Mark walls with chalk line as per the published drop of the cornice.
Cut the first mitre and apply adhesive to glue beds of cornice. (Note on mitres: NMC products can be trimmed with a utility knife to get a perfect mitre. On outer corners, panel pins can be used temporarily to keep mitre firmly closed until adhesive has set.
Place cornice in position with splayed fingers and gentle pressure to avoid finger dents in product. No nails or screws are required – the product is light and will remain in place until glue is dry.
While still wet, scrape any excess adhesive away with a scraper, and wipe down with damp sponge.
Butt join any full lengths with a layer of adhesive between joins (suggested 1 to 2mm). Also use glue in mitres.
Complete the room.
Once adhesive is properly dry, joins can be lightly sanded until smooth. Use cove-bond or NMC adhesive to patch any “dings” or tidy up any visible joins.
Paint directly onto styrene surface (2 coats for best results). If joins remain visible, try coating the join only with an extra coat of paint.
Notes: The cornice can be re-profiled with sand-paper if slightly misaligned. Avoid solvent based products around styrene as they react with the styrene. (This includes some paint primers and undercoats).