How to go about plasterboarding an angled ceiling?

Nightglow · 18 Dec 2013 at 13:06

All plaster has a use by date on the bag, but usually if it's a couple of weeks past that it should be ok to use, if it's kept dry.

Mark A · 18 Dec 2013 at 15:23

2014 it says on the bag so I think I must have just mixed it too thick. It was falling straight off the trowel at first, so i added a bit more plaster and that must have overdone it.

Actually quite enjoyed doing it once I got the hang of it. It's not a job I could do all the time, but enjoyable for some small DIY jobs. Think i'll give a full wall a go in the summer.

Nightglow · 18 Dec 2013 at 18:12

You need the plaster the thickness of melting ice cream, it needs to stay on your trowel, but not runny enough to fall off.

Better to mix two or three small batches, adding plaster to the water, I mix with a paddle on my drill.

See this link explains better.

http://www.videojug.com/film/how-to-mix-plaster

Mark A · 19 Dec 2013 at 11:40

Thanks, that seems about the consistency I had, so It must just be due to me taking to long to slap it on

.

I'm going to tackle the other bedroom next. This one I put full sheets of insulation onto the existing plasterboard and foamed and screwed it in place. Only problem I have now is how to attach the plasterboard to the insulation.

I was thinking of getting some Soudal Fix-all polymer adhesive and glueing the plasterboard to the insulation and then putting some screws through it and into the timber behind.

I'll need 100mm screws to reach the timber. Will it be ok to use 5x100mm wood screws?

Nightglow · 19 Dec 2013 at 14:10

Woodscrews might rust & have staining comes through the plaster over time.

You can get 100mm dry wall screws.

http://www.screwfix.com/p/easydrive-black-phosphate-twin-thread-drywall-100mm-pk250/98617

the_r_sole · 19 Dec 2013 at 15:15

Mark A said:
I'm going to tackle the other bedroom next. This one I put full sheets of insulation onto the existing plasterboard and foamed and screwed it in place. Only problem I have now is how to attach the plasterboard to the insulation.

I would be very wary of doing that, you could run into damp/mould on the existing plasterboard if it's left there

Mark A · 19 Dec 2013 at 17:06

Well no one mentioned anything like that when I made the thread. The insulation is foil on both sides, so i'd have thought this would stop any moisture getting through.

It's a bit late to do anything differently now, so will just have to see what happens. What would you suggest I should have done instead?

Mark A · 20 Dec 2013 at 16:52

http://www.zinsserdirect.co.uk/product_info.php?products_id=11

Does anyone know if you can paper over this product?

Want to seal, prime and add a barrier to stop any stains or mould coming through to the lining paper.

the_r_sole · 21 Dec 2013 at 18:05

Mark A said:
Well no one mentioned anything like that when I made the thread. The insulation is foil on both sides, so i'd have thought this would stop any moisture getting through.

It's a bit late to do anything differently now, so will just have to see what happens. What would you suggest I should have done instead?

the foil on the insulation usually lets some vapour through (otherwise your plasterboard would just get damp)
The best way to do it would have been to remove the plasterboard and insulated between the roof trusses, leaving at least 50mm ventilation gap on the roof side, and then insulated plasterboard (or a thin layer of rigid insulation with plasterboard over) - that way any moisture passing through would be ventilated out through the eaves or ridge.
The danger you have now is that the old plasterboard will be significantly colder than the air passing through the insulation so condensation may form when any moisture hits it

Mark A · 21 Dec 2013 at 22:03

I was hoping that wouldn't be the case as there is some polystyrene insulation on the back of the previous plasterboard, although It's only around 10-15mm.

I'll keep my eye on it and if I see any damp or mould i'll re-do it and remove the old plasterboard. I'll take your advice and remove the old stuff in the next room i do, but I think that's probably a job for the summer.

Mark A · 12 Jan 2014 at 13:02

Put a coat of paint on the ceiling, sanded the hip beam down, lining papered the walls and installed a blind. Looking much better if you compare with the before pics

.

Still needs another couple of coats to cover up that horrible blue paint and then the walls will need a coat.

valve90210 · 9 Nov 2017 at 13:13

@Mark A Massive thread necro here but I was just wondering how this turned out? Did you get it all finished and have you had any problems with damp etc, in particular in the first area you did?

I'm finally doing a bit of work on my house after 4 turbulent years and this is one of the areas which I would like to address as I also have the angle ceiling bits and they do make the rooms they're in cold.

Mark A · 9 Nov 2017 at 13:41

It turned out very well, although my plastering wasn't perfect. The rooms have been noticeably warmer and heat up much quicker and not had any issues with damp or anything. Probably a good idea to follow the advice of others regarding the damp proof membrane etc, but luckily I have had no issues.

valve90210 · 9 Nov 2017 at 14:04

Cheers, Ithink I may have to get on to this sometime soon, my bathroom is one the corner of my house so two of the walls have the angled ceiling and it does get very cold in there very quickly! Good to hear that adding the insulation has made a difference!

Is there any chance you might be able to repost the before and after pics (and if you have any some during photos) at some point please so I can show my diy helpers (parents) what I'm talking about?

Mark A · 11 Nov 2017 at 14:06

Sorry for the delay, had to try and get them off my photobucket account that is now slow as hell to use. I think if I was doing it again i'd remove the old plasterboard and then after adding the insulationboard between the timbers i'd use some insulation backed plasterboard for the final layer. That way the timber doesn't create a cold bridge. Also the insulation backed plasterboard has a vapor barrier integrated. I think someone actually suggested this method, but after I had already done the job lol. It has been absolutely fine though doing it this way, with no damp or anything *touch wood*.

I can't believe they designed houses so poorly when this was built. Although It was a council house, so they probably just wanted to do it as cheaply as possible. I know what you mean about the corner rooms being the worst, this room was freezing before doing this. The radiators are also below the heat leaking sloped ceiling, so a lot of the heat is escaping straight through the roof.

We also had cavity wall insulation done around the same time which also made a small difference. The cavities are only thin in this house as its random stone, so they pumped in expanding foam. that has been good so far as well with no damp issues some on here warned about. The wall on the left was actually black with mold before I started and the wall paper was wet through due to the damp, but 4 years later after the insulation its dry and no mold, so its definitely worked.