Brick slip cladding

What is brick slip cladding?

A brick slip cladding is a thin fired-clay facing element bonded or fixed to a wall system to look like full brick. In Slovak the term is obklad z tehlových pásikov. The slip is a facing, not a wall. The wall behind it carries the structure and the slips only add a weather-resistant skin. The sources in this article are product assessments and manufacturer documents. The numbers belong to the named product, not to every slip on the market.

The European assessment ETA 17/0236 for webertherm ceramic describes what a brick slip is in that system. It is an extruded or dry-pressed ceramic tile with a CE mark to EN 14411. Its thickness is 8 to 15 mm, its length is at most 260 mm and its width is at most 60 mm. The same assessment states that the kit is made of non-load bearing components. They do not add to the stability of the wall, but they can add to its durability by protecting it from weather.

How does a brick slip differ from full facing brick?

A facing brick is a masonry unit. It is laid in mortar and can form part of a wall. A brick slip is a thin element and needs a backing. For that reason a slip finish is a system and not a single material. Its performance depends on the insulation, the adhesive or the rails behind it. The choice between an ETICS build-up and a ventilated substructure is made before the slip is chosen.

Do not use the slips to carry load. The assessments for both route types describe the cladding as non-load bearing. The designer must size the wall, the insulation and the fixings for the weight of the slips. That is why the product weight per square metre matters.

How are brick slips fixed on an ETICS build-up?

On an ETICS build-up the insulation boards are fixed to the wall and covered by a reinforced base coat. The slips are then bonded onto that base coat instead of a render finish, and the joints are grouted. Röben, a slip producer, describes the layers for its slips in its guide to slips on ETICS. The insulation boards are bonded to the masonry with at least 60 % adhesive coverage or with a full comb bed. The reinforced base coat is about 5 to 7 mm thick. The slips are set in a bed mortar of 3 to 4 mm and then grouted. Röben states that the insulation dowels go through the fresh reinforcement layer. It also states that the slips are set in the combined method of DIN EN 12004.

The webertherm ceramic kit in ETA 17/0236 uses the same principle with other values. Its insulation panel is bonded with at least 40 % bonded surface area and also has supplementary mechanical fixings. The cladding adhesive sits between the base coat and the slip. The kit is intended for continuous areas without expansion joints up to 4 m by 3 m. The joint width between slips is 4 to 10 mm. The Granol'therm Brick ETA 25/0947 describes an ETICS kit. Its panels are the thermal insulation product and its discontinuous claddings are the exterior skin. The assessment basis is EAD 040287-00-0404.

The consequence is that the slips are one layer of a complete insulated wall. Changing the insulation board, the adhesive or the base coat changes the system, and the new combination needs its own assessment or approval. An ETICS build-up has no ventilated air space behind the finish.

What weight limit applies to brick slips on ETICS?

No general limit exists. The limit comes from the approval of the chosen system. The table lists the values that the sources give for one named kit and one named wall system.

Item	Value	Source
Brick slip weight per square metre	At most 20.0 kg/m²	ETA 17/0236, webertherm ceramic optima, Annex 2
Brick slip weight per piece	At most 1.8 kg	ETA 17/0236, Annex 2
Slip thickness, length, width	8 to 15 mm, at most 260 mm, at most 60 mm	ETA 17/0236, Annex 2
Water absorption of the slip	Eb of 10 % or less	ETA 17/0236, Annex 2
Frost resistance of the slip	No defects, EN ISO 10545-12	ETA 17/0236, Annex 2
Reaction to fire of the ceramic element	A1	ETA 17/0236, Annex 2
Reaction to fire of the whole ETICS kit	B-s1,d0, EN 13501-1	ETA 17/0236, section 3.1
Maximum load of slips on the AQUAPANEL exterior wall system	40 kg per square metre	Röben guide for architects, section 4

The last row is a different wall system and not an ETICS. It shows that limits differ between systems. Röben states that its products do not usually exceed that value. A heavier slip, a thicker slip or a different adhesive needs a system that was assessed for it. Ask the system holder for the written limit before the order, because the slips, adhesive and grout add weight on top of the insulation.

Are brick slips frost resistant, and which adhesive is used?

