Who this guide is for
- Homeowners rendering or re-rendering exterior walls
- People with older or solid walls needing breathable systems
- Anyone who has seen render crack or fail before
- Owners comparing render specialists and systems
Match the render system to your wall
Different walls need different render systems — modern cavity walls, solid walls and insulated systems all behave differently. A good specialist assesses your wall before recommending a system rather than applying the same product everywhere.
Ask how they decide which system suits your specific walls.
- Ask how they assess your wall type
- Confirm the system suits your construction
- Avoid a one-size-fits-all approach
- Discuss any insulation interaction
Understand breathability
Older and solid walls often need breathable render so moisture can escape; trapping it can cause damp and decay. A specialist should explain why a system breathes or not and why it suits your wall.
Treat breathability as central, not a detail, especially on older buildings.
Read crack-history references
Render's weak point is cracking, so ask to see walls they rendered some time ago and how they have fared. Past work that still looks sound tells you more than a freshly finished job.
Ask how they detail movement joints and vulnerable areas.
- View older completed render work
- Ask how past render has held up
- Discuss movement and crack control
- Note how they detail vulnerable areas
Confirm preparation and detailing
Good render starts with proper preparation and careful detailing around windows, sills and junctions. Ask how they prepare the wall and handle these details, which is where failures often begin.
Poor preparation undermines even a good system.
Brief and compare on the same scope
Give each specialist the same information about your walls and the finish you want, so recommendations and quotes are comparable. Ask what could change once they expose the existing surface.
Confirm insurance and ask to see relevant experience for your wall type.
- Share the same wall information with each
- Compare recommended systems, not just price
- Ask what could change on the wall
- Confirm insurance and relevant experience
Hiring checklist
- 1Note your wall type and any damp history
- 2Ask how each specialist assesses your wall
- 3Confirm the system suits your construction
- 4Discuss breathability for older or solid walls
- 5View older completed render work
- 6Ask how past render has held up
- 7Discuss movement and crack control
- 8Ask how they prepare and detail junctions
- 9Compare recommended systems, not just price
- 10Confirm insurance and relevant experience
Common mistakes to avoid
- Applying the same render system regardless of wall type
- Ignoring breathability on older or solid walls
- Judging only freshly finished work, not how render ages
- Overlooking preparation and detailing around openings
- Comparing prices for different systems and scopes
- Skipping insurance and experience checks
When to involve a professional
- Treat render system selection as expert work matched to your wall type
- Route moisture and breathability questions to qualified specialists
- Ask to see render work that has aged well
- Confirm insurance and relevant experience for your construction
- Remember render and moisture requirements vary by location and project
Frequently asked questions
Questions readers ask about this topic
Does the render system depend on my wall?
Yes. Modern cavity walls, solid walls and insulated systems behave differently and need different render systems. A good specialist assesses your wall before recommending a system rather than applying the same product everywhere.
Why does breathability matter?
Older and solid walls often need breathable render so moisture can escape; trapping it can cause damp and decay. Breathability is central, not a detail, so ask the specialist to explain why a system suits your wall.
How can I judge if render will last?
Ask to see walls they rendered some time ago and how they have fared, since render's weak point is cracking. Past work that still looks sound tells you more than a freshly finished job.
Where does render usually fail?
Often at preparation and detailing — around windows, sills and junctions, and where movement is not controlled. Ask how they prepare the wall and detail these areas, and remember requirements vary by location and project.
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