AQUAPANEL® Cement Board Outdoor

General Information

Knauf AQUAPANEL® Cement Board Outdoor is a robust and stable weather resistant cement-based cladding and directly applied thin-coat render-backer board which is an economic alternative to traditional brick and block construction, as well as a conventional render carrier board.  Multiple render manufacturers have approved Knauf AQUAPANEL® Cement Board Outdoor as a backer board for their renders with many offering a complete joint BBA system certificate. 

• BBA certified (certificate number 09 / 4633)
• Simple score and snap technique
• Does not contain MgO and is NHBC, LABC and Premier Guarantee approved
• A1 fire-rated in accordance with EN 13501-1

Application 

Knauf AQUAPANEL® Cement Board Outdoor provides a solid dry base that can withstand the extreme weathering effects of wind, rain and snow.  Once taped and jointed, it can be left unfinished for up to 6 months, making use of the smallest windows of opportunity to ocmpletely close the external envelope, maximising the efficiency of the project schedule.

Coverage 

• 900 x 1200 x 12.5mm or 1.08m² per board
• 900 x 2400 x 12.5mm or 2.16m² per board
• Fixings on 600mm centred supporting framework - at maximum 250 centres: 15 screws per m² 

FAQs

• What are the maximum framework centres? 

600mm in almost all normal conditions.  In higher wind load zones, the framework should be at 400mm centres and for higher impact environments, the framework should be at 300mm centres.  Contact Technical Services for more information.

• Where should fixings be located? 

15mm from the board edge and every 250mm up the framework.

• How heavy is the board? 

Knauf AQUAPANEL® Cement Board Outdoor has a mass of 16kg/m².  1200mm long board is 17.28kg and 2400mm long board is 34.56kg.  As the board is lightweight and only 900mm wide, it means that it can easily be worked from scaffolding, rather than having to be cut on the ground and carried to the fixing position.

• What else do I need to specify / order to complete my project?

Knauf AQUAPANEL® Joint Filler - Grey, AQUAPANEL® Tape, AQUAPANEL® Screws (dependent on framework type), and exterior thin render coat system (incorporating a modern thin basecoat and mesh, and a finish coat).

• Must I use Knauf AQUAPANEL® accessories? 

In order to comply with Knauf's system warranty, only Knauf recommended accessory components supplied by Knauf should be used.

• Can I use brick slips, natural stone or external tiles as a finish?
  

Yes, a thin coat render basecoat and reinforcing mesh is required beforehand, but a tile finish is possible.  variable tile sizes and weights are possible, stud / batten centres would be specified within your Knauf specification.  Indicative maximum tile weight of 40kg/m² with frame at 600mm centres.  For heavier systems, contact Knauf Technical Services.

• Can I apply a sand and cement render?

When applying a sand and cement finish, it is important to note that sand and cement renders are non consistent mixes, and when they dry are very heavy and brittle.  We would recommend that a modern thin coat render basecoat with reinforcing mesh is applied beforehand, and that a layer of sand and cement (no more than 10mm thick) is applied over this.  Take care if applying a key into the basecoat, not to move or damage the mesh.

Knauf AQUAPANEL® Cement Board Outdoor, and the basecoat and mesh layer will absorb some of the movement from the structure, but cracks and sometimes shelling of the sand and cement finish may still occur.  It may be better to consider liasing with your render system supplier of choice about options for a sand and cement type finish using either the basecoat or a modern finish layer.

• Can I get a timed rated wall with this board? 

Knauf AQUAPANEL® Cement Board Outdoor is A1 rated to EN 13501; it is therefore non-combustible and will not allow fire to spread along its surface.  However, as the board is installed over a drained and ventilated cavity, any fire may get behind the cladding.  A timed fire rated walling system would be accomplished from the sheathing layer inwards.  Cavity fire stopping should be discussed with the passive fire stopping specialists on the scheme. 

• Can I dot and dab to blockwork? 

Knauf AQUAPANEL® Cement Board Outdoor cannot be dot and dabbed only.  This board must be mechanically fixed if applied to blockwork.  Do not use a gypsum bonding adhesive in external applications, use a suitable external grade cement-based adhesive to position the boards before mechanically fixing.  As per the BBA certificates, when applied over timber or steel frame structures, Knauf AQUAPANEL® Cement Board Outdoor shouold be installed onto a drained and ventilated cavity.

• What is the maximum cavity depth needed? 

New build insurance providers state that the cavity needs to be a minimum of 25mm in England and Wales, and 50mm in Scotland, Northern Ireland and Republic of Ireland.

• Do we have to build using a cross battened batten framework? 

