PROWALL for steel frame
Rendered Rainscreen Cladding for Steel Frame

Use ‘helping hands’ systems to fit the ProWall system to steel frame constructions for a seamless rendered finish.

With integrated fire safety ProWall is approved Document Part B Fire Safety compliant and classified as A2-s1,d0 ‘reaction to fire’. The system has premium render carrier boards and a high-quality render finish making ProWall a complete system and an ideal choice for larger public buildings.

The ProWall Helping Hand system for steel frame structures works in conjunction with a number of rail and bracket systems, a solution that eliminates cold bridging.

Using a Helping Hand system allows you to insulate outside the frame, creating a warm steel frame whilst maintaining a clear ventilated cavity between the insulation and rainscreen system.


  • Brackets precision engineered from 3mm structural grade aluminium
  • Rails engineered from 2.2mm high specification 6063 T6 aluminium
  • Designed for fixed and floating points
  • Integral isolation pad to reduce cold bridging
  • Unique three-part design offers superior performance and wider spanning
  • Integral rail location clip to aid initial positioning
  • Rails supplied in 6 metre lengths

Ventilation Profile Base Bead

proboard ventilation profile and base bead

  1. ProWall Aluminium Ventilated Base Bead mechanically fixed to Helping Hand rails
  2. Aluminium Ventilated Base Bead must be to the depth of the cavity
  3. ProWall Base Bead, PWBB fitted to face of Helping Hand rails to create level at base of system and improve impact resistance

Profiles To Apertures

rainscreen for steel frame
Aperture Profiles
  1. ‘L’ shape profiles fixed to Helping Hand rails at base of apertures and jambs
  2. Ventilation profile fixed to frame and Helping Hand rails at heads of apertures

ProBoard To Apertures

rainscreen for steel frame
  1. ProBoard fixed to Helping Hand brackets paying close attention to layout of boards
  2. ProBoard fillets fixed to ‘L’ shape profiles at aperture jambs
  3. Bellcast bead fitted to aperture head

Bracket Types


ProBoard Fixing

ProBoard Installation
  1. ProBoard to be fixed in blockbond style
  2. 3mm spacings required between ProBoards

ProBoard To Apertures

Fixing Spacing
  1. Maximum 200mm centres between screws on Helping Hand rails (subject to minimum number of fixings as instructed by structural engineer/wind load calculation)

Elevation Layout

Aperture Planning
  1. ProBoard fitted around apertures to avoid vertical or horizontal joints at corners
  2. ProBoard joints minimum 150mm from the edge of opening

Corner Fixing

Fixing Spacing
  1. Corner ProBoards fitted alternately block bond
  2. ProBead NMAB to be bedded on at corner during render application

Fire Breaks

Fire Breaks

Fire Barrier
  1. Fire Barrier placed between insulation at floor zone
  2. Continual line of Fire Barrier placed on the perimeter of floor zones
  3. Independent lengths tightly butted

Note: Fire Barrier detail is offered as a guidance detail only. All Fire Barrier designs must be signed off/ approved by appropriate parties


  1. Drainage channels fitted at angle around service to provide drainage
  2. ProBoard surface cut to accommodate service

Expansion And Slip Joints

Vertical Expansion Joint

  1. Expansion joints in substrate to be mimicked in steel frame and ProBoard
  2. ProBead EX6 profile to be installed on surface of ProBoard
Horizontal Slip Joint

  1. Shrinkage allowance provided in Helping Hands and ProBoard
  2. No Brackets to be fixed into floor zone, rails should ‘float’ over the floor zone
  3. ProWall Slip Joint profile installed over surface of ProBoard
  4. Typically this detail incorporates Fire Break shown in figure 22 to ensure compartmentalisation

Note: Where no horizontal movement joint or vertical expansion joint exists in substrate, provision should be made within the ProBoards so that no area exceeds 42m2 or 7.5m (linear) in any direction without a break.

System Ventilation

  1. ProWall cavity runs up to coping or roof structure leaving room for ventilation
  2. ProWall Aluminium Ventilated Base Bead installed to top of system to protect cavity and allow circulation

Note: Alternate ventilation details are available from the SAS Technical Team where different roof structures are present.


ProWall Accessories

Ventilation Bead

ProWall ventilation bead provides protection at the base of the system against insects and rodents whilst allowing the cavity behind the ProBoard to breathe.

Base Bead

ProWall base bead provides protection to the base of the ProBoard whilst creating a level datum to install the ProBoard and a bellcast feature.

