What is a smoothing compound?

A smoothing compound is a thin layer applied on top of the subfloor to remove any imperfections in the finish. As with many projects the preparation is key to ensuring a perfect installation, flooring is no different.

Smoothing compounds are normally applied to a concrete subfloor, although in special circumstances they can be used over timber subfloors.  For more information on the preparation required on a timber floor please see our previous article on Hardboarding.

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Why do I need a smoothing compound?

Every floor covering product has an exact specification for the condition of the subfloor.  Some products, such as wood floors or LVT, are more stringent than other products, such as carpet.

The categories of subfloor condition are:

• Clean
• Dry
• Level
• Smooth
• Sound

For the purposes of this article we are looking at Smooth.

To ensure the subfloor is ready for the floor covering a smoothing compound could be applied to remove any imperfections that would cause a failure in the floor covering at a future date.

What sort of failure do you mean?

A very common failure would be to see the imperfections of the subfloor showing through to the surface of the floor covering.  This could be caused by uneven floorboards or small pits/holes/bumps in a concrete floor.

Another common failure is with plank products; if the floor is not smooth they can be subjected to uneven stresses that can cause the floor to lift, creak and at worst, break.

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How do I know if I need a smoothing compound?

Many subfloors require some work prior to installing flooring.  A professional flooring installer will always examine the subfloor prior to installing your new flooring.  They can then explain what work needs to be carried out and select the correct products to ensure a perfect finish.

Unfortunately if a product is already installed then it is not possible to examine the entire area.  Instead, small areas can be examined (where possible) and an educated guess can be made.  Until the entire floor is revealed however, it is impossible to be 100% certain on any work(s) that may be required.

At Grimley Flooring we always look at the subfloor whilst carrying out a site survey as part of our free consultations.  We can advise on the best solution to ensure your new floor looks great throughout its lifespan.