Phasing
Whole House at Once or in Phases? Where a Render Job Can Stop
Doing the front this year and the back next year sounds like a simple way to spread a whole-house job. On the wall itself, a phase only works if it ends somewhere render can stop cleanly, if putting the scaffold up twice makes sense, and if the later finish will sit acceptably beside the earlier one. This guide looks at those physical limits before the household convenience.
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Where a phase can end on a real wall
Render does not stop gracefully part-way along a wall. A through-coloured finish is applied as one continuous skin across an elevation; K Rend's Silicone TC sheet, for example, asks for work to a wet edge and for continuous surfaces to be finished without interruption. A phase line across the middle of a long side wall leaves a joint that is likely to show in low sunlight for the life of the render.
Workable phase boundaries are the places where the building already changes: an external corner with an angle bead, the line where a rear outrigger meets the main house, a stop bead against brick or stone that is staying exposed, or a projecting band. For example, on a hypothetical pebbledashed semi, finishing the front and the whole gable side first and leaving the back for later puts the joint on the rear corner, where it is seen only from the garden.
A temporary edge also has to keep water out. If one elevation is stripped and re-rendered while the next keeps its old coat, the cut edge of the retained render needs trimming back to sound material and finishing with a bead, not leaving as a broken lip that rain can run behind. Ask how each stopping line will be weathered until the next phase arrives, and whether the old coat beside it is sound enough to wait.
| Item | All elevations together | Phased by elevation |
|---|---|---|
| Scaffold | One erection around the house | Erected and struck for each phase |
| Stopping lines | Only at corners and beads | Temporary edges against old render |
| Curing waits | One elevation cures while another is prepared | Each small phase waits on its own |
| Finish age | One season across the house | Visible age difference at the joint |
What going round twice adds to the work
Every phase brings its own scaffold erection and strike, its own masking of windows and paths, its own removal and refitting of downpipes and fittings, and its own spoil to clear. On a terrace, or a house on a steep plot where the scaffold has to step down a bank or bridge a neighbour's outrigger, that set-up is a large part of each visit.
Phasing also splits the waiting times awkwardly. A silicone system needs its base coat to cure before primer and finish, at least 14 days for K Rend's Silicone TC, so even a small phase sits under scaffold for weeks. Doing two elevations together often takes far less than twice as long, because one cures while the other is stripped and repaired.
There is a building-control angle too. Approved Document L treats stripping and re-rendering as renovating the wall, and Diagram 11.1 takes the element as the whole elevation in which that wall sits. Each elevation is judged on its own share, so a phase that re-renders more than half of one elevation meets the 50% test for that elevation whatever happens to the others. Ask building control how they will view the whole programme before phase one starts.
Matching the second phase to the first
A render that has weathered several winters will not look like a new one, even in the same colour reference. Dirt, algae on shaded faces and sunlight all change the surface. Expect the second phase to read slightly differently, and put the joint where a difference is acceptable, such as a corner between two elevations that cannot be seen at the same time.
Before the second phase, the older work can be brought closer. K Rend's maintenance guidance describes low-pressure washing from the top down with a mild detergent, and a biocide where algae has settled. Where the earlier phase is scraped texture that has faded, K Rend's range includes Colour Enhance, a coating intended to refresh existing scraped render. A deliberate colour change across the retained walls is a separate decision, best made before the second phase is ordered.
Keep a record from phase one that the next contractor can use: system and product names, colour reference, the beads used at the stopping lines, and photographs of the masonry before it was covered. Without it, the second stage starts by guessing what lies behind a perfectly good-looking wall.
A worked example: two ways to phase the same house
Take a hypothetical stone-fronted end terrace with a rendered rear outrigger and a cement-rendered gable that sounds hollow in patches. Option one is a single job: scaffold all round, strip the gable and outrigger, repair, base-coat and finish both, with the stone front cleaned and left as stone. Option two does the gable this summer and the outrigger next year.
In option two the gable phase ends at the corner where it meets the outrigger, and that corner needs a bead and a weathered edge for a year. The outrigger scaffold goes up again, its downpipes come off again, and its finish is a year younger than the gable's. If stripping the gable shows the masonry needs more render repairs than expected, phase two may change too. On an old solid wall SPAB's caution about cement applies to both options: a hard coat over damp stone can trap water whichever year it goes on.
Phasing suits houses with natural breaks and households that can live with mixed finishes for a while. It suits a single long elevation that would have to be split part-way along much less well, or a stopping line that would cross a bay or porch. In a conservation area or the National Park, check the planning position for each phase, because rendering any part of a house there falls outside permitted development. If the overall scope is still open, the Sheffield whole-house rendering overview links each part of the job.
Common questions
Is it acceptable to render only the front of the house?
Yes, if the front is a self-contained elevation that ends at corners or stop beads and you are content for the back and sides to stay as they are. Check the planning position first if the house is in a conservation area or the National Park.
Can all the old render come off now and the new coats go on later?
Leaving masonry bare for months is risky unless it is meant to stay bare. Walls that have been under render often have soft joints and old repairs that were never meant to face the weather. Strip each phase only when its new coats can follow within the system's normal programme.
See housing and planning information for Sheffield and nearby places, including the source and geography behind each figure.
