a photograph.
Repair methods by system
On sand and cement, failed areas are cut back to sound material with a clean square edge, the substrate keyed and dampened, and the area rebuilt in scratch and float coats gauged to match the existing rather than stronger than it.
On thin-coat silicone and K Rend systems, the repair follows the system: base coat with mesh lapped into the sound surrounding base coat, primer, then topcoat in the matching grain and colour. Colour matching on aged through-coloured render is never perfect on day one, and we will be straight with you about that before we start rather than afterwards.
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Common repair situations
Blown render at the base of a wall from bridged ground levels or a missing bell bead. Cracking at window corners with no movement bead. Damage where a satellite dish, alarm box, pipe bracket or old flue has been removed. Hollow areas under a leaking gutter run. Impact damage at low level on garage and boundary walls. Frost damage on north-facing elevations that never dry properly.
Each has a different fix, and in most cases the detail that caused it, the missing bead, the bridged base, the leaking gutter, has to be corrected as part of the work or the repair is temporary.
Domestic and commercial repairs
Domestic repairs are usually single areas or one elevation, often arranged around a decorating project or a sale. Commercial and managed block repairs tend to be scheduled surveys of several elevations, where we map and price the hollow areas so the managing agent can prioritise.
We work throughout London and Kent, including Bexley, Bexleyheath, Sidcup, Dartford, Erith, Bromley and Orpington.
Not sure this is the right specification for your wall? See all of our services, the areas we cover, or go back to the homepage.
FAQs
Render repair & crack remediation questions we are asked most
How much does render repair cost?
It depends on the size of the failed area, access and whether the cause needs separate work. We give a written fixed price after inspecting the elevation, with payments spread across the project. Quotes are free. Small jobs carry a minimum charge.
How long does a render repair take?
Small repairs are quick in themselves, but coats need curing time between them and weather affects the work. The programme comes with your written quote.
Will the repair be visible?
We match the build-up and work the texture back into the surrounding surface. On painted render a repaint of the elevation makes it invisible; on aged through-coloured render there can be a slight tonal difference initially, and we will tell you that up front.
Why does render crack?
Shrinkage, thermal movement, missing movement joints, corroding lintels or fixings, or structural movement. The pattern and position tell us which, and the cause has to be resolved before the repair.
Should I repair or fully re-render?
Localised failure on an otherwise sound elevation is worth repairing. Once a significant proportion of the wall is hollow or cracked, a full re-render is usually better value and gives a consistent finish.
Is cracked render a structural problem?
Often not, most cracking is in the render itself. But some patterns indicate movement or a corroding lintel, and if we see that we will tell you plainly rather than covering it up.
Can you repair K Rend and silicone render?
Yes, using the matching system build-up: mesh-reinforced base coat lapped into the sound surrounding work, primer and matching topcoat grain.
How long will the repair last?
A repair carried out back to sound material, with the cause of the failure dealt with, has the same life expectancy as the sound render around it.
Is the work guaranteed?
Yes: 10-year workmanship guarantee on completed work, and £2 million public liability insurance. We are listed on TrustATrader.
Related work
Often carried out alongside this
Sand and cement render
Traditional hard-wearing render, floated or textured, for walls that need a durable, cost-effective finish.
Read moreSilicone render
Through-coloured, self-cleaning silicone systems that shed water and hold their finish for years.
Read moreExterior damp specialists
We trace penetrating damp back to the failed pointing, render or detail causing it, then put the fabric right.
Read moreFree quote
Fix the crack and the reason it appeared
Send a photo of the crack or the hollow area and tell us how long it has been there. We will inspect the elevation, diagnose the cause and price the repair in writing, free.
- 18 years' experience
- £2m public liability insurance
- 10-year workmanship guarantee
- K Rend approved installer
- Listed on TrustATrader