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135mm Cellcore Cellvent HX Grade 18/24 Ground Heave

135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
  • 135mm Cordek Cellcore Cellvent HX Cellular EPS Void Former
  • Cellvent HX Grade 18/24 Maximum Concrete Depth 660mm
  • Reinforced ground floor slabs where subsidence is not expected
  • Used to alleviate the effects of ground heave and gas venting
  • Combined ground heave protection and passive gas venting system
Estimated delivery:
In Stock
£ 203.76
Ex VAT: £ 169.80
  • Brand: Cordek®
  • Model: 135mm Cellvent HX (Grade 18/24)
  • Dimensions: 2,400mm x 1,200mm x 135mm
  • SKU: 135mm Cellvent HX (Grade 18/24)
  • Product code: P1-3500
  • MPN: 135mm Cellvent HX (Grade 18/24)

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135mm Cordek Cellvent HX Grade 18/24, an EPS void former used beneath reinforced concrete floor slabs to provide a combined ground heave protection and passive gas venting system.

Cellvent HX is available in a range of specifications and can be used in conjunction with gas membranes, vent outlets and venting accessories to form a complete gas protection system.

Cordek EPS Void Former Formwork Cellvent HX is designed for use under suitably reinforced ground floor slabs where subsidence is not expected.

Cellvent HX is supplied with an equivalent ventilation capacity to the Ventform 80 range which includes a 40mm void depth, If a greater venting capacity is required, please contact us.

The depth of the Cellvent HX panel will depend upon the amount of ground heave that has been predicted.

Grade 18/24 is calculated and calibrated for concrete thickness up to 660mm (has been tested to achieve the specified performance characteristics).

Cellvent HX is a highly-durable, BBA certified product which meets the NHBC’s Technical Standards.

One of great things about Cordek Cellvent HX is its very simple to work with and doesn't have much dust off when cut on site.

The cost of manufacturing Cellvent HX is considered linearly proportional to its grade which is based on maximum concrete depth.

Cellvent HX Grade 7/10 price is the lowest compared to the higher grades: 9/13, 13/18, 18/24 (price list available upon request/quote).

Equivalent to 135mm Cordek Cellvent HX is 90mm Cordek Cellcore HX S Under Slab.

Grade 18/24 means that safe load is 18kN/m2 and fail load is 24kN/m2 (kilonewtons per m2).

Safe load is a maximum safe force that a Cellvent HX material offers without fear of breaking.

Fail load is not safe force and will cause permanent deformation of the product.

Shrinkage category of 135mm Cellvent HX is classified as low.

Cordek Cellvent HX Soil Plasticity index is 10-20.




Thickness: 135mm

Size: 135mm x 1200mm x 2400mm

Length: 2400mm

Width: 1200mm

Grade: 18/24

Maximum Concrete Depth: 660mm

NHBC Shrinkage Category: Low

Soil Plasticity Index: 10-20

Maximum Heave Potential: 50mm

Maximum Safe Load: 18kN/m2

Maximum Fail Load: 24kN/m2

Equivalent Cellcore HXS Depth: 90mm

BBA Agrément Certificate: 11/4862


Cordek Cellvent HX Features:

 · Highly-durable.

 · BBA certified product.

 · Patented Product Technology.

 · Lightweight but strong.

 · Meets the NHBC’s Technical Standards.

 · Very simple to work with.

 · Doesn't have much dust off when cut on site.

 · Unaffected by both UV light and water.

 · Robust and easy to install 2400mm x 1200mm panels.

 · Moulded production for enhanced and consistent performance.

 · Reduces the upward force transmitted to the structure from ground heave.

 · Range of thicknesses and grades to suit most project requirements.

 · Available in a range of specifications to accommodate the ground conditions.

 · Provides combined ground heave protection and gas venting capabilities in a single product.


Cordek Cellvent HX Installation Guidelines:

 · The procedure for installing the Cellvent panels is straightforward; the following points should be adhered to.

 · Ensure that the Cellvent HX panels are placed upon a firm, level surface.

 · A concrete or sand/cement blinding will often be required.

 · Do not overload the Cellvent HX panels with reinforcement or surcharge them with concrete.

 · All products are delivered in a polythene wrapping and are clearly labelled.

 · The packs of Cellvent HX can be manually handled and offloaded upon delivery, taking into account site Health and Safety procedures.

 · Due to the relatively light nature of the product, all packs of Cellvent HX should be weighted down or secured if stored outside prior to installation.

