Plastering a Straight Wall


Filling in between guides.


The next stage is to fill in the middle section between your top and bottom guide. Care should be taken not to disturb the guides with your trowel. Just as before you need to apply a thin 1st coat (2-5mm thickness) to ensure adhesion. Rather than covering the entire area it can be easier to split it up into sections of approximately 1metre. If you are right handed then start at the right hand side of the wall. Once this 1st section is totally covered with a thin 1st coat the 2nd coat should be applied. This is where you will concentrate on applying the right thickness. Try to avoid playing around with each individual trowel full too much – just cover the whole section with adequate plaster.

Then when the entire section is covered you can then briefly flatten the whole section with your trowel prior to ruling off with the straight edge. Firm pressure on a flat trowel (10 – 15mm leading edge) will push all the highs into the lows and have a flattening effect. This can be done in an up and down motion or a sideways motion. If your trowel is becoming loaded with plaster then you are scraping – flatten the leading edge in closer to the wall and you should find you disperse the high spots by pushing them into the lows. Aim to have the thickness of this 2nd coat slightly thicker than the guides. This thickness will then be ruled off with the straight edge......


Ruling Off

Learning the correct technique for the straight edge for some people can be harder than the trowel – but with a little practice it does get easier.

With the straight edge in the vertical position you scrape off the excess thickness until the straight edge just starts to touch and mark your top and bottom guide.

If you have not put enough of a thickness of plaster on then your straight edge will hit the guides and if too much pressure is used you may dig into them. The idea is that if an excess is applied to the middle area then your straight edge will hit this first before the guide – you then keep ruling this excess off until your straight edge just touches and marks the guides. Do ensure that you have applied plenty of plaster right into the edge – but don't attempt to get the straight edge right into the corner – always start about 50mm away from the corner. It is good to have this corner bulging – which can then be accurately formed in the next process – 'floating' which is carried out when the plaster has firmed up a little

To rule off:

1. place the straight edge flat on to the wall.

2. Whilst keeping the edge on the wall lift the front (leading edge) of the straight edge away from the wall by about 5mm.

3. Start to slide the straight edge up and down whilst moving across the wall from right to left.Whilst you are doing this you should be continuously looking at where the straight edge is in elation to the guides. If you see a gap then you know you are safe to apply a little more pressure. If you are touching the guides then just start to ease the pressure off that you are applying to your straight edge. If there is quite a gap between the straight edge and the guides then this indicates there is still a lot of plaster to be ruled off.

4. At this stage because the straight edge is in contact with plaster in the middle section this will help prevent you digging in to the guides. Rather than use lots of pressure and try to scrape the excess off all in one go – it is far better to sweep over the area with firm but even pressure several times.

5. When you are ruling off you should be constantly moving the straight edge up and down as you move it across the wall otherwise it may get stuck

6. Carry on taking the straight edge over the plaster until you see marks made by the straight edge all the way along both guides. This means that there is no plaster in the middle section sticking out further than the thickness of the guides.

7. Any areas in the middle section between the guides that are not marked with the straight edge are low spots and need filling with more plaster.

8. Remember to ensure that you put an excess of plaster in the low areas and ensure that you do not go over any ruled off areas with your trowel. This excess can then be ruled off with the straight edge.

9. Keep repeating this process until you have continuous vertical straight edge marks over the entire area.

10. You should always be working to these guides as you know they are horizontally flat to the wall – always rule off the excess in the middle to the same thickness as the guides.

11. If you are having to put a lot of pressure on the straight edge due to the plaster firming up then before starting another section you can apply more water to ensure you control the suction.

12. The whole area between your top and bottom guides should now be filled in and ruled off. Continuous vertical straight edge marks should be seen throughout.

13. Once the middle section has been completed through to the end of your guides – you need to rule off this area again but this time with your straight edge in a horizontal position. Keep doing this until you now see horizontal straight edge marks over the entire area. If you do not see them everywhere then hold a clean straight edge up to the wall so that you can see the extent of any low areas. Often they will be very slight and nothing more needs to be done. If they are quite extensive they can be filled in the same manner as before.

14. The priority now is to ensure that the internal corner is straight vertically. So with your straight edge held in the vertical position – position it on the wall approximately 50mm away from the corner to check it is straight vertically. If not then you will need to do another vertical ruling off – possibly having to fill any low areas with plaster first, if they exist.

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The author cannot accept liability for the use of any of the materials or methods recommended in this manual or for any consequences arising out of their use. The author cannot guarantee the suitability of any recommendations made in this manual and shall not be under any legal liability of any kind in respect of or arising out of the content of this guide.