Sikaflex 522 sealant Review: The Caravan Sealant Professionals Trust
- Caravan Coach
- Oct 12
- 4 min read
Product Category: Caravan Sealant & Adhesive
Brand: Sika
Prices Usually Range From: £7-£16 depending on retailer and colour (white or black)
Best For: Sealing leaks, bonding solar panels, roof vent installations, and general caravan maintenance where flexibility and weather resistance are crucial
Where to Buy: Available at Sealants4All, Amazon, Chase Outdoors, Screwfix, or major caravan accessory retailers
Sikaflex 522 caravan sealant - Introduction
When water finds its way into your caravan, the damage can be costly and time-consuming to repair. I've been testing Sikaflex 522 across various sealing jobs on my own caravan, and this professional-grade adhesive sealant has proven why it's the go-to choice for caravan manufacturers and repair workshops across the UK. This silane-terminated polymer (STP) sealant replaced the popular Sikaflex 512, bringing improved formulation and enhanced mould resistance whilst maintaining the flexibility and bonding strength that made its predecessor an industry standard.
Key Features
Weather-Resistant Formula Sikaflex 522 stands up brilliantly to British weather. The UV-stable formulation doesn't yellow over time, and it remains flexible through temperature swings from -50°C to 90°C, which means it won't crack during winter storage or summer tours.
Multi-Surface Bonding One of the standout features is its ability to bond to timber, glass, metals, painted surfaces, ceramics, and most plastics without needing primers in most applications. This versatility saved me considerable prep time when sealing my awning rail.
Low Emission & Food Safe The sealant meets ISEGA certification for food contact areas, making it suitable for kitchen installations. It's also EC1+ certified with very low VOC emissions and minimal odour during application.
Flexible Yet Strong With 400% elongation at break and Shore A hardness of 40, it provides proper structural bonding whilst remaining flexible enough to handle the natural movement of caravan panels.
Pros and Cons
Pros:
Excellent adhesion on multiple surfaces without priming
Remains flexible indefinitely – won't crack or shrink
Outstanding weather and UV resistance
Low odour makes it pleasant to work with indoors
Mould resistant formulation
Used by professional caravan manufacturers
Relatively easy to apply and finish
Cons:
Short shelf life (9-12 months from manufacture)
Once opened, difficult to preserve for future use
Tricky to remove if you need to make repairs later
Thicker consistency requires a decent caulking gun
Higher price point than general-purpose sealants
Needs proper surface preparation for best results
Performance
The consistency of Sikaflex 522 is noticeably thicker than cheaper alternatives, which works in your favour on vertical surfaces – it stays put without sagging. However, you'll need a proper caulking gun with decent leverage. I've found that warming the cartridge in hot water for about 10 minutes makes a significant difference to flow, particularly in cooler weather.
Application & Working Time You get roughly 30 minutes of working time before it skins over, which is adequate for most jobs but doesn't leave room for dawdling. The sealant tools reasonably well with a dampened finger or a shaping tool, though it's tackier than some competitors. I've had best results working in sections rather than trying to complete long runs in one go.
Curing Behaviour This is where Sikaflex 522 requires patience. It skins over quickly enough, but proper structural curing takes 2-3 days in decent conditions. In cold or damp weather, allow longer. The sealant remains flexible during this time, which can be disconcerting if you're used to adhesives that set hard. Don't panic – this flexibility is intentional and crucial to its long-term performance.
Real-World Durability After months of use on various sealing jobs, the flexibility hasn't diminished and there's been no shrinkage or cracking. The white version has maintained its colour without the yellowing that plagues some sealants after UV exposure. More importantly, it's stayed watertight through heavy rain, including the sort of horizontal downpours that find every weak spot in caravan seals.
Adhesion Strength The bond strength is genuinely impressive once fully cured. On properly prepared surfaces, it creates a permanent seal that's robust. Test pieces I made required considerable force to separate, and the sealant itself didn't fail – the bond remained intact.
Temperature Performance I've used it in varying conditions from chilly spring mornings to warm summer afternoons. Application is noticeably easier above 15°C, but it performs adequately down to the specified 5°C minimum. The cured sealant handles temperature fluctuations without complaint – no brittleness in cold conditions or excessive softening in heat.
Specifications
Type: One-component Silane Terminated Polymer (STP)
Colours: White, Black, Grey
Cartridge Size: 300ml
Skin Time: Approximately 30 minutes (23°C, 50% humidity)
Full Cure: 2-3 days
Service Temperature: -50°C to 90°C
Application Temperature: 5°C to 40°C
Shelf Life: 12 months (cartridge), 9 months (drum)
Elongation at Break: 400%
Shore A Hardness: 40
Shrinkage: 2%
Why It's Recommended
Sikaflex 522 justifies its professional price tag through reliability and performance. After six months of British weather – including heavy rain and freezing temperatures – every seal I made with this product remains perfect. No leaks, no cracking, no discolouration.
The real value becomes apparent when you consider the cost of water damage repairs. An inexpensive cartridge of quality sealant versus hundreds in repair bills makes economic sense. It's also reassuring to know you're using the same product that caravan manufacturers specify for production.
The improved formulation over the old 512 version includes better mould resistance, which matters in damp British conditions. I've had no issues with mould growth around any of my sealed joints, even in typically problematic areas like bathroom vents.
One practical tip: buy it when you need it rather than keeping tubes in stock. The relatively short shelf life means old tubes may not perform properly, and once opened, you've got limited time before it cures in the cartridge. Plan your jobs accordingly.
Rating
Overall Score: 4.3/5
Score Breakdown
Design: 4/5
Durability: 5/5
Ease of Use: 4/5
Value for Money: 4/5
Disclaimer
This review reflects my genuine opinions and experiences. Some of the links in this article are affiliate links, including Amazon Associate links. As an Amazon Associate, we earn from qualifying purchases. This means we may receive a small commission if you buy through these links, at no extra cost to you.
Product details, availability, and prices were accurate at the time of writing but may change without notice. Please check with the retailer for the latest information before making a purchase. Caravan Coach cannot be held responsible for differences between this review and the actual product or service you receive.
