Monthly Archives: March 2017

Admixtures for lime plasters

We recently looked at the various accelerators and retarders available for plasterers A bucket of plaster with a mixing stick in it.working with gypsum, cement and silicone based products, but what about lime based renders and mortars?  Well, as these are the predecessors of modern plastering products there are a multitude of things that can be added to lime plasters and mortars to change their properties and drying times.  The Romans were influential in developing different mixes for different purposes through trial and error, using blood, milk and fats in their lime plasters to achieve certain effects that were needed in different applications.  For example, the mortars and renders used to build aqueducts needed to be as water resistant as possible. These structures needed to last for many years and had constant exposure to water.

As late as 1805, blood was still being used as a plasticiser and water repelling additive; Thomas Telford used it in the lime mortar used to construct the Poncysyllte Aqueduct, to ensure it would weather well and not degrade from the exposure to water.  Times have changed and blood is no longer being used as an additive, but there are still some more savoury options available to those working with this traditional building material.

Sodium sulphonate, usually in the form of coconut oil soap, is used to plasticise and add water repelling properties to a lime plaster mix.  The addition of the soap traps air bubbles in the lime, which remain in the dried final finish, helping it to repel water and stop the ingress of water into the wall behind it.  The lime plaster is also made more flexible, aiding slightly with application, but ensuring that the product does not shrink and crack as it dries, leading to further problems with water getting in.

Fats contain substances called stearates (which are also found in shampoos, soaps and other personal hygiene products) that add a water repellent property to lime mortars.  Acting like the surface coating of waterproof wax on an outdoor jacket, the stearates reduce the surface tension of the lime mix.  This causes water to bead up and run off the surface of the wall (this is called the lotus effect) rather than sit on the lime and potentially be absorbed.  Although nowadays we might use a commercially available product rather than animal fats, olive oil and similar types of fat have the same properties and would have been used by the Romans to create water repellent mortars and renders.

Accelerators are not typically used with hydraulic lime renders, as the product needs at least 72 hours to dry; any shorter and the hydraulic set is not achieved and the job must be done again.  Retarders are useful therefore, to ensure that the surface stays wet for long enough to create the hydraulic set properly.  Methyl cellulose is the product of choice here, and plain sugar is a good cheap alternative to obtaining the chemical compound.  The long chain of the sugar molecules retains water in the mix by creating a gel like substance that holds moisture for longer, increasing the drying time and removing the problems caused by quick drying of hydraulic lime renders.  Sugar is also useful for applying any lime based render to a high suction surface, as it stops the product being pulled into the wall too much.

There are still some plasterers out there using these tricks, and although many conservation purists are against adding anything to lime mortars and plasters in the name of tradition, it seems that admixtures for lime renders is one answer to that infamous question, “what have the Romans ever done for us?”

70891768 - alandroal, portugal - november 18: vhils instalation from portugal , alentejo region, wall of traditional house

Getting arty with render and plaster

Plastering is definitely an art form; it takes time to learn the techniques and when to use them. In the specialist styles of Venetian and fibrous plastering, there is certainly a lot of artistic technique to acquire in order to do the job well.

Portugese street artist Vhils (real name Alexandere Farto) may not be applying any plaster in his pieces, but the way he removes external render is inspired.  Vhils works on a large scale, using the side of buildings as his canvas.  His most well-known and popular works are relief portraits, created by chipping and drilling away at the posters, paint, render and plaster to create a multi-layered and multi-coloured picture that makes use of the properties of each layer to form the image.  Vhils uses drills, chisels, bleach and etching acid to work into the wall surfaces when he is creating his artwork, a process which starts in his studio using photographs of potentially suitable walls.

