20mm Extender Base for Flexi-Level Joist Support Cradles

New product

30 Extenders to fit the Flexi-Level 1250 Cradle (sold separately). 

Flexi-Level Cradles adjust from 12 to 50mm as standard. Increase height with one or more clip-in 20mm high extenders. Cradles come complete with a clip-in moulded rubber base which also fits the extender.



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£ 20.50 VAT incl.

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A pack of 30 pieces of 20mm Height Extenders for use with StrataRise Flexi-Level 1250 Pedestals (sold separately). 

The Flexi-Level Support Cradle is adjustable from 12mm to 50mm as standard. The height can be increased by using one or more clip-in 20mm high base extenders. Flexi-Level cradles are supplied complete with a clip-in moulded rubber base which can also be fitted to the extension base when this is used.

Advanced Features

Flexi-Level Cradle featuresThe cradle can be fixed to the joist after adjustment to allow lifting of the joists to insert interim supports, etc, without losing the cradle position and level

The cradle now has drainage outlets, so water cannot collect and become stagnant. Raises beams above the substrate surface, preventing saturation and reducing potential for rotting.

A new, clip-in, moulded acoustic base pad, supplied as standard with every cradle, provides cushioning and protection when used on top of membranes – it incorporates water drainage channels.

The height range can be increased by using one or more, optional, clip in, 20mm high extensions (supplied separately). The adjustment range of 12mm to 50mm can be increased to 32mm to 70mm with one extender, to 52mm to 90mm with two extenders, etc.

The new Flexi-Level support cradle is rated for an average maximum load of 16.3kN/m² (1,662 kgf/m²) using a minimum of 6 supports per square meter.

StrataRise Cradles... the professionals' choice!

Engineered for practicality

Acoustic Base PadClip-in 20mm Height Extender Base
Moulded base pad StrataRise Flexi-Level Extension
An Acoustic Base Pad is supplied as standard and can be fitted either to the cradle, or to the extension base as required. It provides cushioning and protection when used on top of waterproofing membranes, as well as offering acoustic properties and helping to reduce transmitted noise. StrataRise Clip-in 20mm height extenders now enable the height adjustment range of the cradles to be increased - greatly adding to the flexibility of the product and setting it apart from similar type cradle products.
Provision for fixing to the beamFactory compression tests
Joist in Flexi-Level Cradle with Fixing points Compression Test charts
The StrataRise Flexi-Level Cradle permits easy attachment to the joist after initial levelling is completed. Three screw points are provided for this purpose. This permits lifting of joists to easily place additional supports into position without losing position or adjustment of the installed cradles. Tested in the factory for compression strength and weight bearing capability. Now more than twice the weight bearing capability when compared with the original Rubbertech, Ryno, Quantum Uni-Level cradles which this product replaces.

Upgraded to meet the latest requirements

Flexi-Level Cradle featuresStrataRise 1250FL-DF Flexi-Level Cradles have been custom designed and engineered to meet the exacting requirements of professional users for installing floors and decks in all types of locations for all types of uses.

Based on the original design concept, created by Graham Williams of Rubbertech UK, and later supplied by Ryno, the Flexi-Level has been engineered to be easier to adjust with a profiled adjuster ring, a deep thread prevents cross-threading, provides faster adjustment with additional strength and load bearing capability.

It has been upgraded to incorporate drainage for water, now has added provisions for fixing the cradle to the beams and the capability to accept clip-in height extenders to economically increase the maximum support heights achievable.

Supplied complete with a moulded clip-in base pad the Flexi-Level Cradle offers outstanding value.

StrataRise Cradles ... the professionals' choice!


We suggest a minimum distribution of 6 to 8 supports per square meter, with joists spaced at 400mm to 500mm centres, and cradles positioned at 400mm to 600mm intervals along each support.

Smaller cross section joists and beams are more liable to flex, so typically these require that the cradles are placed closer together. Where high loads are anticipated the weight bearing capacity can be increased by placing the cradle supports closer together.

When installing heavy, pre-built, joist frameworks, take care not to overload any single point of support during initial levelling. This can be avoided by using support wedges or jacks to reduce the weight at corners until the required distribution of cradle supports are in place and adjusted.