Rendering Problems: Causes, Prevention & Solutions
Rendering can significantly improve the appearance and protection of your home’s exterior. However, if not applied correctly or maintained well, it can lead to several issues, especially in damp climate.
This guide covers the most common rendering problems homeowners face, why they happen, what you can do about them, and when professional help is essential.
What is External Rendering and Why is it Used?
External rendering involves applying a protective layer of material to your home’s exterior walls. Commonly made of sand, cement, lime, or modern acrylics and silicones, render provides weather resistance, improved insulation, and a clean finish that boosts kerb appeal. Its ability to protect the underlying brickwork or masonry from rain and frost makes it popular.
While render is durable, it requires proper application and ongoing care to perform well. Different types of renders suit different properties and budgets, so choosing the right kind is key to long-term success.
What Are the Most Common Problems with Rendered Walls?
Cracks in Render
Cracks are the most visible and frequent rendering problem. Hairline cracks may seem minor but can allow water to penetrate, leading to damp. Cracks typically arise from natural building settlement, thermal expansion, or poor initial preparation.
Over time, these can worsen, causing flaking paint, blistering, and internal damp issues. Identifying crack types and their cause early can prevent costly damage.
Blown or Detached Render
“Blown” render refers to sections lifting away from the wall due to failure in bonding. This is often caused by moisture trapped behind the render or poor workmanship. It may present as hollow-sounding patches, bulges or flaking that worsens if untreated.
Staining, Discolouration and Algae Growth
Renders, particularly on shaded or north-facing walls, are prone to staining from algae, mould or efflorescence (white salt deposits). Poor drainage, non-breathable paint, or retained moisture behind render can aggravate this.
These issues mar the look of your home and indicate moisture problems affecting the render’s performance.
Water Ingress and Damp
Cracked or failed render allows moisture behind the walls, leading to internal damp, mould growth, peeling wallpaper and timber decay. Painting over damaged render without addressing the cause traps moisture and worsens the problem.
Most homes, often clad in older solid walls, are especially vulnerable to penetrating dampness.
How Can You Prevent Rendering Problems?
Choose the right render type suitable for your property and climate, preferably breathable silicone or acrylic renders for damp conditions.
Ensure thorough surface preparation and professional application with reinforcement mesh where needed to reduce cracking and bonding failures.
Regularly clean your render with gentle detergents and mild pressure washing to remove algae and dirt.
Keep gutters, downpipes and ground levels well maintained to prevent moisture splashing or seeping behind renders.
Avoid painting directly over damaged or damp render, seek expert advice instead.
When Should You Repair Vs. Re-render?
Minor hairline cracks or small damaged patches can often be repaired locally, extending the life of your render and being cost-effective.
However, widespread cracking, blown render, recurrent damp or extensive staining usually requires full re-rendering for a long-term solution. Acting promptly prevents further structural damage and higher repair costs.
Why Homes Experience Rendering Issues
The damp, variable weather frequently tests external renders. Older properties may lack modern damp-proofing, making moisture ingress more likely. Also, past use of non-breathable paints traps moisture. Poor maintenance or low-quality workmanship exacerbates common problems.
What to Expect From Professional Render Repairs and Maintenance
Comprehensive assessment to identify render defects and underlying causes.
Efficient repairs including crack filling, repointing, or patch render depending on damage extent.
Advice on repainting or applying protective, breathable coatings to prolong render life.
Full re-rendering options with modern materials for increased weather resistance.
Frequently Asked Questions About Render Problems
How long does render typically last?
Modern renders, especially silicone-based, can last 20-30 years with good maintenance. Cement renders have shorter lifespans and are more prone to cracking.
Can I spot blown render myself?
Look for cracked, bulging, or missing chunks. Tapping the render may produce a hollow sound where it has detached.
Is repainting render a good fix for damage?
Only if the render is sound. Painting over cracked or damp render traps moisture and worsens problems.
Will poor rendering cause damp inside my home?
Yes, if the render cracks or detaches, water can penetrate walls causing internal damp and decay.
Taking the Next Step to Protect Your Home
If you notice cracks, stains, or damp patches on your rendered walls, expert help is essential. Early intervention prevents costly damage and preserves the beauty and integrity of your home.
Surrey Dry Lining offers no-obligation consultations and tailored rendering solutions to give you peace of mind and a finish that lasts.
Contact our rendering contractors in Surrey today for advice, a free site visit, and competitive quotes to resolve your rendering concerns with confidence and expertise.
Rendering issues are a common but manageable challenge for Surrey homeowners. Understanding the causes and recognising early signs can save you stress and expense. With the right products, professional workmanship, and ongoing care, your render will continue to improve and protect your home for years to come.
