A concrete floor is a wonderful floor, but it is even better once it is sealed or densified.
Just like your house is better with a quality paint and paint job, a concrete floor or concrete surface really benefits from a sealer or densifier being applied.
What is a concrete sealer, and, what is a concrete densifier?
A concrete sealer, in basic terms, is something that is applied in liquid form to the concrete that protects it. This can be a coloured coating, like a “paint” or a clear resin based coating.
A densifier, is a sealer or protector that works inside the concrete, usually by chemical reaction within the matrix of the concrete. It’s chemical reaction results in production of a gel, that swells up and blocks the pores of the concrete. It makes the concrete more of a solid (denser) and prevents or greatly limits moisture and dust transfer through the concrete.
There are many types of concrete sealers and densifiers, and Floor Masters can help you find the right one for your situation.
The first question is – do you want a clear sealer, a coloured coating or an invisible sealer? Yes most densifiers are invisible, and make little or no visible difference to the surface appearance.
Clear Concrete sealers
We have a broad range of different clear concrete sealers for different purposes and at different costs.
Acrylic Resin Sealers
Our basic concrete sealers are acrylic resin based and suitable for a broad range of applications. They are relatively easy to apply, dry fast and offer medium level performance. They are UV stable (don’t yellow) and do not show scratches as readily as an epoxy coating. They are also very easy to recoat, requiring no special preparation, just clean and coat.
Our Acrylic sealers are available in water and solvent based formulations.
The waterbased concrete sealer is a little softer and does not fully seal the surface as well as the solvent based, but is well suited to indoor applications that are not subjected to lots of water. The waterbased sealer does not darken the surface much, so is better if a muted, opaque finish is preffered. Virtually no odour and 0% VOC. Recoat time of 1-3 hours, suitable for foot traffic after 4-8 hours.
The Solvent based concrete sealers do have a xylene solvent smell. It can be quite strong, but does disapate quite quickly. Suitable for internal and external sealing. It provides a “wet” look, darkening the surface by about 80% (when comparing the surface dry to wet). It is better at protecting against standing water. recoat after 1-2 hours, foot traffic after 2-6 hours. Also available in semi-gloss and Matt.
Epoxy Concrete Sealers
We tend not to use clear epoxy concrete sealers , as 95% will yellow quite badly if exposed to any UV (sunlight or artificial). Epoxy is harder than acrylic, but also show scuffs and scratches much more readily. 8-24 hr recoat time
Polyurethane Concrete Sealers
Not for direct application to concrete. Lots and lots of concrete floor problems relate back to the use of polyurethane on concrete floors. it stems from the change from timber flooring to concrete flooring, and all the timber sanding guys making the transition.
- Clear Polyurethane does not bond well to concrete (it does if you put an epoxy under it – but see note above – it turns yellow)
- A large percentage of polyurethanes turn yellow with UV exposure.
Polyaspartic Clear Concrete Sealers
Our HP Spartacote polyaspartic sealers (Sparta-Flex) are the main reason we stopped using epoxy clear coats (and greatly reduced our coloured epoxy work). Sparta-Flex Polyaspartic coatings are the hardest wearing resin coatings readily available.
Why they are the best
- They offer 3-5 times greater abrasion resistance than epoxy (Probably 8-10 x higher than acrylic).
- The cured resin remains flexible, copes with thermal expansion and contraction much better, and is much less prone to scuffs and scratches.
- 3 x higher heat resistance, can be steam cleaned (the others can’t)
- Very high chemical resistance
- UV Stable – does not discolour or degrade with UV exposure
- Faster install – 1-2 hours recoat
- Faster return to use – 2-6 hours for foot traffic, 8-24 hours for vehicle traffic.
- Better gloss retention (shows less scuffs and scratches)
- Low or 0% VOC’s – safe to work around, little or no odour.
- See more here
Coloured Concrete Sealers (coating or “paint”)
Acrylic – Coloured acrylic concrete sealers
Mainly used to recolour stamped and imprinted concrete driveways. Medium wear resistance, good UV colour fast. Fast drying. Needs reapplication every 3-5 years. Can look patchy if over 2 coats applied as the solvent melt the previous coat and melts them together.
Epoxy coloured sealer/paint
Epoxy is the traditional product used for painting concrete floors. With proper diamond grinding preparation (DO NOT acid wash), epoxy is a good medium duty coating for light to medium use areas. Epoxies have been around for a long time and there are thousands of different formulations based on cost and purpose. It is important to understand that there is not one epoxy that is best for everything and care must be taken to understand each formulation.
Not suitable for external surfaces or high UV exposure.
We now replace epoxy coatings with our Sparta-Guard system, because it has superior performance and wear resistance. Polyaspartic resins are much more expensive, but are faster to install and return to service, so we save a lot of the final cost through time savings.
Polyaspartic Coloured concrete coatings
Floor Masters are New Zealands leading polyaspartic coatings installers. We can offer a system that will out perform a roll coat epoxy system for just a little additional cost.
PLUS we can get the job finished up to 3 days quicker and operational in just 24 Hours.
When Time is Money – we just saved you heaps.
Find our more about our HP Spartacote polyaspartic concrete coating finishes here.
Polyurethane coloured coating
With an epoxy primer coat, a polyurethane coating can offer some benefits. it has higher abrasion resistance than epoxy (not as high as Polyaspartic) and remains semi flexible.
It does not offer the same recoat and return to service as a polyaspartic, but can be applied in thicker layers. But with thickness comes cost.
We have a few Polyurethane car park coating we can apply – call us to discuss
A concrete densifier is a chemical hardner and concrete sealer that works inside the concrete matrix. As such, it can not be worn off like a topical coating. A good densifier has controlled penetration and works in the top 5-10mm of the concrete slab. Below this level a densifier has no benefit (you would need to wear off 10mm of a hardened surface).
A densifier work by chemical reaction, the densifier soaks into the matrix and finds “Free Lime” ( leftover calcium hydroxide), the combined chemistry creates a gel that swells and blocks the pores. This reaction level can vary depending on the chemistry of the concrete, the densifier and amount applied. Curing of the densifier takes between 2-24 hours, and then it is permanently fused in the concrete.
Some densifiers can re-emulsify when wet (scrubbing, washing, rain etc) and over time they migrate below the surface and lose effect. Talk to us about the right product for your situation.
See information about Seal Hard here
See information about Creteshield 101 here