Plastering a wonky wall

[Chapster]

Hi,

This is only the 2nd time I've tried plastering, my main experience has been with rendering and I'm no professional either way. The skill you pros have is beyond belief, it's one of the trickiest things to do even half decently.

I've got a small wall in a bedroom that's old plasterboard, skimmed and painted. It was a walk-in cupboard type thing which I've removed and now I need to make the previously hidden wall prettier. Trouble is that the studs are uneven and the plasterboard and skimming not the best, so a straight edge against it rocks a lot, with a couple of bad bows in the wall.

Since time is short to get odd jobs done (baby on the way) and money is also short, tearing off plasterboard and making a new partition wall which is straight with even studs isn't viable. So, I need to straighten it out which I started to do tonight with base coat plaster - what a nightmare to use (for me anyway). Trouble is, it's too sticky when applying to place the straight edge against to see how I'm doing, and I need to check horizontal and vertical level too.

If I was using render, it'd be simple, I'd do a scratch coat but first splodge lines of mortar vertically and horizontally along the wall and knock a straight edge into it with a level on it until things were straight, remove excess, let dry and then fill the gaps using a straight edge between my level mortar lines. Then a top coat on the level, flat base. But what's the method when using plaster?! There must be one for when using bonding over brickwork that's naturally a bit uneven and wonky, giving yourself a flat, level surface for the final skim of top coat?

Would any one of consider a blob of plaster in each corner and at intervals in between, then use a straight edge to press into them until the straight edge is level and above bows in the wall, then fill inbetween with base coat?

Please help!

 

[Alastairreid]

I'd do a scratch coat but first splodge lines of mortar vertically and horizontally along the wall and knock a straight edge into it with a level on it until things were straight, remove excess, let dry and then fill the gaps using a straight edge between my level mortar lines. Then a top coat on the level, flat base.

what's the method when using plaster?

You've answered your own question

 

[Chapster]

Ah, so you can do the same with plaster?! I just assumed it'd be a different method especially as plaster's so sticky and less easy to lob about than mortar. Had visions of it pulling off stuck firmly to my straight edge.

 

[Alastairreid]

use the same process chapster........i actually find it easier with plaster due to the better suction.

 

[roughcaster]

Ah, so you can do the same with plaster?!

Alastair's right, you can straighten walls with plaster, (mostly onto brick/block), without any problem.
The only trouble with your wall though is, it's onto plasterboard, and if the plasterboard wall is "too badly bowed" from end to end, it's not a good idea to try and straighten it up with a thick coat/s of plaster. The best way for you, and the quickest, would be to take off the sheet/s, straighten up the studs then re-board and tape. I'd do it that way if it was me. You'll get bogged down going with the plastering solution, and in my opinion, if the stud wall is as bad as you say, plastering out "too thick" onto p/board is not really advisable.

 

[roy c]

You could also dot and dab plaster boards over the whole lot and level it through with the amount of adhesive you put behind the boards(ie..more on hollows less on the highs.) find your highest point and level from that...You could put a nail in each end top and bottom then pull a string through onto the 4 nails and find out what the gaps are like in relation to the string line...

 

[Chapster]

Many thanks to everyone for offering their advice. Because of cost limitations, I've had to stick to the original plan of levelling off as best I can and hoping the job looks half decent at the end (it'll be wallpapered anyway as other walls in the room aren't perfect and aready wallpapered).

I've only got a wooden straight edge here and it was sticking to the plaster, so I've used it to show hollows, filled them out and when dried a bit used the edge again to see if it's right or needs a bit more. Using this method it's pretty straight now and required a few mm in the hollows to do that.

I was never perfect at rendering despite doing it quite a lot of times over the years, but a few walls here and there each year isn't the same as it being your trade and doing it day in day out. Rendering is hard and plastering is an art form and one I will always be in awe at! It's so hard, and yet a professional makes it look so fast and easy. I enjoy watching pro plasterers at work, it's almost miraculous, especially if you've tried it yourself. I just wish I could afford to get a pro in and see a brilliant job done in no time at all, compared to my slow lumbering after work with results that don't compare. My wife thinks I'm too critical of my work but I know I don't have the skill that takes years to gain.

Top coat will be the next job, and after finding out how the extra I was adding in to hollows dried in 10 seconds on the dry base coat beneath it, and having to spray water on it first to stop that, I must ask: is it best to PVA the base coat before the finish coat, or just spray with water? Bear in mind I'm slow compared to you lot and need extra time to get it anything like smooth.

Odd thing, only used and seen pink plaster before, but the base and finish plaster I've bought is whitish grey. Any real difference between the two other than colour? Says it's gypsum on the bag.

 

[Micilin]

First of all, fair play for giving it a go .
You've got advice, weighed up the options and made a decsion.

You'll get more satisfaction having done it yourself, and for one wall it won't be a disaster

PVA the wall and leave for a day. This will kill the suction. Then PVA again before plastering and coat while still tacky. IF the PVA drys out in an area, coat again Dry glue is no good for sticking to.

Grey plaster will work just a well as pink.

It might have very slightly different properties, but it will make no difference to you as you are not using one kind or the other week in week out.

 

[Chapster]

Well, I've done a small area of wall next to the door, and the bit of ceiling. My opinion is that there are now two things I've found myself to be useless at: spray painting and plastering!

I don't get what's going wrong, the bit by the door was an area less wide than the float with a flat door frame on one side and metal corner edging bead on the other, and yet running my hand along the finished surface shows it to be bumpy as can be.

Did the ceiling earlier which is only about 18 inches by 6 feet and although you'd all laugh if I told you how long it's taken me to do these tiny areas, the results are poor. The ceiling has the same bumpiness (slight), things I call pock marks dotted around despite taking the time to fill them and flatten them as I saw them, and the join is dreadful where it meets the original ceiling. Kind of bulges down a bit where it meets and then pock marks and hollows and, just urrggh.

I don't expect to be anything like a pro from a few attempts and a bit of previous rendering experience, but I'm clearly doing something wrong. I know it's hard unless watching me do the job to say 'oi! whaddya doing, leave that alone, put more plaster there, don't do that!' etc., but what might I be doing wrong? I just want to be able to do a job that's passable. I do what I've read you should do, first coat and flatten a bit, 2nd coat to fill in areas and flatten more, leave to firm up a bit then bit of water spray and smoothing, then later more water and polish, but...

Tomorrow it's sanding that join and filling it in a bit I suppose?!

 

[1john]

now it is fairly tidy you can leave it dry out, PVA it and have another go over it, you wont need much plaster, it will be on thin and dry out quicker. i find that when i do small areas i mince about with it too much and dont do myself any favours, on the other hand when i did a large (to me) ceiling off a little hop up i found i was a bit to slow and had to flat and polish it all at once, that was a bit worrying, thinking i would have to go over it all again from scratch but it turns out ot was ok with one coat.

My next house will have all the right sized walls and ceilings.

Don't give up, you will get there and it is VERY rewarding, everyone who see's what i have done has been suprised i have done it myself and complemented me on it.