As part of a re-furb in the cloakroom - new lighting and different
plumbing, I'll have to replace the plasterboard ceiling. Approximately
1.4 x 1.2 meters. Joists along the major axis.

About half way along those, the ceiling changes to a slope - part of the
original roof design. So the joint in the pb at the bend at right angles
to the joists. And the old was cracked there - despite not being that old.

What was a sloping roof above is now a roof terrace, and IIRC the joists
for that not connected to this ceiling ones.

What would be the best way to avoid the new cracking? Suppose I could fit
noggins to support the ends. I don't intend having it skimmed, as that
would require trades brought in. (The old was skimmed but cracked anyway.)

--
*Women like silent men; they think they're listening.

Dave Plowman London SW
To e-mail, change noise into sound.

On Monday, 26 October 2020 at 14:21:25 UTC, Dave Plowman (News) wrote:
As part of a re-furb in the cloakroom - new lighting and different
plumbing, I'll have to replace the plasterboard ceiling. Approximately
1.4 x 1.2 meters. Joists along the major axis.

About half way along those, the ceiling changes to a slope - part of the
original roof design. So the joint in the pb at the bend at right angles
to the joists. And the old was cracked there - despite not being that old..

What was a sloping roof above is now a roof terrace, and IIRC the joists
for that not connected to this ceiling ones.

What would be the best way to avoid the new cracking? Suppose I could fit
noggins to support the ends. I don't intend having it skimmed, as that
would require trades brought in. (The old was skimmed but cracked anyway.)

--
*Women like silent men; they think they're listening.

Dave Plowman London SW
To e-mail, change noise into sound.
Noggins will certainly help. As you do not intend to skim, presumably you are going to use drywall filler on all the joints in that case joint tape will prevent cracking. Apply a thin coat of filler either side of the joint press the joint tape into the filler with scraper then overfill the joint and tape. Allow to set then apply final coat of filler feathering it out for at least 150mm each side of the joint.

Richard

On 26/10/2020 15:41, Tricky Dicky wrote:
On Monday, 26 October 2020 at 14:21:25 UTC, Dave Plowman (News) wrote:
As part of a re-furb in the cloakroom - new lighting and different
plumbing, I'll have to replace the plasterboard ceiling. Approximately
1.4 x 1.2 meters. Joists along the major axis.

About half way along those, the ceiling changes to a slope - part of the
original roof design. So the joint in the pb at the bend at right angles
to the joists. And the old was cracked there - despite not being that old.

What was a sloping roof above is now a roof terrace, and IIRC the joists
for that not connected to this ceiling ones.

What would be the best way to avoid the new cracking? Suppose I could fit
noggins to support the ends. I don't intend having it skimmed, as that
would require trades brought in. (The old was skimmed but cracked anyway.)

--
*Women like silent men; they think they're listening.

Dave Plowman London SW
To e-mail, change noise into sound.
Noggins will certainly help. As you do not intend to skim, presumably you are going to use drywall filler on all the joints in that case joint tape will prevent cracking. Apply a thin coat of filler either side of the joint press the joint tape into the filler with scraper then overfill the joint and tape. Allow to set then apply final coat of filler feathering it out for at least 150mm each side of the joint.

Richard


+1
Paper tape and plasterboard joint filler

I've been using this on some ceilings over-boarded with plasterboard and
then (paper) taped
https://tinyurl.com/yym7re4t

Note the powder takes a lot more water than you first think, mix well
and leave for a few minutes before deciding that the mix is correct. It
appers that ready mix jointing compound in a tub ALWAYS requires extra
water and thoroughly re-mixing to knock out the air in order to get the
best results.

Probably going to the extreme with specialised tape.
https://www.youtube.com/watch?v=65Id0fuTCj0

The Vancover Carpenters Youtube drywall "mudding" (covering joins)
videos are quite good. There are a lot of them.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

alan_m wrote:

+1
Paper tape and plasterboard joint filler

I prefer the fibreglass mesh tape.

On 26/10/2020 16:10, Andy Burns wrote:
alan_m wrote:

+1
Paper tape and plasterboard joint filler

I prefer the fibreglass mesh tape.



Many youtube videos indicate for corners paper is always used.
For patching flat walls etc. (where no movement is expected) mesh can be
used.

Before I embarked on re-boarding a couple of ceilings I watched a LOT of
youtube videos on "drywall" and jointing including quite a few on the
mesh vs paper

Just search Youtube for mesh vs paper
Example: (on of many on a similar theme)
https://www.youtube.com/watch?v=VhsbU6lTrnM

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 26 Oct 2020 at 17:21:39 GMT, "alan_m" wrote:

On 26/10/2020 16:10, Andy Burns wrote:
alan_m wrote:

+1
Paper tape and plasterboard joint filler

I prefer the fibreglass mesh tape.



Many youtube videos indicate for corners paper is always used.
For patching flat walls etc. (where no movement is expected) mesh can be
used.


I used paper for the corners and flat panels - worked fine. The V seemed to
give a nice bed for the filler.

--
Cheers, Rob

alan_m wrote:

On 26/10/2020 16:10, Andy Burns wrote:
alan_m wrote:

+1
Paper tape and plasterboard joint filler

I prefer the fibreglass mesh tape.

