Lisnastrain Cavity Trays

26/05/2026

In warm weather, effective cavity trays with attached lead play a vital role in protecting masonry from moisture pe*******on. As temperatures rise, building materials naturally expand and contract, increasing the risk of water ingress around roof junctions, chimneys, and cavity walls.

A properly installed cavity tray channels water safely out of the structure, while the attached lead flashing provides a durable, flexible seal that performs exceptionally well in changing temperatures. Lead adapts naturally to thermal movement, making it ideal for warmer conditions where expansion can compromise weaker materials.

The result is improved weather protection, reduced damp issues, and longer-lasting structural integrity — especially important during hotter months when buildings are under greater thermal stress.

Quality installation and the right materials make all the difference.

20/05/2026

Despite the rise of alternative flashing systems, I still believe cavity trays with attached lead flashings remain the benchmark detail for long-term masonry performance.

There’s a reason they’ve stood the test of time.

✅ Why lead-attached cavity trays still work exceptionally well:

* Proven durability over decades in real-world exposure
* Excellent weathering performance in harsh conditions
* Reduced reliance on multiple interfaces and joints
* Less risk of separation between tray and flashing
* Strong compatibility with traditional masonry construction
* Easier to achieve a robust, continuous waterproof detail

While modern alternatives are often promoted for speed and cost savings, the reality is that many failures occur where separate components have been poorly coordinated or installed.

With an attached lead cavity tray system, the detail is simpler:
➡️ one integrated waterproofing solution
➡️ fewer opportunities for installer error
➡️ better long-term reliability

Yes, lead requires skilled installation and proper allowance for movement — but when detailed correctly, it consistently outperforms many lightweight alternatives in lifespan and resilience.

In an industry increasingly focused on programme speed, we shouldn’t lose sight of what matters most:

Durability and performance over the life of the building.

Good detailing is never just about getting through the next inspection — it’s about ensuring the façade still performs 30+ years later.

What’s everyone seeing on current projects?

Are lead-attached cavity trays still your preferred specification, or are clients pushing toward alternative systems?

11/05/2026

Living in Ireland and the UK means one thing for buildings: relentless wind-driven rain. 🌧️💨

That’s why cavity trays are such a critical part of modern construction. Installed correctly, they help redirect moisture out of cavity walls before it can cause damp, staining, or structural issues inside the property.

In climates like ours, where heavy rainfall and changing temperatures are constant challenges, cavity trays aren’t just a building regulation requirement — they’re essential protection.

Too often, water ingress problems come down to poor detailing, incorrect installation, or missing trays altogether.

Good construction isn’t only about what you can see — it’s about the hidden systems that keep buildings dry for decades.

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23/04/2026

How to Measure the Quantity of Lisnastrain Stepped Cavity Trays

When installing stepped cavity trays accurate measurement is essential to ensure proper damp-proofing and avoid material shortages or waste.

What Are Stepped Cavity Trays?

Stepped cavity trays are used where a pitched roof meets a cavity wall (roof abutment). Their role is to intercept water penetrating the outer leaf and safely discharge it, preventing internal damp issues.

Key Method for Measuring Quantity;

The main accepted way to calculate the number of stepped cavity trays required-

Vertical Measurement (Most Common Method):

📏Measure the vertical height of the abutment (in metres).

➗Divide this by the coursing height of the masonry (typically 75mm for standard brickwork).

Formula:
Number of trays=
Coursing height (m)➗Vertical height (m)
​

Example:
Vertical height = 1.5m
Brick coursing = 75mm (0.075m)
1.5÷0.075=20 trays
➡️ Result: 20 stepped cavity trays required

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02/04/2026

Lisnastrain Cavity Trays is now closed for the Easter holidays 🐣

We would like to wish all our customers a very happy and relaxing break!

We will reopen on Thursday 9th April and look forward to seeing you all again then.

01/04/2026

Busy week at Lisnastrain Cavity Trays!

🚀As we approach the Easter break, orders are flying out the door! 🐣🧱 Our team is working hard to ensure all pre-formed cavity trays, chimney trays, and lead flashings are delivered on time to keep your sites moving.