Vhils selects the walls on the basis of their surface covering, as he has no way of knowing what is underneath that last layer; the discovery of the colours and patterns underneath is part of the excitement of creating the piece.  Using a pen and paper he sketches out the portrait, before using a computer to split the portrait into three layers, almost like a stencil.  These layers represent the layers of the render he works on, so the portrait makes the best use of the natural differences in renders and posters to add depth and form.  The final choice of which layer will be used for which part of the design, does not happen until the artwork is already well underway.

Vhils came to prominence in 2008, when his work was exhibited alongside Banksy at the Cans Festival in London.  Banksy’s agent took an interest in the unusual medium for street art and secured spaces for Vhils to work in London, with several of his pieces being published soon after the exhibition.  Vhils method of “destruction as a form of construction” was influenced by his upbringing on the outskirts of Lisbon, in the late 1980s and 1990s, which still showed the effects of the unrest and revolutions that had been occurring in Portugal for some years in the damage to buildings and walls around the city.

Next time you have to remove plaster or render, why not have a go at creating an image, or carving your name into the wall as you chip it off?  Of course, it takes years of practice to be as skilled as Vhils, but we all have to start somewhere.

The exception to external rendering rules

We recently looked at external rendering, from the purpose through to the execution, butillustration of vector building modern icon in design this focused mainly on new builds and other modern buildings (anything from around 1960 onwards). Older properties, including Victorian, pre-War and even pre-1800 buildings are a different story when it comes to external rendering practices.

Of course, the main function of an external render is to keep excess water out of the building and stop rainwater from getting into the bricks and mortar of the wall and undermining the structural integrity of the building.  On older buildings, however, there is often no damp proofing or the ability to easily retrofit a suitable one, and this needs to be remembered when rendering properties of this type.  Cement based renders do not allow the walls to breathe, and should never be used on older properties as they will exacerbate any existing damp problems and could cause more.  Instead, lime based renders should be used, as they protect the external wall surface while allowing any moisture in the wall to evaporate.  The use of lime render is often stipulated by building regulations on listed properties, and is the better choice for older properties even if it is not dictated by building regulations.

Lime renders are the best option for old buildings and those that are subject to movement; movement in walls often leads to water ingress, but if the external wall surface is entirely breathable that water can evaporate eventually, rather than being trapped behind a layer of non-porous cement.  Lime render is also more flexible than cement, which is prone to cracking on older buildings that move with seasonal and climatic changes.  Cracks in external cement renders contribute to damp problems, as rain can get in behind the render layer and penetrate into the wall making any existing damp problem much worse.

What is usually seen in properties where a cement based render has been wrongly used on the exterior of a building is that the plaster will blow on the internal walls, as it can no longer stay stuck to the damp wall.  Many homeowners don’t realise that their problems with damp and peeling internal plaster is caused by the treatment of the exterior wall, and will overlook this, leading to repeated re-plastering of the internal walls without addressing the underlying cause – the lack of breathability of the exterior wall surfaces.

When scoping out an external (or internal) re-plastering and rendering job it is worth checking the state of the interior and exterior corresponding surfaces.  Once you explain to the homeowner that damp plaster on the inside of the home is often caused by improper render on the outside you can start to address the problem, rather than just re-plaster a room knowing that it will not take.  This will also help build your reputation as a thorough tradesperson, as well as avoid the fall out from doing a repair job that you know won’t work, simply because the homeowner thinks they know best and wants to save money.  Not addressing both sides of external walls is like painting over cracked plaster and expecting that to solve the problem, or like putting a sticking plaster on a broken leg.

While not all plasterers and renderers are familiar with lime based products it is well worth getting some experience with them, as the market for property restoration and traditional building methods is lucrative and showing some growth.  Being able to offer the right external rendering solution to your customers will get you good word of mouth recommendations and more work, so it’s well worth learning about lime based renders and mortars to add another string to your bow.

Stay away from the doctors

59972882 - keep fit measuring tape concept illustration design graphicPlasterers are at risk from workplace related injuries and long term complaints, especially in the major joints of the upper body, as the shoulders and elbows do a lot of carrying, holding and moving during the course of a day.  Knees, hips and ankles also take the strain of standing for long periods of time, so what can plasterers do to stay fit and healthy?

