Repairs & Faults to Hardwall Plastering
With over 30 years experience in Hardwall Plastering, Michael and Larry Florido has just about seen every problem there is in internal and external hardwall plastering. Like most plasterers they had the learn the hard way and that is by making the mistakes themselves.
The only positive with making mistakes is that you soon learn not to make them again as it can be a costly exercise to your business.
Below is a constructed list of FAQ's for hardwall plastering that Michael and Larry have received from customers over the years. This list was constructed in the endeavor to help resolve any questions associated with Hardwall Plastering?
IMPORTANT: The views outlined below are from our own personal experiences and may not necessarily be the opinions and views of other hardwall plasterers.
"When the walls are plastered perfectly, you notice the house. When the walls are plastered poorly, you notice the wall." - Michael Florido, plastering for 38 years.
FAULTS – INTERNAL & EXTERNAL HARDWALL PLASTERING
"Aren't All Plasterers The Same?"Like every profession there are people that are very skilled and then there are people, not so skilled. Plastering is no different, just because a plasterer can hold a hawk and trowel doesn't necessarily mean that they are good at their trade? But in saying that there are a lot of quality plasterers out there so getting a good tradesman shouldn't be very difficult if you follow a few basic steps.
Word of mouth: Word of mouth would have to be one of the best ways in securing the services of a quality tradesman. Why? Because their work now has a history. The longer the history the better the recommendation.
Checking their work: If you have chosen someone from the yellow pages or have googled their services on-line then the only other way of making sure the tradesman is suitably qualified is to check their work.
For external wall plastering, tell the plasterer you would like to see work that they did a few years ago. You can have a look at their new work but that really doesn’t give you an indication as most newly completed jobs (good and bad) will look pretty good. It normally takes a couple of years of wear and tear for you to know whether or not a plastering job is really any good.
When checking out their work, you should be looking for flat walls without too many marks or hairline cracks. The walls should show no signs of deterioration and have nice straight corners. Correct margins should be apparent and the render on the window sills should be on a very slight chamfer downwards away from the window so as to avoid any pooling of water.
If your only option is to look at their new work then do as above and check the margins, corners and window sills. You should also be checking that the render on the wall goes all the way down to the footings of the house which will help prevent rising damp.
Another important aspect of external render is that the render mix should be strong with a full 20kg bag of GP cement used in every mix. It should also contain a damp proofing solution (to manufacturers specifications) which will help prevent the paint or texture from bubbling off a couple of years down the track. Overall this mixture is a lot stronger than the mixture used for the internal render because the external render has the environment and weather to deal with and is not protected the same way as the internal render is.
For internal wall plastering (finished unpainted new walls) rub your hand across the wall. It should feel silky smooth without too many bumps. Next, stand close to the wall and turn your head to the side and look down the length of the wall. You should see a reflection coming off the wall like you would with a glass window (see second picture below). And lastly give the walls the fingernail test to see if they're hard. Your fingernail should bend and not penetrate the wall.
Price: When you receive a price for a job, I want you to think more about that price and why the contractor gave you that price? There are a number of reasons to consider. For example, if the price is way over the top, then perhaps the contractor has enough work on the books and isn't interested in your job or it could be that your job is too difficult? If the price is too cheap, then the contractor may be inexperience and is not aware of the actual work involved. That doesn't necessarily mean you're getting a bargain? It might mean that he once he realises that he has made a mistake, he might not turn up or if he does turn up he might not finish the job.
Remember, all plastering teams aren't the same. Small teams may not have the speed that large plastering teams do but their quality should be a lot better. This is because most large teams are more interested in how many metres are done instead of how the metres are done?
Finally before deciding on who gets the job, please remember that plastering walls is in my opinion one of the most important finishing trades there is. Why? Because the walls of your home are the first thing you see and not just once but every time.
"Why Can I See The Brick Outlines Through The Render (commonly known as Grinning and is very common in creme finished renders)?"The reason why you can see the outline of the brickwork through the render (normally after heavy rain) is because the render has absorbed moisture which has soaked through to the mortar joints therefore outlining the brickwork.
To prevent this you can paint over the render (which is not always possible because of bubbling (see below "Why is the paint on the plaster bubbling?") or the plasterer should have added an additive that makes the render damp proof therefore stopping the render from absorbing moisture.
