Page 65 - CFJ_Jul26

ADVICE & INFORMATION

Andrew Mees

Raising the level

Andy elaborates on solutions for situations where floor levels need raising quickly and easily

HERE’s a wide range of smoothing in the mixture when it cures so that internal subfloors in both domestic and
Tcompounds on the market that can flooring contractors are not forced to commercial environments.
typically be applied up to a maximum wait an extended amount of time for The product is suitable for use over
thickness of 20mm ahead of the all of the water to evaporate naturally a wide range of absorbent and non-
installation of floorcoverings. However, as they would if applying a regular absorbent subfloors, including sand/
sometimes flooring contractors need to smoothing compound. Consequently, cement screed, tile backer boards,
raise the level of a subfloor by more than the drying time of Stopgap 600 is concrete, plywood, granolithic, terrazzo,
50mm before new floorcoverings can be dramatically reduced, and it sets in as epoxy and polyurethane resins, ceramic
installed – after removing thick ceramic little as three hours after application, and quarry tiles, as well as Stopgap
tiles and adhesives, for example, where meaning it’s a much quicker option waterproof surface membranes.
underfloor heating needs to be encased, than multiple applications of a standard It’s walk-on hard from three hours
or simply for aesthetic reasons. smoothing compound. It can also be after application and ready to receive
The challenge pump applied over large areas to save floorcoverings in as little as 12 hours.
This is when problems can occur using further time. A note on priming
standard smoothing compounds, It’s almost always essential to prime
which are primarily made up of cement a subfloor before the application of
and are often combined with water, a smoothing compound. Used over
allowing them to flow easily but absorbent subfloors, including porous
potentially leading to a separation of the concrete and sand/cement screeds,
components in the compound (eg sand, primers create a film to prevent
aggregate and cement) when applied the unacceptably rapid drying of a
thickly. This separation can lead to layers smoothing compound, which helps
forming, some weaker than others, with to develop both the overall strength
the densest materials at the bottom, performance and open time. Priming
compromising the strength of the also reduces the formation of ‘pinholing’
smoothing compound when dry. caused by the slow escape of air from
Also, when cement reacts with water absorbent surfaces.
it results in an exothermic reaction, When used on non-absorbent
which can lead to a buildup of heat and surfaces, such as waterproof surface
thermal expansion of the product when When sufficiently set, these base membranes, terrazzo or ceramic tiles,
applied at thicker depths, increasing the compounds can, if required, be capped primers serve the important role of
risk of thermal cracking when the heat with another smoothing compound to promoting adhesion between the
dissipates and the material contracts. create a perfectly smooth surface ready subfloor and smoothing compounds
The solution to receive floorcoverings. However, applied over it.
For situations where floors need only smoothing compounds that will This is particularly desirable where
raising by more than 20mm, chemically bind all of the water into the smoothing compounds are applied at
smoothing compound manufacturers mixture should be used. thicknesses greater than 20mm, where
have developed deep section base Underfloor heating the bond line is subject to increased
compounds, such as F Ball’s Stopgap When working over electrical wired or stress as the smoothing compound
600, which can be applied at thicknesses water-fed underfloor heating systems dries. F Ball’s Stopgap P141 primer has
between 5-75mm in one application. that are increasingly installed over been specially formulated to create
To minimise the capacity for thermal subfloors as part of new build or a textured finish and enhance bond
expansion, the amount of cement in refurbishment projects, it is advisable performance between subfloor and
these products has been reduced. As to allow at least 15mm of a specialist smoothing compound, making it an ideal
decreasing the amount of cement smoothing compound above the pipes to choice in these situations.
would weaken the material, the water avoid hotspots and ensure its structural Final steps
content in the mix is also reduced. This integrity. Once the smoothing compound has
helps to limit the flow of the smoothing F Ball’s Stopgap 1600 is a fast- sufficiently dried, a flooring contractor can
compound and minimise the separation drying, fibre-reinforced smoothing proceed to install chosen floorcoverings
of components when the compound is compound that is formulated especially with a compatible adhesive. 
applied in a thick section. to be applied between 3 - 40mm thick www.f-ball.co.uk
Stopgap 600 is also formulated to to encapsulate underfloor heating Andrew Mees is a technical service officer
chemically bind all the remaining water and cooling systems installed over at F Ball and Co

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