Ceiling Fan Install - Joist Off Centre

Sebo027

Good day. I want to install a ceiling fan onto the ceiling of a Victorian era flat. Access from above is not possible. 

I picked up a cheap boroscope and was able to locate a joist that runs adjacent to the position of the current light fixing. It's edge is maybe 2 or 3 inches, from the centre. I could fit the fan directly to this joist but it would look daft on this ceiling given the plasterwork. 

So, am I correct in saying my only option is to open up the ceiling, fit a timber beam between the joists, close up the hole, replaster and paint?

Murmansk

I guess it depends how heavy the ceiling fan is. Depending how big the bit of the fan that attaches to the ceiling is and taking into account how close to the light fitting you say the beam is, maybe you could cut into the ceiling and attach something to the beam that would be solid enough to attach the fan to? Putting something between the beams would entail a massive hole in the ceiling unless maybe you could do a bit of "keyhole surgery" but it'd be very awkward!

Alderbank

It looks a bit plain for a Victorian ceiling but if it is then the ceiling will be horsehair and plaster over lath. Very messy when you cut into it.
If it were me I would buy a centre rose like this https://www.toolstation.com/classic-coving-ceiling-rose/p24337?store=G5&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=&pkw=&pmt=&gclid=Cj0KCQjwr4eYBhDrARIsANPywChcFeK_vkPTCEvgm0grfW275Yuvrj-u4JJibvwAd9lY3RvtoUHd1kgaAlArEALw_wcB&gclsrc=aw.ds
to go in the centre to cover your handiwork.

Edited to add:
Is it floorboards above?
Possibly a bit cheeky but if so you might be able to screw brackets into the floorboards above to suspend your fan from.
Ceiling fans need a firmer fixing than a pendant light because of the sideways thrust every time they are switched on.

grumbler

Buy a MDF ceiling rose.

I think 200mm will be fine, but you can use 550mm.

Fix it in the centre by screwing reliably to the joist and with en extra screw or two to the lath ceiling. For the ceiling use something like