A wall from scratch

Skimming a wall;

An explanation of how a wall gets skimmed from start to finish...

From the start a plasterer will invariaby ascertain the severity of any suction that my be present, after making his/her assessment steps are taken in order to control the suction using an appropriate method. There are several methods all of which are used depending on the substrate; Bond-it is a product that is gaining popularity over PVA (PolyVinylAcetate or "Glue" as most people know it)
the only negative side (if one wants to call it that) is the 24 hour curing period that Bond-it needs, PVA on the other hand is good to go after 30 mins usually. So an appropriate measure has now been taken to ensure that the skimming will go without a hitch (the suction has been controlled) now onto the mixing...

Mixing finish plaster can also be a little tricky, basically this consists of a large bucket (around 30 litres) which is filled upto halfway then the powder is poured in steadily until a small hill can been seen sticking out of the top of the water, a powered paddle mixer is then put in and the mixture is whisked a little until the water takes on a pinkish appearance, more powder is added until a creamy consistency is reached. Once the plaster is mixed you have around 30 mins to use it! The plasterer scoops some plaster from the bucket and places it onto his/her hawk then with a controlled glancing motion takes some plaster off the hawk onto the trowel, from here they proceed to start from the top (either left or right depending on handedness) and works their way across until they reach the other end, dropping down and going back to the beginning only this time starting from the bottom and working into the section of the top that they have previously put on. Once the wall has had one coat of finish plaster they then clean the trowel/hawk, bucket and whisk off and then using a wet trowel go over the first coat of plaster to flatten out the lines, another batch of plaster (usually half the amount of the first) is then mixed up and this is laid on over the top of the first coat, only slightly thinner and smoother this time, once the wall has had its second coat it is then left for 10-15 mins, whilst this setting time is happening the plasterer cleans off all tools/buckets etc.

It's now time to start the actual process of getting the wall flat and smooth...

Starting from the top again the plasterer now flicks a very small amount of water onto the surface of the plaster in order to give him/her some lubrication so the trowel will glide as opposed dragging or digging in, with controlled sweeps the plasterer systematically travels across the top of the wall until they reach the end, now they start at the bottom again and travel to the end overlapping the top section a little in order to blend any joins in.

Time to leave it again for at least 15 mins...

The plasterer now goes over the wall again, only this time the plaster has started to set a little more making the surface taught, any trowelling now will produce a flatter appearance. It's just a matter of trowelling the wall until the plasterer is happy with the finish, sometimes this can take as many a 4 trips to the wall, once the plaster has started to show signs of complete set, in other words there are dark patches on the wall that cover it around 40% a clean wet trowel is used horizontally only with a firm pressure working from right to left (or left to right depending on the handedness) closing in the surface to give it a nice satin finish that is smooth, once this step is done the wall is finished and just needs to dry out, drying will take around 2/3 days usually after which any painting can then be performed.