Frost resistance is a property of the ceramic element, tested to EN ISO 10545-12. ETA 17/0236 lists it as no defects for the slips allowed in that kit. The sources opened for this article do not give a number of frost cycles, so none is stated here. Ask the slip producer for the declared frost resistance and water absorption of the exact slip.

Water absorption matters because it limits where a slip can be used. Röben says the approvals for slips on ETICS set different limits, from 3 % to more than 20 % by DIN EN ISO 10545-3. On EPS the absorption of the slip may be up to 20 %, depending on the approval. On a wood fibre insulation only slips with 6 % or less may be used, and that build-up is not covered by an approval.

The adhesive is part of the system. In ETA 17/0236 two named flexible tile adhesives are listed as the cladding adhesive between the base coat and the slip. A different adhesive is not covered by that assessment. Röben requires that the slips are set only in the combined method of DIN EN 12004 and then grouted.

Which insulation can sit behind brick slips?

Röben lists mineral wool, expanded polystyrene (EPS), resol foam, polyurethane foam and wood fibre insulation as bases for slips on ETICS. It states that mineral wool and EPS are possible up to 300 mm. The kit in ETA 17/0236 uses an EPS panel and its dowel table covers insulation thickness up to 200 mm. Each insulation type has its own approval conditions.

For EPS, Röben states that fire protection measures against fire from outside are required and are set in the approval. It also notes that very dark slips with a light reflectance value below 20 can cause local heat build-up in the ETICS. This is negligible on mineral wool but needs a closer look on EPS, where the producers specify a thick-layer base coat build-up.

How are brick slips fixed on a ventilated substructure?

On a facade substructure the insulation sits on the wall. A ventilated air cavity lies behind the cladding. Rails or brackets carry the elements. This article did not find a slip product documented for this route. The values below come from ETA 16/0645 for the FAVEKER FV kit, which uses extruded ceramic tiles to EN 14411 on an aluminium subframe. It shows how a ceramic cladding behaves on rails, and the numbers do not describe brick slips.

The ETA states that the kit is intended as external wall cladding in ventilated facades (rainscreens). Fixings between the brackets and the substrate are not part of the kit. The joints between the elements are open, therefore the kit is not watertight. The ETA also advises that the first layer behind the air space, for example the insulation, should have low water absorption. The reason is that the joints are not watertight. The cavity lets moisture drain and dry, which is the logic of a ventilated facade.

Which route suits a Slovak family house?

There is no single right answer. The table sets out the differences that the sources show.

Aspect	Brick slips on ETICS	Ceramic cladding on a ventilated substructure
Fixing of the finish	Bonded to the reinforced base coat, with dowels for the insulation	Mechanically fixed to rails or brackets
Joints	Grouted, 4 to 10 mm in ETA 17/0236	Open, so the cladding is not watertight
Air space behind the finish	None	Ventilated cavity
Fire behaviour	Class given for the whole kit	Follows the insulation when EPS, XPS, PUR or PF is used
Assessment document	EAD 040287-00-0404 for ETICS with discontinuous claddings	EAD 090062-00-0404 for kits for external wall claddings

Whichever route is chosen, the fire classification must be checked for the specific wall and insulation. ETA 17/0236 and ETA 16/0645 both note that no European reference fire scenario exists for facades. Both say that an additional assessment under national provisions might be needed. This article does not state a Slovak fire rule. The fire safety designer of the project sets the requirement for the facade.

The cost depends on the system and not on the slip alone. The insulation, base coat, adhesive, grout, dowels or rails, and the trims at edges and openings all belong to the price. Compare quotes for the whole system and do not compare slip prices only.

What are the common misconceptions about brick slip cladding?

• A brick slip wall is a brick wall. It is a facing finish. The structure is the wall behind it.
• Any slip works on any insulation. The system is assessed as a kit. The insulation, adhesive, base coat or substructure must match the assessment for that product.
• The weight does not matter. The limit is set by the approval of the system, for example 20 kg/m² for the slip in ETA 17/0236.
• Dark slips are never a problem. Röben says dark slips cause local heat build-up that is negligible on mineral wool and needs a closer look on EPS.