If these are generally present then it’s important actually pre-treated otherwise when you use an electrical washer or you will be just taking the heads of such clumps and leaving the root base behind, this generally means that a couple of weeks later they will be growing back more powerful than ever.
Cleaning it with a high pressure water jet can work wonders in getting eliminate all of the above and leaving the paving looking like new again. A note of extreme caution, block paving should only be sometimes be pressure cleaned as this can weaken the sand bed that the block paving is laid on creating it to sink. This is why I would always advocate sealing the obstruct paving once it is cleaned so that any future cleaning requires only a hosing down and not a vigorous pressure washing.
NEW PAVING Before applying sealer ensure introducing is clean, dust free and that no efflorescence (surface whiteness) is present. If efflorescence is visible ensure it is given efflorescence remover, then rinse down thoroughly with clean water. Allow 4-6 weeks after treatment to ensure efflorescence does not re-appear.
EXISTING PAVING Before applying sealer to existing introducing it must be clean, free of stains, dust, algae, weeds and efflorescence. For ideal results, treat paving with fungicidal wash prior to cleaning with a pressure washer. Check that the introducing is dry by scraping out the sand between the blocks to a depth of 5-10mm.
When the sand is dry, the paving is now ready for sealing. With a sanding broom sweep additional kiln dry sand into all joints. Ensure there is no surplus fine sand on the face or beveled sides of the blocks. Guard areas such as plant beds, ponds and nearby areas from splashing. Guarantee temperature is between 7-23 degrees and this no rainfall is forecast for at least 4 hours.
The majority of manufacturers recommend applying two coats of paving sealer for optimum results, departing at least 2 hrs between applications. Use 4″ paint brush to apply block paving sealer to borders. Block paving sealer can be applied by using a sprayer unit, roller or brush. To fully solidify the jointing sand apply at a rate of 2m2 per litre first coat and 3. 5 m2 for each litre second coat.
Two-coats are best applied for ideal protection. Virtually all block paving sealers will be tack free within 2 hours at 20C and feet traffic may be authorized after 4 hours. Automobiles should be kept off the sealed area for a minimum of one day at 20C.
Maintenance High quality paving sealer will offer many years of protection to the surface, but it is recommended to apply a single top up coating of block paving sealer every few years. Block paving in Cambridge sealer will minimise maintenance for the homeowner. But as with all external paving products, some level of routine maintenance is required. An total annual gentle wash down to remove dust, plus the occasional program of fungicidal wash is necessary to keep the prevent paving in pristine condition.