FREQUENTLY ASK QUESTION
Food Hygiene Plants all have resin floor coatings in order to comply with the governing authorities, and will at some stage need the resin coatings on the floors replaced; or at the very least repaired.
A business that is already running does not want to close down for any period of time to have a floor coating laid- That’s why we work a lot of weekends in our industry.
Even though it is usually a 3 or 4-day process, we often push the limits for customers; starting on a Friday night working night and day to have a finished floor on a Sunday night, ready for reinstatement of machinery and work to start the Monday morning.
This work isn’t for the faint hearted, as apart from the hard yakka of jack hammering, Diamond grinding and diamond cutting, (all before we get a real sweat on from laying the resin coatings) we will more than likely have to work long irregular hours.
For our resin coatings to stick, the substrate (usually concrete) needs to be dry. This means that water / moisture is our enemy.
As all food processing areas are flooded with water every day as part of the cleaning regime, getting the floor dry enough for us to work on is usually our biggest challenge.
There are a large number of systems available and they all have their place. The process involves applying a non slip roll coat system to rejuvenate an old work flooring system.We often use a Methyl Meth acrylate (MMA for short) as this has a very rapid dry time. The only downfall is the strong odour during application; however this dissipates quickly with the correct air movement.
An MMA based schedule for an average food plant floor involves
SATURDAY 6 am till 7 pm:
Diamond grind all areas to be repaired
Problem solve moisture issue
Diamond grind the entire floor
Fill in repairs with epoxy mortar.
SUNDAY 6 am till 8 pm:
Diamond grind to flush repairs
Mask and Prime
Mask and lay none slip broad cast coat
Mask and apply topcoat
THURSDAY Procure all materials and gear.
FRIDAY 4pm until midnight
Set up drying gear
Find and mark all defects to repair
Diamond cut and excavate with jackhammers
Clean up and set up drying fans
This is a lesson in there being more than one way to skin a cat!
Traditionally, there are two ways to end up with a concrete bench or shelf in your house:
- Pour insitu (box up a mould and pour it in place). The downside? This often has defects to repair unless the guy pouring has lots of experience and forethought.
- Made off-site and installed (just like a granite bench top). The downside? As you can imagine your design is limited to weight and being able to carry it into place, without cracking and using only manpower.
So, what’s the alternative? If you’re after the concrete look (without stone exposure) there is a much easier option available…
Imagine making the bench or shelf out of wood (any sheet materials like ply or chipboard) and then coating it to look like concrete. We’ve made many ‘concrete-look’ kitchen and bathroom benches and floating shelves, with great success.
I must say that 60 mm thick floating concrete shelves look awesome, and would be very tricky to achieve with real concrete.
Is it any cheaper than real concrete? On coverage I would say yes, but that depends on a number of factors like the size of the job, accounting for the concrete needing resurfacing if not laid perfectly. Insitu pours pretty much always need repairs and as fillers jump out as different colors, we often resurface the entire concrete bench anyway. Whether it’s real concrete, or an overlay, it will be sealed for ‘cleanability’, otherwise they will stain and be ruined.
So to cut a long story short, it is much easier and cheaper to make a wooden structure and applying a cement based decorative overlay can give you a number of in-vogue finishes, with plain old concrete being one of them.
A water based sealer will leave the finish with lighter shades of colour while a solvent based sealer will darken the job up significantly. Like when you put varnish on wood.
The darker solvent based products are generally better wearing, but the think the decision should be made on weather you like the darker or lighter colour.
I have coated old work desks, chests of draws and polystyrene statues and made baths.
I’ve used decorative overlays to fix broken bricks, replaced missing tiles (that couldn’t be bought) and covered walls to look like stone.
One of my favorite systems is creating tongue and groove wooden look floors from these cement-based products.
I hope you are getting the idea that the versatility of decorative overlays are pretty much limited to your imagination.
Have you ever seen paint peeling off a concrete floor, or bubbles in lino?
After the concrete floor has been prepared (before the lino is to be laid), check to see if the surface is wet, or if a white powder is present; the white powder is called efflorescence, and is a tell-tale sign that water has been traveling through the concrete and left the mineral salts behind as it evaporated.
Why does moisture travel through the concrete? And how does it move at rates that can build pressure and cause lino to bubble, and paint to pop off?
Concrete is like a sponge and soaks up and releases water as it tries to equalise itself with the
environment around it.
To set the scene, on your average rainy day in New Zealand, the relative humidity (amount of moisture in the air) is high, around 90%. On a sunny day the relative humidity can be as low as 40%.
When you get a big fluctuation in the weather like this, the moisture (usually in vapour form) rushes out of the concrete, and this is when issues arise. If the vapour hits something solid like lino, it turns back into water and builds pressure until it can escape into the atmosphere-which is where the bubbles can come from.
When I did my substrate preparation apprenticeship, it was compulsory to attend a moisture vapour seminar, which turned out to be really interesting. I never would have thought water can turn into vapour, travel through steel, and then turn back into water before evaporating into the atmosphere.
It also turns out that there are two types of moisture to be found in the concrete. One is caught up in a cellular level from the laying stage, and the normal one that you picture cycling in and out as it rains.
Most issues in the resin coating game are caused from the cellular level moisture which is still being released after concrete is laid. A rule of thumb is to wait one month per 100mm of thickness for the hydration process to expel enough moisture.