First time using plaster to repair my ceiling. I have experience in DIY sheetrock, stucco and small concrete tasks, but never worked with real plaster.
I am located in Miami, Florida USA.
A bit of background. Early September 2016 hurricane Irma hit Florida and broke off a 10" diameter tree branch about thirty feet long and it collapsed on my flat roof. One of the side branches penetrated the roof and broke part of the ceiling off, made a total mess and flooded the space below.
To make a long story shorter, we eventually cleared off the big branch from above, repaired the roof, and cleaned up the mess below. Next we need to repair the ceiling.
The original ceiling from 1955 consists of a three ply system. A gypsum board about 1/2" at the base, that's nailed on to the framing lumber above. Then a 3/4" layer of brown coat was floated over, then a thin 1/16" layer of egg shell plaster over that, then over the years several layers of paint, and texture, and paint.
The damage is more than the hole in the ceiling, as the force of the branch not only punched a hole, but also caused delamination of the brown coat and veneer plaster nearby, I made a straight line cut along the ceiling to make a rectangular area about 4' wide and 12' across (from edge of wall to edge of wall).
Since the original ceiling is over an inch thick, I installed stripsof thin wood furring across the joists, then 5/8" sheetrock over the area. I also had to install additional junction boxes in the ceiling due to some rewiring from electrical wires severed by the tree branch.
This is what I have after installing the sheetrock. The sheetrock is not completely flushed with the original wall, it is about 1/8" to 1/4" recessed (higher) then the original ceiling.
In order to prevent cracking along the seams between the old and new ceiling I decided to float a layer of base plaster on top of the sheetrock to make it flush with the existing ceiling, then a thin layer of veneer plaster over that, then texturing and paint over.
The base plaster I used is the USG Structo-Lite basecoat plaster. I first applied a bonding agent over the sheetrock - I use Lanco high strength blue bonding agent, brushed on and waited two hours before troweling on the base coat.
I used a 10" long and a 14" steel trowel for this. I have never done this and I couldn't smooth it really well. It didn't bother me too much because I know the basecoat being not smooth helps the finish coat application. But I know I need to do a better job when it comes to the finish coat. I did the base coat in two halves because I was going slow. Troweling here and troweling there not knowing what I was doing and having 30% of the mud falling off the hawk and some splashed into my face, neck, even armpits.
So this is where I am today. The basecoat is on and ready for finishing.
The finish plaster I have is called WONCOTE. It is a smooth interior plaster.
Sorry for the long post but now I would like to ask some specific questions.
(1) Can I apply this finish coat in two halves? I work slow, I believe I need to mix and lay the mud within one hour before it's too dry. Can I do a section of 4'X6". Stop, rest, go mix some more, and come back to apply the other half? Is this OK or will it create a problem because the first application will have a feathered edge and the second application will be feathered over that?
(2) Any tips and tricks in getting a smooth finish would be greatly appreciated. I understand once the mud is laid you can come back to trowel it smoother, and a second time after that. What is the timing of this? How long do I wait before attempting second trowel? Am I troweling HARD or am I troweling gently?
(3) I heard about using a sponge float to create a smoother and straighter finish. I have a coarse float and a dense float. I have read mixed opinions on this. Should I sponge float at the end? I have also seen some use a squirt bottle to mist the plaster before sponge floating. Is this advisable? If I do sponge float, how long do I wait after the initial mud laying do I do this?
Thank you for your time reading all this and have a wonderful new year.
I am located in Miami, Florida USA.
A bit of background. Early September 2016 hurricane Irma hit Florida and broke off a 10" diameter tree branch about thirty feet long and it collapsed on my flat roof. One of the side branches penetrated the roof and broke part of the ceiling off, made a total mess and flooded the space below.
To make a long story shorter, we eventually cleared off the big branch from above, repaired the roof, and cleaned up the mess below. Next we need to repair the ceiling.
The original ceiling from 1955 consists of a three ply system. A gypsum board about 1/2" at the base, that's nailed on to the framing lumber above. Then a 3/4" layer of brown coat was floated over, then a thin 1/16" layer of egg shell plaster over that, then over the years several layers of paint, and texture, and paint.
The damage is more than the hole in the ceiling, as the force of the branch not only punched a hole, but also caused delamination of the brown coat and veneer plaster nearby, I made a straight line cut along the ceiling to make a rectangular area about 4' wide and 12' across (from edge of wall to edge of wall).
Since the original ceiling is over an inch thick, I installed stripsof thin wood furring across the joists, then 5/8" sheetrock over the area. I also had to install additional junction boxes in the ceiling due to some rewiring from electrical wires severed by the tree branch.
This is what I have after installing the sheetrock. The sheetrock is not completely flushed with the original wall, it is about 1/8" to 1/4" recessed (higher) then the original ceiling.
In order to prevent cracking along the seams between the old and new ceiling I decided to float a layer of base plaster on top of the sheetrock to make it flush with the existing ceiling, then a thin layer of veneer plaster over that, then texturing and paint over.
The base plaster I used is the USG Structo-Lite basecoat plaster. I first applied a bonding agent over the sheetrock - I use Lanco high strength blue bonding agent, brushed on and waited two hours before troweling on the base coat.
I used a 10" long and a 14" steel trowel for this. I have never done this and I couldn't smooth it really well. It didn't bother me too much because I know the basecoat being not smooth helps the finish coat application. But I know I need to do a better job when it comes to the finish coat. I did the base coat in two halves because I was going slow. Troweling here and troweling there not knowing what I was doing and having 30% of the mud falling off the hawk and some splashed into my face, neck, even armpits.
So this is where I am today. The basecoat is on and ready for finishing.
The finish plaster I have is called WONCOTE. It is a smooth interior plaster.
Sorry for the long post but now I would like to ask some specific questions.
(1) Can I apply this finish coat in two halves? I work slow, I believe I need to mix and lay the mud within one hour before it's too dry. Can I do a section of 4'X6". Stop, rest, go mix some more, and come back to apply the other half? Is this OK or will it create a problem because the first application will have a feathered edge and the second application will be feathered over that?
(2) Any tips and tricks in getting a smooth finish would be greatly appreciated. I understand once the mud is laid you can come back to trowel it smoother, and a second time after that. What is the timing of this? How long do I wait before attempting second trowel? Am I troweling HARD or am I troweling gently?
(3) I heard about using a sponge float to create a smoother and straighter finish. I have a coarse float and a dense float. I have read mixed opinions on this. Should I sponge float at the end? I have also seen some use a squirt bottle to mist the plaster before sponge floating. Is this advisable? If I do sponge float, how long do I wait after the initial mud laying do I do this?
Thank you for your time reading all this and have a wonderful new year.