The reasons why the plasterer may not have added the additive is because he either, doesn't know about the product, knows about the product but doesn't like using it because the render is harder to apply or it could be that he may have simply forgotten.
Another way of preventing "grinning" is to apply two coats of render. A scratch coat one day and the finishing coat the next. This method was used extensively in the old days and is still used today by some plasterers. The reason why it has lost its popularity should be obvious. If the job takes twice as long to do then the cost goes up and possibly the chance of loosing the job.
"Grinning." The outline of the brickwork is showing through the render.
"Why Do The Walls Inside My House Chip Easy?"Too many times I've had phone calls from people asking me why their plaster is easy to chip or when they pull tape off the wall the plaster sticks to the tape. For you to understand why this happens you first must understand the process of internal wall plastering.
When plastering internal walls there is a two-step process. The first step is called 'Floating' and the second step is called 'Setting'.
Step 1. FLOATING as we call it in the industry is cement (usually mixed with lime, sand and water) which is applied by hawk and trowel directly to the substrate (normally brick). It is then ruled to create a flat surface.
Step 2. SETTING is white plaster (normally formulated with lime putty and hardeners) that is applied by hawk and trowel over the "Floated" surface. Most experienced plasterers will have their own recipe for setting which they have perfected over years and should result in a hard, flat and smooth surface (picture below) that is ready to paint when cured.
But if the walls don't come out as I have described it above, it doesn't necessarily mean the plasterer has just got the recipe wrong. It may just mean that he has not taken all of the other factors into consideration, like the weather conditions. If it is too hot then the walls will dry out too quickly leaving visible spider web cracks. If it is too cold then the walls will take a very long time to dry leaving visible trowel marks. But basically a good and experienced plasterer will know how to set in all conditions.
If you are not sure if your walls are done right then give your walls the finger nail test. Normally after a couple of days of application the walls should be as hard as rock.
The finished walls should be smooth, reflect like glass and be as hard as rock.
"Why Is The Paint On The Plaster Bubbling?"The reason why the paint on the plaster is bubbling is simple. Whether it is on the outside or the inside of your home the reasons are the same, “Water Ingress”.
Water Ingress is when moisture penetrates a product. In the case of paint bubbling on the plaster, the moisture travels from one side of the substrate (usually brick) through to the other side under the render. And because the render absorbs moisture like a sponge, the paint on the plaster starts to bubble.
This is very common on the inside of your home where a wall backs onto a wet area like a bathroom. If the wet area i.e. shower recess is not completely waterproof, then this will allow water to escape. The moisture created will eventually travel through the tile grout, through the brickwork, and finally into the plaster.
The same principle applies to render on the outside of your home like a retaining wall. The moisture is trapped in the soil and will eventually make its way through the brickwork and into the render causing the paint to bubble (see picture below).
How do you fix this? To patch the render normally requires the services of an experienced plasterer but there is no point in repairing the render until the source of the problem has been fixed.
To fix a leaky shower recess, there are products available at your local hardware store which can easily be applied without too much fuss or mess.
Ugly - This wall is less than 5 years old
"Why Do I Have Big Cracks In My Walls?"The reason why you may have big cracks in your walls is not because of the plastering or bricklaying work even though it maybe easier to blame the plasterer or bricklayer but because a large crack or a structural crack is caused by the movement of the foundation (the existing soil). This in turn may cause the strip footings to move (created by "differential settlements") which in turn may cause the wall to crack, which is very common in retaining and screen walls.
There are a number of reasons for "differential settlements" like "varying foundation" (different soil types), "varying compaction" or it could be that the project was simply "under engineered". In other words, the footings and wall may not have been constructed the same way that your house has been constructed, ie to BCA (Building Code of Australia) requirements.
To fix a structural crack on the inside of your home, there is a method that plasterers use which involves meshing a wall. But it is important to note that this is only a band-aid fix. The theory is that the wall can move behind the mesh leaving the render on top in tact. But if the crack is structural and most big cracks are, then the problem will more than likely reoccur and be ongoing for the reasons mentioned above. On the outside of your home this process should never be used because the elements will eventually cause the mesh to rust. To fix any structural cracks properly will normally require the intervention of suitably qualified engineer.
"Why Do I Have So Many Hairline Cracks On My Outside Walls?"The reason why you may have so many hairline cracks on your external walls is because the plasterer may have put too much lime in the mix. Lime is a hardener that plasterers add to the cement mix to give it added strength. Lime also aids the plasterer in making it easier to apply. If too much lime is added, yes the render is easier to apply but it also has the side effect of causing excessive hairline cracking.
