Monoblock Sealer- Info image

Monoblock Sealer- Info

Solvent Based v Water Based and Polyurethane Sealers.

Most professional monoblock sealer companies use a  acrylic based sealer in preference a polyurethane sealer or water based product. This is because they are more 'technically stable' and less likely to be adversley affected by the often damp climate in Scotland. For a homeowner considering a DIY project It is far easier to use a solvent based monblock sealer for driveways or patios. 

Commercial Polyurethanes sealers  

  • Tend to be very expensive, but hardwearing
  • Excellent resistance to chemical spillages.
  • Ideal for certain commercial applications such as on petrol forecourts,airport runways where the surface would be subjected to petrol and diesel spillages.
  • Generally regarded in the industry a ‘over specfication’ for domestic driveway's


Waterbased sealers 

  • Far shorter lifespan than other sealers with minimal resistance to stains,
  • Suitable for domestic or internal applications only.
  • The water based sealed finished surface appears slightly opaque, unlike urethanes or solvent based acrylics sealants (which are clear) so the natural colour of the monoblock is not enhanced in the same way.  

The key things for a professional contractor to consider when using a water based sealer or polyurethane sealer are that if  a, moisture affects the sealer during the drying process (remember we are sealing exterior areas and subjected to various weather conditions) or b, when an area would benefit from additional coats of sealer, it is only the solvent based product that can be re-applied.

Polyurethane sealers 

  • Are not affected by solvents, such as xylene and therefore ‘just melting’ the defective sealer and allowing it to reset is not possible.
  • Any areas where problems have occured would need to be totally removed using aggressive chemicals or by mechanical means such as shot blasting both of which would be expensive and time consuming.
  • In the case of a reseal, to rejuvenate an area, the sealed surface must have a mechanical key in order to enable a good 'grip' between the original sealer and the new sealer.
  • This would require significant additional preparation work. Also consider that the sealed surface will naturally develop a 'thicker layer' which can make the monoblock less authentic looking. and more artificial in most cases.Thicker layers of sealer will also considerably reduce the skid resistance values of paved surfaces, important for external areas.

Water based sealers

  • Are partially, but not totally affected by solvents. The solvent partially melts (and damages) the sealed layer however it does not change back to its original finish.
  • The damaged layer would need to be removed before it is resealed with any type of sealer. In order to fix a damaged area, the original layer needs to be totally removed before the area is resealed.
  • For future reseals, or to rejuvenate an area, the original layer requires a mechanical key, just like a urethane, and just like a urethane, a thicker layer is formed on the surface, making the area less authentic and reduces skid resistance values.

Regarding refurbishment, after two or three re-applications, both these types of sealer would generally be removed in order to ‘start from scratch’ for any other future refurbishment work.

Solvent based acrylic sealers

  • Produce a totally clear film, therefore enhancing the sealed surface to maximum effect.
  • Should there be a problem with the sealed surface, xylene (solvent) is applied to the area, the sealed layer is melted, it resets and the area is rectified.
  • It may need a light application of sealer in certain places and if it does, bonding is not a concern as a new layer of sealer will always bond to an existing layer of sealer as the new layer will ‘melt’ the exiting layer and the layer will ‘become one’.      
  • Refurbishment is equally easy. The sealed surface is simply melted using just xylene to bring it back to new, and if an area has worn in places, it can easily be recoated with another layer of solvent based sealer, which will bond totally to the underlying layer. If required, areas that have been sealed with a solvent based acrylic sealer can easily be kept in pristine condition.

Although all three types of block paving sealant can be used successfully to seal areas of external paving, listed below are the main positive and negatives of each type of sealer.



  • Hardwearing, highly chemical resistant.
  • Expensive, problematic to resolve defects, problematic to refurbish or reseal.


Water Based Acrylics

  • Solent free, no smell, environmentally friendly.
  • Opaque film, problematic to resolve defects, problematic to refurbish or reseal.


Solvent Based Acrylics

  • Totally clear film, easy to solve defects, easy to refurbish or reseal
  • Smell, hazardous material.


Although we can supply all three different types of sealer we would recommend acrylic sealers for the reasons above, for further information on any type of block paving sealer call us on 0845 618 2770 or fill in our online form