Driveway cleaning is straightforward and useful. Sealing is the upsell that follows it and it is genuinely contested, with real benefits and real drawbacks depending on the surface and the product. The honest answer differs by material, which is why a blanket yes or no from a salesperson is a signal in itself.
What cleaning involves and what it costs
Most driveway cleaning is pressure washing, sometimes with a flat surface cleaner attachment which gives a more even result than a lance, followed by resanding the joints on block paving because washing removes the kiln dried sand that holds the blocks together. The price follows area and access like any external work. The resanding is the part that is sometimes left out and it matters: unsanded joints let blocks move and weeds in.
The pros and cons of sealing block paving and other driveway surfaces
For: on block paving a sealer stabilises the joint sand, makes weed growth and moss slower, resists oil staining and can deepen the colour. Against: it has to be reapplied every few years, it can leave a sheen some people dislike, it can trap moisture if applied to a damp surface or the wrong material, and a poor application leaves a patchy or slippery finish. On gravel it is irrelevant, on tarmac it is largely cosmetic, and on resin bound it is generally unnecessary because the surface is already bound. Ask which surface argument is being made to you.
Removing oil from block paving, moss and the ordinary problems
Oil on block paving is best tackled quickly with an absorbent to lift the bulk, then a degreaser made for masonry, and on a stubborn old stain the practical remedy is to lift the affected blocks and turn or replace them, which is block paving's genuine advantage. Moss and algae respond to a proprietary treatment and to keeping the surface draining. The best time to treat moss is when it is growing and the weather allows the treatment to work and the surface to dry, which in Britain means the milder months rather than midwinter.
The driveway maintenance that actually matters
Keeping the drainage working, so water is not standing on the surface or against the house. Keeping the edge restraints intact, because a failed edge is how a paved drive starts to spread. Resanding block paving joints after cleaning. Topping up gravel. And dealing with a small area of failure early, while it is still a small area. None of that is sold to you at the door and all of it does more for the life of the driveway than sealing does.
Questions people ask about driveway cleaning and sealing cost
Is sealing a block paved driveway worth it?
It stabilises the joint sand, slows weeds and resists oil, and it needs redoing every few years and can look glossy or go patchy if applied badly. It is a reasonable choice on block paving and largely pointless on gravel or resin bound.
Does pressure washing damage block paving?
It removes the kiln dried sand from the joints, which has to be replaced afterwards. Excessive pressure can also erode the block surface, so a flat surface cleaner at moderate pressure is better than a lance held close.
How do I get oil out of block paving?
Absorb what you can immediately, then use a masonry degreaser. For an old set in stain, lifting and turning or replacing the affected blocks is the reliable answer and is one of block paving's real advantages.
What is the best time of year to kill moss on driveway surfaces?
While it is growing and when the weather lets the treatment work and the surface dry, which in Britain means the milder months rather than midwinter.