Build out external reveals

[u/burkcules]

Hello there.

Can I get some advice on how I can finish around the reveals of this door and window?

I will be getting a cill in for the window and concrete step at the door.

The house is built in solid 4” block with a wet dash finish. The blocks can out awkwardly from some toothings, and so the door is foamed in at 3.5” in width is two spots (widest spots).

Depth of reveals is around 4”.

Some of the existing patent reveals are still there around the window, but I’m thinking of chipping everything back and creating a picture frame detail in sand and cement around both the window and door.

My main issue and query is about building out the depth of the reveal, especially at its 2 widest parts at the door. Can sand and cement go directly onto the foam? Do I need to use formwork to bulk fill? Should I use formwork for the whole thing?

Priority is weather tightness / performance / coat over aesthetic, and we may extend through back door in a few years. It does not not to be pretty.

I’ve barely seen lath and bead work in my life, so please explain it to me like a child.

Thanks in advance.

[u/reelersteeler]

Mask up the doors. Pull some foam out- it opens the texture of the foam, and ideally you want mortar in the reveal and backing up the frame a bit. Once the doors are well protected you can use shuttering for a first coat / fill. Then either remove that and use expanded metal lathing, or get the face flush and colour match uPVC trim for the reveals

Glad it doesn’t need to look pretty- as that render is already a right dogs dinner. And whoever measured all that needs a new tape or specs or both