Cutting holes in plaster....

[7mmMag]

I'm looking at running some duct work to the 2nd floor of my house so I can get central air up there. I need to cut some holes in the ceiling for the vents but the problem is that the rooms are plaster. Does anyone have experience in cutting holes in plaster. I know I'll end up cracking it some but I obviously want to keep it as minimal as possible. Any tips/advice/ideas would be much appreciated.

 

[guywhofishes]

https://thecraftsmanblog.com/how-to-cut-plaster-walls/

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multitools are miracles of the modern age

 

[LBrandt]

They make "plaster cutting blades'' for sawzalls just have to take it slow and easy. Acme or any of the big box stores have them. Made out of tempered steel so will handle the sand in the plaster.

 

[Achucker]

Multi tool or router. Get the right bits and get a lot of them

 

[guywhofishes]

multi-tools never ever jump or grab - the control is amazing

and they plunge cut - so you can cut plaster laid over studs right down to the stud and stop - with precision/control

not so with a sawzall

 

[eyexer]

I would cut the hole square and use a concrete blade in your circular saw. You will have to cut the lath/wood out behind it anyway. You can use the sawzall on the square hole to finish it out. Then just mud in around the duct work afterwards.

 

[Kickemup]

If I need to make a precise cut I use a 4” grinder with a diamond blade. It is dusty but keeps the edges clean.

 

[muzzyhunter]

I also like the 4" grinder and diamond blade and once through the plaster cut lathe with multi tool.I havent found a blade for the multi that will stand up to plaster but havent found a better blade for everything else than the dremel carbide.

 

[Dad]

Sorry can't help, working on post count.

 

[guywhofishes]

lol

 

[Yoby]

Sorry can't help, working on post count.

You have along way to go with only 47.

I have found the grinder method the best option when remodeling my old 52 house. Run shop vac

 

[dust in the wind]

Hole saw, drill and a hammer

sort of like this

 

[ORCUS DEMENS]

If this is tradtional wood and lath plaster, make sure to provide backing for the cut lath. Nothing worse than than having everything installed and cracks develop or chunks fall out because the lath lets go.