I'm stupid. Help me figure out coving.

[KindersFeepers]

Just moved into a new flat. There's currently coving on one wall, and I want to DIY coving across the full room.

I've YouTubed how to cove, and I get the basics. But how do I match up coving in the corner with this existing piece of it? Meaning, how do I get that shape to line up so it doesn't look botched. I understand how to use the mitre box, but how do I get the exact match to this bit?

Is it polystyrene or plaster?

Polystyrene I think 👍

Then you should be able to cut into it.

You need a 45 degree angle at the corners, you can't match up to that existing piece.

Either cut a small template piece with the correct corner angle for that wall and use it to cut it back. Or cut out the end segment and fit a new piece at the end with the correct angle for the corner.

You might be better taking that piece down in order to cut the mitre in the corner. Start with a new pice. How long is it?

@gapattachment Oh perfect! I was wondering if I would need to cut it. I honestly can't thank you enough - my poor simple brain was releasing steam trying to figure it out.

Geometry was never my forte...

If you do cut out a section of the existing wall's coving to refit, then join the flat sections at 45 degrees horizontally rather than 90 degrees as it's easier to blend them in.

Or as pp says take out the whole piece depending on how long it is.

Like this if you can cut in-situ with a Stanley knife.

Oooh thank you. I'm kinda tempted to rip the whole piece out to be honest, because I hate how messy the join looks. It's only about 60cm long.

Can you not just buy corners?

Hmm that's ugly. You should be able to sand back that filler and re-do it neatly before you re-paint.

I was wondering why they hadn't done all the walls, but maybe they had such a traumatic time with the first corners they gave up!

I can, but I was trying to figure out if there was a way to match up a new piece with the existing coving. Now I know I can cut into it, thanks to the beautiful on this thread who know what they're doing!

You can buy pre cut corners for your cornice, think Wickes does it, but others do to

Lol right? It's right next to an interior coving corner that looks great. It was just the exterior one that put them in a bind.

@AnOldCynic @gapattachment Where do you rate DIY coving on a scale of difficulty? Just out of curiosity, before I start a project that ends up being way too ambitious...

Get a coving mitre box. Use a multitool to cut down the coving that is there and put new coving up. When you cut the miters (using your mitre box) use mitre glue to stick them together and fix them to the ceiling with coving adhesive and small nails. Then caulk the joints and the nails and paint them.

its not difficult, but it needs 2 people and ladders (unless you do it in parts, but don’t cause the joints always show).

Coving mitre box:

https://www.diy.com/departments/wood-coving-mitre-box/1782811_BQ.prd?storeId=1257&&&&&gad_source=1&gbraid=0AAAAADt-XHk6kOaIJKmZVNjiqoN_056TF&gclid=Cj0KCQjw3vO3BhCqARIsAEWblcBjdenJWHQAEiqtYYgRyWIRWHB-7w-wRuEIL9M5K0pY7UaJtyBbroMaAo5LEALw_wcB&gclsrc=aw.ds

Mitre Bond:

https://www.screwfix.com/p/mitrebond-aerosol-kit/28848?ref=SFAppShare

Coving adhesive:

https://www.screwfix.com/p/supercove-coving-adhesive-white-310ml/28537?ref=SFAppShare

You can use leftover coving adhesive instead of caulk, it can be painted over

@Hiddenmnetter Thanks for being an amazing human. I really appreciate your help!

You could just scribe the new piece like you would a skirting board, then you don't need to touch the existing

@KindersFeepers no problem

It's a lot easier if your corners are properly square.

<eyes wonky house>

Polystyrene coving - not that difficult as long as you have time and patience and prepare the walls.

I personally don't think you need 2 people for polystyrene coving. I did it on my own and didn't have much DIY experience at the time (and have had compliments on its neatness lol), although I had a platform ladder rather than a stepladder. It's light, you can easily manoeuvre an entire piece alone.

Depending on the length of the walls it might be inevitable to have joins - unless you only have short walls.

As long as you hold the coving securely in the mitre box and cut carefully (with the right type of saw and tpi) you should have neat joins. If you let the coving slip down in the box as you cut (even just slightly) then you'll end up with funny angles and having to do lots of filling and smoothing. If you can afford to sacrifice at least part of one piece to practise it might not hurt.

The coving adhesive I used was a brown colour. It was perfectly fine to use for joins, but it required extra coats of paint than if it had been white.

Wickes how to video:

And guide:

https://www.wickes.co.uk/how-to-guides/decorating/fit-coving

Oh yeh that is also true