Short answer
Sealing block paving is worth considering if you want it to be easier to keep clean, to help the joint sand stay put and, with some sealers, to enrich the colour. It is not essential, it will not fix damaged or loose paving, and it needs re-applying over time. The paving must be thoroughly cleaned, re-sanded and dry before any sealer goes on.
What a sealer actually does
A block paving sealer is a liquid applied to the surface. Depending on the type, it soaks into the blocks or forms a thin film on top, and most also help bind the top layer of sand in the joints.
The practical benefits are that spills and dirt sit on the surface rather than soaking straight in, the joint sand is less likely to wash out, and the paving is often easier to sweep and rinse. Some sealers give a darker, richer look or a slight sheen; others are designed to leave the surface looking much as it did before.
What sealing will not do
Sealing is sometimes sold as a cure-all, so it is worth being clear about its limits. It will not level sunken blocks, fix a failing base or stop movement in paving that is already loose. It does not remove stains; anything left on the surface when it is sealed is locked underneath. It does not make paving maintenance-free, and moss, algae and weeds can still appear, especially in shaded or damp spots.
Sealers also wear. Tyres, footfall, weather and sunlight gradually break them down, so a sealed drive will need re-sealing at some point. How soon depends on the product, how the paving is used and how exposed it is, so follow the manufacturer's guidance.
Weighing it up
In favour: easier cleaning, better resistance to spills, joint sand held more firmly, and the option of an enhanced colour. Against: the effort of preparing and applying it properly, the need to re-apply, a change in appearance you may not like, and some finishes becoming slippery when wet if an unsuitable type is chosen.
For many homeowners, a good clean and re-sand followed by regular sweeping is enough. Sealing makes most sense on newer paving in good condition, on drives where drips and spills are a worry, or where joint sand keeps washing out.
If you decide to seal: prepare first
- Clean the paving thoroughly and treat any stains. See our guide on how to clean block paving.
- Re-fill the joints with kiln-dried sand and let it settle. Our re-sanding guide explains how.
- Let the paving dry out completely. Sealing damp blocks can trap moisture and leave a cloudy or patchy finish.
- Choose a dry, settled period with no rain expected while the sealer is applied and curing, and avoid frost and strong sun. The label will say what conditions the product needs.
- Try the sealer on a small hidden area to see how it changes the look of the blocks before committing to the whole drive.
- Apply it as the manufacturer instructs, usually in thin, even coats, and keep people, pets and cars off until the label says it has cured.
When not to seal
Hold off if the paving is loose, sinking or due for repair, if it has not been properly cleaned, or if damp is rising through it. Very old or porous blocks can react unpredictably, so a test patch is essential. Natural stone setts and some decorative paving have their own care requirements, so check the supplier's advice before applying anything designed for concrete blocks.
If weeds and moss are your main concern, read our guide to weeds and moss in block paving first, as sealing alone will not solve that.
When to call a professional
Sealing is unforgiving: poor preparation or the wrong conditions can leave a blotchy finish that is hard to put right. Consider a professional if the area is large, if you are unsure which type of sealer suits your blocks, or if the paving needs a deep clean first.
When we clean block paving, the joints are re-sanded with kiln-dried sand, and sealing is something we discuss on site rather than add automatically, so you can decide whether it is right for your drive.
Rather have it done for you?
Block paving jet washed, weeds and moss cleared from the joints, with re-sanding discussed on site. Family-run by Jason and Lucas Prior, covering south Essex.
Frequently asked questions
Is it worth sealing block paving?
It can be if you want easier cleaning, better resistance to spills and firmer joint sand. It is not essential, and good cleaning, re-sanding and sweeping may be enough for many drives.
How often does block paving need re-sealing?
It varies with the product, the amount of traffic and how exposed the paving is. Sealers wear gradually, so follow the manufacturer's guidance and look for signs such as water no longer beading on the surface.
Will sealing stop weeds growing in block paving?
It can make it harder for weeds to establish by binding the top of the joint sand, but it will not stop them completely. Seeds can still settle and grow, particularly in damp, shaded areas.
Related guides
- How to clean block paving: step-by-step cleaning for block-paved drives and paths, including how to pressure wash without blowing out the joints.
- Re-sanding block paving after cleaning: why the joints need refilling after a clean, why kiln-dried sand is used and how to brush it in so it stays put.
- How to remove weeds and moss from block paving: why weeds and moss take hold in the joints, how to get them out roots and all, and how to slow them coming back.
- What affects the cost of driveway and patio cleaning: the factors that change a driveway, patio or jet washing quote, including surface type, condition, re-sanding and sealing, and how to compare quotes.