Paving Sealing - Checklist & Testing FAQS

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Paving Sealing - Checklist & Testing FAQS

Paving Sealing - Checklist

There are several different types of Paving Sealers in terms of their chemistry and technology, and they all may have their place for different domestic and commercial pavement sealing applications and requirements, which can also be very different, for example when you are sealing newly installed paving, or you are looking to refresh and refurbish existing paved areas. It is therefore important to be extremely clear in defining your specific paving project's sealing requirements, and in terms of application of the sealer, and the performance of the sealer in service – It really is ‘Horses for Courses’ in paving sealing.

It may sound pedantic or over the top, BUT we always say that writing all these requirements down for your paving sealing project is the best way to start, especially if you are dealing with other people, this could be your partner, your client, or your contractor.

It is best that everybody is involved in the assessment, so they properly understand and can ‘remember’ the same requirements, the product selection decisions made, and why these decisions were made! You can then properly evaluate alternative solutions using different products and material technologies available, together with their respective advantages and disadvantages.


We have therefore prepared a Checklist that is designed to help you in defining all of your specific requirements and the key selection criteria for your paving sealing project. This Paving Sealing Checklist provides the key criteria that should always be included in your assessment, there may be more. – A copy is also available to download in PDF format below:

Checklist Paving Sealing - Project Assessment
  • Type of Paving e.g. Natural Stone or Concrete? If natural stone then what type, and what size elements and with what type of paving joint mortar…?
  • New or Existing / Refurbishment?e.g. Is the paving new and recently laid, if so, when? If it is a refurbishment, has it been sealed before and if so with what, are an areas also newly laid as repairs or repointing etc….?
  • Surface conditions – e.g. Is the surface clean or does it need cleaning and if so, what needs to be removed is it dirt and grime, green growths, blackspot9lichens) or other types of staining and if so what…? If the surface needs to be cleaned, does it need repointing after cleaning…? Always check after cleaning and use a suitable repointing mortar.
  • Surface permeability / porosity – e.g. Is the surface permeable / porous – Yes, or No ? …. Somewhere in the middle...? What does this mean ….? How do I decide…? (There is a simple droplet test for porosity - see web page)
  • Traffic Anticipated – e.g. is there pedestrian only or pedestrian and vehicular traffic over the area – What is this– foot traffic only / cars / other….?
  • Traffic Frequency – e.g. Is this area continuously or infrequently trafficked and is this every day or only occasionally….?
  • Durability – e.g. What is the service-life required before and replacement or recoating / refreshing of the paving sealer…….? How easy is it to access the area and also to close it for any such future maintenance and recoating...?
  • Visible Finish required– e.g. Do the owners want the seal to effectively be invisible, or maybe to enhance the finish or even to give the surface a gloss finish – also known as a wet-look (not recommended - see webpage)
  • Colour Enhancing – e.g. the colour is enhanced but without a temporary gloss look than can soon wear off and in patches to look very unsightly?
  • Access and Site – e.g. Are there any access or other local restrictions, or any sensitive adjacent surfaces / equipment / planting ...?
  • Weather Conditions – e.g. What time of year will the paving sealer be applied and what will be the likely temperature (maximum and minimum) during the application and drying, if rain is a possibility can the area be covered and protected….?
  • Environmental Conditions – e.g. Are there any other exposure limitations or considerations for application and/or in service….?

Download a PDF Copy of the NCC Paving Sealing Checklist Download

Paving Porosity / Permeability
How to Test Your Paving Permeability / Porosity
A simple water droplet test to confirm if you really need to seal your paving………?

This simple test is what our technical specialists recommend to quickly check and assess the porosity, or not, of paving surfaces when on-site, plus this is also a very good way to find out how easily water borne salts and stains will behave on your paving; it can also be assumed that oil-based stains will generally always be more penetrative - as an easy clue!

This is a simple surface permeability / porosity / absorbency test that is widely known as the Water Droplet Test. This was originally developed for use in the resin flooring industry, where it can be critically important for the resin primers to penetrate the concrete base slabs, or the resin floor will not have sufficient adhesion. In preparation for seriously expensive resin flooring works, this pre-testing and substrate evaluation is carried out very precisely using a pipette and strictly measured, timed, and controlled as shown in the examples below. Whilst paving sealing is not in the same league of costs or detailing as resin flooring, a variation of this test can easily be made on site to confirm the porosity or otherwise of the paving elements before sealing them. The key information gained will be a good visual understanding of how well any water and/or water borne de-icing salts or stains, including the ubiquitous red wine, will also be able to penetrate and damage or disfigure your concrete blocks or natural stone. If water does penetrate easily and continue to be absorbed into the surface, then you would be well advised to consider the use of a paving sealing solution to protect your investment and maintain its good appearance!

Water Droplet Test Procedure:

This involves the application of single droplets of water onto the concrete / stone paving surface, whilst closely observing the behaviour and any movement of the droplet, whilst timing and monitoring the rate of absorbency into the substrate. This gives a good indication of the surface density and permeability, and if a paving sealer might be a good idea.

To correctly carry out the Water Droplet Testing, use a pipette or suitable dispenser and make groups of approximately 6 water droplets in different elements and areas of the paving, including on any areas that are discernibly different in appearance, texture, or profile (to check consistency in results – or more importantly variations in permeability that are always possible and best found with water now, rather than later with oil or red wine etc.)

Place the droplets using a simple ‘dropper’, syringe, or pipette (available from any chemist) type dispenser to suit, positioning them together within an area approximately 10cm x 10cm, be sure to always test at least the centre and the perimeter areas of your paving elements with different groups of droplets if necessary, and according to their size.

Example of Droplet Test on Dense Paving Surfaces

(i.e. smooth, hard and almost ‘shiny’ surfaces)


Water Droplets: Pipette Application
Note - No immediate absorption!


Water Droplets: 5 Mins Later
Note - No absorption evident!

If these were the surfaces of your concrete or stone paving, then a surface sealer is probably not required as water cannot easily penetrate and therefore the paving will be resistant too frost damage, plus as water cannot penetrate then it is most unlikely that the surfaces will be stained either.

Example of Droplet Test on Open-textured Paving Surfaces

(i.e. – surfaces that are ‘dull’ and not shiny in any areas, such as those that have been riven, sawn, or which have already been mechanically prepared e.g. by blastcleaning or grinding etc.).


Water Droplets: Pipette Application
Note – Absorption is immediately visibly evident


Water Droplets: 5 Mins Later
Note: - Absorption continues & diameter of penetration increases

These clearly porous concrete or natural stone paving elements are therefore highly likely to benefit from, or perhaps even need the application of a suitable sealer to prevent water penetration and future damage and / or being disfigured by unsightly and unhygienic staining.

So - A simple test and a good way to help you or your customers decide what makes sense for your paving projects. We hope that you find this additional information and advice helpful for your project.

For any more information on Paving Sealing for your specific project, please call 01257 266 696 for our FREE expert advice and assistance.