Moisture is one of the leading causes of flooring failure, yet it’s often one of the most overlooked. Even when a screed appears dry, residual construction moisture can delay flooring installation while the substrate reaches the required moisture level.

PrimeMore MVS, a ready-to-use moisture vapour suppressant, was developed to cut installation times on screeds that already contain an effective structural damp proof membrane (DPM).

Where a structural DPM is already present, rising moisture isn’t the issue. Instead, the screed simply needs more time to dry before floor coverings can be installed. PrimeMore MVS helps overcome this by allowing installers to prepare the floor much sooner, helping to keep projects on schedule.

When should you use PrimeMore MVS?

PrimeMore MVS is designed for use on interior cementitious screeds and concrete that already have an effective structural DPM.

It can be used on:

• Unheated cementitious screeds with moisture readings up to 95% RH
• Heated cementitious screeds with moisture readings up to 85% RH
• Concrete subfloors with moisture readings up to 95% RH

If there’s no structural DPM present and the installation needs protecting from rising moisture, a two-part epoxy liquid DPM should be used instead.

What makes PrimeMore MVS different?

Unlike a traditional epoxy liquid DPM, PrimeMore MVS is supplied ready to use, meaning there’s no mixing required. Any unused product in the tub can be resealed and used again, helping to reduce waste and improve cost efficiency.

Its highly pigmented purple colour also makes application easy, allowing installers to clearly see where the product has been applied and helping to ensure complete coverage.

By using PrimeMore MVS, you can also benefit from a quicker application process, helping to reduce project times. PrimeMore MVS is applied in two coats with the first coat typically drying in around 20 minutes, followed by a second coat that dries in approximately 30 minutes. After around an hour, a compatible levelling and smoothing compound can be applied.

When paired with Kelmore’s ultra rapid-setting smoothing compounds, such as LevelMore Rapid 30 or LevelMore Absolute 30, installers often complete floor preparation in the morning and begin installing floor coverings later the same day.

Can PrimeMore MVS be used with underfloor heating?

Yes. Underfloor heating systems should be fully commissioned before application. Once moisture testing confirms the screed is no greater than 85% RH, the heating should be switched off for at least 48 hours before PrimeMore MVS is applied.

Preparing the subfloor

Before applying PrimeMore MVS, remove all surface contaminants, such as laitance, paint overspray and general construction dirt.

Where required, rough or uneven surfaces can first be smoothed using one of Kelmore’s moisture-tolerant levelling and smoothing compounds, such as LevelMore Pro, LevelMore Absolute 30 or LevelMore Flex&Fibre.

Apply the first coat of PrimeMore MVS in one direction using a short-pile roller. Once dry, apply the second coat at 90 degrees to the first to achieve full, even coverage before applying a compatible smoothing compound.

If a smoothing compound isn’t applied within 24 hours of the second coat drying, a further coat of PrimeMore MVS should be applied before continuing.

Helping reduce installation delays

PrimeMore MVS has been developed to help installers overcome project delays caused by residual construction moisture, allowing floor preparation to begin sooner.

With its fast-drying, ready-to-use formulation, highly visible purple pigmentation and ability to suppress residual construction moisture, PrimeMore MVS provides a quick and efficient solution for preparing floors before installing floor coverings.

Written by Chris Pratt, Technical Support Manager at Kelmore.

Our Technical Support Team is available Monday – Friday, 8:00am – 4:30pm on 01257 830511 or technical@kelmore.co.uk. Please don’t hesitate to contact us for any advice or support.