An experienced plasterer would be aware of this and therefore only add the required amount.
"What Is And What Causes Drummy Render?"Drummy render is when the cement render is pulling away from the wall. It has a kind of hollow sound when you tap it, which is very different to when you tap a part of the wall that has not drummed.
What causes drummy render has always been a contingent for debate amongst plasterers. Some plasterers say it is caused by heavy vibrations and some say that it is caused by water ingress. Others say that it is because there is not enough cement in the mix, or that render has been put on too thick. Others also believe drummy render is created when plumbers and sparkys chase up the walls and the dust left behind forms a membrane on the wall separating the render from the substrate.
In my opinion it could be any or all of the above but their statements do warrant further investigation.
Heavy vibration: This statement does make sense because when you think about it, heavy vibration can’t be good for anything unless you’re mixing a tin of paint. I have repaired many drummed walls in my time especially next to wooden door frames caused by repeatedly slamming doors. To avoid this, an experienced plasterer when finishing will always cut a deep line separating the wooden frame from the render which is then skirted by a quarter-round bit of timber.
Water Ingress: This statement is definitely true as I have repaired more than my fair share. Water ingress is when the external render is penetrated by water usually through cracks.
More information on water ingress is available below; "Why does cement render crack?"
Not enough cement in the mix: If this statement were true than the whole mix (approximately 5 m2) would be affected and not just a small section of the wall. And an experienced plasterer would know instantly if there wasn’t enough cement in the mix just by looking at it.
The render has been put on too thick: How thick should the render be on a wall you ask? It has been recommended that render should be approximately 10mm thick (give or take) but unfortunately this may not always be possible. Sometimes the plasterer has to put the render on thicker because if a wall has been constructed poorly and/or has a bow in it (which unfortunately happens more frequently nowadays). It is the plasterer’s job to fix the wall, make it acceptable for the builder and for other trades to follow.
Dust created when a plumber or electrician chases up a wall: This statement would make sense except for most experienced plasterers normally sweep or hose down the walls on a new job before applying any render.
How do you fix a drummy wall? I am not aware of any quick fixes and can only recommend the old fashion way of removing the drummy section and replacing it with new render.
"I Know Cement Render Cracks But Why Does It Crack?"One of the most common failings associated with painted cement renders is surface cracking. To understand why this happens, you must first understand the process.
Cement Render - These started off as 'Hairline Cracks'.
Cement render: no mater how it is formulated (usually sand, lime, cement and water) is highly alkaline and extremely rigid. Once mixed it is then usually applied by hawk and trowel to a brick substrate.
Curing time: The cement render then requires 28 days curing time to allow the alkaline to stabilize before the painting process can commence.
Painting: The next step is for the render to be painted. This is usually painted with decorative conventional paints (roll on) that are a low film build and lack flexibility. The main reason why builders sometimes use this process is normally economics.
Cracking: What happens next is the render is exposed to extreme variations in temperatures. This causes the render to expand and contract causing stress. Because the render is a very hard and an inflexible product, the only outlet for this kind of stress is for the render to crack.
Drummy Render: In the beginning these cracks are relatively small and appear as hairline cracks. They are more evident when the surface gets wet. What happens next is if the cracks are left untreated they will over a period of time allow water, corrosive and atmospheric pollutant to ingress. This in turn may lead to a bigger problem like drummy render.
So basically you have two choices.
1. You can do nothing and watch your walls deteriorate or you can
2. Texture coat your home with a Dulux AcraTex 3-coat system that will hide all hairline cracks and look brand new and fantastic for years to come.
Dulux AcraTex is a Flexible, High Build, Acrylic Base texture coat that can easily accommodate cement render daily stresses. In other words Dulux AcraTex will not develop any hairline cracks because its main binder is an Acrylic Resin and not cement.
More information including "FAQ's" is available here. "What is AcraTex?"
Dulux AcraTex "You won't see any Hairline Cracks here - Ever".
"Why is it rusting on the outside corner of my home?"The reason why there is rust on the outside corner or your house is because there is more than likely a steel corner bead under the render. Because the corner bead is made of steel, it will be prone to rusting created by moisture from the weather. It may take a few years for the rust to start showing through but it is only just a matter of time.
