How best to fill this gap?

[DanielWestern]

We recently had an extractor fan fitted in our bathroom in a Victorian terrace house. Some of the plaster and some of the cornice had to be cut away to access the wire. Now I am wondering how best to fill this gap in the plaster/cornice to cover the wire, its a couple of cm thick. I guess this is too thick for a regular filler like polyfilla, so would I be best off using some kind of two pack filler here? Any recommendations?

 

[fernicarry]

Maybe pack it out with newspaper or tissue first to reduce the depth, and build up in layers according to the filler's instructions.

Chamfer the top edge with a stanley knife so that you can feather in the last layer more easily. The trick will be sanding it to match the profile of the cove so that it doesn't stand out like a sore thumb.

 

[DanielWestern]

Maybe pack it out with newspaper or tissue first to reduce the depth, and build up in layers according to the filler's instructions.

Chamfer the top edge with a stanley knife so that you can feather in the last layer more easily. The trick will be sanding it to match the profile of the cove so that it doesn't stand out like a sore thumb.

Thanks for that - I like the idea of packing it with paper first then I can just use a regular filler, which I have plenty of. I guess something like chicken wire would also work here.

Can you explain a little more what you mean by this: "Chamfer the top edge with a stanley knife"?

 

[a twig]

Toupret interior filler (the powdered one that you mix up, not the naff premix in a tube or tub) will do the job at the entire depth in one go.

Shape it as close as you can to the surface and shape of the cornice, erring in the side of leaving it a little bit proud if having trouble, then sand it back if needed once dry.

 

[DanielWestern]

Thanks. I don't have any toupret but I do have some polyfilla already. Would that do the job as well? Would I need to seal the edges of the coving and the brick with some PVA first?

 

[a twig]

There are lots of variants of Polyfilla but generally I find that it can’t be filled as deep in one application, and suffers more from shrinkage so you’d need to build up in several applications or pack out as suggested above.

Shouldn’t need to seal anything.

 

[a twig]

Blue Peter style here is one I did in a rush earlier (2 years ago) that I haven’t got round to sanding or painting yet, literally just splodged Toupret in until it reached the surface then ran a small decorators knife over it to get it flush

At some point I’ll use a bit more to tidy up the edges then it will get sorted if we ever get round to re-decorating this room

 

[Cubist]

Thanks for that - I like the idea of packing it with paper first then I can just use a regular filler, which I have plenty of. I guess something like chicken wire would also work here.

Can you explain a little more what you mean by this: "Chamfer the top edge with a stanley knife"?

The meaning is to remove the exposed raw edges of the gap by cutting a 45 degree slope no more than 5mm wide and 5mm deep. This provides the filler with a larger surface area with which it can bond and allows a cleaner join to the surrounding plaster and coving after sanding. Also, with this kind of repair always use 'uphill' strokes to apply the filler - if you don't you can end up simply pulling the filler down and into the fan body.

If using a Stanley Knife to cut the chamfer make sure to avoid that cable at all times if you don't want a shocking result.

May also be an idea to remove the fan cover before making the repair to give yourself more room to work.

 

[DanielWestern]

Yeah sorry I should have been more specific, it's the "All Purpose polyfilla" which according to the tub can fill up to 1cm so I might need to build it up in layers a little if using that.

Cubist - thanks for that, that makes total sense now. And good tip about the upward strokes!

 

[stuart45]

Fillers tend to shrink into the repair. To get a seamless finish I tape and fill a day later with paper tape and a few coats of Knauf fill and finish.

 

[DanielWestern]

I see. I have some Tesa crack tape in the house. Would using that, together with some easy fill and then with Toupret fine surface filler, both of which I have, do sort of the same thing as what you are referring to? Obviously that would be at the end, once the main filling of the hole has been done.

 

[a twig]

Honestly, at the risk of sounding rude (but honestly not meaning to) I think you're over thinking this, it's a pretty small hole, so essentially two solutions:
1) Chuck whatever muck / newspaper filler etc you have already paid for in up to the maximum depth it recommends on the instructions. Let it dry, chuck some more in if needed, rinse and repeat until hole is filled, then tidy up at the end with sandpaper if required.

2) Spend £10 on £2kg bag of Toupret interior filler, fill the whole gap in one go, sand / use your fine surface filler to tidy up any last snags, stick the rest of the bag in a tupperware for future use.

 

[Jonty1234]

I'd tend to agree with twig here. The hole isn't that big so should be fine just to use any interior filler. I've never had any problems with the Toupret ready-mixed pot but you can buy it in powder form too. If you are worried that it might not hold all in one go, just apply it bit by bit and build it up over a couple of days. Toupret is particularly easy to sand and the patch is probably high enough that any imperfections will be undetectable to everyone (apart from you who will likely look at it each time you enter the room).

As Cubist suggests, removing the rough edges of the cornice before filling will help achieve a smoother finish.

 

[DanielWestern]

Yeah you're both probably right about the overthinking! Some great advice here, thanks s all

 

[Eric56]

Another vote for Toupret. Have the Red and also a Tub of pre Mix. Also get some bendy "filling blades" -easier than the trowel I was using before. One blade packs it in then a wider bendier one to wipe the excess.
Watch the Toupret channel on YT to study their application technque and see the tools they demonstrate with.
Only downside if you then wander around putting filler all over your house..

 

[Janela]

old credit cards are also good as filling 'blades' I found them great for plastering in small pokey areas. and of course if you are restoring an old house you will have a good supply of worn out credit cards with no credit left!!

 

[DanielWestern]

Ain't that the truth...

 

[Cubist]

old credit cards are also good as filling 'blades' I found them great for plastering in small pokey areas. and of course if you are restoring an old house you will have a good supply of worn out credit cards with no credit left!!

I like the idea and can see some obvious benefits but..... there are some inherent risks to anatomical features that need to be born in mind as well.