straw and plaster ceiling cut

[svouts]

I need to install a chandelier around 15-20 pounds heavy in my ceiling. Now there is a lightweight pedant light that is hanging from an attachment with two screws into the ceiling.

For the chandelier I need to find the wooden joist to install a hook for hanging the heavy chandelier.

How can i cut a 4 inches opening the straw and plaster ceiling to see where is the wooden joist, without damaging the ceiling?

Any special tool or method to open the hole in the ceiling without cracking it?

 

[frutbunn]

Isn't it horsehair?

 

[svouts]

I can see the straw, as in the picture, so I assume it is a straw and plaster ceiling. In another room I can see a bit better through the crack and looks like straws.

 

[StephenStephen]

Why do you need a 4" hole to find the joist? Surely you only need a hole big enough for a screwdriver or piece of wire to locate where you are above the ceiling?

 

[svouts]

Why do you need a 4" hole to find the joist? Surely you only need a hole big enough for a screwdriver or piece of wire to locate where you are above the ceiling?

it might be OK with a bit smaller hole, about 2-3". I might need to insert my hand inside so as to install a hook or a bracket on the joist. i will then install a rosette so the hole will not be a problem.

My concern is that if I cat it with a plasterboard saw, it might crack the ceiling?

 

[StephenStephen]

What's above the ceiling? Can you post a photo of the ceiling from above?
That second photo looks like lime on reed or lath and plaster - it's difficult to make out

If it were me I'd:

-Go above it, find it, and work out how to make a secure point to fix it from above (joist/noggin/bracket etc)
(if you need to stick a wire/coathanger screwdriver up through the hole you've already got to help locate it (watch out for live cables))
I wouldn't be wanting to make any holes bigger than you've already got

 

[svouts]

Above there is a room with wooden flooring. On top of the joists there are three layers of wood, 18mm original boards, then 12mm chipboard sheets and on top 14mm oak flooring. Overall thickness is of the boards is 44mm. I am not having access from above. I might be able to fix a bracket like the one below with 35mm long screws and some epoxy glue but I am not sure how strong will be?
https://www.abitofbrass.co.uk/zp-hd...ant-twist-plate-suspension-bracket-2738-p.asp
https://www.abitofbrass.co.uk/hd-steel-zp-chandelier-ceiling-hooked-suspension-bracket-3393-p.asp