Window Protection

ProWall window protection bead ensures a clean line to the window frame along with a water tight seal and added protection during render application.

Noseless Mesh Angle

ProWall noseless meshed angle bead ensures clean yet concealed lines to external corners along with added protection to vulnerable areas.

Window Head

The ProWall window head bead ensures good drainage from the face of the render and provides a neat edge.

Slip Joint

The ProWall Slip Joint ensures that deflection and differential movement are allowed for within the cladding design.

  1. ProBoard joints should be taped using ProRend Lite and ProMesh Grade 3 mesh cut to 300mm wide strips.
  1. Using a Hawk and Trowel, apply a 3/4mm coat of ProRend Lite to the textured ProBoard surface.
  2. Embed ProMesh Grade 3 into the applied material.
  3. Overcoat with a 2/3mm coat of ProRend Lite.
  1. Elevations must be fully meshed with ProMesh Grade 3 reinforcement mesh.
  2. Ensure a minimum of 100mm overlap between mesh.
  3. Apply ProMesh Grade 3 in 300mm x 300mm squares at 45° to corners of all openings.
Mesh Layout
  1. Using a spatula, rule off ProRend Lite to give a flat and even surface.
  2. The minimum finished thickness of ProRend Lite is 5mm.
  3. Allow ProRend Lite to cure for a minimum of 48 hours before applying other ProRend products.
  1. Apply ProRend Colourtex Primer with a roller or brush ensuring complete coverage of the ProRend Lite basecoat.
  2. Allow to dry for 24 hours.
  1. Using a Hawk and Trowel, apply ProRend Colourtex decorative topcoat in a tight coat to the thickness of the aggregate within the material.
  2. A wet edge and uninterrupted application must be maintained at all times to avoid scarring.
  3. Allow approximately 10-30 minutes depending on conditions for material to ‘pick up’.
  4. Finish ProRend Colourtex decorative topcoat by rubbing with a smooth plastic float in either a horizontal, vertical or circular motion.

Application reference

  • For all ProRend renders BS EN 13914-1:2016 Design, preparation and application of external rendering and internal plastering; part 1, external rendering to be followed at all times.
  • Other advice and guidance is available in BS 5262:1991 Code of practice for external renderings, predecessor to BS EN 13914, and BS 8000-10:1995 Workmanship on building sites; code of practice for plastering and rendering.
  • Surface preparation requirements for ProRend renders are the same as for ordinary sand and cement renders. Surfaces must be clean, suitably dry, sound and free from anything that may interfere with the adhesion of the materials to be applied.
  • Only clean water fit for drinking should be used for gauging.
  • Scaffolding must be independently tied to allow uninterrupted application.
  • Masking should be used to give protection to adjacent work and to give clean straight edges. It should be removed immediately after finishing.
  • Remove splashes of material from glass or aluminium immediately as they may etch the surface and leave a permanent mark.
  • Walls should be protected from rain or other inclement weather during application and curing, ProRend renders should not be applied to substrates which are frost laden or have recently been exposed to prolonged rain.
  • When applying in hot weather, it is advisable to ensure that work coincides with the shaded areas of the building.
  • Local weather and site conditions must be taken into account by the applicator before any ProRend product is applied.
  • ProRend renders should be applied between 5°C – 30°C. Materials should not be applied if temperatures are expected to drop below 5°C within 24 hours.
  • ProRend materials applied to a render elevation should either be of the same batch number or thoroughly mixed together to ensure colour consistency.
  • Care must be taken to protect cement products from rapid drying conditions such as exposure to direct sunlight or drying winds. In these conditions it should be kept evenly damp for 3 - 7 days by lightly spraying periodically with clean water. This is to ensure complete hydration of the cement.
  • Polythene or Hessian sheeting is recommended during curing and should be arranged to hang clear of the face of the wall in such a way that it does not form a tunnel through which the wind could increase the evaporation of water from the rendering. Intermittent contact with the render must be avoided as this may cause a patchy appearance.
  • Cement based ProRend renders should be stored off the ground, under cover in dry conditions.
  • ProRend Resin renders should be stored in dry cool conditions at a temperature greater than 5 o C. Protect from sunlight and sources of direct heat. Containers should be kept sealed when not in use and stacked no more than four high.
Tensile strength200-240 N/mm2
Yield strength170 N/mm2 min
Shear strength125 N/mm2
Brincell hardness60 HB
Thermal conductivity149 W/mK
Electrical conductivity39.4%
Coefficient of thermal expansion23.5x10 -6 1/K
Elastic modulus70000 MPa