Which type of plastering

[Seanie_230]

Hello all
So far I have had two rooms skimmed and get hairline cracks everywhere, I know my house is old
So my next room is the kitchen and the original render Is loose falling off etc, what is the opinion of the wonderful people here.
In our houses is it best to dot and dab plasterboard or get new render put up?
Either way I will have to knock of the existing render but want no know which is the best way for our dated houses.

Also I will be putting back in timber sash windows so either way the windows will be done before the plastering so the plaster is the right depth for the architrave.

A always thanks all

 

[plasticpigeon]

Hello Seanie, your house looks like it could be quite similar to mine! I had one room plasterboarded and I have vowed never again. I don't have any problems like damp or anything, but there are lots of things I don't like. For example, I hate that the walls sound hollow in places but the main problem I had was attaching skirtings. In the end I glued my skirting onto the plasterboard after it was skimmed. It is not satisfactory as the walls and skirtings are never straight and really need mechanical fixings to get them close. I suppose it would be possible to put a wall plug through the plasterboard and screw the skirtings on, but this would only work where there is adhesive behind the hole, if there was a void I'm certain the board would get damaged in that area. It would also be possible to cut out gaps below skirting height, and put in a wooden block to space out the skirting which is what I did in one place, but it is a lot of work and I think a messy solution. I also damaged a bit of board when putting on a skirting that was a tight fit, as it pushed against a bit of board with no adhesive behind, bending the board and cracking the finish. Another thing is that although plasterboards are flat I've seen many instances (including in my house) where the plasterer hasn't managed to get the boards on the wall in the same plane as each other. Having a number of flat surfaces slightly misaligned doesn't necessarily look bad, but when you try and put up picture rail or skirting then there will be gaps to fill. I have vowed to use wooden grounds from now on, both around windows and doors and for he skirting boards. If these are carefully set up, I believe it should help considerably with getting the wet plaster flat for a superior finish and also making sure that the woodwork fits properly. I suppose wooden grounds could be used with plasterboards to aid getting them on the wall flat, but I don't think I will use boards again although it is a much faster process.

even though you didn't mention windows, I thought I'd just say that I think ones with weights are far preferable to ones with spiral balances.

I look forward to what other people say about this, As I may have not used the best method for fixing my woodwork to the plasterboard.

 

[Seanie_230]

great points i will stick with sand and cement / gypsum Dri-Coat as it seems to be quite good stuff for keeping any old damp salts from showing on the treated walls.
suppose that means pulling down all the old plaster and hoovering for weeks

 

[Moo]

hoovering for weeks

If you add 'not' to that phrase life suddenly becomes much easier.
The trick is not to hoover for weeks. Too much manic effort alerts it to what you're doing and it then flies upwards in a panic.
Give the stuff plenty of time to settle and then go at it very gently, so as not to disturb it.

 

[Penners]

If you have damp in your walls, it's not a good plan to use cement and gypsum products - these will tend to seal the damp in. The best course of action would be to hack off any existing cement render and/or gypsum plaster from they damp walls and leave them to dry out. Then, once the masonry has dried, re-plaster with lime, ensuring that your final surface finish is breathable (ie: no vinyl paints!).

So far as drying the walls out is concerned, it's unfortunate that we're just starting the winter. This will tend to lengthen the time that you need to leave the masonry bare and could, particularly in a kitchen, tend to exacerbate any condensation problems.

Unpopular thought it may be, your best plan would be to leave the bare brick walls until next summer before you apply the lime plaster.

 

[Penners]

The trick is not to hoover for weeks. Too much manic effort alerts it to what you're doing and it then flies upwards in a panic.
Give the stuff plenty of time to settle and then go at it very gently, so as not to disturb it.

Ah yes, the famous Moo/Quentin Crisp approach to housework. :wink:

 

[plasticpigeon]

I'd second thinking about lime rather than cement. I don't think it's as scary as people make out. A bonus is that the lime stays workable for longer than cement. I also think it may be slightly kinder to the house. I'm no plasterer, but I'm learning, and one thing I now know is that preparation (ie putting in grounds or screeds) is very important if you want something approaching straight walls!

 

[Seanie_230]

Hi there
I don't use sand and cement I used gypsum dri-coat as an undercoat plaster as it helps with the damp if any and allows for a little movemement to avoid cracks with the house moving.

 

[Essex]

Lime not scary. Sent other half on a lime plastering course (I think Mike Wye), and we haven't looked back. Saved a shedload of money and got spec we wanted.

 

[Seanie_230]

Hi there, Is my house currently lime?
How can I tell

 

[Zebra]

I believe the standard test to see whether something (plaster, pointing, etc) is lime or not, is to hack off a small chunk and pop into a glass of vinegar. Being highly alkaline, lime will fizz. If it does nothing, it is not lime. Even centuries old lime will fizz in vinegar.
Don't use the vinegar on your chips afterwards.

 

[plasticpigeon]

your house looks like a late Victorian semi detached to me. Is that right?? I would bet the plaster was lime originally. I'm not as anti gypsum as some people, but I'm not keen on plasterboard, although I can't see plasterboard causing any damage. I prefer solid plaster and to be honest I think lime is more forgiving than gypsum for a diy hero like myself. Dri coat is cement based so would be impervious to damp, but hopefully all else on your house being in decent condition, it shouldn't need to hold back water. The discussion about plaster could go on forever, I'd avoid cement based products personally as I don't like the idea of using a coating that is stronger than the bricks, but that is my choice, not necessarily the right choice!!!!!

 

[MatthewC]

Seanie

I would be 99% sure that your house is lime-based. I had my entire house re-done with lime and it is one of the best decisions I have made. The house started to dry out before the plastering and continued for the best part of a year. It was pretty good last winter but now, 18 months after we finished, it really is warm and cosy. There is not a sign of dampness anywhere - we even had some neighbours come in and stand in front of the woodburner saying that their house was so cold - I've not been in theirs but I bet it's due to dampness.

You need to let the walls breathe and start to dry by removing the present plaster; we actually started plastering only 8 weeks after the house was made water-tight. If existing plaster is not popped (sounding hollow when tapped), you can leave it - just remove the large areas where it is falling off the wall, or if it crumbles when tapped! The trick is to work away from the good patches by making an angled cut with a knife and then using a chisel or scraper by hand. Then you do the first two coats of lime mortar to that level and apply a lime skim over the top. See my blog (blue spot on the right) for more details and lots of photos.

However, it is of course slow and expensive... this was the one place where my guesstimate was out by a huge factor.

NB I would guess the reason you got hairline cracks in the rooms you have done is precisely because it was gypsum-based and thus rigid. Lime is a bit flexible and so you don't (shouldn't!) get hairline cracks in it - we haven't, but there are already some gaps in the (gypsum) new extension!.

Matthew

 

[DJH]

Sorry to go off topic here but I've just read the section of your blog dealing with secondary glazing Matthew. How are you getting on with the acrylic now it's in position. Are you getting condensation at all, and if you are, is it on the window glass or the acrylic?
I'm also guessing that in order to fix the sheet to the window frame you've removed the window furniture? I'm contemplating doing the same thing here. Do you have any close up pictures please?

 

[Zebra]

Going back the the plastering question, without wanting to curtail your window discussion DJH, I am in a similar quandary, and it is good to read various comments above encouraging the use of lime. My plan was always to use lime plaster upstairs in the bedroom, which is old timber frame, but the boards to stick it to are quite expensive.
Currently I have an OSB sheathing board attached directly to the timber frame. The plan is to attach woodwool boards to this, and lime plaster straight onto the woodwool boards. But they are certainly five times the price of plasterboard!