The steel corner bead was put there by the plasterer who rendered the wall to make his job easier. Plasterers sometimes do this because they don't have the expertise of making a corner straight and need the assistance of a steel bead. The unfortunate part of this is that the home owner won’t know of the mistake until many years later when it is too late.
Steel corner beads are designed for the internal walls of the house only (except for bathrooms). They are nailed onto the corners to prevent chipping. On the outside of the house you never use steel beads for the reason mentioned above. The render is also a lot stronger to accommodate extreme weather conditions. This doesn't mean that it won't chip as easily, but the odds of chipping the outside corner of your home are a lot less as there is normally a lot more room for passage, as compared to narrow hallways on the inside or your home. And if you do happen to chip the corner it is a lot easier and cheaper to repair a chipped corner without a steel corner bead than it is to remove and repair a rusted bead.
FAULTS - BLUE BOARD
"Why Is The Texture On My Blue Board Cracking?"The reason why the texture on your Blue Board is cracking is because the blue board sheet joints have not been prepared for texture coating to manufacturer’s specifications. The cracks are appearing where the two recessed edges are for jointing.
Over the years I have notice that this is becoming a more frequent occurrence as builders search for alternative methods of building to meet with economic demands for affordable homes. This is especially true in the construction of a second storey extensions. While the engineer has done his job in making sure the home is designed to Australian Standards, the builder has not done his job in making sure the application of texture coat is done to "manufacturer's specifications".
Note; The cracking won't appear straight away but it will appear once the blue board sheets start to expand and contract with the changes in weather temperatures.
To fix a problem of this nature you have a few options. One is to turn the cracking into a controlled joint so it is clearly visible which is probably your best bet. Another is to remove the existing sheets and replace them with new ones and start the application process again. And the final option is to remove the texture from where the two recessed joints meet which is an extremely tedious and time consuming task.
Another hurdle you will be faced with is, because blue board applications is very common in the construction of two-storey homes you will need scaffolding. The only problem with this is, by the time you notice the cracking more often than not the house has been completed, which means the roof is on. If the roof is on how are you supposed to erect scaffold? Basically you can’t which means working on a roof which can sometimes be at a very steep pitch. Not only are you working in an unsafe environment but Work Safe would have a field day if there was an incident.
I was once told by a homeowner that their builder has said that they will leave the texture coating (on the second storey) for them to complete once the house has been finished (you would have to ask yourself why would a builder would say that?). The homeowner agrees, unaware of the full implications of what they have agreed to. The end result is the homeowner has paid the builder, moved in and is phoning texture applicators asking them for a quote?
More information including "FAQ's" is available here. "What is AcraTex?"
Texture System Failure - Texture on Blue Board cracking where the two panels meet.
FAULTS - TEXTURE COATING
"Why Do Some Texture Systems Fail?"Too many times I have been asked to inspect a texture system that has failed. The reason for this failure is simple. Whenever you apply texture coat to a suitable substrate (surfaces) there is a strict preparation and application process that must be adhered to. If any step is missed throughout any of these processes then there is a very good chance that the application may fail.
It is important to note that a texture system failure may not be evident straight away. This is because when a product is new, like most products it will look and perform beautifully. The problems normally start occurring once the product has been exposed to extreme variations in weather and environment conditions. Dulux AcraTex is no exception to this rule, if the substrate is not prepared correctly and if the application of AcraTex is not applied correctly, then there is a very good chance that the system may also fail.
This is one of the reasons why Dulux have gone to great lengths in promoting that their product (Dulux AcraTex Systems) be applied by qualified Dulux Trained Applicators. Dulux AcraTex when applied correctly is in my opinion the best exterior finish there is, so it is important that the product gets the recognition it deserves.
The truth of the matter is most untrained and inexperienced applicators don’t even know themselves if the system that they are applying is going to fail or not. They generally only find out sometime later when they receive a phone call from the concerned customer informing them of the problem. One of the unfortunate parts of this is the home owner or builder who has to deal with the failed textured system instantly gets a disliking to the product swearing that they will never use it again when in fact there is no better product on the market today.
DISCLAIMER: Any advice recommendation information assistance or service provided by Professional Plastering Services in relation to goods manufactured by it or their use and application is given in good faith and is believed by Professional Plastering Services to be appropriate and reliable. However any advice recommendation information assistance or service provided by Professional Plastering Services is provided without liability or responsibility.