🚐💨No delays, just top-quality, approved trays to stop driving rain in its tracks. 🌧️

✅ Pre-formed for fast installation
✅ Factory-fitted lead for superior waterproofing
✅ Delivered to site

Need last-minute supplies before the break? Give us a call at 028 8676 4433 or check our online shop.

26/03/2026

Proud to support local manufacturing across Ireland and the UK👍

Lisnastrain Cavity Trays Ltd, based in Cookstown, Co. Tyrone, we are leading the way in producing high-quality cavity trays using locally sourced materials and skilled craftsmanship. As a family-owned business at the heart of Mid-Ulster, we manufacture bespoke cavity trays and lead products designed specifically for the Irish and UK construction industries.

By using materials such as milled lead and durable polypropylene, combined with modern manufacturing techniques, Lisnastrain ensure every product meets the highest standards of quality and performance. Our commitment to local sourcing supports suppliers across both Ireland and the UK, while also delivering fast turnaround times and dependable service nationwide.

Supporting companies like Lisnastrain means backing local jobs, local materials, and regional expertise—helping to build stronger communities across Ireland and the UK.

Call now to connect with business.

25/03/2026

Another load of rolled flashing heading out the door. Saving joiners/roofers time and money having all pre-made in house .

19/03/2026

Why a stepped cavity tray manufactured in polypropylene with attached lead is better option than all lead tray?

A stepped cavity tray made from polypropylene (plastic) with an attached lead flashing is often preferred over an all-lead tray because it combines the strengths of both materials while avoiding their weaknesses.

🧱 1. Better durability (less risk of failure)

Polypropylene won’t crack from fatigue like lead can over time

All-lead trays can split due to:

* Thermal movement
* Repeated expansion/contraction

👉 The plastic tray provides a stable, long-lasting waterproof barrier

🌧️ 2. Improved water management

*Stepped trays are designed to follow brick courses especially over openings
* Polypropylene trays are factory-shaped for consistent falls and drainage

👉 This reduces the risk of:

* Water pooling
* Incorrect installation
* Leaks into the cavity

🔩 3. Lead only where it’s needed

* The lead flashing is still used externally where flexibility and weatherproofing matter most
* But internally, polypropylene replaces bulky lead

👉 You get:

* Flexibility outside
* Stability inside

⚖️ 4. Lighter and easier to install

* Polypropylene is much lighter than full lead trays
* Easier to handle on site
* Faster installation, fewer mistakes

💰 5. More cost-effective

* Less lead = lower material cost
* Reduced labour time

🧪 6. Resistant to chemicals and corrosion

* Polypropylene won’t corrode from:

* Mortar chemicals
* Sulphates in bricks

👉 Lead can degrade in certain conditions over long periods

🔥 7. Lower theft risk

* Lead is valuable and can be stolen from sites
* Using less lead reduces this risk

🧠 Bottom line

A polypropylene stepped cavity tray with lead flashing is better because it:

* Lasts longer
* Is easier to install correctly
* Manages water more reliably
* Costs less and is safer on site

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17/03/2026

Why you should not rely on lead flashing and render alone for a damp proofing solution:

Using render alone (without a cavity tray) is generally not considered best practice in modern construction—especially in places like the Ireland and the United Kingdom where damp protection standards are strict.

🔧 What a cavity tray does

A cavity tray is designed to:

✅Catch water that penetrates the outer wall (like render or brickwork)
✅Redirect it out through weep holes before it reaches the inner wall

🧱 Render alone — how effective is it?

Render (cement or monocouche) is:

‼️Water-resistant, not fully waterproof
‼️Prone to cracking over time (movement, temperature changes)
‼️Vulnerable at weak points like window/door openings

So while it reduces water pe*******on, it doesn’t stop it completely.

⚠️ Risks of no cavity tray

Without a cavity tray, water that gets behind the render can:

😭Track across the cavity
😭Cause damp patches internally
😭Lead to mould or structural damage over time

This risk is higher:
⚠️On exposed elevations (wind-driven rain)
⚠️In older or poorly detailed builds

🧠 Bottom line

Render alone is not reliably effective as a sole defence against water ingress. A cavity tray with factory fitted lead flashing is a critical backup system, not optional detailing.

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