Tony K

You might be right @JohnMo, that's why I'm asking!

I was going to build an enclosure around the ASHP and paint the walls black before applying the protective paint. One reason for thinking about ivy is that it gives such good coverage that the wall would barely be seen anyway. That's why I haven't rendered it.

For context, this is the courtyard garden of my SB. The wall on the right is the one I am thinking of treating with the paint, mesh, and ivy. You can see that I've rendered around the windows so that the areas the mesh will not cover are presentable.

Thanks all. Just to reiterate, I'm not thinking of just growing ivy on the wall of the house. I am thinking about painting the wall of the house in a silane-based, nanoparticle paint, as per the spec in my original post, affixing metal mesh proud of the wall, and growing ivy on the mesh. I am aware if the need this will generate for me to trim the face of the ivy yearly and to cut it back at the edges. My uncertainty is over whether this paint can actually prevent the plant from attaching itself to the building as advertised. I have considered various other climbers instead but, even though some flower beautifully in summer, many die back in winter. I'd be looking at a bare wall half the year. Or, they seem to grow quite slowly.

Thanks @JohnMo and @saveasteading. The wall in question rises up to a parapet above a flat roof, so I don't need to worry about ivy getting into a loft. In fact, it would be pretty easy to trim at the top if needed. I had thought about honeysuckle or other climbers, but few of them are evergreen like Ivy, nor are they as quick growing. Are neither of you convinced by this arrangement of mesh sitting proud of a wall protected by this magic paint?!

Its not evident from the photos, but the roof runs to a gutter at the rear. I know what you mean about GRP vs Rubber, but for a garden building I think I'm pretty comfortable with rubber. I might even put a simple green roof on it to prevent crow attacks!

Now that, is a good point!

Morning My SB is an L-shaped bungalow which creates an internal courtyard garden. One of the walls facing the garden is exposed blockwork at present. I had been toying with cladding it, but prefer a slightly different idea.... I am considering erecting mesh frames onto the wall and growing ivy all over it. Regarding preventing attachment (or damaging levels of attachment) to the house wall, the RHS says this: Application of two coats of ‘Easy-On’, a clear anti-graffiti, silane-based, nanoparticle paint, was as efficient in preventing attachment. Application of another, petrochemical-based paint, while not completely preventing ivy attachment, significantly weakened it, thus easing ivy management. This advice comes from the attached study. I am investigating the costs of appropriate paints, mesh, etc. The obvious, and pertinent, question is: am I being mad?! J-O-L-A-2016-Volume-3-Issue-1-Blanusa(etal).pdf

No, I might not need to create an air gap as such. As you say, the shape of the corrugated sheets will do the job. I may end up doing it anyway, though, as I need to fix battens to the wall to attach the corrugated sheets onto, and they will create a (larger) gap. In fact I will probably double layer the battens, as I need the first batten to run vertically so that water can escape, then the second batten to go horizontally for ease of fixing the sheets. I can't see a more efficient way. Regarding Ivy, I think I would be able to get to the vulnerable bits in the case of this project and regularly rim any stray parts of the plant from going where it shouldn't!

Something like this I think. The red is the housewrap stuff. The fascia is that which you can see in the photos,v so I will build outward from that.

The corrugated sheets should be rainproof, it's just that rain would have gotten behind them anyway via the gap at the top.

I'm sure you're right. I'll use corrugated sheets as cladding, which will allow me to put the dedicated flashing trim they do over the top, albeit mounted on a batten to bring it further out from the sheets.

Actually, why am I questioning it?! It won't do any harm to protect the top opening at all, even if it's belt and braces. Ta.

Mind you, AI also says this, depending on what you ask it! At the top of external cladding, you must install a head trim, flashing, or a vented closure profile. This seals the top edge, sheds rainwater away from the wall, and keeps an open gap for necessary cavity ventilation.

Yes, hence asking on here at this early stage! Mind you, I've read a good few things on line suggesting that rain can and will get behind cladding, and that it's fine. I mean, surely hit and miss cladding proves that cladding isn't intended to act as a proper waterproof screen for the building? This is AI but has good references... Because water gets behind the boards, professional installation relies on a specific design to manage it safely: Vented Cavity: Installers use battens to leave an open air gap (usually at least 25mm) behind the wood. Breather Membrane: A water-resistant yet vapour-open membrane is wrapped over the main structural wall to block water from entering the building. Drainage and Airflow: Gravity pulls water down the back of the cavity, while continuous airflow evaporates any remaining dampness.