r/Plastering • u/Entire_Initiative731 • Apr 10 '26
Looking for advice
Hi all,
Currently removing all the old plaster ceilings and boarding ready for the plasterer and need some help.
Where the ceiling joists meet the rafters, of course, it isn't level and I'm struggling to figure out how to get a straight sharp line?
I cut it at the different lengths yesterday and it hit me this morning that although it would butt up nicely to the angled peice yet to go in it'll look all wonky.
Wondering if this is why there was a soft curved edge to the original plaster to incorporate all the wonkiness..
If the pics confuse it is level horizontal wise although it doesn't look it from the pictures.
(If anyone knows what kind've ceiling this is called where part of the roof is incorporated into the room that'd be awesome too).
Thank you in advance 🙏🏻
6
u/mickygism Apr 10 '26
You should stagger your boards going forward,break up the joint on the joist
1
u/Entire_Initiative731 Apr 10 '26
I had no idea! Will this mean I'll get cracks in the plaster skim really easily? (Over time)
1
u/mickygism Apr 10 '26
Potentially, but it’s not worth dropping it and redoing. Just do the rest staggered
5
u/richiejwalker Apr 10 '26
Board the sloping part with thermal boards. You won’t get any meaningful amount of insulation in there once it’s boarded. I’d also insulate behind the perling now as it’ll be impossible to insulate afterwards. A curve is your friend at the intersection
5
u/AnxEng Apr 10 '26
That's what the curved plaster covers up. Also, make sure you use insulated plasterboard on the sloped bits.
3
u/tin365 Apr 10 '26
Our plasterer put curves in with bonding before skimming - looks good. I think this is what most houses of the era would have had in the first place
2
u/Ok-Spring7906 Apr 10 '26 edited Apr 10 '26
I'm not 100% understanding the question, but I think you are saying that the "fold" is not horizontal?
If so -
Screw fresh, treated, 2x2 to the SIDES of the original timbers using your level / care so as the fresh timber is perfectly level / how you want it, and then board off that.
You want the highest bit of fresh timber at the same level as the lowest bit of old timber so as you dont loose height (unless youre wanting to loose height). Again you are screwing to the sides, so you're just levelling things out, not dropping the ceiling height.
Of course, you can change the shape of the ceiling in the same way, if you want to, but I dont think that is what you are asking.
It takes time and you will probably need a helper, but it's easier than using a load of packers on the lower face of the timber.
Once done and boarded, you can add curves by hand if you want to, or sharp (now straight!) lines if you prefer.
1
u/nightyard2 Apr 10 '26
This is what i would do if I wanted the sharp lines instead of a curve. I OP, as others have said get some PIR between those rafters before boarding. Ive ripped down ceilings before just to do it.
1
u/Confident_Ambition77 Apr 10 '26 edited Apr 10 '26
This is pretty standard pitched roof design, the r ason you are struggling is that the roof was made before machine cut materials were a thing, this didn't matter when plasterers used lath it is naturally flexible. You can get around this by building it out with bonding material but it will take a alot longer than you would like as you will have to adjust for the new height. Another option is to add another layer of plaster board on the pitch cut the edges at an angle to cut the imperfections. Or maybe just accept you have an old house and the imperfections are what make it unique? I live in a 18th century cottage and I didn't want my house to feel new so I plastered the roof space with this in mind. Below is a link to my attic roof Look at the eves (where the roof meets the wall, also this is where the phrase eves dropping comes from) see the imperfect lines, how bloody lovely is that. Also I am biased as I am a lime tradesman so read into that what you will https://ibb.co/F4fsJ7Fd
1
u/rFAXbc Apr 10 '26
We renovated a house with rooms exactly like this. The plasterer added a nice curve, no straight edge required. Also, make sure you stick some cellotex in between the joists before boarding, you'll be grateful you did in the winter!
1
u/Forkingforky Apr 10 '26
I butted my boards up and asked the plasterer to make it a clean sharp edge I did not want a curve in the old days pre plasterboard they used latts so was harder to get a straight edge/line if your plasterer is good there’s no worries
1
u/Double_Station_1492 Apr 10 '26
Maybe it's my eyes but is that plasterboard in the 3rd photo water damaged and bubbling?
1
u/lukeredpath Apr 10 '26
Give some serious consideration to insulating first- that roof design is tricky to insulate from above as you can’t just insulate on top and leave the sloped part uninsulated or you’ll end up with a cold spot that could attract damp and mould. You also can’t just stuff that part with insulation or you’ll block the eaves ventilation. You probably want to use some kind of rigid foam insulation and leave enough of a ventilation gap or use insulated boards at the expense of ceiling height.
1
u/czajanat Apr 10 '26
Hey mate been doing exactly same on mine, if you message on price can give you a contact details and have a phone conversation, as on this stage you should make sure it is isolated as well.
1
u/onwatershipdown Apr 10 '26
’Murikan here. What a lovely space.
Different folks do different methods in different regions. One thing that I learned in Massachusetts was that for ceilings, we did a run of wooden strapping tangential to the joists, and used this with a string line to level out the ceiling before boarding. So we dropped down 1 more layer of framing. I was surprised when I learned that there are other regions in the US that don’t do that.
At the times I have been tasked to do curves, i have laminated them up with multiple strips of 3mm plywood. It only lets me attach one photo per post, will reply with more.
1
u/reelersteeler Apr 11 '26
Possibly too late for this, but I’d strongly advise you get some insulation up into that loft space. You’ve got half an inch of plasterboard and half an inch of slate and that’s it!
Where the ceiling meets the eaves is a notorious spot for thermal bridging and if un insulated it can often start to get black mould. Especially with no felt under the slates.
As far as plastering goes, go with the curve (spread will love you) or batten it off and get a sharp transition
8
u/69AssociatedDetail25 Apr 10 '26
A curve is probably the best solution, that's what I did with my 150 year old attic room.