Good footwear is essential for posture and can make standing all day a lot easier on the body if they are supportive and sturdy.  Boots that support the ankle and keep the foot in the correct position help to reduce strain on these joints, and in turn relieve pressure on the knees and hips.  People with fallen arches should invest in a good pair of orthotic insoles, to help support their arches and keep their lower body in alignment.

There’s no getting away from the high levels of physical activity required of a plasterer, so it is important to take steps to reduce the strain wherever possible.  Taking regular breaks, putting down the hawk and trowel and letting your muscles and joints relax frequently throughout the day, helps the body cope with repetitive actions and holding the same posture for long periods.  Even ten minutes every hour and a half can help relieve tense muscles, and if you use that break time to stretch you’ll find it a lot easier to keep going at the same pace all day, rather than slowing down towards the end and feeling shattered by home time.

If you notice a niggling ache or pain that comes back every day, it is a good idea to see a physiotherapist; you can do privately without being referred by your doctor.  Physiotherapists can give you some exercises that will help strengthen the muscles around a painful joint and prevent a problem from becoming worse.  Ignoring it and hoping it will go away never really works and more often than not, you find the problem gets so bad you end up needing time off work as a result.

Keeping fit in general means your body is more able to cope with a physically demanding job, and the main focus should be on the upper body.  Strong muscles support the joints and reduce unnecessary wear and tear on the ligaments and cartilage in the joints, which are often the first things to wear out leading to more serious joint problems.  Being proactive in staying fit and healthy means you can stay in work for much longer than someone who doesn’t exercise and ignores the warning signs of injury or muscular conditions.  Many plasterers will tell you that staying in work and keeping moving makes conditions such as arthritis much less painful than stopping work and becoming more sedentary – the more you move, the easier it is to stay mobile.

Swimming and weight training are both good ways of keeping your muscles strong and exercises your upper body in ways that you wouldn’t normally do at work, which helps maintain a fit body.  Other stretching-based exercise such as yoga and Pilates, also help you stay flexible; they focus on core strength, something that is very important when lifting is a big part of the job, as a strong core reduces the strain on your spine when bending and lifting bags of plaster.  Cardio workouts are less helpful in building muscle and flexibility; but do help with stamina and overall fitness levels, which can help you maintain productivity throughout the day.

Lastly, if you find yourself taking over the counter painkillers on a regular basis to deal with recurrent pain, it is probably time to see the doctor; as taking paracetamol frequently puts a strain on the liver, and long term ibuprofen use can lead to stomach problems.  They may refer you to physiotherapy to deal with underlying musculoskeletal issues which can relieve long term pain and reduce your use of painkillers.  It’s important to care for yourself as much as possible, but also not to ignore pains that plague you every day that don’t improve with self-care.  You only get one body so treat it well!

Plastering in 2017

plastering-apprenticeThe plastering trade does not change dramatically year on year – the tools and techniques have been largely unchanged for centuries and although equipment like the Nelaflex and new additives and finishing plasters are being brought to the market reasonably regularly, the big developments are few and far between.  With this in mind, what can plasterers do to keep 2017 interesting?

One way of making work more exciting is to branch out into different types of plastering.  Learning about fibrous plastering, Venetian plastering or even external rendering can make a big difference to the job satisfaction of the average spread as each day could be different.  Using your existing skill set as the basis for learning a new type of plastering is an easy way of getting into a related trade, as the techniques will come easily to those used to working with plaster products.  Evening classes, residential courses and even work experience, are all great ways of learning a new type of plastering, so check out your local adult education offering, or get in touch with a local trades person who may be able to offer you some on the job training.  Apprenticeships are also an option for some; although there are some restrictions on age and education level, there are still apprenticeships available to people aged over 25, in some trades.  Even if you can’t get onto an official apprenticeship, it is worthwhile contacting the companies advertising these positions to see if they might be interested in having a time-served plasterer on their books as a trainee specialist plasterer.