 · Information contained is for guidance only, and it is intended for experienced construction industry workers.

 · It contains summaries of aspects of the subject matter and does not provide comprehensive statements of construction industry practice.

 · As conditions of usage and installation are beyond our control we do not warrant performance obtained.

 · The information provided within is based on data and knowledge correct at the time of writing.


*Further information may be found in our Downloads section.

Fairly easy access to all PDF files.

Datasheet ǀ Declaration of Performance - DoP ǀ BBA Certificate ǀ Installation Guide ǀ Certificates ǀ Brochure ǀ SPEC Sheet 

*Special Product - Non returnable cancelable.

Board covarage 2.88 m2
Colour White and Green
Consistancy Rigid cellular void former
Length 2400mm
Material (EPS) Expanded Polystyrene
Size 135mm x 1200mm x 2400mm
Thickness 135mm
Width 1200mm
Shipping method Rigid Vehicle ǀ Courier
Grade 18/24
Applications Beneath reinforced concrete floor slabs
BBA Certified Yes, no. 11/4862
Maximum depth of concrete 660mm
ETA Notification Yes
Features Ground heave protection gas venting system
Safe load 18 kN/m2
Shrinkage Category Low
Manufacturer Cordek Cellvent HX®
Plasticity Index 10-20
Fail load 24 kN/m2

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We deliver insulation materials to Mainland UK only. Deliveries to Highlands, Northern Ireland, Isle of Wight etc.. might be possible at additional cost.
We offer free delivery on most of the orders above £300 (excluding VAT) (except special products - shipping cost via courier - products marked ''Request A Quote'')

Delivery of some insulation materials might be extended due to the current situation (Covid-19, stock shortages, allocations).
If you need materials quickly please contact us - we will do our best to help you source materials needed.

We do not deliver on weekends and bank holidays. Sometimes we can deliver on Saturdays - please check with us before placing the order.
If you need any further information please contact us tel. 02081910776

We can help to calculate price per m2 or linear meter (one meter in length) cost, please just contact us via phone 02081910776, email or live chat. Alternatively, you can work it out yourself quickly and easily: to get cost per meter square please divide price shown in orange area by ''Required area (m2)'' Example price of £28.80 divided by board coverage 2.88m2 = cost of £10.00 per m2.


No matter whether you choose a local installer or a national company, there’s a few tips to help you find the right installer for your home insulation improvements, such as asking for recommendations and making sure that they’re part of a certification scheme. This makes sure that they have the right skills and standards of workmanship to carry out the installation, and you can be sure that they know exactly what they are doing.


1. Thermal inspection picture in portfolio

It’s worth seeing a installer’s previous work. There’s no harm asking if you can see any properties nearby that they’ve installed insulation in. Best way would be to see Infrared Thermal Imaging Inspections. Thermal cameras spot small, but key changes in temperature in different areas of a house, identifying problematic areas that the human eye never could and some that a visual inspection could only hypothesize.

2. Reviews

Along with checking recommendations and previous work, finding reviews online can often be a great way to find out if they provide a good service or not. However, it’s best not to solely rely on reviews you may find or review websites, as there’s no controlling who writes them.

3. Compare prices

Comparing prices will also ensure companies can’t take advantage of you and give you a fair price. 

4. Word of Mouth

The best way to find a great insulation installer is through recommendations. Make sure you ask friends and family. They will most likely give you their honest opinion and can tell you from first hand experience.


Whether you require a wall, cladding, external wall, loft or floor insulation fitted, you can find and hire your local insulation installers from popular UK web pages. A simple internet search will return thousands of potential installers near your area.



We are the stockist of construction materials and related products for both trade and DIY from most recognizable brands in the UK like Cordek, RCM, Promat, Rockwool, Isover, Celotex, Xtratherm, Ursa, Low-E, Cedral, Kingspan, Dufaylite, British Gypsum, K-rend, Ecotherm, Iko enertherm, Kay-Metzeler, Terrawool to allow you to complete your insulation job on time at competitive prices and the highest standards.


Whether you are a large company or a DIYer, if you need a large amount of insulation materials, we can offer quantity discounts at the best prices. Please contact us and our friendly customer service will try to find the best and cheapest solutions for you. We value your time and we will try to deliver the products as soon as possible at a reasonable price to your construction site or house. The UK's leading insulation supplier near you and your needs. Price List available upon request.
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
135mm Cellcore Cellvent HX Grade 18/24 Ground Heave
£ 203.76