Knauf details show a cross battened framework, but usually there is not a need for the horizontal batten; a single vertical batten can be used being fixed through the breather membrane to the timber studs behind.  The cross battened system is used when the cladding is needed to be pushed away from the structure to align other cladding, or if the vertical battens need to be closer due to wind loads and / or impact performance - the horizontal battens are fixed back through to the timber studs and the vertical battens to the horizontal battens (ensure fixings between battens are suitable for the application and cladding weight). 

• Does the cross battened system need to be horizontal to the structure and vertical behind the Knauf AQUAPANEL® Cement Board Outdoor? 

Yes, the vertical battens MUST be behind the Knauf AQUAPANEL® Cement Board Outdoor as any moisture that may form will be to the coldest surface which is the back of the cladding - a vertical batten behind this face allows any moisture to drain downwards.

• How do you fix battens to a SIP Panel System? 

SIP Panels do not have studs within all of their structures; however, the outer OSB layer is thick enough to take the cladding system directly fixed to it.  Battens must be screw fixed to the outer SIP OSB layer (though the breather membrane).  Refer to the SIP System supplier for qualification. 

• Is the system ventilated at the head of the cladding? 

Yes, the cladding must be ventilated at the head of the cladding with a minimum gap of 10mm between the top of the rendered cladding and the structure above (soffit box, coping etc.).  This allows any warm moist air to escape from the cavity.

• Can the Knauf AQUAPANEL® go down onto a walling below? 

No, there must be a drained and ventilated cavity at the base of the cladding.  The minimum gap must be 15mm + any expected settlement, expansion or deflection.  Contact Knauf Technical Services on how to detail this junction.

• Can you use this to fire encase steel? 

No, this board is not approved for this use.

• Do l have to finish the board? 

The Knauf AQUAPANEL® Cement Board Outdoor, once taped and jointed, may be left exposed for up to 6 months before a render basecoat and reinforcing mesh must be applied as aminimum - this cannot be left un-rendered indefinitely and is not suitable for direct painting.  The render basecoat acts to weatherproof the systemand maintain Knauf's requirements.  The basecoat and reinforcing mesh may be painted without having a topcoat render applied, however in these cases, the tape and jointing process must ensure it uses the 200mm wide tape rather than the standard 100mm tape.

• Can this board be used indoors? 

Knauf offers AQUAPANEL® Cement Board Indoor for internal applications.  However, any Knauf AQUAPANEL® Cement Board Outdoor panels not used can be used in internal applications.

• Do I render to the rough or smooth face? 

We recommend that the smooth face is rendered onto.  If the boards have been installed rough side out, make a note of the batch number against the project name and render can be applied to the rough side.

• Can Knauf AQUAPANEL® Cement Board Outdoor be installed to offsite fabricated systems?

Yes.  As the boards are easily curved without any detrimental effect to their performance, they can be installed, and taped and jointed in an offsite factory application and moved around without issue.  suitable flexible finishes can be applied offsite as well, but consideration as to installed cladding alignment should be made (sometimes better to finish on site).

• Do I have to render Knauf AQUAPANEL® Cement Board Outdoor straight away?

No, the boards can be left without the 3 to 5mm gaps being filled for between 4 to 6 weeks before the modern thin coat basecoat, mesh and finish have to be applied to weathertight the facade.  Apply the thin coat basecoat into the gaps before applying the full surface application.

• How long can the Knauf AQUAPANEL® Cement Board Outdoor be left exposed before I should render them?

If the Knauf AQUAPANEL® Cement Board Outdoor boards are taped and jointed using Knauf AQUAPANEL® Joint Filler - Grey and AQUAPANEL® Tape, the facade walling is temporarily weathertight.  When taped and jointed, Knauf AQUAPANEL® Cement Board Outdoor can be left exposed through all UK weathers for up to 6 months.  Prior to applying the render finish, check the boards are clean, not damaged and completely dry.

• Do I have to tape and joint the boards?

Knauf recommend that the boards are installed with a 3 to 5mm gap all around the boards, and all joints are taped and jointed using Knauf AQUAPANEL® products (this must be done for soffit applications).  If the thin coat render basecoat and mesh layer is going to be applied within 4 to 6 weeks of the boards being installed, the tape and jointing application can be omitted, but the basecoat must be applied into the gaps prior to application of the basecoat and mesh layer.

• Can this board be curved?

Yes, as a full board, a radius of down to 3m is possible.  If the board is cut into 300mm strips, then a radius of as little as 1m is achievable.

• Does the board have good pullout strength?
  

No, this is not a cement particle board and any fixtures should be planned in advance such that ply (or similar) pattressing is included in the grid system.

Additional Information

Case Study: Icon outlet at The O2

Offsite Case Study: Care home in Winnersh, Berkshire