MyBuilderMyBuilder - Plastering questions and answers
We get alot of querys to our website asking the same questions. It has come to our attention that the questions are relating the My Builder website. We can only assume its part of the vetting process.
The vetting process of any trade website is to filter out the bad plasterers from the good. Now if you really dont feel confident or even competant, please do not even try to register to the website. I can absolutley promise you, you will get a bad reputation quicker then you are able to get a good one.
Just Gypsum Limited
What happens when plaster goes off too fast and what can you do to make good?
Plaster will Craze or crack, this can be rectified by applying a third coat, controlling the suction and/or envioment. The damaged area may need to be removed then made good or repatching with plaster.
Give an example of low, medium and high suction backgrounds
Concrete block - Low suction
Common house brick - Medium
Thermolite block - High Suction
Now describe how each one should be plastered.
Concrete block should be dampened down with clean water then apply thistle bonding coat to the required thickness. Ruled plumb and flat with sufficient key on completion. Then finish off with 2 coats of thistle multi finish.
Common house brick. Should be dampened down with clean water this may take a bit of water due to the suction. Then apply thistle hardwall to the required thickness ruled plumb and flat with sufficient key on completion. Then finish off with 2 coats of thistle multi finish.
Thermolite blocks will need a lot of water to control the suction. Gyp prime can be used if suction is an issue. Then apply thistle hardwall to the required thickness ruled plumb and flat with sufficient key on completion. Then finish up with 2 coats of thistle multi finish.
How would you make-good when scrim falls off the ceiling during the finish coat?
I would stop during the laying on process and reply new scrim to the area then continue my plastering.
How much do you polish and sand a finish coat?
Finish plaster should not be polished. Plaster should be finished to a flat matt finish and not require any sanding
List Thistle plasters fromm the heighest to lowest grit.
Thistle plaster doesn't contain any grit. It's a trick question. (If your a plasterer then you should know this)
Describe how you would apply a lasting render to external masonry.
The background should be free from loose debris and dampened down then apply sand and cement render with a ratio of 1:1:4 scratch coat and allow to dry. Then apply render at the ratio of 1:1:5 top coat.
Mix ratios may vary from plasterer to plasterer; each have own preferred mix. The render mixes must contain and waterproofer and plasticiser. Plasticiser improves workability and the waterproofer will help protect the wall from the elements, EML can be also be used if it's old brickwork.