Cavity Trays Ltd


Type E Cavitray

for insertion into existing
walls

in brief...

  • Brick-sized cavitrays permit progressive insertion
  • Anticapil interlocking to form long runs
  • Cavity widths compatible - upstand adjusts to suit
  • Unobstructed cavity compartment area with stand-alone discharge
  • Easy compliance of building regulations
  • Minimal disturbance to masonry - fitted from outside

   
   designers'
   comments
    
    The positive upstand 
    jointing between trays
    was established many
    years ago as our most
    reliable format.
    We rejected overlapping
    and sticking as, in our
    tests it proved less
    reliable as the integrity of
    the adhesive/join in the
    cavity spanning portion
    was unsupported and,
    being an existing wall, 
    the access/working
    space to make the
    overlap was 
    limited.  The superior 
    results we obtained
    when anticapil clipped
    together dictated we
    adopt the cavitray with
    end upstands.  
    It is  interesting to note
    that each  tray being self-
    contained, means pin-
    pointing of any area 
    problem can be located/
    identified with accuracy 
    and speed - not an easy 
    task with the alternative 
    stick together / open run 
    format.  The rigid
    panoplied lip has proved 
    essential in exposed
    applications and high
    inter-sections.  Stopends
    and weeps are promoted
    in BS8215:1991 and the
    latest BS 5628:3-2001.  
    These features have 
    formed part of our Type E
    system for many years, 
    thus Type E cavitrays 
    more than satisfy the
    latest standards.  Type
    E cavitrays also have a 
    cavity upstand height of
    150mm to satisfy the
    standard requirements - a
    dimension which is not 
    matched by all 
    manufacturers.

 

use
To damp-proof an original outside wall which has become an inside wall by virtue of an extension being built.  Also suitable for remedial work where an existing DPC has failed.  See nest product entry describing Type E for remedial and corrective applications.

introduction
When an extension is added to a building, the problems of inserting a DPC at the horizontal intersections must be faced.  By present methods this is not an easy operation.  In many cases complete strutting is necessary.  In all cases the amount of brickwork which must be cut away to permit the insertion of a DPC extends to 300mm or more in depth.  This means four courses of bricks for the whole length of the DPC.  In the case of the shored wall, there is considerable making good to brickwork, plasterwork, ceiling and decoration.  The use of the Type E cavitray overcomes all these problems.


 type E cavitray
The Type E is a preformed DPC unit, two bricks in length.  There are upstands at either end of each tray that clip together.  Trays are inserted into a cavity wall one at a time.  Long runs are thus created with a series of connected but self-contained Type E units.  The preformed ends coincide with masonry perp joints.  No reliance is therefore placed on gluing or sticking adjoining lengths - an exercise that can be difficult when inserting any DPC medium.

All Type E cavitrays have an extended cavity upstand that runs the length of the tray.  The upstands automatically adjust for any cavity width from 50mm up to 120mm, ensuring compatibility with the cavity encountered.  The front projecting lip of each tray is designed to provide protection of the bedding course against wind-driven rain.

Apart from the financial saving, the advantages of the preformed Type E cavitray are considerable.  There is no shoring and therefore no making good, thus workmen do not need to enter the building.  Only one course of brickwork is distributed therefore no large scar remains after insertion.  Time taken to install represents a small fraction of time taken by the traditional method.  





 The awkward and sometimes suspect running joints of a normal DPC or tray installation are eliminated.  The adjustable cavity upstand accommodates the 'as built' cavity status rather than the anticipated status.  Type E cavitrays are extensively used on commercial, industrial, educational and domestic extension work.

sizes
The standard cavitray sizes shown suit most brick dimensions. The unique U clip design enables adjoining trays to be slightly 'adjustable' to help match 

   existing bond.  Please compare your brick size with our standard tray size and notify us should you require alternative dimensions.  Trays can be supplied in almost any special size.

material
Polypropylene solid DPC, injection moulded to ensure uniform thickness.  Trays can also be supplied in other materials to suit special applications.

colour
Black.

bill of quantity
wording
Type E cavitray from Cavity Trays of Yeovil, Somerset BA22 8HU (01935 474769).

Size as standard (or specify size of tray required).  Cut out masonry in the external skin of cavity wall in accordance with the installation instructions provided by Cavity Trays of Yeovil.  Insert one at a time into the existing external skin.  Incorporate flashing under cavitray if appropriate.  Replace bricks into the cavitray within the wall.  Ensure tray and all bricks are correctly bedded in mortar.  Slate pin to make safe and firm.   Incorporate weepvent in the middle of each cavitray.  Adjoining trays clip together automatically.  Continue operation until required run is completed.


Cavity Trays     phone 01935 474769 fax 01935 428223 email enquiries@cavitytrays.co.uk