Alternatives to plastering a wall?

[dave163]

Not sure where best to post about alternatives to plastering.

I have an top floor attic "spare room" that currently has plastered and light brown painted brick walls to three sides and one lath and plasterboard wall, as in photo. On that wall the ceiling (white) slopes to meet the roofline, and there is a small cupboard door (bottom left of photo) that gives access to further storage space under the roof. The quality of the plaster on the other walls is a bit uneven so it's not top quality decor, and but most of the time the room just stores junk. However it does double up as the guest bedroom so needs to be clean, dust free and reasonably nicely decorated for the occasional visitor. The original plaster has badly cracked and started coming off so I've removed most of the loose bits now. The plaster on the sloping ceiling is firmly attached and doesn't need redoing (and I need to take care not to loosen it when I remove the final bits of loose wall plaster.

I'm reluctant to get the wall replastered for several reasons - I've never managed to do any decent plastering myself, it's only a small job so not much chance a decent plasterer will be interested in it any time soon, and we have guests staying in two weeks' time so ideally I need to start work this weekend.

Can I board over with something other than plasterboard e.g. fibre board, cement board or MDF? Idea would be to remove all the plaster up to just below where the wall starts curving to the ceiling, board over and fill the gap between top of boarding and bottom of decent plaster with an appropriate filler, then paint over the board (I would prime it first if MDF). The total height is around 1.1 metres and the width of the room 3.8m so a couple of 4x8s should be enough. If using MDF I'd envisage mixing glue and sawdust between the vertical cracks.

Is that a reasonable bodge or a recipe for disaster?

If there are suitable alternatives, should I cover the lath with thin board (e.g. 9mm), or strip it off and attach a thicker board (e.g. 18mm) to the vertical posts that support the lath?
What would be the most suitable product to give a surface with a reasonably plaster-like appearance after painting? For instance, I'm not interested in OSD (unless I papered over it) as the grain would be out of place even if painted over. If people recommend fibreboard, cement board etc, can they be painted on directly or do they need a primer?
Are there any build regulation issues to be aware of if I'm not going to use plasterboard and plaster?
Can I mount the electrical switch (right hand corner) onto MDF or other board? It's get an external box behind the switchplate that is currently sitting on top of the plaster with the wire coming through the plaster from behind.

 

[Wayners]

Rip all that wood and plaster off and board with insulated plasterboard.
Or.
12.5mm board on bedroom side.
Fill void with insulation. Wool or kingspan.
Cover loft side with hardboard to sandwich in insulation and protect.

Fill joints with toupret powder filler and joint tape. Sand and paint

 

[freddiemercurystwin]

Why not just board over what you have with plasterboard? Get tapered boards. Obviously made more awkward by the removal of some of the original plaster so that would need some packing behind. Fill the seams and then paint over. Obviously that would require the skirting boards to be removed/replaced. But really unless they're paying, can't guests just put up with what you have and be understanding atm?

 

[dave163]

Thanks, duh wasn't aware you could paint directly onto (primed) plasterboard, when I paid to have another room completely replastered with plasterboard the guy skimmed it all over and it was super messy and took weeks to dry.

The lath strips overview each over and are wobbly so really need to go, and it will be a faff to pack the vertical posts to take plasterboard to the right thickness to meet the plaster on the (sloping) ceiling as nothings straight in this house. But the gaps are already insulated from behind as the cupboard on the other side is lined with wooden panelling. Every day's a school day...

 

[Koolpc]

Remove and replace as Wayners suggested. Best to do it right now and be done with it then...

 

[Wayners]

You can dot and dab board to pack out level with existing surface which I've done. Cheaper job than rip out and dispose. Better to strip the lot out. I don't like covering up damage like that

 

[dave163]

OK so an update from someone who's never so much as held a plastering trowel before. I extended the hole in the loose plasterwork to where it was secure, which was just over 1800 by 1100mm. This meant I was able to fit a couple of boards of 1800x900, cutting one down to 200mm and nibbling out a bit around the wall socket which didn't need to come off. I screwed them onto the existing vertical posts that the laths were attached to, and the laths in place as the total thickness with the new plasterboard was very close to the surface of the remaining plaster. I filled the gap between old and new with Wickes general purpose filler and put plasterer's tape over the horizontal gap between the two new boards. ONce dry, I skimmed over the remaining cracks with Wickes' skimming plaster, though ended up covering the entire board in a thin layer. For my first attempt at plastering I'm really quite pleased with the result (seasoned plasters look away now...):

Being a tight git who just wants free advice from an internet forum aspirational DIYer who relishes every opportunity to learn new skills and practice on a spare attic room that is rarely used so it doesn't matter too much if his first attempt is a bit of a bodge, I've got a couple of questions please.

1. Besides years of practice, what's the secret for avoiding raised streaks around the edge of where I've just pulled the trowel? I'm getting things mostly smooth under the trowel, but just can't seem to avoid the streaks on the side. If it's just a matter of experience, will it look dreadful if I chisel or sand them off afterwards? It never seems to happen in all those Youtube teaching videos from pros who make it look so so easy.

2. Because the original plaster isn't completely the same thickness from top to bottom, the lower half of the right hand side of the new board stands slightly proud half of the adjacent plaster. It's probably only a couple of mm and I've tried to build up a gentle "ramp" to the level of the new plasterboard but it's proving rather difficult as I just end up sweeping the skim under the trowel up to the junction with the plasterboard, or if going left to right, forcing the skim straight down into the dip, isntead of having a smooth gradient, if that makes sense. What am I doing wrong?

 

[23vc]

You go through a 2-hour ish process, laying on, flattening, laying on a second coat, flattening again, troweling up with a bit of water, and by the time you’ve finished it’s like a sheet of MDF, totally flawless Matt and flat. I don’t really know what you did but if you’re happy with it great. Some enthusiastic sanding might get it in a state you can paint and see how it looks, but it’s always going to be “rustic”.

Just google “skimming” and look at the many videos of how to apply 2 coats of multifinish to get an idea.

 

[dave163]

Thank you for all contributions. Some vigorous sanding left a much less bumpy though still imperfect surface that was similarly uneven to the rest of the room. I had wondered if it was too perfect, whether the new board would stick out like a sore thumb. It isn't, and it doesn't. I'm quite pleased with my first ever attempt at plastering (most of) a wall.

 

[Koolpc]

Well done for having a go etc..