Taking on an apprentice of your own will also bring some change to the routine of work.  Although it can be frustrating to teach someone how to plaster from scratch, it is also very rewarding to train an interested person and see them develop their practical skills, as well as grow as a person.  Having a bit of company and a new face to talk to also makes the day go a bit quicker, especially if you often work alone.

Investing in some new tools might also make life interesting; perhaps you have always wanted to try a particular style of corner trowel, really get to grips with a pipe or midget trowel, or maybe it is time for a new set entirely.  Treating yourself to some new plastering tools or a radio might not be the biggest investment in the world, but if you can make your working environment more enjoyable, even when it changes from week to week, and learn something along the way then no two days will be the same.

It’s also a good time of year to look back over the past twelve months and take stock of any significant mistakes and successes that happened in 2016.  Using past experiences can help inform you of a better way of working or reduce mistakes and ensure that your business continues to do well.  Perhaps scheduling work over the summer got out of hand and you had to cancel or postpone a holiday?  Careful planning and working with contingencies can lessen the knock on effects of one project going over the deadline, meaning everything stays under control and you still get your time off.

If your workload allows it, taking a regular half a day off in the middle of the week during 2017, can help restore the work life balance that many of us have lost.  Using an afternoon to pursue a hobby, go to the gym or even just spend time with family can break up an otherwise monotonous week and inject a bit of life back into you when you need it most.  If you were thinking of retraining or learning a new style of plastering, this could be the perfect time slot – still working and learning but in a different environment.

Similarly, taking half a day off a week to learn something completely different is also a good way to make the working week more enjoyable.  A second language is very useful, especially when on holiday abroad and language courses are offered at many colleges and adult education programmes.  There are even language learning CDs and podcasts that help you practice at work or in the van and by this time next year you could be fluent in another language; thinking of the rewards and achievement obtained by learning something completely new can inspire you to get started and stick with it.

We’ve given you a fair few ideas of how to make your working life better in 2017, but if you think we’ve missed anything please share it with us and everyone else in the comments below.

Screw and fixing organisers

22889287 - toolbox , box for metal bolt, nut, screw, nail isolated on a white backgroundHow long do you spend looking for the right nail, screw or other fixing, then think you have the right one, only to find its a quarter inch shorter than the one you need?  The organised and sensible person may well never spend ages searching in the back of the van, under the seats, in the glove box and everywhere else, because they have sorted all their screws into a compartment box.  Of course, you still might get the wrong one, if they are not properly labelled, but it’s still better than rooting around for that open packet of tacks, that were definitely there the last time you looked.

There are hundreds of compartment boxes out there; from the flat ones that slide easily into the spaces under racking and van seats, to the multi layered ones that open out like a toolbox.  There are even plastic drawer units designed for sorting small items and you may even find that craft and sewing stores have a unique range of these organisers, that aren’t usually found in hardware stores.

The flat styles are great for space saving, but they are not easy to label.  Labelling the lid is one way to go about it, but it does mean lifting and closing the lid to check each time you need a nail.  Labelling the inside of the compartments is better, but when they are full the labels can’t be seen.  The same issue arises with the toolbox style models, although they usually have deeper compartments that can be labelled more easily as well as more space, meaning you can keep different lengths of the same fixing away from each other.

The drawer style organisers are great for labelling and allow you to find the right fixing at a glance.  Some of these models have drawers that are all the same size, and some have different sized drawers in the same unit; so depending on the type of fixings you have and the ones used most often, you may be better off with a choice of drawer size.

Whichever model you use, it is important that they fit well into your van and can be easily removed and taken onto site when needed.  Some van racking systems have nail and screw drawers, but if they are fixed into the van they’re not much use when you need a variety of different items on one job