How to seal a patio and apply patio sealant – Expert Guide

How to apply patio sealant, aftercare and spring cleaning

At Universeal, we have over a decade’s experience in the development and refinement of quality, effective patio sealing formulas.

On this page you will find much useful information to help you choose the best patio sealer for your outdoor stone floors. Read our 5 step sealing process and the tips & tricks needed for professional results as we tell you exactly how to seal a patio, plus recommendations on the best patio sealer money can buy. We will also give you professional guidance on the best ways of treating problem areas and general advice on low impact spring cleaning for your sealed stone patio and paving.

If you need any further technical advice or help with regards to our outdoor patio sealing products, please call 01300 345 898 (local rate number).

Patio Cleaning with New Clean 60 Patio Cleaner

Watch our Colour Enhancing Patio Sealer in action

The quick video shown here demonstrates the brilliant and transformative effect of Universeal Colour Plus Outdoor Sealer. If you have a patio or garden paths that has a dull or faded appearance, this could very well be the solution for you. With the powerful colour boosting solution, you can really transform and enhance the appearance of your garden patio and with little effort you can achieve results that dramatically improve the the colouration and look of your outdoor patios & terraces. This video gives a quick overview of the methodology required for best results, read on below to find out how we recommend you undertake patio sealing projects for the very best results.

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How to seal a patio to protect your outdoor stone?

If you are asking yourself, should I seal my flagstone patio, then the answer is very probably yes! If you have invested time and money into some beautiful natural stone flags, such as Indian sandstone or slate and limestone, you will want to preserve their natural beauty for as long as possible and make your ongoing care and maintenance as effortless as possible. So, let’s talk patio sealing…

Step 1. Prepare the working area

Always ensure you have a good foundation for your patio sealing project. Make sure the area has been thoroughly cleaned and allowed to dry fully. For full guidance, read our guide to patio cleaning.

To let the patio sealer perform at its best, it needs to make good contact with the stone surface:

  • Always sweep away any loose surface coverings such as leaves, soil, stones, etc. We recommend using a stiff outdoor broom to make short work of cleaning up.
  • If there is a large degree of wetness or damp, please allow time for the surface to dry out. Look at the forecast and try and pick a period of sustained dry and fair weather.
  • Check your grouting or pointing where applicable, and make repairs if necessary – it’s always better to repair and make good prior to sealing.

Step 2. Use PPE for your protection

Our outdoor sealers are professional strength formulas for outstanding sealing results, and whilst they are not acidic, the ingredients are chemicals and extra care should be taken when using it. Whether water-based or solvent, the ingredients can irritate skin and could be harmful.

Please follow these guidelines:

  • We recommend you use Personal Protection Equipment (PPE) when applying our patio sealing products. The minimum kit required would be gloves, googles or glasses and potentially a respirator mask (especially important if applying the sealer with a sprayer).
  • We sell a PPE bundle at a low cost, specifically so our customers can work safely. Available to order via the shop.
  • Our patio sealing solutions are to be used neat, without dilution. Always follow the recommended guidance on drying time between coats, the minimum coverage and coats needed. If you encounter any issues with the application, be sure to follow our problem-solving guidance (see ‘step 5. Application Issues’).

Step 3. Test Area Sample

When using a product for the first time it is sensible to take precautions. Universeal’s powerful outdoor sealers might change and/or enhance some surfaces – always try product in an inconspicuous area on-site prior to use:

  • Choose an area in the corner or out of view, and apply a very small amount of the sealer.
  • It is then very important to allow the product to dry on the stone surface for the recommended time (between coats).
  • If the results look good, proceed to seal the surface with the label directions. If the sealer hasn’t given the finish you require, try some extra coats where needed). This test will then tell you your required coats/application for the main project.

Step 4. Sealing

After performing an on-site test with one of our patio sealers, and if you are satisfied with the results of the sealant, you are ready to apply the patio sealing solution. Follow the instructions on the label, and take into consideration the following helpful points:

  • Be aware of the weather conditions before you commence the project. Is it raining heavily? This will interfere with the sealing process. Is it gusty? Wind will spread the sealer and it may land upon sensitive surfaces, additionally coverage may be reduced.
  • Is there vegetation close by? Typically your stone area (patio or path) will next to lawn or flower beds – if so, apply extra caution at the edges not to over-spray too much onto the vegetation. If you do, get a hose and carefully dowse with clean tap water to dilute the sealer away.
  • Use masking materials on other hard surfaces nearby as it is very hard to remove the sealer once it has cured.
  • Make sure that children, pets and anything non-essential are removed from near the sealing area, and keep them away for the duration of the sealer’s curing time.
Outdoor Sealing Range

Step 5. Application Issues

Our outdoor sealers works extremely well in the majority of cases, however if you make a mistake in the application process, or if the weather interferes you may find some uneven or patchy deposits. In the first instance consult the label to see suggested fixes, if they are not applicable to your situation, either call our technical line on +44 (0) 1300 345 89 or read the following tips that may help you achieve the desired finish:

  • If your application looks uneven and patchy, you could try a second, repeat application to even out the sealer’s distribution.
  • If you have over-applied the sealer, you might have unsightly white patches. We recommend these are scrubbed back with an abrasive and one of our stripping agents, such as Pro-Strip. Once the worst of the white patches are removed, re-apply a coat of the sealer to even out the surface.
  • For ongoing maintenance, we recommend you clean treated areas with Universeal Easy Clean, do not use harsh or abrasive cleaning agents as this can have a negative effect on the treated surface.
  • Remember the test application, it gives a good indication of how the sealer will work – in the unlikely case that if you think it may not work properly then don’t use the product and return it for a refund!

