How to fill a large gap between wall and ceiling after removing old cornice?

[zangy86]

Hi, I have removed old cornice (as it previously had water damage) and have been left with quite a large gap all around where the wall meets the ceiling. I want to make it a straight 90' corner (without cornice) if possible but am unsure of how to fix the large gap? Any help would be appreciated. 

Thanks!

[MitchellMc]

Welcome to the Bunnings Workshop community, @zangy86! It’s wonderful to have you join us, and many thanks for your question about repairing plasterboard after removing cornice.

I presume you've resolved the issue that caused the damage to the cornice. It's important this is done before performing any repairs.

Cornice serves both a decorative purpose and as a way to hide the junction where the wall and ceiling sheets meet, as it's tricky to get a perfectly sharp right-angle joint. In your case, not only do you need to fill the gap left by the cornice removal, but you'll also need to ensure that the joint between the wall and ceiling is smooth and seamless for that 90-degree corner look.

If you're keen on achieving this, you’ll likely need to use plasterboard repair patches to fill any large gaps. Once the patches are in place, a joint compound should be applied, followed by careful sanding to create a flush finish. Achieving a crisp 90-degree corner without the help of a cornice can be quite challenging as it requires precise workmanship and a lot of patience to avoid cracking at the joint over time.

For larger gaps, you might need to install some backing (like additional plasterboard strips or a corner bead) to help reinforce the area before applying compound. This will ensure a solid base to work from. After that, it's a matter of using a fine filler and sanding back to get the perfect angle.

However, unless you're really set on a clean, modern 90-degree corner, reinstalling a new cornice would be a much easier option. Cornices are relatively simple to fit, and you'd avoid the challenge of perfectly finishing the wall-to-ceiling junction. This would also save time and reduce the risk of future cracks appearing at the joint.

If you're not experienced with plastering or joint work, I'd recommend enlisting the help of a professional. Creating that perfect 90-degree finish can be quite difficult, especially if the gap is large or uneven.

Please let me know if you have any questions.

Mitchell