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Home / Active Vent
Shop the Active Weep Vent
FREE EXPERT GUIDE
Get Your Free Damp & Condensation Report + Free Delivery
Our Damp & Condensation Report is written by our founder, who has over 20 years' experience in the building and damp-prevention industry. You'll also get the WELCOME code by email.
First order only. Orders under £50: free delivery. Orders of £50 or more already ship free, so you'll get 10% off your next order instead. One per customer.
Trade & Bulk Orders
Trade accounts: trade pricing from 1,000 units, and we will quote on smaller trade orders
Configure Your Order
£90.00
£1.80 per vent
FREE DELIVERY £50+
£1.80 per vent: 25% less per vent than packs of 10 (£2.40). Save £30.00 vs buying the same number in packs of 10.
Pre-order: we'll confirm your dispatch date with your secure payment link.
Total units: 50
Select Colour
Material: Polypropylene (PP)
Choose your pack
Need 1,000+ vents, or buying for a merchant or housing portfolio? Contact us for trade pricing.
Join our mailing list for free delivery on your first order.
First order only. Orders under £50: free delivery. Orders of £50 or more already ship free, so you'll get 10% off your next order instead. One per customer.
Complete the whole-house system Add Active Trickle Vents to your windows (2+ per window). Price on request →Active Vent - Premium Quality
Bigger packs cost less per vent
£90.00
£1.80 per vent
£1.80 per vent: 25% less per vent than packs of 10 (£2.40). Save £30.00 vs buying the same number in packs of 10.
Pre-order: we'll confirm your dispatch date with your secure payment link.
Terraced home ~40 vents, semi ~50: the Whole House Pack covers both. Every home differs, so work out your exact number. Need 500+? Trade pricing
Free UK delivery from £50 Made in Cardiff · ISO 9001 manufacturer
Product Description
The Active Weep Vent is a new kind of weep vent: wind-powered and cross-ventilating, from a single unit (patent pending). Unlike one-way passive vents, its shape uses the wind blowing across the wall to draw air through the vent, helping damp air move out of the cavity rather than sitting in it.
At 0mph it works like a standard vent. Once the wind picks up, it ventilates actively, and it works harder as the wind speed rises. It needs no electricity to run.
Key Benefits
- Designed to help reduce damp and condensation in the wall cavity, which can lead to mould
- Designed to help keep cavity insulation dry, so it can perform as intended
- Wind-powered: no electricity, no wiring
- Designed to support Building Regulations Part C (cavities) and NHBC guidance
- Designed to resist rain getting in
Damp has several possible sources, such as leaks and plumbing faults, that a vent can't fix. If you have one of these, it needs repairing first.
How It Works
When wind passes the specially designed shape of the vent, it creates a low-pressure zone at the outer face that draws air and moisture out of the cavity. In our own side-by-side tests, once the wind reached around 20mph the standard weep vents and weep holes stopped letting water out of the test cavity, while the Active Weep Vent kept draining it, and the stronger the wind, the more it drew out.
Technical Specifications
Materials
- Standard: Polypropylene (PP)
- Crystal Clear: Polycarbonate (PC)
- Recycled Black: 100% recycled polypropylene
Colours Available
- Natural (transparent)
- Grey
- Terracotta
- Black
- Buff
- Crystal Clear (+10p per vent)
- Recycled Black (100% recycled)
Dimensions
- Size (W × H × L): 10 × 65 × 100mm
- Fits: a brick perp joint, chased out
- Power: none needed (wind-powered)
- Manufacture: made in Cardiff by an ISO 9001-certified manufacturer
Installation Instructions
Comparing options? Read our weep vents compared guide, covering the main UK types, spacing rules and prices.
Spacing
- Along the DPC: one vent every 900mm (Approved Document C, para 5.5(c))
- Above each opening: a maximum of 450mm apart, with at least 2 per opening (NHBC guidance)
A terraced home typically needs about 40 Weep Vents, and a semi-detached home about 50. Use our weep vent calculator to work out the number for your walls, windows and doors.
New Build Installation
- Mark vent positions following NHBC spacing guidance
- Place Active Weep Vents in the perp joints as the brickwork goes up
- Keep vents flush with the external wall face
- Make sure each vent opens into the cavity and is not blocked by mortar
- Bed in mortar as normal bricklaying practice
Retrofit Installation
- Identify existing weep vents or mark new positions
- Chase or chisel out the mortar from a brick perp joint (the vertical joint between two bricks) to suit the 10 × 65 × 100mm vent; don't drill a round hole
- Clear the opening through to the cavity without damaging the DPC or cavity trays
- Insert the Active Weep Vent flush with the wall surface
- Check it sits securely and point around it if needed
Optional higher row (being tested)
An optional layout we're testing adds a second, higher row at about 2.1m, also at 900mm centres (roughly one vent per 2m² of wall). Low vents help clear the moisture that sits low; high vents help clear the humidity that lingers higher up.
We're testing this layout now, so this guidance may change.
Safety Warning
Always wear safety equipment and check for cables and pipes before cutting into a wall. Take extreme care not to damage the DPC, cavity trays or lintels. Consider professional installation for complex retrofits.
Frequently Asked Questions
How many vents do I need?
Approved Document C (para 5.5(c)) sets weep holes every 900mm along the damp-proof tray at DPC level. Over windows and doors, NHBC guidance is a maximum of 450mm between weep holes, with at least 2 per opening. A terraced home typically needs about 40 vents and a semi-detached home about 50, which the Whole House Pack covers. For your own home, the weep vent calculator counts them from your wall length and openings. We're also testing an optional second, higher row at about 2.1m, so this guidance may change.
Do the vents work in all weather conditions?
At 0mph it works like a standard vent. Once the wind picks up, it ventilates actively, and it works harder as the wind speed rises. The design is intended to resist rain getting in.
Will the vents affect my wall insulation?
Active Weep Vents are designed to help keep the cavity, and any insulation in it, drier. Wet insulation doesn't insulate as well as dry insulation.
Do the vents require maintenance?
They need no power supply. Inspect them periodically; the removable insert makes it quick to check and clear.
Will they fix all my damp?
They're designed to help reduce damp and condensation caused by moisture in the cavity. Damp also has other sources, such as leaks and plumbing faults, which a vent can't fix and which need repairing.
Do you deliver?
We deliver to UK mainland addresses as standard: £3.99, or free on orders from £50. Worldwide delivery is available on request at the customer's expense; contact us for a quote. Active Vent is on pre-order, and we'll confirm your dispatch date with your secure payment link.