Secondary Glazing Vertical Slider Unit


Vertically sliding secondary glazing designed primarily for refurbishment and upgrade of older properties, historical and listed buildings. Individually pre-tensioned spiral spring balances control the motion of the sash. Can be supplied with arched or gothic head profiles and with stacking units. These units are normally used on vertical sliding sashes with the meeting rails aligning with the primary window meeting rail.


Tested and approved to the following British Standards:

  • BS 1474 (Aluminium Alloy).
  • BS 7386 (Polypropylene draught strip).
  • BS 6375-1 (Performance - Water tightness - Test pressure class 300 Pa).
  • BS 5368-1 (Performance - Air permeability - Test pressure class 600 Pa).
  • BS 5821-3 (Acoustic performance - Weighted sound reduction index, minimum Rw 49 dB).
  • BS 6206 (Glazing).
  • BS 2782 (Gaskets).

General information


As drawing

As schedule

Uniclass 2015

Pr_30_59_98_02 Aluminium window unitsPrimary


null Secondary glazing system

L10/580 Secondary glazing system

Specification data - Aluminium window units

Product Reference

Secondary Glazing Vertical Slider Unit



Balanced vertical slider.


Tilt-In balanced vertical slider.


Vertical slider.


As drawing

As schedule

Special features

Not required

Arched head

Gothic head

Stacking units

Frame finish

Anodized, natural

Polyester powder coating, white

Polyester powder coating, van dyke brown

Polyester powder coating, RAL

Special order, insert colour requirement.


Acoustic glass, 6.4 mm

Acoustic glass, 6.8 mm

Clear float glass, 4 mm

Clear float glass, 6 mm

Laminated glass, 6.4 mm

Laminated glass, 6.8 mm

Toughened glass, 4 mm

Toughened glass, 6 mm






Chubb locks

Flitch locks

Restricted opening locks







6 x 15 mm D.B.N

6 x 33 mm D.B.N

6 x 43 mm D.B.N

6 x 21 mm S.B.N

6 x 27 mm S.B.N

6 x 37 mm S.B.N

6 x 44 mm S.B.N

6 x 55 mm S.B.N

6 x 75 mm S.B.N

Grounds/ Sub frame

21 x 45 mm hardwood sub-frame, standard fix

21 x 62 mm hardwood sub-frame, reveal fix

30 x 30 mm hardwood sub-frame, bay adaptor


Face fix

Reveal fix

Standard product features


  • Aluminium 6063 T6 Alloy to BS 1474.
  • Weather pile:
  • Polypropylene draught strip to BS 7386.


  • Water tightness (to BS 6375-1): Test pressure class 300 Pa.
  • Air permeability (to BS 5368-1): Test pressure class 600 Pa.
  • Acoustic performance (to BS 2750-3, BS 5821-3): Weighted sound reduction index, minimum Rw 49 dB.

Product Options

Product reference:

Tilt-in versions are fitted with toughened safety glass as standard and can be pivoted through virtually 180°.

Size (w x h, maximum):

  • Balanced vertical slider: 1500 x 3000 mm.
  • Tilt-in balanced vertical slider: 1400 x 2700 mm.

Frame finish:

Anodized to AA5 - BS 3987 or polyester powder coating to BS 6496 to give a 60 micron high gloss finish. Stock colours are white and van dyke brown, other RAL colours available on request.


Glazing to BS 6206. Available with acoustic glass, clear float glass, laminated glass or toughened glass, all in a range of thicknesses.


Extruded to BS 2782. Standard colour black, 4 mm white gaskets available on request.


Available with a range of ironmongery.


Hardwood or PVC-U trims colour coded in a range of sizes.

Grounds/ Sub-frames:

Available with hardwood sub-frames to suit standard or reveal fix, or with bay adaptor.


Consult Ventrolla for recommendations and details.

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