How to install clay cladding on cement fibre board and plaster?

Question

Hi, installing lightweight clay brickslips/cladding onto cement fibre board, and plastered block wall. The walls will be close to a wood burner.

What DAVCO primer and adhesive would be recommended?

Interested in both powder, and premixed.

Cheers, Wayne

waynehazell · Answer

Hi, thanks for the reply - the supplier uses MAPEI products, and has recommended to use the likes of ECOprim T+ primer, with S2 T Flex adhesive, or an equivalent.

THanks, Wayne

MitchellMc · Answer

Hi @waynehazell,

This one really needs to be approached in two steps to make sure you end up with a system that’s actually supported and warranted.

First step is to go back to the supplier of the brickslips (this applies equally to most Bunnings supplied stone-style cladding products as well). They need to nominate the type or class of adhesive that their product has been tested with and is approved for. Because these lightweight brickslips vary quite a bit in composition, adhesive manufacturers like Davco generally won’t specify or warrant a product unless it aligns with the cladding supplier’s tested system.

Once you have that information (for example, whether they require a highly flexible adhesive, epoxy etc.), then I can go to Davco and select a suitable product that matches those requirements. Without that step, any recommendation is essentially guesswork and won’t be backed by warranty.

Regarding primers, I can be more specific, but I need a bit more detail on the plastered block wall. The fibre cement sheet is usually straightforward and just requires a compatible primer depending on the adhesive chosen. However, for the block wall:

* Is it cement render or a hardwall plaster finish?
* Is the plaster painted?
* How sound is it (any drummy or weak areas)?

It’s also worth noting that plastered block walls can sometimes be a questionable substrate for cladding systems, especially if the plaster layer isn’t well bonded. These finishes can delaminate under the added weight and thermal movement of brickslips, particularly near a heat source like a wood burner.

For most stone or brick cladding systems, the requirement is a solid, stable substrate (e.g. properly prepared masonry or suitably rated fibre cement board). So confirming the suitability of that plaster layer is important before selecting primers and adhesives.

If you can check with the brickslip supplier and come back with their adhesive requirements, I can help narrow down the appropriate Davco primer and adhesive options.

Please let me know if you have any questions.

Mitchell