Typical applications for Universeal outdoor patio sealers:

Sealing patio and paving

Patio Sealing

Our range of professional outdoor stone sealers are developed to offer maximum protection when sealing patio surfaces that are laid with porous natural stone including limestone, sandstone, natural slate, terracotta, quarry tile, yorkstone, along with engineered stone types such as block paving, concrete and brick. Outdoor patios suffer with the British climate and grime and organic growth is very typical on most natural stone surfaces so a sealed patio vastly reduces ongoing maintenance and upkeep. We believe they are the best patio sealers, and think you will too!

Sealing brickwork and walls

Vertical Sealing

A common problem with the British climate is the annual development of damp conditions, and these can affect both horizontal surfaces and vertical areas such as walls, pillars and gates. Brickwork can frequently become covered in green organic growth (such as moss and algae) and also certain bricks are prone to calcium deposits, which is referred to as efflorescence. By sealing brickwork, tiled walls and pillars, you can drastically reduce the appearance of the annual grime and save time and money on maintenance. Remember, a wall is only a floor that has been flipped 90 degrees!

Roof Sealing

Whilst certainly less common, it is possible to effectively seal tiled roofs. In the UK, we have many different roofing materials to choose from, however many properties will have standard engineered terracotta style roofing tiles – these are very susceptible to organic deposits such as moss, algae and stubborn lichen. By thoroughly cleaning the roof tiles, and then applying an outdoor sealer, you can really reduce the build up of grime and organic matter on roofing, plus the stain and water barrier created means that rainfall will slide off more effectively and the roof will not accumulate as much dampness.

Sealing block paving

Block Paving Sealing

Driveways laid with block paving are very susceptible to grime, stained, deposits, along with lichen and black spot growth and can quickly look tired and dirty. After cleaning with Paving-PRO Cleaner or similar, you will avoid repeated cleaning exercises by applying one of our durable, long-lasting outdoor sealers. For heavy traffic areas of paved surfaces that are laid with porous, engineered stone types such as block paving & pavers, as well as traditional clay based block paving, we recommend our topical sealers as these create the strongest surface tension and offer maximum protection.

So which products should you choose?

Water-based, Matt Finish Patio Sealers

The following Universeal sealing solutions from the outdoor range are all ideally suited for large outdoor surface areas, including patio, paths, paving, driveways, walls, tiled roofs and more. Our matt finish formulas are ideally suited for people who would like to achieve excellent levels of protection whilst maintaining the stone’s natural appearance. Matt stone sealers are impregnating sealants that are absorbed into the top strata of porous stone and when applied correctly will generally leave the stone’s looks unchanged. Whilst the majority of our matt finish sealers are suitable for all kinds of outdoor porous stone surfaces, please check the suitability of each product for your specific patio sealing requirement.

Water-based, Colour Enhancing Patio Sealers

The following Universeal sealing solutions from the outdoor range are all ideally suited for large outdoor surface areas, including patio, paths, paving, driveways, walls, tiled roofs and more. Our colour enhancing formulas are aimed at people who would like to both protect and enhance the colours and hues of their outdoor stone paving.  Colour enhancing stone sealers are impregnating sealants that are absorbed into the top strata of porous stone and delicately boost the colours of natural stone materials, making hue, veining and details really stand out, whilst maintaining a matt, non-sheen look. These patio sealing formulas will definitely change the appearance of your outdoor stone areas, so are ideally suited to materials with plenty of colour character, such as natural slate, rainbow sandstone, etc. Whilst the majority of our colour enhancing sealers are suitable for all kinds of outdoor porous stone surfaces, please check the suitability of each product for your specific patio sealing requirement.

Satin Finish, gloss effect Patio Sealers

The following Universeal sealing solutions from the outdoor range are all ideally suited for dedicated outdoor surface areas, including patio, paths, paving, driveways, walls, tiled roofs and more. Our satin finish formulas are designed for people who would want to achieve maximum protection with a sheen, smooth gloss effect to the surface of their outdoor stone areas.  Satin finish stone sealers are impregnating, or more often topical (top coat) sealants, that coat and cover the top level of porous stone, creating a super durable polymer matrix barrier, this often translates to a wet sheen look that boosts the colours of natural stone and will increase in effect with the more coats you apply. These patio sealing formulas will completely change the appearance of your outdoor stone areas, so are ideally suited to materials with plenty of character, such as slate, sandstone, limestone, etc. Whilst the majority of our satin finish sealers are suitable for all kinds of outdoor porous stone surfaces, please check the suitability of each product for your specific patio sealing requirement.

The Universeal Sealants Product Range

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