Plastering – Taping and Jointing. Tools and Lessons Learnt.
I finally completed installation of the plasterboard with the help of the mechanical plasterboard lifter and I have now just started taping and jointing. I decided on the international method of finishing the plasterboard rather than the Irish method ( see previous blog https://selfbuild.blog/2016/07/10/plaster-board-plan/) . If one is determined to use the traditional Irish method of wet plastering the whole wall I would still tape the joints with paper tape rather than the nylon/plastic mesh. The paper tape ensures the fire proof rating and from my research it is a stronger joint.
Below is an image of what it looks like when one applies the first joint filler tape coat. There are two to three more coats of plaster filler/compound required to hide the joints completely and some sanding.
I tried different methods and tools such as using a hawk instead of a mud pan to hold the plaster. For me the 12 inch mud pan worked out the best .
The tape dispenser is more important than I thought. The unit I purchased was a good design on paper but not very practical. If I was purchasing a unit again I would go for the steel design . The current model I am using is as shown below.
For ones own safety one must be able to roll the paper up after taping the joint as the hanging paper can become a trip hazard when moving around. I would try this steel one instead if I was starting again (see below).
Another item is a glove for the knife hand. If one is working with the filler for a few days I have found it to be very rough on the hands. Over time the skin will toughen up I suppose.
There are two main types for corner beads used for edge finishing . The steel micro edging (first image below) or the paper tape reinforced with steel (second image). I found it easier to use the steel micro edging rather than the reinforced tape edging. I tried a few methods of attaching the mesh and I settled for first applying the compound and using a few stainless steel staples(the standard ones are not stainless steel) to fix it securely while applying a finishing coat to fully bed it in. Note-ensure that one fully cleans the stapler after doing this.
The steel micro edging I feel is a better method to finish an edge and it is easier to sand and clean when applying wet filler.
Another idea that I did not get to try but it looks interesting is the use of pre-formed corner / edges using plasterboard. This avoids the use of beads and it is called the ZaapSystem from Prodar.
The reinforced tape comes into its own when one needs to tape two walls that meet with slight angles. The price of this varies from €15 to €30 for the same length.
I tried different fillers/joint compounds . Gyproc dry wall filler (it comes in a bag and is quick setting ). One mixes it with water and it requires the use an electric mixer to prepare it. This bag works out fairly economical but the time spent mixing, the dust, washing out the bucket every hour or so is very time consuming. Another disadvantage is that it sets very fast and is very hard to sand afterwards. The colour is also a disadvantage as it does not blend well with the plasterboard. An advantage is that it works out well when fixing the steel micro mesh.
The next product I tried is the Gyproc bucket version (pre-mixed) 15 litre. This is easy to work with but again it is a white finish which will make it harder to blend into the wall and will require more painting. It is also very expensive.
The best product I found and the most economical for the joint is supplied by Greenspan called USG plus 3 (it is an American product) and it comes in a 17 litre tub. It has the best colour blend for the board, it gives a finer finish, and is easy to sand. It does require a small amount of water to be added to make it extra easy to work with (this makes it go a bit further).
- When applying filler near floor level increase the width of the filler to ensure that any skirting board lies flush against the plasterboard.
- Use paper rather than plastic mesh for a stronger and fire safe joint.
- Practise filing joints in a non critical area such as behind future wardrobes, en-suite or storage room etc.
- Have a rag /clothe clipped to your belt to wipe away any dried plaster pieces before they get caught in the fresh new compound and leave streaks.
- Use the 4 inch knife to remove any dried plaster compound or for checking screw heights. The other knives need to be protected from any edge damage or you will get streaking.
- If the corner is less than 90 degrees I found it difficult to get a clean edge as there was limited space. In this case I made a finishing tool cut to the angle of the wall and ceiling with a rigid plastic cover to give a smooth surface.
- I found it helpful to have the 4 inch knife stuck to the pan with a magnet. It saves some time bending down or climbing down the ladder to get it when using two other knifes. I typically would have the 6 inch knife for finishing edges and either the 10 inch or 12 inch for finishing butt or tapered joints. The 10 inch stayed in the back pocket .
- Fully clean the knifes and dry them at the end of the day.
- You will notice the difference between good quality knives and low cost knives.
- If a knife should get damaged by a screw head I used a sharpening stone to repair it.
- In order to minimise sanding sometimes it is better to re-apply another filler coat to get a perfect finish.
- For corners I found it easier to use a corner knife (90 degree angle) and feather the edges with the 10 inch knife.
- Use the 4 inch knife to clean away any small hardened plaster bumps before starting the second coat.