Looking after render
Keeping a Maintenance Record for a Rendered House
Render lasts longest when small problems are caught early: a leaking downpipe joint, a sill that has lost its drip, soil piled against the base of the wall. A short yearly check and a simple record of what you saw and what was done are enough to keep most rendered houses in good order.
On this page
What to check each year
Walk round the house once a year, ideally after heavy rain. Look for streaks or green staining below gutters and downpipe joints, which mean water is running down the face. Check that sills and copings still throw water clear; K Rend's design guidance asks for them to project with a drip, and a sill that lets water run back onto the render leaves a dark stain below it.
Look at the base of the wall. Render should stop above the damp-proof course on a bead, and paving, soil or gravel should not be built up against it; anything that bridges the DPC gives damp a route into the wall. Note any cracks, and photograph them with a coin or ruler for scale so you can tell later whether they have grown. Check the sealant around window and door frames, where render meets the frame.
Keep the photographs together. A single picture of the entire exterior, taken from the same spot each year, gives an index to everything else: where a later repair was made, which walls were recoloured, how algae spreads on the shaded side. Recolouring can hide earlier repairs from view, so keep the old pictures as well as the new.
| Where | Look for |
|---|---|
| Gutters and downpipes | Leaks, overflow, streaking below joints |
| Sills and copings | Drips working, no staining beneath |
| Base of wall | Render above DPC, no soil or paving against it |
| Wall faces | New or growing cracks, hollow-sounding patches |
| Frames | Sealant intact where render meets windows and doors |
Cleaning and algae
Green and black growth on render is usually algae, worst on north-facing walls and below leaks. It is cosmetic at first but holds moisture against the surface. K Rend's maintenance advice for its finishes is a warm power wash with a suitable detergent, with the pressure adjusted so the render surface is not damaged, and an annual fungicidal wash on walls that tend to stay wet. It notes that power washing is not suitable for dry dash finishes, which can lose stones.
Before cleaning anything, find out what the finish is. Limewash and lime render are soft and are cleaned far more gently, and some coatings have their own cleaning instructions. If the product is unknown, test a small hidden area first.
Climbing plants deserve a note in the log too. Ivy and similar plants hold moisture against the wall, and their roots work into cracks and under loose edges. Removing them can pull off weak render, so cut stems at the base and let the growth die back before taking it down, then check the render underneath.
The render repair service explains what a repair involves if the yearly check finds hollow or cracked areas.
When to recoat
Different finishes age at different rates. Limewash on lime render is the most frequent: Mike Wye's guide expects recoating every three to seven years on average. Painted sand-and-cement render needs repainting when the colour fades or the film starts to chalk. Through-coloured renders and silicone finishes do not need painting for colour, but can be recoated later if you want a change; K Rend says its render can take masonry paint.
Before a new colour is applied, share your record with whoever is quoting. The coating guide explains why previous coatings and repairs matter to the choice of product.
Small jobs, and the ones to leave
Some maintenance is well within a homeowner's reach from the ground: clearing soil and leaves back from the base of the wall, re-sealing a gap between a window frame and the render, cleaning a low wall gently, or getting a leaking downpipe joint fixed. These stop small problems growing and cost little.
Other jobs are better left. Do not climb to tap or poke high render, and do not try to knock off a loose patch from a ladder; render is heavy and falls unpredictably. Avoid filling a crack with ordinary filler and painting over it until you know whether the render around it is hollow, because the patch will hide the evidence. Pressure washing at full power can cut into soft finishes and strip stones from dash.
For example, a hypothetical owner might notice a vertical crack below a bedroom window during the yearly check. They photograph it with a ruler, note the date, and look again after winter. If it has not grown and the render taps solid around it, a fine crack can be filled and repainted. If it has widened, or the render sounds hollow, the log entry and photographs go to whoever assesses it.
What to write down
Keep one simple log: the date, the wall, what you saw, and what was done about it. Write observations as observations, such as a hairline crack below the bathroom window, rather than guessing a cause. When work is done, add the product names, colour references and who did it, and file the invoice and any data sheets with the entry.
Store the original specification and photographs of stripped walls from any re-render, because they show what lies behind the finish. Give files plain names with dates. The Doncaster homepage links the services that future work may need; the record lets that work start from facts about your walls rather than memory.
Common questions
What if I have no records of the original render?
Start now with what you can see and what you know: dates you moved in, work you have had done, and photographs of the walls today. Do not invent a product name to fill the gap. A surveyor can often tell cement from lime, dash from a textured coating, and painted from through-coloured render, and that observation can become the first entry.
How often should rendered walls be cleaned?
Only when they need it. Many walls never need more than an occasional gentle wash; shaded walls near trees or leaking gutters may need treating for algae every year or two. Fix the water source first, because a wall that keeps getting wet will keep turning green however often it is cleaned.
Is a hairline crack in render something to worry about?
Usually not on its own. Fine surface crazing is common in cement render as it dries and ages. Record it with a dated photograph and check it each year. It becomes a concern if it widens, if the render around it sounds hollow when tapped, or if staining or damp appears near it, because those signs mean water may be getting behind the coat.
See housing and planning information for Doncaster and nearby places, including the source and geography behind each figure.