Many youtube videos indicate for corners paper is always used.

you're right, I was forgetting Dave's join is at an angle. for that I
use a paper tape with metal strip, similar to this.

https://www.toolstation.com/plasterboard-corner-tape/p10867

alan_m Wrote in message:
On 26/10/2020 16:10, Andy Burns wrote:
alan_m wrote:

+1
Paper tape and plasterboard joint filler

I prefer the fibreglass mesh tape.



Many youtube videos indicate for corners paper is always used.
For patching flat walls etc. (where no movement is expected) mesh can be
used.

Before I embarked on re-boarding a couple of ceilings I watched a LOT of
youtube videos on "drywall" and jointing including quite a few on the
mesh vs paper

Just search Youtube for mesh vs paper
Example: (on of many on a similar theme)
https://www.youtube.com/watch?v=VhsbU6lTrnM


"Quick set mud" "air dry mud" ?

Muricans.

I'll stick w fibreglass mesh.
--
Jimk


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 26 Oct 2020 at 16:05:59 GMT, "alan_m" wrote:

On 26/10/2020 15:41, Tricky Dicky wrote:
On Monday, 26 October 2020 at 14:21:25 UTC, Dave Plowman (News) wrote:
As part of a re-furb in the cloakroom - new lighting and different
plumbing, I'll have to replace the plasterboard ceiling. Approximately
1.4 x 1.2 meters. Joists along the major axis.

About half way along those, the ceiling changes to a slope - part of the
original roof design. So the joint in the pb at the bend at right angles
to the joists. And the old was cracked there - despite not being that old.

What was a sloping roof above is now a roof terrace, and IIRC the joists
for that not connected to this ceiling ones.

What would be the best way to avoid the new cracking? Suppose I could fit
noggins to support the ends. I don't intend having it skimmed, as that
would require trades brought in. (The old was skimmed but cracked anyway.)

--
*Women like silent men; they think they're listening.

Dave Plowman London SW
To e-mail, change noise into sound.
Noggins will certainly help. As you do not intend to skim, presumably you
are going to use drywall filler on all the joints in that case joint tape
will prevent cracking. Apply a thin coat of filler either side of the joint
press the joint tape into the filler with scraper then overfill the joint
and tape. Allow to set then apply final coat of filler feathering it out for
at least 150mm each side of the joint.

Richard


+1
Paper tape and plasterboard joint filler

I've been using this on some ceilings over-boarded with plasterboard and
then (paper) taped
https://tinyurl.com/yym7re4t

Note the powder takes a lot more water than you first think, mix well
and leave for a few minutes before deciding that the mix is correct. It
appers that ready mix jointing compound in a tub ALWAYS requires extra
water and thoroughly re-mixing to knock out the air in order to get the
best results.

Probably going to the extreme with specialised tape.
https://www.youtube.com/watch?v=65Id0fuTCj0

The Vancover Carpenters Youtube drywall "mudding" (covering joins)
videos are quite good. There are a lot of them.

(Even) I had some success replacing the boards to a water damaged wall and
ceiling. I used pre-mixed, and didn't need to dilute it, and a key tool seemed
to be the special 'spreader' - thin, wide and bendy.

--
Cheers, Rob

On 26/10/2020 14:12, Dave Plowman (News) wrote:


What would be the best way to avoid the new cracking? Suppose I could fit
noggins to support the ends. I don't intend having it skimmed, as that
would require trades brought in. (The old was skimmed but cracked anyway.)


A photo may help but stopping one side of a join moving with respect to
the other side with noggins or a strip of wood would help prevent cracking.

Also pre-filling any largish void in the join before taping helps.

Was there any tape beneath the skim plaster?

Plasterboard (USA drywall) jointing compound is very easy to sand but
try to get a decent finish when applying compound and avoid a LOT of
dust later.

Based on my experiences....

https://www.screwfix.com/p/ph2-drywa...2-2-pack/6623v
Plasterboard screws should not penetrate through the paper. The bits
above in a power tool stop the screw going too far in. Otherwise drive
the screw most of the way in with a power tool and then use a manual
screwdriver to finally tighten the screw so it's just below the surface
of the board.

To fill any screw holes apply the compound in one direction and
immediately wipe of any excess in another direction. It usually takes 2
or 3 applications to fully hide a screw head if not skimming. Let the
compound dry between applications.

A proper jointing knife helps a lot
https://www.screwfix.com/p/forge-ste...-6-152mm/7738c
these blades have a lot more flexible than a blade perhaps used for
stripping wallpaper etc. The flexible blade helps with feathering edges.
Note these high carbon steel blades can rust easily so after use and
cleaning dry immediately with a cloth or kitchen towel.




--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Monday, 26 October 2020 14:21:25 UTC, Dave Plowman (News) wrote:
As part of a re-furb in the cloakroom - new lighting and different
plumbing, I'll have to replace the plasterboard ceiling. Approximately
1.4 x 1.2 meters. Joists along the major axis.

About half way along those, the ceiling changes to a slope - part of the
original roof design. So the joint in the pb at the bend at right angles
to the joists. And the old was cracked there - despite not being that old.

What was a sloping roof above is now a roof terrace, and IIRC the joists
for that not connected to this ceiling ones.

What would be the best way to avoid the new cracking? Suppose I could fit
noggins to support the ends. I don't intend having it skimmed, as that
would require trades brought in. (The old was skimmed but cracked anyway.)


Scrim over the joint. Retrofit on existing plaster by grinding away the plaster on either side of the joint, Apply the scrim with Polyfilla of similar.
https://www.randjbuildershardware.co...astering-tool/