ᐅ Larch wood façade on 36.5 cm Poroton blocks – with or without base coat plaster?

Dear forum,

We are building a house. In the scope of work description, it was agreed that the bay window would be clad with larch wood as follows:

36.5cm (14.4 inches) Poroton T10, 2cm (0.8 inches) base plaster, 2.5cm (1 inch) batten construction, 2.5cm (1 inch) larch wood shiplap cladding.

However, it has now been installed without the base plaster (urgent issue!), with the explanation that this makes it easier to align the plaster joints with the rest of the house.

But: is this correct??? Isn’t a base plaster necessary? The construction manager is also willing to reduce our costs (less material, less work).

However, we don’t want shortcuts!

Is it sufficient to have the Poroton, screw the battens directly onto the bare masonry, and then install the larch wood cladding over that?

Thank you very much for your expert input and best regards

OdinBoxer

Hello, I can’t help you with your specific case, but I can tell you how it was done in our situation. We built with 42.5 cm (17 inches) expanded clay walls and also partly applied a ventilated larch wood cladding. In our case, a base coat of plaster was definitely applied; I don’t understand why that should cause any issues with the connections to the plaster facade. However, I also have no idea whether that might be a problem in your case. For solid masonry walls, I would have some concerns about airtightness despite the interior plaster...